major blunt chest trauma

C U R R E N T PROBLEMS

IN SURGERY E D I T O R I A L B O A R D

~lark ~I. ]~avitc'h, M.I). (:l,~irmm~

l':(]wi~t IL l':]]iso11, ,kl.l). ()rmaml C. J,llian, M.I). Alan 1! "I']m], M.1). Owcn I I. \Vangensteen, M.D.

A Series of Monthly Clinical Monographs May 1969

M A J O R B L U N T CHEST T R A U M A

Emil Blair

Cemalettin Topuzlu

Robert S. Deane

I'E'R OOK MEDICAL PUBLISHERS, INC./CHICAGO

T A B L E O F C O N T E N T S

THE PROBLEM

PATHODYNAM ICS

RELEVANT ANATOMY.

PHYSIOLOGY.

PATHOPHYSIOLOGY

DIAGNOSIS

MANAGEMENT

Chest Wall

P leura l Cavi ty

Lungs

Hea r t

Major Vessels

Med ia s t i num

Tracheobronchia l

Esophagus

D i a p h r a g m

COMPLICATIONS AND DEATHS

VENTILATORS

Classification

Physiologic Effects

Pa t i en t M a n a g e m e n t .

Wean ing Pat ient from the Resp i ra tor

NASOTRACHEAL INTUBATION

TRACHEOSTOMY

SUMMARY . . . . .

Q

3

6

10

13

14

17

22

24

28

29

31

33

35

35

36

36

37

42

43

4S

49

55

57

59

61

2

is Profe~,~or of Surgery , Univers i ly of Vermont , and £:l]ief of Thorac ic and Card iovascu la r Surgery at the Medica l Center H ~ s p t a l . After receipt of his M . D . from the Medical College of Gt~3rgia, hd c¢impleted his surgical and thoracic surgical residencies at l~alt.imore Ci ty H o s p i t a l s and the Uni.- versify of M a r y l a n d Hospi ta l . where he subst~tuently became a~sociated with the Clinical S h o c k - T r a u m a Uni t . He comple ted research fellowships at Duke and at the Univers i ty of Colorado. l-te was a recipient of an N I H Career Ft.c.-search Deve lopment Award. His interests include phys io logy and managemen t of ca rd iopu lmonary problems and in shock anti t rauma, f i e is best known for his contr ibut ions to the p h y s i o l o g y . a n d clinical use of hyImthermia.

J

is Assis tant Professor of Surgery at the Univers i ly of Hace t t epe in Ankara, Turkey . I)r. Topuz lu received his M.D. from the Unive~; i ty of Is tanhul College of Me~tieine and served his surgical r~,~idency at tt~e Medical Center Hospi ta l of Vermont . He was appointed to the Attending Staff for 2 years prior to re turning to Turkey . t ie has pursued a wide spec t rum of activi t ies, with special interests in water and e lec t ro lyte naetabo!ism, the lympha t i c sys tem and in problems in shock and t ramna,

U __, L ~...Z.

is an A~sistan| Professor of Anesth~sia (Clinical) at the Unive r s i ty of Vermont Medica l College. He r~:eived his M.B. , B.Ch. degree at the Univers i ty o f the Witwatersrand, South Africa. and compleh.~l his resi- dency in Anesthesia at Ihe Medica l Center Hospi ta l in Bur l ington, Ver- mont. He is a Dip lonmte of the American Board of Anesthesiology and a Fellow of the Amer ican College of Anesthesiologists . Dr. Deane ' s respon- sibilities are in the R~aspiratory T h e r a p y Division of the A n ~ t h e s i a Depart- meat and his interests are in the rt.~piratory care of the t raunmtized patient .

THE PROBLEM

I N 1966, there were 13 mi l l i on traffic acc idents wi th a death every 10 minutes and a ser ious in jury every 10 seconds (68). Acc idents rank third as a cause of death in the Uni ted , States , behind cardiovascular diseases and cancer. S ince -1966 , a u t o m o b i l e acc idents have accounted for over 50,000 deaths a n n u a l l y and are respons ib le for a lmost one ha l f of aII acc idental

NOTE: Sup,~orted by U , S . P . H . S . Gran t No. H E 11493, the Surgical A~oc i a t e s Fund and the H e r m a n Bla i r Research Fund .

3

D e a t h s I n j u r i e s

(mi l l ions}

All ~ I o t o r veh ic le F a l l s

T A B L E 1 *

A.~I"VIOTOR VEHICLE ACCIDENTS

1950 19,55 1960 1965 1966

34,763 38,426 38,137 49,000 52,500

1,799 2,400 3,078 4,1 O0 4,400

I~.~CoMPARATIVE ACCIDENTAL DEXTH RATES 1950 1955 1960 1965

N o . % :No, o~ N o . "~ N o . "- , ' O O , O

91,249 ~ 93,443 ~ 93,806 ~ 108,f~34 34,763 38 38,426 41 38.137 41 49,163 46 20,783 23 o 0 . , l a2 ~, oo . _ 19.023 . 20 19,9~4 19

~ 'From Statistical Abstract o1 the United States ¢~,Vashington, D.C.: U.S . B u r e a u of the Census , 1967).

fatalities. (Table 1). Most victims are in the young product ive age groups, second through third decades. In the 50,000 deaths, 25% were due entirely' to thoracic injur ies while in ano the r 50,,~.b, chest involvement was a major factor. Thus , major chest in ju ry figures in about 75% of dea ths from traffic accidents. The reported statist ics from several series of hospital ized pat ients a t t r ibu te traffic mishaps as the cause of chest t r a u m a in 40-73,.~ (4, 7, 11, 26. 33). The next most common type of accident is falls (15-25°/~), followed by b lunt missiles, indust r ia l crush injuries, contact sports and other miscel- laneous violence (l l, 36). Over-,all accidental death rates have increased progressively during the pas t 20 years. Those due to motor vehicles rose from 38% in 1950 to 46.~ in 1965, while falls as the cause declined from 230o to 19%. The type of chest in ju ry (flail) with accompanying (lung contusion, ma jo r vascular) or subsequent ly developing (pneumonia, tension pneumothorax) complicat ions exerts significant influence on morbidi ty and on morta l i ty . Limited to serious problems of the chest alone, mor ta l i ty varies from 4 to 8 ~ (4, 33, 35, 48). If ano the r organ sys tem is involved, the dea th rate jumps to 13--15,aTb and with two or more sys tems accelerates to 30-35¢)/~ (4, 7, 20, 35, 58). Significant mul t ip le injur ies occur in over one half of pat ients , with f rac tures predominat ing , followed by head injuries and to a smal ler extent in t ra -abdomina i injur ies (20, 35, 36).

Th e in ju ry rate is es t imated at 16 per 1,000 populat ion, amount ing to a total of over 4 million in ].966 (Table 2). About 1 0 ~ of hospital admis- sions are for accidents. Over 65,000 hospital beds are needed at present to

T A B L E 2.--ETIOLOGY

CAusE

A u t o m o b i l e Fa l l s Misceltaneous~"

TOTAL

* M e d i c a l C e n t e r H o s p i t a l , m o n t .

¢ I n d u s t r i a I , spo r t s , f ights. I I III

i i i i

OF T R A U ~ A *

No. PEa CE,~T

48 68 14 20

8 12

70 ~66

B u r l i n g t o n , Ver-

4

treat injuries. It has been e s t imated that over 2 mi l l ion work ing m a n - y e a r s are lost through disabi l i ty from accid~mts.

The injur ies in a seriously t r aumat ized pa t ien t can compile themselves exponent ia l ly into a vector, which can lead to death. The avowed purpose of resusc i tat ion and t r e a t m e n t is directed at reversal of this vector. A s ingu- larly impor t an t e lement is e l iminat ion of delays, e r ror and impropr ie ty which often serve as positive feedbacks, pushing the vt.ctor forward at a more rapid rate.

Th e problems with respect to the resolution of the cver-all difficulties include clarification of pa thoana tomy and pathophysiol( ,gy, correct emergency care and subsequent proper management . Pa thophys io logy is based on a n a t o m i c abnormal i t i es . Crit ical features often m a y not be m a n i f e s t as direct correlatives of clinical signs and symptoms. Nevertheless, the basis for logical decisions and execution rests with a good grast);of the fundamen- tals. At the acc ident scene, care tends to be spot ty and f requent ly a m o u n t s to nothing or to inappropr ia t e movement and handl ing of the injured. Pa- t ients are f requent ly t ransfe r red wi thout p roper care or a t ten t ion in ambulance inadequa te ly equipped and staffed. Often the victim is admi t t ed to the emergency room in a s ta te considerably de ter iora ted from that immedia te ly following the injury. Figures for the numbers of pat ients who might poten- t ial ly have been saved have not been documented , but could be anywhere from 10 to 25%.

In the emergency room, the Tack of deve lopment or enforcement of a p rog rammed protocol for ascer ta ining the immedia te critical problem(s) continues to be the dominan t factor in de layed or missed diagnoses (DOMD.) Fl i r ta t ions with disaster are all too common. The obvious con- t inues to command a t t e n t i o n ~ h e a d and facial in jury : lower ex t remi ty fractures. Awareness of thoracic in jury , a i rway obstruction, or major vascular involvement lurks somewhere in the s t ream of the subconscious. Too often the first call for taelp rings out to the neurosurgeon or the orthopedist . The penchan t for asking for lab results and the man ia for get t ing (and wait ing for) x-rays compounds delays and may accelerate the pathophysiologic vector.

' F A B L E 3 . ~ B I O D Y N A ~ I I C S T E R ~ f I N O L O G Y

TERM

Impac t fcrush)

Accelerat ion

Decelera t ion (nega t i re a c c e l e r a t i o n )

Tors ion Shear ing Cornpre~sion

Decompress ion

DEFINITION

Direct collisive force

Increasing forward mot ion

Decreas ing /or~,ard mot ion

Force tangent ia l to a surface Force radial to a surface increase in p r ~ s u r e in a

closed sys t em

Decrease in pr~ksure in a closed sy-~tem

CHar~.xCT:ErtmTICS

Magni tud0: dura t ion; onset and decay rate; area appl ied,

Highest to lerance vertical to long axis (cilest to back}; lowest parallel to long axis (falls).

Ra~e of change i,n veloci ty: mass; dis tance: t ime.

R a t e of change in veloci ty; mass; distance: time.

R ~ u l t s from decelerat ion. Resul t s from a pressure wave, Externa l force: magni tude :

dura t ion; veloci ty; resistance of a systetn .

Removal of force: t ime: recoil of sys tem.

. . i - - , : . . . . . . . . . . . . . . . . . . . .

5

The third phase is entered after initial evaluation and resuscitation. Tb.e l)atient is in the intensive care unit, plugged into .monitors, on the respirator, and fluids are pouring in. The patient is surrounded by attentive, de- voted nurses. There is a period of emotional and mental letdown. However, this gratification due to immediate rescue may dissolve with rupture of an aortic transection, a major blowout of a contused lung, or creeping pneumonia. Programmed pursuit at a high level of tension is essential. Table 3 defines relevant biodynamic terminology.

PATHODYNAMICS

Blunt chest t rauma is defined as injury to the chest in which no com.. munication of the internal organs with the outside environment results from the 1)rimar>, impact. This is distinguished from perforating chest injury such as occurs from missiles or knife wounds. In a strict sense, there should be no communication, but secondary forces do act occasionally to cause communication through avulsions or rib penetrations. The definition of blunt chest t rauma refers to the causative agent ra ther than to patho- anatomy.

The destructive nature of forces in chest t rauma are direct and indirect. T h e d i r e c t collisive impact produces injuries primarily to the chest wall: as from steering wheel or dashboard, blunt missile,, crushing load or a flying tackle. Indirect forces are princil)ally responsible for injuries to intrathoracic contents. These mechanical phenomena include positive accelera. tion, negative acceleration (deceleration), shearing, torsion, compression and decompression.

Mechanically, the body is characterized as a heterogenous visco-elastic system which is nonisotropic* and highly damped (free vibrations disal)- pear quickly), especially soft tissue (16, 42). The thorax in particular is a flexible, semirigid, open system (the airway and the mouth) , the maj(~r por- tion of which is air containing (the lungs). A significant but smaller influ- ential segment is fluid containing: the heart and aorta.

Table 4 lists pr imary and secondary pathodynamic mechanisms of various types of blunt chest t rauma.

DIRECT IMPACT.~The extent of injury produced by direct impact is related to (1) the mag~itude and direction of the force applied: (2) the area of application; and (3) the ra te of onset and decay of the force (68). Over 50/~ of automobile injuries occur at speeds below 40 mph with a decelerating force of 20G (16) or less. At 60 ml)h, the force rises to 60G. At 36 mph, on the instant of impact, the unrestrained occupant continues in forward motion, but exponentially decelerating so that the chest strikes the steering wheel or ins t rument panel (the impact barrier) a t less than one-half the original velocity, 15 mph (42). Impact t ime is brief, 1-20 msec., which is fortunate. The thorax can withstand a load of 600 lb., and, for ]0 msec. one in excess of 1,000 lb. Impact tolerance is highest for force applied in the front-to-back direction or at right angles to the long axis of the body, as in steering wheel injuries (68). By contrast, tolerance is least to forces exerted

*/qot equal ly elastic in all directions.

6

T A B L E 4.~PATIIODYNAMICS IN BLUNT (?lit:ST 'FRAt,?,IA

,.~TRI?CT121IE

A. T h o r a x S o f t f i s s u e

Ribs S te rnum

B. Pleura

(2. Lung

t7). T,-;.mheot>ronchus

E. "Me~liast inure

I)X,M AGF ~'1 ECI 1..~ N 1.'4 31 I Ni : I I ) I :N( ' t l

Pr imary Se~'ondary

H e m a t o m a Energy diss ipat ion Rib f ragment Cnmmon ( heat

hnpact-vc~,~el rupture

Tear . ]:lib f ragment " 'Bu r s t " Comrn,em avulsion, i )he/}Oll l t? l l i Tmnet ration

Frac ture I)irect impact (7(mr r(-coup (7ommon Fracture ; ])i rt~.'l imlmCl ~ Uncommcm

dislocat ion Tea r Rib f ragment " ' B u r s t " Commo~

l)h eIlo| l | (?]llt Tear Rib fragment ~ Common Hupture Clos~xt ~yslem ~ Common

corn Dress ion H ema toma Rib fragment Closed .system (:k)mmon

corn p,'( .~sion Contusion Compre.~sion 1 P,~q)id Common

decompression deceloralion Tor.~ ion "Forsion ~ Ha re

( lobar l lup ture "Torsion, shear ing, tliI~ f ragment Uncomn~on

compression Hemaloma " 'Bu r s t " Shear ing Common

( p/'im-~ r y ) F, henomena F. H e a r t

Pericarditllll " ] ' d m p o n a d e Pericardial vc.~sel Heart, amrta Uncommon rupture

Myoea rd ium Contusion I.)irect imlmet Comt)re~sion Fa i r ly (ym~mon Alria, vena cava l;aceration Rib fragnSenl t lup /ure t la re Val\,t_-s, chordae, l i up lu re Comprc.,ssion Ilib f ragment Hare

sepi a G. G rear v~.,s~;el:~

Aorta Transec t ion Deceleration. ~ U n c o m m o n shear ing

Subchlvian Transect ion Decelerat ion. --- Hare shear ing

(; rear veins Tea r l)irt~q impact Shea ring Hare F 'u lmonary "I'rart,4~?t icm Direct impact Shearing l la re

H. D iaphragm Huplure Compression Shearing Uncommon I. Ii;sopha~us Hup! ure Comprc.,ssion Shear ing l l a re

in the long axis, as in falls in which tile subject lands on the feet. The mass ( w e i g h t ) of lthe object (occupant) , the distance, to the steering whee! and the velocity are significant factors in the actual impact force sustained. Est imates of impact force are highly variable, anywhere from 300 to 3,000 lb. or more (42, 60).

The energy of direct impact is partially dissipated as heat. Vascular damage and bleeding may occur from compression and, with sudden rise in intravascular pressure (about 150 mm. Hg) , from bursting (16). Clothes provide effective cushioning and protection for the skin. Unbruised and undamaged skin often conceals the extent of underlying soft tissue damage and the severity of intrathoracic injuw. Muscle avulsion may occur from shearing phenomena, but most often from rib fractures. The extent and wide distribution of rib fractures are due in part to the disseminat ion of force (in turn influenced by tissue structure-: :bone, cartilage, muscle) and in part to secondary, compressive force. The sharp rib fragment may tear

7

INTERCOSTAL ARTERY TEAR

LUNG HEMATOMA RIB(double) ---FRACTURE

MUSCLE DAMAGE , #

• #

# • . • - • , . .

\

LUNG "

CONTUSION

'I'.i ,,~ " " " '"

.... ' " - - - - , , - , t - ..::!

2

PNEUMOTHORAX

LUNG TEAR

MYOCARDIAL/ CONTUSION

l:'lr~ l . - - D i a g r a m m a t i c ¢x~rnlx)site of blunt chc,-s:t t r auma involvement. A-s a rule, thoracic and l u n g i n j u r i e s a r e u n i l a t e r a l .

pleura and /o r vessels (intercostal, internal thoracic). Exper imenta l studies have demonstrated that tho force of impact can actually press the sternum almost against the spinal column (37) (Fig. l ) .

C O M P R I . : S S I O N / D E c o s I I ' I { E S S I O N . - - A second action of the direct impact is compression with a sudden increase of pressure within a closed system (29, 40, 51). Ordinari ly the airway is open. At,tlm moment of or just prior to impact, the open system in the awake and aware subject, is converted into a closed bo× by closure of the glottis. The increase in pressure may result in bursting phenomena, mediastinal, pleural, traeheobronchial cr in t rapulmona~, damage. When the force is removed (occupant is thrown backward), the distorted thorax springs back, creating an instant of increased negative (decompressive) intrathoracic pressure. ' One possible mechanism for tung contusion may lie in these compressive/decompressive phenomena. At the moment of impact, a segmental or subsegmental bronchus is suddenly pinched off. The pressure within the alveoli, served by this segmental bronchus is suddenly elevated. The limits of intra-alveolar pressure are exceeded. The alveoli burst and capillaries rupture. Along with this disruption of alveoli, blood extravasates within the enclosed area: Just as suddenly the compressive force is released. There is an explosive decompression with abrupt negative intra-alveolar pressures leading to alveolar collapse: hence, the morphologic picture of patchy, disseminated congestive and hemorrhagic ateleetasis. The characteristics of lung pathology are probably related to combinations of these secondary forces. Shock waves, from blast phenomena or seeonda .ry to an impact, with a velocity of 66 ft./ see. and a durat ion of 0.5 msec. or less can produce lung injury (61). Ex- perimentally, abrupt deceleration from a terminal velocity of 1.00 ft./see. or higher resulted i s diffuse pulmonary hemorrhage; at 75-100 ft./see.,

8

more localized lesions; and a t 66--75 ft./see., mult iple scat tered foci (1). S imi la r ewmts may explain the dynamics of in ju ry with respect to the

d iaphragm, the tracht,a or bronchus and the esophagus. The sudden increase in presstlre causes not a lacerat ion but a rupture . Secondary shearing tangent ia l forces may also contribute.

Th e compressive force in automobi le injuries is of spli t-second durat ion. In industr ia l accidents, such as mine cave-ins or landslidus, which produce sus ta ined crushing loads, the compressive force is reslao1~sible for most of the injuries.

OTHER SECOND,UtY FORCES. -Mediast inal injuries rare ly result from direct impact; the lungs (moment~{rily a t positive pressure) p resumably serve, as protect ive cushions, somewhat like plastic air spl ints (13). The damag- ing forces are compressive, decelerat ive, shearing and torsion (Fig. 2). At chest bar r ie r impact, the s t e rnum is thrust posteriorly.. T h e hear t is displaced and twisted to the left. T h e forward motion of the thorax is suddenly ar res ted while mediast inal c(mtents continue to decelerate.* The decelera- tiozl is arrest(,d sharp ly at points of a t tachment , such as the l igamentum ar te r iosum of the aorta. This action alone, however, cannot account for t ransect ion, which is more common than "tears ." Torsion stress is more critical at. the base of the heart , w'~th shear ing stress at the liganaentum (15). Force per sc does not caus(; the injuries, but an imbalance o1 forces of accelerat ion and restraitat (16). S imi la r stresses would account for. the rare avul-

'::Negaiive acceleration (Newton's second law of motionS.

}"lt~. 2 . - -P robab l e action of secondary forcc.~ on the t~eart and aor ta (details in text).

.....4, r' !

D Lig. Art,

T , S

C

(O) DECELERATION (T) TORSION

(S) SHEARING (C) COMPRESSION

)

(D) DIRECT I M P A C T

9

sion of a ma jo r pu lmonary vessel or lobe. The rar i ty of aort ic transection in survivors suggests (1) that the stresses are not very great: (2t tha t unusual tissue capaci ty t,xistz; for dis tensibi l i ty and energy absorpt ion of stress e n e r -

gies: and (3) that the mechanisms have yet to be fully documented. In falls, where loads are less well tolerated, vertical deceleration is the primary factor in aortic tears, all of which are at the l igamentum.

In the medias t inum, the sudden decelerat ion in a relat ively closed system can cause burs t ing of smal ler vessels and therefore m a y well a c c o u n t for the deve lopment of the hematomas. Shear ing forces may also supp lement lhis. The mechanisms for myocardia l contusion probably include a combination of direct impact as well as shearing force (56~,

RELEVANT ANATOMY

RIB cact~.--.The thorax is designed s t ruc tu ra l ly to resist a tmospher ic pressure so tha t the necessary negative dynamic in t rap leura l pressure dif- ferentials m a y develop in order to permit normal flow of air into the lungs and minimal impedance to venous return. In addition, the thorax also serves as a protect ion against, possible injury, not only to in t ra thorac ic contents but also to s t ruc tures in the uppe r abdomen. In accordance witb orthopedic principles, f ragments of long bones resul t ing from fractures are influenced by force of the impact and by muscle pull. In rib fractures , the force of impact is far more impor tan t than tha t of muscle pull. On the other hand. the muscu la tu re of the chest wall by spl int ing does exercise an influence over a flail segment , albeit t empora ry , because of reactive :~pasm secondary to t rauma. The principal muscles involw:,d are- listed in Tab le 5. The twc- toralis major and minor spl int p r imar i ly tmtential an te r io r and anterolateral flail segments while the posterola tera l segments also include action of

T A B L E 5 . ~ I U S C L E S OF T H E T H O R A X

~ ' | IJSCLE O R I G I N l NSERYlON

AnL scalene C3-Cc Firsl rib ,k~,d. scalene C~-C7 Firs l rib Post. scalene C7.-C.: Se~'ond rib Major pectoral Medial 2, 3 clavicle. Humerus

s~emum, 2 - 6 costal car~ ilagt~, rectus alxmeurosis

Minor lm<.toral 2-5 ribs Scapula t Coracoid)

Ant. ,~erratus

Pos I. ,serra I us

Ext. intercoslal

Int . :nterex~sla }

Su},~oslal

Transverse ~horacic

I)iaphr~grn

r, o,a Sea pu ta

C,;--7 ; T t -q ; T l t~ l ::: Li-2 I~wer rib margin

inferi~or rib marg in

Inner rib surface

Posler ior xiphoid an,,] sten~um

Xiphoid , s te rnum, ribs 7-12, lumbar vertebrae

'~ ~, ribs ~-12 ribs Upper margin of

next rib Upper margin of

next r i b Ix~wer marg in of

upper rib 3-6 ribs

Lumbar vertebrae

ACTION

t';tev-~te rib l', le'¢ate rib F leva le rib Shoulder girdle

fixed, raises ribs

Scapula fixed, raise~ ribs

I:'r~_~s~ scapula to tSora x

Elevate 2-5 rib.,; Ia~wer .q-12 ribs t!:}eval e ribs

Lower ribs

Lower ribs

l~ower ribs

Alter thoracic cavity

10

the a n t e r i o r and lms te r io r s e r r a t u s muscles. Pos te r io r ly , the back muscles, inc lud ing the trap~,zius and the spinal is group, which a re e x t r e m e l y s t rong, accoun t for the fact t h a i pos te r io r flails r a re ly lm , sen t any prob lem with respec t to chest ins tab i l i ty following t r amna . On the inne r sur face c.K the chest: wall, ltle suheosta l musc les con t r ibu te t~ the sp l inI ing of pos te r io r f r ac tu res ot ribs 8-10. An te r io r ly , the t r a n s t b o r a c i c musc les m a y con t r i bu t e to spl in t ing, but tbese a r e r a t h e r de l ica te sl ips and probab~5 , have no sig- n i f icant ett'ect. T h e first rib is r a re ly f r ac tu red , due to ~t~e fact tha t it is qu i t e small and p ro tec t ed by the shou lder girdle. F r a c t u r e of the fil.'s.'t rib is a lmos t a lways a c c o m p a n i e d b x, a f r ac tu re of the clavicle and gene ra l ly ind ica tes t h a t the force of the impact, mus t have been t r emendous . To produce a flail chest , double fraet.ures of several ribs m u s t occur (Fig. 3). As the spasm wears off, the re la t ive ly mino r effect of the intc, rc<~stals, the sub- costals a~d the transverse thorac ic muscles is overcome easily by forces in the oppos i te d i rec t ion (flail s egmen t and g rav i ty ) . T h e p lane of the pos te r io r (p rox imal ) r ib f r ac tu re s m a y remain u n c h a n g e d or m a y be ele- va ted s l ight ly (more so in the u p p e r 3-6 ribs I, while the f loating s egmen t re ta ins a posi t ion below (1 t ) . An associa ted f r ac tu r ed clavicle m a y accen- t u a t e the d o w n w a r d d i sp l acemen t of the flail por t ion.

tRibs 3-10 a re most c o m m o n l y f rac tured . T h e s e a re Pro)re exposed and }laVe the least musclt ~ protecti{m. T h e Iower r i b s ' a r e not: fractured as fre- quen t ly , p r i m a r i l y due to an increased degree of mobi l i ty and e las t ic i ty even. in older subjects . In y o u n g e r 1)atients, f r ac tu r e s are seen r a t h e r in- f r equen t ly , desp i t e app l i ca t ion of a r a t h e r large force.

PLEURAL SPACE'S.~'Fhis is only a potent ia l space. Viscera l and par ie ta l 1)leura us;ually easi ly s e p a r a t e because of a i r or blood or both, inc ident to t r auma . On<:(, the spac¢, is c rea ted , the relatiw.,ty n e g a t i v ~ f , r ap leura ] pressure is conver ted e i ther into a posi t ive p re s su re or neulr'F~ized to zero, in-

Fro, :Tk--Flail chesi and tung contu.~ion, al~proxin-mlely 6 hcmrs afler accident.

11

hibiting lung expansion. The pleura is reflected across the mediastinum, with tears permit t ing entry of air.

TIlE LUNGS..The lungs functionally may be classed as open-ended air- containing elastic cushions surrounded by a vacuum. The air sacs are in a constant state of imminent collapse, due to the elastic force. Surfactant in conjunction with the negative pull (force) keeps tlle alveoli open. Thus, a balance between forces exists to maintain the intra-alveolar norm. Disrup- tion of this balance often results in alveolar collapse. The alveoli are sep- arated by capillary networks resting on a delicate stroma. The air sacs are connected to ducts (devoid of cartilage) and to respiratory terminal) bronchioles, which have some, but scant)', cartilage. Both structures are richly supplied with elastic fibrils. The communications continue to l~rogres- sively more rigidly supported segmental lobar and stem bronchi, The peripheral (lateral) surfaces abut the inner chest wall. against the ribs. The bases sit astride the diaphragm anti the apices crowd into the narrow, but solid, uppPr thorax. The medial surfaces wrap around the mediastinal contents, serving as protective cushions, part icularly effective under increased transl)ulmonary pressure. The hila are fairly fixed although they are relatively mobile in children. These vital regions also are protected by the pulmonary air cushion.

TRACHEOBRONCHIAL TREE. This is fairly well protected by its anatomic location and its relative resistance to imbalance of force. The most common site of injury is at the origin of the main stem bronchus. The lung is most mobile at this region.

MED1ASTINUM..The upper third of the mediast inum is encased in a fat ty areolar pad, through which course many small blood vessels. Gener- ally these are well protected by the relatively rigid upper thorax and direct "crush" rarely produces serious damage. On the othor hand, sudden decelerative phonomena may result in bursting of these vessels, producing hematomas.

HEART.--Relatively speaking, the heart dangles freely in the mediast inum suspended from tile aortic root and encased in the relatively stiff pericardial envelope. At the moment of impact, the s ternum moves backward disl)lac- ing the hear t to one side, producing shearing and tangential forces. The point of suspension to the aortic root is a critical area of injury. Sudden deceleration may result in damage to high volume-low pressure regions. accounting possibly for most of the injuries to the right side (atrial and vena cava. On the other hand, anterior "crush," involving part icularly the costal cartilages by direct injury may produce cardiac tears (53). Sudden decelerative and /o r compressive phenome:na probably account for bursting lacerations of the valves. Direct impact has some bearing, producing myocardial contusion, but decelerative and shear phenomena resulting in capillary rupture and a diffuse hematoma may be just as significant, The left ventricle is rarely ruptured, the right x;entricle only occasionaI]y. The pericardium contains many blood vessels, rupture of which probably accounts for tamponade in the absence of direct injury to the heart or a coronary vessel. The pericardium is rather firmly fixed superiorly around the aortic root and the pulmonaD, vessels. Tha t it is a closed sac accounts for the drastic events following an acute effusion. I t is somewhat grudgingly elastic and can accommodate fairly large-sized effusions if they develop slowly.

12

On the other hand, the sudden ingress of a relatively small amount (2-300 ml.) may result in tamponade of sufficient magni tude to cause cardiac arrest. The pericardium, although rarely burst by decelerative phenomena, .may be lacerated by stmrp rib fragments.

LARGE VESSELS.~The aorta is fixed by its a t tachment anterior to the heart at the root, superiorly by the three major arterial dirt:dons, and posteriorly by the l igamentum arteriosum. Distally, it is encased firmly in pleura, the point of maximal fixation in the thorax. These are, therefore, critical points of stress. The nature of damage is a transeeti m and not a " tear ," as popularly conjectured. The reasons are: (1) the ] igamentum is the last fixed point parallel to the long axis of the body; (2) the pleura! at- tachmenks distally are at a right angle to the long axi+; and (3) the attach- ment is stronger (more rigid) than those at the root o~ l at the arch branches. The secondary forces are therefore more effective at this site,. The proximity of the subc'lavian ar tery to the l igamentum accounts for its occasional involvement (46). Other major systemi<: arteries of significance are the intercostals and the internal thoracic. Because of their proximity to ribs, damage is due to laceration from rib fragments. The major systemic veins are concentrated in the superior mediast inum, huddlin,, beneath the firm protective roof of the clavicle and the first two "Abs. An unusual ly large direct impact force is required to produce damage. Even where the first rib is fractured, underlying vascular inju~, i~ rare. The clavicle receives the brunt of the impact, so that the ribs ten,,~ not to be displaced.

Pu lmonary hilar vessels are protected by the lung air cushion and, in contrast to the bronchus, by their own elasticity. Direct impact or shearing and torsion phenomena can cause injury only if the5' are of enormous energy. Damage is unusual, but usually lethal (31).

DIAPHnAGM.~The extreme degree of mobility of the d iaphragm generally permits a wide lati tude in position. At the moment of impact there is a sudden posilive intrathoracic pressure which appears to be well met by a positive intra-abdominal pressure. This neutralization of pressures appar- ently accounts for the fact that diaphragmatic injuries as burst phenomena are fairly uncommon. Other causative factors include tangential shearing and tensing during rib cage deformity (from the impact) and a secondary stress on release of the impact force. Injury is almost always to the left, m o r e mobile, leaf. The immediate ly adjacent subdiaphragmatic str,lctures, the spleen and liver, are impor tant to bear in mind.

PHYSIOLOGY

From the functional s tandpoint t h e lungs serve to mainta in normal oxygen and carbon dioxide tensions. This is accomplished by the mass movement of air in and out of the lungs by virtue of al ternat ing intrathoracic pressures, with the chest wall serving as a buffer against the relatively positive atmospheric pressure. Uniform action of the thoracic muscles and of the diaphragm results in a geometric enlargement of the intrathoracic volume and, at the same time, an increase in the relative negativity of the int rapleural pressure. This pressure differential permits air to flow into the lungs. Conversely, recoil of the lungs and the upward movement of the

13

tI.--(;~~~ss.~rtr- rw Tr.:~tsis ~ f > f t ~ l A l . \ r , \ ~ . ~ r ~ ~ - ~ ~ ~ ~ ~ B l i ~ . \ ~ O t t ~ ~ ' 1 1 ~ ~ 1 1 ~ 1 . 0 ~ ~ ~

~ I ~ : . \ s I N G N I ~ N A I ,

nlvtwl;tr 0. 1 O I I S ~ O I I in nun. f lr: I 10-120 :\rttbri:~l O2 t e n s i o n i n 111111. 1 ig !NLl 1 0 i \ l ~ ~ ~ b I : l r - ~ ~ r t t * r i i \ \ 0: ~ r a ( ! ~ w > t 5-C ;( 1, t l lvr~)l iar CO: tcw\ion tn mtn. 1 1 ~ :W--i2 fr;ictiori o f cx1)r r c ~ l (.'Or 40-1f; ( t ~ I ( i c r 1 y ) 11,-tei-iitl (7 t2 f c r ~ . . ~ n t ~ S:II~IC! ti- 1'102 i~rtvri: l l C02 uontm t i n Vol ",', 5f4C) ticlnl volulrrt. in vr. 5OOt rninutil v c n t i l n t ~ c m ( t o t i l l ) in cc. (io()Ot c1l~k'CJlitr ~ ~ n t ~ l r ~ t 1011 rn i'c. 42i)Ot " ~ h v z i o i c ~ ~ ~ c " tleiccl sl1;tc.c in cc . 100"~; 0: =: 111:ls. f i 0 ". h r o r n c 4 r i c ~ ~ r c w u r c i l l nun. 11g I 00 (stw I w t ~ l )

v+iitt*~. w l w r Iwc.;,iirtl 111 1111r\ tlg 47 fr;icbt ton oi ir~.sy>irrt l 1 = l ( w ; vtsnt t h t ion-perfu-.ior~ rat ro 0.7-11.8

r-umntanv~*s. this ir/Q may hv altrrtd. resulting in anha.; wi th adtyllntt~ r l

jrtbrf ilsii~rt hut i rmh.luattb vtlntilat ion. f his, also, has h c ~ n ttlrrntd 1)tlysio- I r ~ g i c b sh tr lr t i ry . Di ffusion n t m s s t h ~ alvwloi.a~)iliary rncmhranf* is prcqwr- tirbnal to g;i..; prtessurc! gradients and to t h ~jhysical stat(> o f thr n,t.rnbmnc~ i tscaIf.

PATHOPHYSIOLOGY

~ 1 1 I ~ I N Z ~ W LLLIN IITS

SHUNT UNIT DEAD SPACE

° , l o o ° °

o 0

- o o-t..~o + .~.o o . ~ , . ( . ++' .4OL.o°; , o o ° ° ,,,," ° . . ° °2 o+,,0

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v v

NORMAL-- ~2 3

Q 5

Fro. ,l.---l)iagrammatie representation of funclional puhnonary unils. Tim "shunt unit" is cansitler~i Io be the ba,ds of hmg dy,+funetion in chest /rauma,

th(, g r a d i e n t witll the a tmosl)here . T h e loose segment (flail) is pushed in- ward. On exp i ra t ion , the g rad i en t is reversed: T h e intrath<~raeic pressure exceeds atmt:~st)horic and the flail s e g m e n t is sho~'ed ou tward . I t has been specu la ted t ha t a segment of a i r moves, lmradoxicallv., and uselessly, l~ack" " and for th be tween the two lungs, resu l t ing in increased (lead space ventiIa- ti(m. Tht , m a g n i t u d e (d' th(" l)(.nd~ l luft m a y not be as s ignif icant as former ly beli<,ved (,19)+ Th e r e su l t an t bobbing back and for th , toge ther with a i rway <4~struction from secret ions , causes increased res i s tance and de-

.¢ + "I~ creased COml)liance (30). ( ,as d i s t r i bu t ion is imlmired , caus ing a ne t reduc- t.i(m in alvt ,olar vent i la t ion which, with a con t inued per fus ion , resul ts in disl~rOl)ortion in Q/Q relationshil~ (14). In an a t t e m p t to overcome this. r e sp i r a to ry work increases. T h e a c c u m u l a t i o n of a i r or blood or both in the l~h:'ural space rodm'es the ventilablo lung volume p roduc ing a res t r ic t ive l )uhnonary i nsuffi('i(,ncv. A/so, th(:, nozmlal negat ive p res su re d y n a m i c s of

r e s L t a n ( _ ( _ t o a i r the in t t ' ap leura l space are a l te red , resu i l ing in increased , ' s "~ flow wi th in the lung, con t r ibu t ing t.o an increase in r e s p i r a t o r y work. Pa- r enchyma l damage , p u l m o n a r y con tus ions or i n t r a l m l m o n a r y b e m a t o m a s resul t in a dec rease in compl iance and an increase in e las t ic work. T h e P a o : is dec reased with reduct ion in ne t diffusion across the a lveo |ocap i l l a ry m e m b r a n e . A s s u m i n g tha t porfus ion is relatively a d e q u a t e , and tha t the hemoglobin also is wi th in normal l imits , tho reduced gas oxygen t r a n s p o r t cu lmina te s in a dec reased a r t e r i a l oxygen tension (Paoa) . Pos i t ive iden- t ification of the defec t is obta i~ed by ana lys i s of the Pao~, a m a n d a t o r y p rocedure in eva lua t ion ( l l , 75). T h e reduct ion in oxygen tens ion produces h y p o x i a which in tu rn causes a reflex h y l m r v e n t i l a t i o n lowering Pco, and p roduc in g r e s p i r a t o r y alkalosis . T h o ini t ial von t i l a to ry insufficiency is for oxygen. If this d i s a r r ay is a l lowed to persist , or if s econda ry eom- pl icat ions such as a i r w a y obs t ruc t ion f rom secre t ions or a s p i r a t e a re permi t t ed to in t e rvene , the insufficiency sp reads to inc lude carbon dioxide and ro sp i r a to rv acldosL. C o n t i m m d hvpox ia even tua l ly causes increased anae rob ic ce l lu la r me tabo l i sm wi th a c c u m u l a t i o n of fixed a c ~ d . ~ m e t a b o h c a c i d o s i s ( F i g . 5 ) .

1 5

PATHOPROGR.ESSION

CHEST TRAU MA

Si°ck ~'T~ '~A~ ~ub.utCara:ac~" ~ ~I,

FaO 2 ~, , a ~ - , o 5 i - t

FIG 5.--Palhopro~r.~-.~ion :n ch,~t t rauma.

The degree of pulmonary dysfunction existing in a pat ient at initial ob- servation in an emergency, room often is compounded significantly by' development of secondary complications dur ing the interval from accident to admissic~n. These usually are relaled t.o (a) airway obstruction, !b~ iatro- genie venti tah:rv restriction and l c.~ shock. Reta ined secretions, aspiration of vomitus or blo(~d from tacia} injuries lead to airway obstruction, which increases alveolar hypoventi iat ion, a irway resistance and work of breathing, S t rapping the chest with devices to diminish the flail often inhib}ts contralateral mechanical ventiiat]on. Immense acute gastrie di latat ion is very common in trauma° causing restriction of d iaphragmat ic motion and vomiting. Shock. when present, results in diminished gas transpc~rt, ag- gravating tissue hypoxia.

Putmonar3, function often is .further hampered by impropriet ies of management, tack of intensi ty of vigil and follow-up and by pneumonia. Re- tained secretions with persist~:~nt or recurring auflectasis lead to fur ther de-

15

creasf, in compl iance and e levat ion of a i rway res is tance, with concomi tan t worsen ing in a lveolar hypoven t i l a t ion . Overzea lous fluid t h e r a p y m a y produce "wet lung." Pneumcmit i s , c o m m o n l y c'~:m~plicating lung contus ion, and occasional ly "b low-outs" and p n e u m o t h o r a x du r ing r e sp i r a to r t h e r a p y add f u r t h e r i n c r e m e n t s of i m p a i r m e n t .

DIAGNOSIS

Prompt assessment of the nature and magnitude of blunt chest trauma is neces sa ry to save the life of the pa t i en t or to reduce morb id i ty . S ince injuri~,s a r e of h ighly complex, mul t ip l e organ n a t u r e as a ruh~. the examina t ion of the pati~,nt mus t inc lude a su rvey of all possible involved sys tems.

In mos t ins tances , the diagnosis and eva lua t ion of s e e o n d a ~ ' complica- t ions <:an be m a d e by accu ra t e h i s tory and by the four m a i n s t a y s of physical diagn¢>sis: inspecti~m, pa lpa t ion , percuss ion and auscu l ta t ion . Infor- ma t ion re la t ive to lhe in t ens i ty ~>t' the acc ident is avai lable fr¢~rn the Italics:', or from a m b u l a n c e a t t endan t s . In every au tomobi le accident , the possibi l i ty of b lun t ches t t r a u m a should be raised. T h e bu rden of ru l ing t:his out rests on the phys ic ian . A c c i d e n t vict ims s i t t ing in the d r iver ' s seat or in the f ront passenger sea t a re more prone to hart, blun t ch~:,st t ra t ma because of sudden iml ,act aga ins t the st.e~,ring wheel or dashb( ,ard. T h e pa t ien t ' s pas t h i s to ry is of impor t ance , pa r t i cu l a r ly as re la ted to his p u l m o n a r y .,atatus. P a t i e n t s with chrc-mic lung disease to le ra te chest in jury very poorly.

I_~S}'ECT~Oz.~Careful sy s t ema t i c inspect ion provides valuable informa. tion abou t the t~aii, 'nt 's ven t i l a to ry pa t t e rn , skin color, menta l s ta tus , col- lat~se (~r d i la ta t i fm of periph,~ral vt,ins and a flailing chest segment . Ap- pr( ,ximat~Iy .'~5"~£ ~f pa t ien t s with c rushed chest fail to show an,,, thora,ric wall aI:,n,:rmatitv wh~n ini t ia l ly seen. and the obvi~ms flail develops subs~*- quen t tv (7. 1!). Repeat~,d e x a m i n a t i o n is~,sst~ntial. T h e d a n g e r o f m i s s i n ~ th{, flail i~, gr<'al~,st when it is in the }at{.ral and pos te ro la te ra l par ts of the

thorac ic cage and may be respmlsible for " 'h idden" hypoxia . Absence of motiem in the hemi tho rax is usua l ly the resul t of a sizable, p n e u m o t h o r a x or hemc, th~,rax...Exit* " e-.m~, d is t ress in resp i ra t ion , together_ with devia t ion of the, trach~.a fr(~m tlm midi ine, is due to tension p n e u m ~ t h o r a x , massive h e m o t h o r a x or ma.~sive at:electasis. In the first two ins tances , the t r achea deviat~,s contra la t¢ , ra l ly and in the last. io the ipsilat~,ral side. S t r i d e r poin ts to ¢,bstruction in a ma jo r a i rway . Pa l e .~kin and flat pe r i phe ra l veins m a y be the r,:,suIt of m a j o r h e m o r r h a g e e i the r in the chest , a b d o m e n or in the ext remi ties. su g,,,,esti ng twImvolemia with possible shock. Dila ted pe ri p he ra] veins, espec ia l ly in the neck, should sugges t possible p resence of card iac t a m p o n a d e or impa i r ed my~n~ardial funct ion.

PALPATION., Subcu tnneous e m p h y s e m a ind ica tes an a i r leak. s6condary to torn lung or to a t ra ( 'heobronchia l rup tu re . Absence of tac t i le f r emi tus is u sua l l y the resul t of pneum(~thorax. In most ins tances in which the flail sef~munt is not obvious a t inspect ion, careful pa lpa t ion will dis~-Iose its presence, M o s t s te rna l in jur ies ( f rac tu res or s~,parat ions) can be accu.

ra te !y diagnes~,d by ( 'arefu] pa lpa t ion . Manua l e x a m i n a t i o n of the l a~ ,nx and t r a chea can lead to ear ly d iagnosis of f rac tures or (-ontusions. I,oca]iza-

17

t ion of tile s ide of the rib f r ac tu res m a y po in t to possible u n d e r l y i n g organ d a m a g e in the upt )er abdomert .

AVSCI.'I,TATION.--Absence of l~reath sounds suggests l )neumottaorax, he- m o t h o r a x or a le lectas is . Bowel sounds in t lw ehe~t indicate-, d i a l )h ragmat i c r up tu r e . A u s c u l t a t i o n of tile h e a r t sh(mld be 1)('rform~-d mt,ticulou~,"y but the d is t ress a n d labored b r e a t h i n g of the pa t i en t fr~,qu(,ntly r~,ndr,r l>hysiea] e x a m i n a t i o n diflqcult. D i s t a n t or absen t hea r t so~mds should suggest the l)r(:sence of a ( 'ardiac tamt)onade . A b n o r m a l m u r m u r s m a y be seconda ry to a to rn valve. Fr ic t i tm rubs, p a r t i c u l a r l y those s y n c h r o n o u s wi th the hear t sounds, should suggest l )er icardial involvement .

PERCu.ss loN.~The loss of no rma l chest r e s o n a n c e is u sua l ly the resul t of an abn()rmal col lect ion of a i r or fluid. Dul lness should raisv th,:, qu~,stitn~ of henaothorax and hy t ) ( ' r resonance of p n e u m o t h o r a x . Pe rcuss ion ~ rar(,lv helpflll in d i s t ingu i sh ing med ia s t i na l hemor rhage .

RADIOLOGY.~Too often in the rou t ine of the e m e r g e n c y room. the ad- moni t ion is: get the blood pressure , s t a r t an I .V. ' and get an x-ray. Al though t he r e is no ques t ion t ha t x - r ays a re of g rea t value, most of the pati~'nt 's cr i t ical p rob lems can be evaluat(:,d by t)hysical examina t ion . X - r a y s ar~., supplem( ,nkary and for conf i rma t ion of ini t ial iml)re~sions only when t ime permi ts . In t )a r t i cu la r the l)r~Jsence of tension pneumoth(~rax, ma~siv~, h(:,mothorax , or ca rd iac t a m p o n a d e is , , s t a b l i s h e d on clinical gr()unds and t)rol)er thera l )y ins t i tu t ed without de lay for x - ray ( ,xaminat ion. Th,:, asc(:,rtainm~,nt of a p a t e n t a i r w a y and s tab i l iza t ion of ven t i l a t ion and of |a(~modynami('s a re u r g e n t r equ i rem, ,n t s p r io r to moving a pa t i en t about . T h e de lay in ge t t ing films (which a re f r ( ,quent ly of l)oor qua l i ty due to the rusht~d cir- cums tances ) and the difficulties in in te r l ) r e t a t ion ( .ontr ibute to miss(,d or de l ayed d iagnoses of ser ious complicati(nas s e c o n d a r y to the ('h,.~st in jury . S imp le P A l)roject ions of the ches t will SUl)ply most of the informati~m requ i red in b lun t chest t r au ma . Mos t of th(., rib fractur~:,s (-an t)(, readi ly seen, but in ce r t a in ins tances , la te ra l f r ac tu res are not visible. Costal car- t i lage invo lvement will not show. In the imm(~diat(, per iod, d~,lin(,ati:m ,.,f the rib f r ac tu res is super f luous and de l ays t h e r a p y . Also. phys ica l ~,videnc(, of rib f r ac tu re is more dependab l e than radiogral )bic evid(,nce.

PNEUMOTHORAX.~Nlost sizable p n e u m o t h o r a c e s are readi ly visible ra- d iograph ica l ly . In a small p n e u m o t h o r a x , t)hysical signs will be abs(,nt and the x - r ay m a y be inconclusive. N() i m m e d i a t e l y ser ious p rob lem is th(:~n present , but s ince the a c c u m u l a t i o n of a i r m a y be s o m e w h a t de layed , re- pea t e x a m i n a t i o n s a re i m p o r t a n t .

HEMOTHORAX.~The blood which eni.ers the p leura l cav i ty u sua l ly re- ma in s liquid. In most i~s tances , the blood flows with g rav i ty and the re fo re is in a d e p e n d e n t t)osition. An u p r i g h t film best es tabl ishes the m a g n i t u d e of the h e m o t h o r a x . At t imes, the l a te ra l decub i tus posi t ion m a y demon- s t r a t e a ve ry smal l hemotho rax , a l t hough this i n fo rma t ion is r a r e ly of practical value. W h e n blood and a i r a r e l ) resent in the p leura l space, the resu i t ing air- f luid level will p e r m i t easy de tec t ion in the s t a n d a r d u p r i g h t film.

LUNG CONTUSION.~Parenchymal inf i l t ra tes in the lung mos t of ten a re due to con tus ion a l t hough t h e y m a y resul t f rom h e m a t o m a s and lacera- t ions . Contus ions m a y be focal or d i s s e m i n a ~ d and range from mild l inear

18

to n o d u l a r inf i l t ra tes , and f inal ly to r a t h e r massive spn . ad and some df,gre~, of consol idat ion. N - r a y r~,cognitima of p u l m o n a r y con tus ion is difficult t<, d i f f e ren t i a t e from o ther lyl~('s of infiltrat(,s. T h e ron tus ion usua l ly app , . a r s a f t e r i n ju ry , bu l m a y be de law.d as long as 48-72 hours. T im radiologic c r i t e r i a for diagnosis of p u l m o n a r y contus ion are: (1) i sola ted or confluent r egu la r n( ,dular &,nsi t ies with per ib ronchia l and pe r ivascu l a r infiltrat(,s: (2) hom(~genous ol)acification resul t in~ from intra-alv~,(dar hen .o r rhage and t r a u m a t i c rupture, of the alveoli: t3} a combina t ion of the ;tbt:V~, with and wi thou t l m l m o n a r y effusion. R a r e l y , when f rank conso l ida t~m o('curs, the p a t t e r n does not conform to the s hape ~)f any lung segm(mt. Usua l ly tim, m a x i m u m changes occur in the first 48 hours, tResolution s u b s e q u e n t l y ix ('Oral)fete in 5-10 days (5.5 -!: 2.9 days in our pa t i en t s ) . \Vors~,ning, of the: p ic turo should raise the possibi l i ty of a sup(- 'r imposed l)n,,mmonitis.

LACERATED Tt',ACHEA OI{ BRONCHI;S.~In mosi ins tances , I);~tie',lt.s with t r acheobronch ia l r u p t u r e will dem( ,ns i ra t , , Imeumom( ,d i a s t i num and sub, cu t aneous eml )hysoma ex tend ing up into the neck. Ips i l a t e ra l rib f rac tu res of ten a re I)r('~ent. F r a c t u r e s of the first and s(,cond ribs, which a re rela- l:ivelv unusua l , should raise a qu(,st ion of bronchia l i n j u r y since t h e y in(It- cat(:, an i m p a c t of u n u su a l malznitude. Occasionally, ()nix" i m e u m o t l m r a x m a y b(, p resen t and very l i t t le in t.ho way of a l )neumon~edias t inum. %us- picirm should , ,scalate wh(,n t he re is ( ' (mtinued mass ive ~'scal)e oI a i r the., , ~ h a t-horacot(mlv tube. Def in i t ion of a r u p t u r e m a y be 'ob ta ined th rough lami- nogra l )hy and bronchoscopy. B r ( m c h o g r a m s are ra re ly requi red .

t:_2sot'}t,~(;l 's.~Damage if) the e sophagus is e x t r e m e l y rare. T r a u m a i i c r u p t u r e of th,~ u p p e r s~.grn~,nt causes med ias l ina l and cervical cnl l )hysema. I n j u r y in the lower ~,sot)ha~tJs is accoml)ani~,d by hydropneumoth (~rax in abou t 50c'[, of instances. T h e (-',ffusion m a y be bi la teral . Shou ld a n y qu~,s- t ion exist, a gastrograff in swallow ix diagnost ic .

AoI~T,x AND LARGE VESSELS.-~It has been e s t ima ted tha t onIv 2005 of pa- t i en t s with. t rmmaat ic r u p t u r e of the ao r t a live long' enough to a r r ive in an e m e r g e n c y roon;. In a pred~m~inantty thorac ic injur>,, ex is tence of struck should lead to su~:)icion l,f a ma jo r vascu la r in ju ry . Th:.. i n i t i a l .x - ray is of impor t ance , parti( 'u'~arly if there is a mass ive h e m o t h o r a x on tht~ left side.. The sign which is most oftr, n search(,d for is widen ing of the m e d i a s t i n u m . U n f o r t u n a t e l y this is slot a very a c c u r a t e guide in the absence of left s ide effusion. M a n y factors can produce widen ing of the rned ia s t inum, the mos t comnlon of which a re inad,: ,quate po r t ab le films (which falsely en la rge the med ia s t i na t a r ea l and med ias t ina l herna tomas . P u r s u i t with r epea t films is cri t ical . Mos t of ten a ques t i onab ly wide m e d i a s t i n u m "pres~.nt" on the admiss ion will " reso lve" wi th in 24 hours with p rope r ly ob ta ined ches t films.

CARDIAC TAMPONM)E.~The classic Beek ' s t r i ad is a small , qu ie t hea r t with an e leva ted venous pressure . T h e rap id effusion of blood m a y be suf- f icient to induce a ca rd iac a r r e s t , bu t a t the s a m e t ime m a y no t radiologi- t a l l y d e m o n s t r a t e e n l a r g e m e n t of the hear t . T h e d iagnosis should be m a d e in i t i a l ly on clinical g rounds and if a n y ques t ion exists, pe r ica rd iocen tes i s should be per formed .

DIAaoHRA(:;M.~Most t r a u m a t i c r u p t u r e s occur in the left h e m i d i a p h r a g m at the dome, pos te r ior ly . P a i h o g n o m o n i c x - ray ev idence is a gas-filled viscus above the level of the d i a p h r a g m . Sugges t ive findingss inc lude an a b n o r m a l l y

19

high d iaphragm, f luoroscopic ev idence of absence or decreased m o v e m e n t or disk- l ike a l e l ec tas i s above an e levated d iaphramn. T h e inject ion of contrast media into the u p p e r or lower G-I tract m a y be required.

LAr~OnATORY.~Initial i m p o r i a n t laboratory e x a m i n a t i o n s inc lude a hema- t(x'rit, ur ine sample s and arterial blood -as,-,: S tud ie s in our inst i tut ion

T A B L E 7.~DELAYED OR MISSED DIAGNOSES ( D O M D ) . ANATOMIC

2. Frac turc~t ~(t islrma.a't t~t )

stO!Tlum ]/. l . u n e s and P l e u r a

I . C o n t u s i o n

T IME I . n s m x W n Y D O M D I )L~G.','osr~c Ares 1NTERVAL

A. T h o r a x M u s c u l a r sift int i ng ; Ca refu 1. ! horou.gh 1 41 hou r s I . F l a i l d o u b l e f r a c t u r e s not I m l p a l i o n : r epea t

v i sua l i zed b y x - r a y e x a m i n a t i o n (cos ta l ( 'art ilagt~}

Same San le

:2. T(?n,;l()n i)tleu- t l lolhorl tX

C. t4ear( I , } t emol~ . ' r i -

c a r d iu~n

2. (7'olal u,~iorl

3. T e a r

4. V a l v e r u p t u r e

I). G r e a t V ~ e l s 1. &or t ic ruT)lure

2. L u n g vt~;.,;el l a c e r a l i o n

E, M i s c e l l a n e o u s 1. Trach¢~ ,h ron-

claim r u p t u r e

"2, I ) m p b r a g m a t i c

3. E . ,mphagea 1 r u p t u r e

.%" a m e

D e v e l o p s in 2--2,1 hours ; x - r a y e v i d e n c e non - Slux'ific e a r l y

l n a d e q u a l e awa/enc..ss a n d exan~ina l ion

N o l e o n s i d e r t ~ | ~ p h y s i c a l find in:z,~ n()nsl~ycifl c

P h y s i c a l f i n d i n - s non- ,,t)e(-iiic: m l l i a l I : 'CG r m r m a I o r nonspec i f i e

No( s u s [ u ~ t e d

N o t stlspt.K:h'd

]:Jnrting,~ nonspL<-ifie ,n two t h i rd s

No t s u s p e c t e d

N o l susl~.~ct ml

N o s p e c i f i c s i g n s

N o t s u s i e - e t a {

Arterial blood gases : ('al('ulal ion of -~,-aI),:),,: se r ia l X - r:! ~'S

lni t i a l - -Myspnee . . cyanos i . - : h, l e r - - i nc rea sed leak:

tdLvset,na : x - r a y H i g h index e l s u . p i -

('ion. elevale,'l C V I ) : d LM er~,h,,t ;'let:'k \~eil'l'~: tlu{)- 1"O-(X~;)3'. l)erica r- d iocenl (~is

H i g h re,alex of ,~uspi- l ' i o , l : reDe;, l I: :( ' (1: pn , co rd ia I I " ' in : am.if e [a~It~re

Con l inure{ bl(~'d in.,_, f rom I hor,~c,,)lomy

M u r m u r of in:~ulli- (-iency; h e a r l fail ure

W i d e n i n g m e d i a s ! i- /lUID : h y p e r t e n - s i o n ; lo.~s o[ fem- ¢)ral |)uls(.~: h e m o - t h o r a x {lett) ; s h o c k ; a o r t o g r a n !

(?ont inutet b r i sk b l e e d i n g f r o m t h o r a c o t o m y tube : shock

(7on l inued and pro- n o u n c e d a i r leak f r o m (bOr:.acolomy tube" | e n s i o n p n e u m o tho ra x :,

e m p h y ~ , e m a Bowel in ch(..-st

i a m ; c u l t a l i o n a n d x - r a y )

S u b c u l.a n(~.)us ,em ph y s e m a:

h y d r o t })orax

4-4,q h o u ~

4 - 2 4 h o u r s

~)ll'l P n ~~v('r

12-48 hmlr~

I )a y:,.-n~onl h:~

4 h o u r s - ] ; ; dav.~ ~orll hs-fear:-~

4-12 hour s

4 - 7 2 hou r s M on ( h.~-yea rs

4~-72 hot~rs "~" ears

24-72 h o u . ~

20

have demons tra ted that 80qo of pat ients who arrive in the em ergency room with major blunt chest t rauma are hypoxic . Es t imat ion of the alveolar- arterial oxygen gradient ( A - a D o : ) provides important informat ion about pu lmonary function, part icularly shunt ing (3. 75) . Th i s can be obtained bv having the patient breathe 1 o+ . 00+0 oxygen for 30 minutes through an en- dotracheal tube or a wel l-f i t ted mask. N o r m a l A-aDo_, values range from 8--60 ram. Hg, depending on concentrat ion of inspired o x y g e n .

SPECIAt, PROCF.~URES.--Special procedures are des igned Ii2"i~narily for conf irmat ion of suspic ion of critical les ions such as tension pneumothorax . aortic tear or bronchial laceration.

Thoracentes i s is an e x t r e m e l y useful procedure to diagnose s izable pneumothorax or hemothorax . T h e insert ion of a large bore needle m ay prove l i fesaving in tension l m e u m o t h o r a x . T he suspic ion of a cardiac t am ponade should i m m e d i a t e l y lead to a pericardiocentesis . Aortography is essent ia l if aortic injury is suspected. Faci l i t ies and trained staff on a 24-hour basis must be available. This should a lways be done ut i l iz ing an artery in the Upl)er ~,xtremity. Double venous inject ion has been used, but v isual izat ion is not nearly so sat isfactory. Frequent ly bronchoscopy or l a m i n o g r a m s will reveal a tracheal or bronchial tear.

DELAYED OR MISSED DIAGNOSES ( D O M D ) . - - D e l a y in detect ing a serious injury or miss in~ it (:'on, t~ lete ly is the t)rimary cause 9f early postadmiss ion deaths (Tables 7 and 8t',. Pract ica l ly all are preventable. The "sudden" deluge of an ( ,mergency room bv several ser iously injured victims: the turbulent traffic of ambulance at tendants , pol ice officers, orderl ies , nurses , doctors, students , technicians: delay in gett ing lab reports: poor x-rays: the puzzle of who the patient "belongs" to-:: all serve only as weak excuses . A simph, , logi<'al routine, well deve loped and str ict ly adhered to, can be a lmost foolproof. D e m u t h cata logued 17 cases with 10 deaths (22). Tens ion pneumothorax and severe heart contus ion were the most c o m m o n D O M D and were fatal in me, st instances. Aortic rupture when missed is a lmos t

T A B L E ~ _ i . - - D E L A Y E D O P h { I S S E D DIAGNOSES ( D ( ) h I D 1 P t t Y S I O L O G I C

I)FF!CIT

A. 1t Yt)oxi;:~

B. Hyr×)volemia

C. C a r d i a c dys - fUIlCt ion

~,-Vn y I . K ) M I )

C l in i ca l s igns !dys - pnea , cyano~ i s ab3ent ; rt~I les~- hess attributed to head i n j u r y

A r te r i a l prex';u re and pulse m a y be mis leading : bleeding not ob- v ious ; underest i - m a t e d u e to lack of appraisal

Not susp*.~l(~t in i t ia l ly

(. 2,~ U :4 ES

A i ~ v a y obstruct ion: flai! chest: h.m~ +mntu- ~;iOll; let/?~,i(,lll i)lletlillO- thc~rax : l : la~sive a Iel+~cta,;is

Norl I boracic inju rw: lacerat ion of izller- (R)~[~tI VtNst~'I;, :torI~c rupl ul~.: p u l m o n a r y vt.,s~<.:l tear

[)!AGNOS'rlc A :Ds

A i r w a y a.~pirat ion; btoc~'t gas t~ : A-sd)+.v,

[,)iagno-~l ic /hc+racrntesi,<; x-ray.~: o x y g e n ad- m m ist t,al ion

Ca refut e x a m i n a t ion I al'~4lo,"llen, flvac!tlr~} ; t}mra<'entesi~,: h igh in+ dex of sttspicion: aO I'I,0~ l"t~, Dby

T a r n po ha.de ( . ,ontusu n: h,~c'era!iorls;

a r r h y t h m m s

I ) i s t end~t neck v+.-in~: e!eval+,x| C V P ; low outpu~ syndrome: di- a~no;¢fie ~×~ric~n:tio.

t~.~siMent b l ~ l i m l au~euRa~ion: 1"; CG,

2t

uni formly disastrous. Diaphragnu.itic rut)tures arid traeheobronchial tears are frequ(,ntly missed, but not so l ikely to be fatal. In our exper i ence flail ches t was missed in the ea r ly I)('riod (3-6 hou r s ) , and was det(:,eted on the next morn ing ' s rounds. Th , , t ime of de l ay in D O M D is of i n t e re s t and emphas izes that iri the vast major i ty of eases there was adequate t ime afforded to haw: made the neces sa ry detect ion: t ens ion p n e u m o t h o r a x ~ 1 0 hours to 2 days; aortic rupture . 4 hours to 16 days; myocardia l contus ion 6 hours to 10 days. D O M D is due to failure to ( ,xercise clinical a c u m e n and to ad- here to an establ i shed and proved protocol.

MANAGEMENT

PRINClPLEs.--Thoracic,--The fundamenta l principle in therapy of chest t rauma is the reversal of the pathol)hysioh.)gie vector by correct ion of (1) a n a t o m i c defects (flail, p n e u m o h e m o t h o r a x , ate lectas is ) and (2) w m t i l a t o r y defici ts (flail, con tus ion ) . T h e rationale, for the a n a t o m i c cor rec t ion is based on the physiologic changes . Both p r o b l e m s art,, treated at the s a m e tim(., and the most ideal and practical so lut ion is use of I P P V (5, 11, 26). Sta-

T A B L E 9.--EMERGENCY h.'IANA(;EMENT

[)LACE PROB l.g.'~l

A. On-site (Tru.~he(t ches't

13. I n - t r a n s i t

1 ~ I eo:l i ng

Fraetur(~ C a r d iae arrest H e a d in jury (Tnished chest | ~, h.~'* I i ng Fracturc.,s Cardiac a r r ~ t Crusht~l chc%t

t~le~Ming

~2 r~t c ~. tl r ~

Head in jury :~b(lonien

R e n a l

C. Emergency room

I)ROCEDURE " ~ | . ]:,xtern~ I splinl /s trap-lvpe)

Oropharyngea l tube O r o - / n a . s o p h a ryngeal stic( ion Oxygen by mask I P P V by hand-bag (7ompresses (no tourniqueLs!) I.V. with Ringer ' s Spl int (cushion tyl)e) Externa l massage [)rf..,s.s (q'~:~n woun(l (~ontint ¢~ A,

Nasot raeheal inlubation I Pl)V (r(eq:)irator or hand-I)ag) ln~ratracheal suction Oxygen ;it 1()()% I{emove external st)lints, ch)thes Chest (ube (.:htst x-ray I'.;CG Con l inue Ringer ' s ; blood, if indicate*] Insert C'VP catheter H e l n a t o c r i t ~ a r c h for site In spl int . "I'hese can wait

(except for vasc.t~tar involvement) Slabil ize car(liol)uhnorlary, then a t t end Careful ~ln(] repeai exam Cathe te r lavage X- ray Careful and repeat exam Urina lysis IVP

- - , . , - ' : : . . . . .

22

T A B L E 10.~RATIONALE OF I P P V TttERAPY

A N :VFO M 1 (7:

I 'HYSIOIX)GIC:

CI . INICAI . :

l /es tore lhoracic cage s tab i l i ty l l e s lo re inlralhoracie vo lume lmDrove a lveolar venti lat ion Decrease work of breathing Res tore Pao2 l~.elieve anxie ty Rel ieve pain

hilization of t h e thorax and restoration of thoracic volume and ventilable lung v ( ) I u n l t ' are the ) "' anat(mlc goals. Continued clearance of airway ob- structions and assurance of restoration of lung v()lume by rapid removal of intrapl(:,ural air or fluid or both by intrathoracic catheter a le similarly important (Tables 9 and 10).

A patient should not be permitted to work excessively for air since h(, is already hypoxic and lhe effort increases his oxygel~ r(;quirement. The initial and vital factor with r(,spect to use of I P P V is the elimtna.tion of the pressure differential l)h('nom(:'na resl)onsible for flail and their replace- m(,nt by controlled I)ositiw,-zero l)ressure system. With I P P V the l)ressure d i f f e r e n t i a l is al)olished. The loose, bot)bing segment is pushed and kept out,ward by the lungs which s(,rv(, as internal splinls. The fragments are rt,duced by the constant and steady I)ush of the lungs against them. The free, displace(t and rotated segment falls back into what is usually satisfactory realignment. Stability is (hen maintained by the lungs under l)osi- tive-zer() pressures fc~r tlmt t)ericd of time required for adequate healing, as in any fracture.

Physiologically, I P P V ventilation s~,rves as tim only consistently effective m e a n s ()f overcoming the insidious effects on ventilation that result from (1) diministmd chest exlmnsion due to initial muscular spasm, (2) the flail, and (:3) the X//Q disturbance secondary to ateleetasis, l)ulmonary contusion~ asl)iration l)neum(:mitis. The impact of tim dysfunction causing hyi)oxia can be assessed early and accurately only by arterial gas tension analysis. The increased dead space ventilation may be reduced by traehe- osfomy, but initially nasotrachea] intubation is most satisfactory- or, in the unconscious 1)a{i en t, orat racheal i n tubati()n.

C a r d i o u a s c u l a r . .... Assessment of myocardial states is critical especially if general anesthesia and surgery are contemplated (Fig. 6), ~Severe contusions likely are the cause of acute failure or of cardiac arrest. Hypo- volemia requires whole blood transfusion. Basing estimates on hemotoeritas in these circumstances with dilutional modifications resulting from rapid fluid admin i s t ra t ion m a y lead to ser ious errors. Re l iance for r e p l a c e m e n t solely on aqueous solutions is as unwise as overtransfusion with blood. The best indices are (1) overt loss from h e m o t h o r a x or other obvious active major bleeding, mult iple lower extremity injury with or without pelvic fractures which may signifv huge loss of blood and l)lasma into the soft tissue; (2) ur inary output: (3) CVP change vAth test loads; and (4) clinical evaluation.

Clinical S t a t e . - - A third and important factor in the cl inical s tate of the

23

&

, . . ° . • ,

LOW BLOOD

FLOW

r (3 ~ ~ 0

O

T./?.A UM.4 ,~

• • HYPO" -

/ i \ %,_ j¢" }.

..A

f"t~;, f ; . ~ T h e domh~.ant ins~igatin~ fa t (or in chc..-st t rauma pa(hophys;iology is hypoxia, a l though si~nxfieant , : .~mtributors~c:lude hypo-.'oh.,n~ia a n d / o r heart contuMon. Any ~r ~! }e~v:t to tow ttow, l)revention (~f which is ~chiev(~'.t by corre~.:tion of the deiicit.s

patient . Dyspnea , anxie ty , restlessness and pain are common features of the cri t ically crushed chest victim. T h e proper use of I P P V el iminates th(~ first three symptoms and. by producing dis t ract ion of the rib fragments. relieves pain. P r u d e n t use of narcotics and of sedatives may be required. Oceasiona!ly au tomat ic control vent i la t ion seems indicated and necessi tates heavier sedat ion and cu rare-}i ke d rugs.

C H F.~'r WALL

T h e most s t r ik ing and critical injuD, to the chest wall is a flail due t[o f rac tures of m a n y ribs including double f rac tures of several. In addit ion. there is considerable damage to chest wall muscu la tu re causing reactive spasm. Occasionally there may be a lacera t ion through the chest wall muscu la tu re arid a t )onetrat ing wound.

MINOR TRAUS'IA.~Minor t r a u m a usual ly encompasses one or more rib

24

T A B L E l ] .- ..-MA.YOk' T t t O I : A C l C T R A I ' M A : I N I T I A l , P A T t t O A N A ' r O M Y

] . . )EN( 'PI t ' I I , ,N N,). t 'tiF~ ('t.L.'¢'I l)12.-4'Vdl, 'II,C< .NO l~Ii;t'; (;I;N'T

Non, . 15 21 l.un~z T h o r a x ( . : o n t u : , u . , n 3 8 5 7

S u t , c u h m e ~ m ~ Alelc~:-I a s i ~ 7 l ( ) e m ph?, ' .~pn~a 212 -tG T r a c h e o b r o n c h i a I

F l a i l , m a . l o r 5 2 7 4 T r a c h e a ] l F l a i l . m i n ( ~ r ] b 2 t ; l { r o n c h u , ; '2 3 S t e r n u m 7 1 () I ) iaphra lem ~'i :~ .I

I n ! r a I ~ ] ( ' u r a J ( . ' a r ~ l l i o v : ~ s c u l a r ] ~n(- 'u:l lr~t h o r ; t x 21 :{(1 C o r l / u.~ lo l l l ,. ''~ ] "~" l - { o l l ' l o l h ' , ) r a x I t) 14 A o r t i c r u t ) l u r e ] l l -] ( - InO ! m e u m o t h o r a x U,l : {4 | )U l IIlO~ILI I" 3" i1 ['I ('F.V

('~ t:]l b i n a t }(:)tl :5::) 7! ~ i"tl p [ U r, ~ ] l

' t - ' l a i t Dlu-~ m i r : ~ p l t , u r : d .

f r a c t u r e s wi th (,r without . I m e u m u t h o r a x . T h e r e is no flail and no s i gn i f i c an t l ) a r e n c h y m a l i n j u r y .

iN]A JOt', T R A U M A ( T a b l e 11 l . - - T h e flail ches l ( xms t i t u t e s lh(i n i a j o r t)rob- i(.,m. In (~tlr s e r i e s of 70 p a t i e n t s , al-)i)rt~ximat(qy one t h i r d did nt:t ddmon- strat( , th i s a b n t ) r m a l i t v in the ~'m('rR('nc," r(~t,)m d u e to the m a r k e d d e g r e e of m u s c u l a r s l )asm. T h i s t)roblu.m has J)t~t,n obse rved b~' o the r s (7, 20). T h e timutabt(-, (,f a i ) p e a r a n c e oi flail is se(m in TM)le 12. F l a i l is a l ) p a r e n t in rooM. (~f lh(- I)aii,,mt~ w i t h i n 3 h~.~urs a n d in all w i t h i n 1.2 h o u r s a f t e r t hVa t ' c i den t . Mark , ,d inM.abi l i iv ix a ,~(,ri()us c()nsequenc(:, t)f D O M D , m o s i p r o m i n e n t w i t h i n 1-6 h (mrs aft~,r the:, accider~t. B i l a t e r a l ches t i n j u r y was p r e s e n t in _a;.,, of the. ,T)at ients-Ph( ~ flail was (m the r igh t in 4 5 % a n d ~n ,~,,5'~;'-o on th(, 1(41. In mos t i n s t a n c e s , (; r ibs (,r less wer(~ invo lved in t he flail segm(mt , T h i s includ( ,s ~ a t i e n t s with b i la t ( , ra l th()racic cage r ib f r a c t u r e s . P a t i e n t s witt l b i l a t e r a l i n j u r i e s Icnd.,,d to tmv~, .f(.w{,r f r a c t u r e s (.m e i t h e r s ide w h e r e a s in. tho~,( * wi th flail ches t s inv (dv ing on ly a h e m i t h o r a x u s u a l l y 7-9 r ibs we re involv~,d. Basst , t t hi) ted s i m i l a r (~xi,~&d. of i n v o l v e m e n t (7), T h e n u m b e r of f rac tur( .d r ibs was hi~:h,,,r in i m m ( , d i a t e fa ta l i t i e s . I- ' igures o f t en do no t att.,,,st to th(:, n u m b e r of t m t i c n t s who h a d c~)stal a r i d / o r str, rnat d a m a g e s ince thes(, w e r e noi d i s c e r n i b l e by x-ray . F a i l u r e of c l in i ca l d e t e c t i o n is d u e to i n a d e q u a t ~ p h y s i c a l e x a m i n a t i o n .

T i i e /tail s e g m e n t s we re m o s t l y l a t e r a l or p o s t e r o l a t e r a l w i t h a n t e r i o r or a n t e r o t a t e r a l loca t ions nex t in f r e q u e n c y , L a t e r a l p r e d o m i n a n c e hats been r e p o r t e d (7). D e g r e e ()f d i s l ; l a c e m e n t of i h e rib f r a c t u r e s w a s ' m i n i m a l in 21.%, m o d e r a l ( , in 68% and m a r k e d in 11%. T h e s t e r n u m was invo lved in

_ . ~ : ~ . . . . V " . . . . . T A B L E ] o ~ 3 I~ ~E ]NTER A~, IN (~.LIN1CAI. A P i . E A R A N C E OF F L A I L

I-T oLms P T A I ~'~ 2, 4 G 12 "4.~ 48 N o . r,-,,

SI)Jint 1 '2 3 5 1 1 . . . . '2'2 ,.3I F l a i l 4 4 :~ | ) 1 1 4 5 ~22 31 N o n e '2 l 1 ] 0 I l .~., 7 t0 N o : - t ~ o r d 1 0 t .~° ~.~ t =9 0 ~ 19 28

" P r i o r to admis .~ ion . J , c c - • _ :

25

T A B E E 13.~DI.:RATION O~" (CONTIN I'OVS } I NTEtlMITTENT P O S I T I V E P I { E S S U R E V E N T I I . : ~ , T I O N { I P P V

l ) . ~ s (I-2 ;~-7 ,q--I2 1 3 - 1 7 1,'4-21 o., ,,r. N o I P P V ~ - - - . d - . )

Numl , * , r () 12 ] d 1;'; . 1 6 d 7 P e r cen t O l ~; '2:~ 11.~ 23 :~ 1 (I

a b o u t 7-15a/, of p a t i e n t s w i th e i t h e r a f r a c t u r e or a d i s loca t ion . T h e s e were a.~<ociated wi th a n t e r i o r rib f r a c l u r e s .

RESP[I{ATOR ~MANAC, l ' : . ' , l gXT.~Naso t rachea l i n l u b a l i o n and I P P V u s i n g 100% O=. s h o u l d be i n s t i t u t e d i m m e d i a l e l y in the em~,rgency r ,mm. T i m du- r a t i on of 1 P P V v a r i e s c , :msiderablv del )m~ding on the p a t i , m t ' s r~,s.1)on,~e a n d d e g r e e of l u n g dy.~funct ion. T in , d e l { , r m i n a t i o n of w h e t h e r I P P V s h o u l d be cont inue~l d e p e n d s e n t i r e l y ~m ar/~,rial blood gas ( t , . , terminal ions . App}ox- i m a t e l y 30% of ou r pat im~ts d id not rece ive l ) ro longed ] P P V th~ ' rapy s inc~

};'t~; 7 , - - P ; h ~ ) d ga.~ a n d p l i d a l a in che.-,l t r a u m a p a i i e n l s . I n a b o u ! o n e thir ,{, i lait ~a,~ no i c l i n i c a l l y ap l ,a ren l , T h e " ' h i d 4 e n h y l ~ x i a " ~va-~ reveale, t by l lu, r~Juce, t l ' a , , , ,'\~ Ih,, l~me of ,,~d,mis~ion r e s p i r a t o r y a lk~do-ds w a s pr~-.~,enl in -*II bu t one , A f l e r i n , lilt .Hion ot I I ' I ' V l d a y ] i , }'a**2 r ~ e , ~ h i h . a l k a ] o , ~ s ~va-'- n l a i n l a i l l e d ,

* - , ..% ' ~ • •

e.: LI e 6 I e Q

IP • Q • | " ,,

O B g ~ ~

D t l l Q

2-~. ~, • ~ k ~ D D O ~

. •

~ O D O

" -

°~,

50

I0

7 -,? t..

750

Pa C mrr,: Hq

III I I

- " -

pH

o~

,Fso , , ~

i - - ~ _ _ ~ _ ~ ~ - - ~ - 7 : _ ~. _ ~ ~ . . . . . . 1

r 2 -~ a 5 6 D~YS

26 0

the flail p roved t(~ be r a t h e r small . T h i s is in agr,.,~,ment wi th (~th~,r r epor t s (14, 2(:,). In m(~st oth~,r individuals . I P P \ " th~'ral)y was ("~mlinu(,d up to 2 w(,eks iTabh , 13). T h e r e ap l )ea red t,~ be n{, r~,Jati,-mshil~ of , .×terna] th,m.~(-ic cage i n j u r y to the (lurati~m (ff the tim,, r,.qt, irvd for I P P V t h e r a p y except in thosv ind iv idua l s wi lh ani~.rior and ant~,r~lateral in ju r ies wb~ gem,ra l ly r( ,quired l r ea lm( .n t for longer l~('ri(,ds of limt,. T h e l.)res~,nc(, of o lhe r com- l)]icati()ns, such a.¢, tung contusi(m, nect,ssital~.d l ) rohmged th(.~al Y. Admin- i s t ra t ion of ] P P V was &line, s* 100% (,ff,,('tiv,, in s tab i l iz ing the t~]~ ra t io tag,, . E a r l y r~,storali(m of /h~)ra('ic v(dum,,* was n(~t as cor~sisl~-.nt (11!. In 28",7,. t:her,, was n o iml)r(w~'ment and in 5°,',, the t.h()ra(:i(" x,olume a( ' tua l ly d~,- creas~,d s (mu,what m~m,. F'lail.a of the la te ra l rib cage were, h,s~ l~r(me to ear ly rt,const:ructi~m.

T h e physi(,lc, gic s ta tus ~f the l~atieni is mon i to red by bl,,od gas,,s ( I:'ig,~. 7 and F,). In pa t i en t s frbe ,ff s igni f icant l:mr~,nchymal dis,~ase, the. P a o t~rior to insl i tut i~m (,f ih,."ralLv was unif~wmlv ~ow. va ry i ng f rom 25-65 ram. t /g , wi th rn(~st pa t i en t s at 50 rnm. Hg. In only about one th i rd of the pati,.,nts in

f-'m ~ - - l ~ ' I a i l c h e s l W i t h i n i t i a l I r e a l m , , n t ,~{ l rach~'oslov~,y ;-lla(] h u m i d i t i e d t~xy~;en. I b m , con-

-tth ,,t~,, v

pH D 'o CO~

I['|>V mstiltded s~tlb h~q~rovenu-nt in lun~ f u n c t i o n t m

mrnN0

NAS&L 0 2 ~PPB

1 1

C~ ~ 2'9~'~ F L A ~ CNES~

7 70-T- 50

760 -~-- 40

~so4-3o

740 - 2 0

P

f

pH

P C 0,.

300

200 ~

I00~ l I

%

0 ~ * - - ~ _ _ L . . . . . . . . . . . . . . _ . . L . . . . . . . . . . . . _ . L . . . . . . . . . JL . . . . . . . . . . . . . ~ , ~ . . . . .

0 ; 2 3 ~ O A Y S

6 ?

27

A-oDO 2

mmHg

600

500

4 0 0

300

200

100

0

@

@

@

• @

, %.

' v O •

O

@

O •

• O •

Ii - ." tt I °

I 2 3 4 5 6

D~YS

FIa. ,9 .~A-aI)o2 in ch(~t t rauma. Values of 3(~1 ram. H¢ and above indicate si~;nificant lung contusions complicat ing flail chr..,sts. Resolut ion btgin_,~ about the 4th or 5th day in the major i ty .

whom init ial blood gases were ob ta ined was the flail obvious. F()llowing the in s t i t u t ion of I P P V , a r t e r i a l blood gases improved p rog re s s ive ly so tha t it was soon possible to reduce the oxygen inpu t into the respi ra tor .

D e l a y of t h e r a p y usua l ly was because the flail was not cl inical ly evident . In s i t ua t ions such as this. the pa t i en t s a p p e a r to) do fa i r ly well as deter- m i n e d by clinical signs, bu t even tua l ly a severe degree of h y p e r c a r b i a develops. One such ins t ance is descr ibed in F igure 9. Desp i t e t r e a t m e n t with 100% nasal O~,, the P a o , r e m a i n e d low. On the fifth day , h y p e r c a r b i a developed. T h e n I P P V was i n s t i t u t ed with e l imina t ion of the high Paco._, and a rise in Pao..,.

In the l i t e r a t u r e i t is c o m m o n l y s t a ted t ha t pos te r io r flails genera l ly a re no t ve ry ser ious (36, 66). T h i s is gene ra l l y t rue. bu t in our s t u d y some of these pa t i en t s showed reduc t ion in Pao... and the re fo re were m a n a g e d with I P P V t h e r a p y .

PLEURAL CAVITY

T h e d e v e l o p m e n t of p n e u m o t h o r a x usua l ly is due to p u l m o n a r y tear . as a ru le re la t ive ly smalI. T h i s occur red in 30% of our pat ient% Other s have r epo r t ed inc idences from 12% to 33% and, bilaterallv,~ in 6-1,)/o" c ~ of pa t i en t s (7, 26, 30, 35). T h e mos t ser ious consequence is t ens ion pneumothorax , w h i c h m a y occur because of a t r e m e n d o u s loss of a i r t h r o u g h a

28

l ace ra t ion communica t ing with a re la t ive ly large bronchia l division. FI(,m(~- thoraces due to lung tears or sevt,r~,d int(,rc'ostal v(:,ssols occurred in 21 °- O

of pa t i en t s in our series. T h e inc idence may be as high as 36ffo (26), In both s i tua t ions , it is u rgen t to e l imina te lh~, ~,xistin~- dead space and th,, r e s t r i c t ion of venti labl( , lung by p r o m p t evacua t ion of all a i r or bl,,,od, Mul- t ip le and de layed a sp i r a t i ons of blood a re Imor and improp( , r subs t i tu tes (26). A large ('he~t- tub(, should b(,, placed in the thorax by_ the qla:np t,~ch~.ic T r o c a r s l imit ( ' a the te r size and a re hazardous . T h e anc ien t ~i(t .a of bh,od in the in t ra l ) leura l space ser~'ing as a t aml )onade to a bh 'ed iag x'(,s~(,l i~ un founded , Full inf la t ion of the lung is the first r~,quirement, "Phi, ch(,st tube cons t i tu tes an i m p o r t a n t m e c h a n i s m for m a n a g P m r n t of the, 1)ati~.n(, n(.,t only in ( ,vacuation of a i r and of blood but also in the det(:,ction of continu~,d bl(,eding from a m a j o r source. If con t inuod blood loss is nm,~siv,~"or "ii" r(.- 't,l, .eding occurs, opera t i (m is indicah,d. A n y l)robabh ~ in ju ry to a maj(:,r ,~, ~.'m(mary or systemic" vessel should qui(,klv b(.'('ome ch,ar.

LUN(,.

D a m a g e to tile lungs consists of t:mlmonar3." contus ion, I)aren(.t~ymal t(,ars. i n t r a l m l m o n a r y h e m a t o m a s , a sp i r a t i on p n e u m o n i t i s . a n d atelectasis . In the late stag(,, the d e v e l o p m e n t of pneumon ia s , p a r t i c u l a r l y as a sequel lo con. tus ion is a ser ious ma t t e r .

CONTUSIONS.~Pulmonary contusi(m cons t i tu tes one of the most ser ious compl ica t ions in chest t r auma , Pa thogenes i s is poor ly unders tood . I t is the mos t fr(,qu(,nt p u l m o n a r y ( 'ompl icat ion in t r a u m a with an over .al l incident:(-, as ~, ia .,-, 70-75% (74), Fla i ls a re compl ica ted by con tus ion a t the ra te of 57 Cr* , ' . ~ ,. ,.o (~ , , Fig. 9') C(mtuslon~ occur wh(,n the re a re no rib f rac tures , par - tic~ularly in the y o u n g e r individual . Clinical ly, the. p a t i e n t m a y not app~-,ar a t all incapacitat(. .d soon a f t e r the accid(mt. F u r t h e r decept i (m due to in- decisive x- rays de lays p r o p e r t reatment . T h e Pao~ and, especial ly , the A - a D o : cor rec t ly iden t i fy the ser ious degree of involvement . Oxygen gradients m a y be incrt.asecl enormous ly . \Ve have found the A-aDo~ to be the most reliat)le m~oans of assess ing pa t i en t s ta tus , p rogress and prognosis, A-aDo~ changes of ten precede x - ray evidence of p rogress ion and of resolution.

T h e ess(:,ntials of t h e r a p y include a p a t e n t a i rway , con t inuous I P P V , 10()'~5 h u m i d i t y and sc rupu lous antibacterial measures . T h e cgn tused lung m a y p recede the mos t ser ious compl ica t ions in b lun t ches t t r a u m a : Imeu- monia , and blow-outs wi th tens ion p n e u m o t h o r a x . I t is abso lu te ly vital t h a t a decompres s ing t h o r a c o t o m y tube be inser ted and re ta ined , w h e t h e r or not a p n e u m o t h o r a x is present . T r a c h e a l suc t ion ing mus t be per forn ied only u n d e r asep t ic condi t ions, u t i l iz ing a steri le , d isposable c a t h e t e r each t ime, L u k e n ' s tube a sp i r a t e s a re cu l tu red a t least eyeD, 4.8 hours with an t ib io t ic m a n i p u l a t i o n s as indicated. T h e cr i t ical per iod is 5 -7 days , D e c r e a s i n g Pao~ and widen ing A-aDoa .herald s p r e a d i n g i n f i r m i t y and pneumonia , C o n s t a n t nu r s ing a t t e n t i o n and f r e q u e n t s t a tu s review a re _.ss(.ntlal. 1-1espi- r a to r a d j u s t m e n t s a re crucial in o rde r to m a i n t a i n an a d e q u a t e P a o : a t the m i n i m a l oxygen i n p u t (Fig. 10).

HEI~'.~.TOI~AS.-.~These resu l t from severe localized t r a u m a to the lung

29

A-aDO 2

mm Hg

PO CO 2

mmHg

pH

800

6 0 0

4 0 0

200

0

50

50

I0

770

7 50

C M, 29d" FLAIL, LUNG CONTUSION

..J I I * | I I [ I I I ml _ l i I I I . I I L I

I I I1 I I I II I I _ _ . ' _ ' 7 ; - ' - J

7 3 0 - - , ~ , , , ,, - - , - , ,,,,~, ,

D A Y I 2 :5 ¢ S

f"3(; I { ) ~ : \ - a l ) o , , in flail ch(~t w i th lu, ng c o n t u s i o n p m g r e s s i v e ! y d a y ° d e c l i n i n g t h e r e a f t e r a.~ the ~'oll{usioll cleart~l.

6 g

ro~e with a peak at t he 4{h

ti&sue in the rogion of the actual injury (40, 59, 73). They are associated w i t h s ignif icant destruction of lung par(mchyma and hemorrhage. Sh(mring and crushing r)f lung parenchyma against ('h(,st wall or laceration of the hmg by a rib fragm~ent are the probable reasons for the dev(.]opmont r,f pulmonary hematoma. Hematomas may be central or t)erit)h('ral, Cc.ntra] hematomas, appearing in the central portions of the lung shortly af ter the injury or several days later, are poorly defined densities and beer, m e more circumscribed a pp rox ima tdy 3 clays io 2 weeks af ter injury. Several months may be required for tot.a] resolution. Air-containing cystic cavities may develop when the damage has been extensive. Slowly resolving hematomas tend to develop characteristics suggestive of a solitary coin lesion and at times patients have been explored .... with findings of a cystic cavity containing blo(xt., surrounded by an area of dense injured lung tissue.

Per ipheral hematomas consist of subphmral accumulations and are probably more common., Radiologically they al)pear as ex!ensive lateral densi- ti(~ and arc:, difficult to distinguish fronl organized hemothora× in the pleural space, The t rea tment of pu lmonaw hematomas is expectant, with m[x-~t tending to clear eomp-tetely, A small number resolve as cysts and a few heat by ~-arring.

30

LACERATION.. .... Lllng tears are due to direct in jury from a f rac lured rib. * ( • Occasionally a shear ing effect may cause a lear {3,}, 70) 'I?he sev~,rity of

the ]ac,,raticm is variabl,:, but it usual ly is superfi, ' ial and l)rocduc~,s relatively lilth, bh,c, ding ~r air leak. ()n thv otht,r hand, th,, lacerat iml may involve pu lmonary vesst,ls and scgm,mtal brmlchi, l,,ading to ma jo r }n:,lno- thorax and lmt,umothorax. In the absence ~ff siianificant berne- -~r l)m,um,>. thorax, the diagnosis of the lung tear m a y be difficult until !h, ' re is sore** clearance of infi l t rates in the lacorat~,d area. The major i ty 6f lacerat ions may be treated ctmservativ,,lv with tube th~m~cotom\" in the l~resmw~ , of t)neumoth()rax and }lomotll(~rax.

\VET !A'NG SYNDR(.-)ME.~Tho we| ]tltqg s'cn(]r()lll~', was described as an on/it:y, a.s a r(,sull of oxperien('e with \Vorld \Var 1I casualti~s, ~l(~st of thesc, individuals suffer, 'd blast injuries, not sp,,cifically thorax'i,-. 'I'h,, syndrome was ,"harac'teri.:ed by. largo am(rants ,,f fluid a..,.umulat,,d" c. in tin-, tracheobronc'hial tr~,:t ,, considc, rabh, reslf i ratory difficulty and hypoxia. I t was believed that the n~echanisms were p u l m o n a r y t rauma, increas~,,d rvspi r- a torv effort, trach,,a] obstruction and anoxia. The wet lung syndrome is most lik~,ly a s i iuat i ,m quiW diff~,r~,nt from that of t rue pu lmona ry contusion. Exp0ri,,nct,s in t{~:,r(,a and mor~, r(,cr.ntly in Vi~,t Narn suggest anoth(.r "'wet lung" syndrome, lmdmblv du~, to ovt:,r.enthusiastic fluid r(-,pla(-,:mont with r(:,~ultant ('Ollgostioll and (-,dl,r/la, rI'~h(~ t r( 'at lTl(,Ylt°of IV(?I lung syndrome is <,ssentiallv that of tmlmonary contusion. If it in sex'~,r,.,, nasotracheal in- tubat ion and 1PPV are necessary. Gri~at care must b~ excised in adminis- t rat ion of fluids. In some instances, it m a y bc nt,t',,ssarv to use diuretics, such as e lhacryn ic acid and Mercuhydr in , to assure removal of fluid.

IA:N(, IIEt{NIATION.~OccasionalIv a comt)]icatiot~ of thora¢ o lom. , tmrnia- lion is r awly observed a f te r blunt chest i n ju ry (10). Repa i r in not required since the:, hernia is qui te small, as a rub-,.

I ORslON.~T~~rsicm of a 1ot~o is a rare and t~izarre occurrence, developing in childr,m (64). I~olmrts have includ~,d middlt~ lobe, clockwi.~e and left lung c~mnterch~('kwise torsion. The involved structure, is infarc ted and req u ires rein 0val.

HI~A aT

t-Iemot.~ericardium is diflhmlt to diagnc, se unless l:here is a massive effu ~on. Admission x-rays often are ,.~quivocal. Por tab le films are d~.,ceptive due t o a lend,racy toward ~..xagg~,ration of lhe medias t ina l shadows. Should any suspicion exist (and it of!tern should) , pericardi~cenl~,sis is requir~,d. T h e incidence is h igher than is .u(-,nerally suspected (~q, 56). Large amoun t s of in t rapor icardia] blood usual ly signal ca tas t rophic in jury , such as aort ic rut)ture. On the o the r hand, there have been a number of instanc(.,s" of hemoper ica rd ium wi thout rup tu re of the large v(:,ssels, probably due to rup tu re of per icardia l w~ssels (59). The diagnosis too of Wn is established a t th ~ mom ent of ci rcu I at ory eel lapse.

T h e c i rcumstances of mwidents con~ider~,d toge ther with the dynamics of impact and the subsequent force.¢ which are d(welop~,d su,~g(,st that injur ies 1o th,.o }wart wc, uM N:, common as.. indeed, ihey are, but not, utffort.u- nately , as a clinical problem t I8, 35.36"). Pa t i en t s who die imm<~l.iately or

31

shor t ly a f te r autcmmbile accidents actlially, do demons t r a t e a high inci- dc.m,o (~f hoar! in ju ry at autol)sy (56). On the other hand. in pa t ients who survive or who die some days or wet,ks aftc,r t he in jury, the incidenct, seems to be unusual ly small, S tudies of immedia te fatali t ies have demons t ra ted there is a 6 5 % incidence of rul)turo of one or more chambers of the heart , a 12% rate of contusion, and a -16% rate of pericardial lacerations. In prac- tically all, hemol:~ericardium was present . Repor t s from immediat t , survivals have indicated tha t myocardia l contusions occur at the rat(, of ap- proximate ly 7--8%. On the basis of e lec t rocard iographic changes, the incidence might have been construed, a t anywhere, between 17 and 40,,o c~- (2,1). T h e actual incidence in survivals is not ye t established. The problem is nlucla mort" than an academic one. Myocard ia l contusion, on whicll may be super imposed hypoxia from the chest in ju ry a n d / o r secondary perfusion deficits from hylmvolemia, readi ly leads to cerebral anoxia and to cardiac arrest:. It has been suspected by a number of invest igators tha t the occurrence i'~ much more common than repor ted or suspected.

Contusions occur more f requent ly in the r ight (38%) than in the left (18/o) ventricle, and have been noted to be bilateral in ,)qcz,_,_,,,o of pat ients (56). 'Phe, contusions have been described as being anywhere from a few mil l imeters to more than 3 cm. in d iameter . The appea rance is that: of an ear ly infarct with inters t i t ia l hemor rhage and subendocardial or epicardia] hematoma. Progressive changes have demons t ra ted behavior v e r y much like tha t of an infarc t dur ing the heal ing process (23). Occasionally the sep tum may also show hemorrhagic and necrotic changes. R u p t u r e s are obsen, ed only in f requent ly in the emergency room because few pat ients survive the accident. T h e few who do reach a hospital are D O ~ I D , and the reports are based on autopsies with an occasional one from operat ion. Eight per cent of pa t ien ts with these critical cardiac injuries do reach a hospital and could be saved. In au topsy studies, the rup tures noted were as follows:

lv~:', r ight a t r ium, 12'7o" left a t r ium, 7c.r~;" r ight ventrle, ,.19 r~-''.,,o, left ventricle, ~, ~.o, and nmlt ip le chambers in 30%. The in te rven t r i cu la r septum was rup tu red in (c~" ,),~,o~ i ," e - , • .),o and the in tera t r ia l sel)tUm in 7% of cases. The re is a _..,,.o ncld_.n(.t of rup tu re of the aor ta in these fatal injuri(,s. The coronary vessel was lacerated in approximately. ~3°'/o. with a tear of a papi l la ry muscle in 7°o. T h e few successfully t rea ted pat ients were able to survive the initial acute epis(×hi~, Most of these were leaflet ruptures , detected subsequent ly by signs of aort ic or: t r icuspid insufficiency. An occasional right atr ial or vena cava tear has been opera ted on because of cont inued bleeding thz'ough the chest tube, with diagnosis establ ished at thoracotomy.

Definit ive signs and symptoms often are masked by vir tue of the na tu re of extensive t rauma. In the ear ly s tages , friction rubs. chest pain, tachy- cardia or a m u r m u r often are a t t r ibu ted to problems other t han cardiac. W h e n the init ial crisis ~has become stabilized, the persistence of precordial pain or tnchycardia , or the presence of a systolic m u r m u r or a fr ict ion rub should signal the possibili ty of myocard ia l in jury . T h e E C G const i tu tes the single most useful aid, However, the very signs which would indicate myocardial damage un fo r tuna t e ly are nonspecific ischemic R S - T and T-wave changes, tn hypoxic patienk~; these abnormal i t i es may be presen t in the al-rsencx~ of myocard ia l damage, Never theless , the E C G remains valuable

3 2

and should be t aken among the first p rocedures in the e m e r g e n c y room evaluat ion . Th i s is often done. T h e "'~,rr{~r" ii,,s in the fa i lure of repe t i t ion , since the ini t ial h]C(; m a y a p p e a r normal . T h e ECG has been noted to be abno rma l i n 37 ,-d 9S ins tances (24). l n 18 of the a7. howew,r, previous record searches ind ica ted pre -ex is i ing EC'G a l te ra t ion . In the oth(,r 19, posit ive changes were m a n i f e s t e d by S T depress i (m with T-wave inversion. Also, 1,I of the 19 s u b s e q u e n t l y d e m o n s t r a t e d f la t tened inversion of lh " T - w a v e in 4 V F and in V~ leads. ECG changes m a y pers is t a n y w h e r e l rein 5-20 days and most often a re picked up several days a f te r the i n ju ry , emphas i z ing the need for pursu i t . In a small n u m b e r of pa t ien ts , the i n j u r y is made obvious by at rim f ibr i l la t ion or f lu t ter a n d / o r pulsus pa radoxus .

Con t inued brisk b leeding from a t h o r a c o t o m y tube in the r ight beret- thorax mus t lead to suspicion of a m a j o r vascu la r source. T h e probabi l i t ies are an in te rcos ta l or in te rna l thorac ic a r t e ry , but m a y be the r ight a t r i u m , SUl)erior vena t a r a , or a l m l m o n a r y vessel. T h e ra te of bh,eding is an im- 1)errant index and should be recorded. T h e l)recise d iagnosis is es tab l i shed at t ho raco tomy .

T h e m a n a g e m e n t of myoca rd i a l con tus ion is precise ly tht; s ame as that of a( 'ute m y o c a r d i a l infarc t ion (23). I t is obvious tha t a diagnosis or a s t rong suspicion of a la(:'(,ratic, n of a c h a m b e r requi res i m m e d i a t e el)oration, H e m o l ) e r i c a r d i u m ord ina r i ly is a d e q u a t e l y t r ea t ed by l)ericardiocenl(~sis, at least in t)en(~trating injuries . On the o the r hand, in b lunt in jur ies although an ini t ia l per i ( 'ardioc(mtesis perhal.~s folh)wed by a second one m a y be successful , the persist~mc'e ()f a s ignif icant a m o u n t of blood in the l,~(:,ricardiat sac n(,~cessitates opera t ive i n tervent i (m. T h i s is p a r t i c u l a r l y t rue becaus(, most often the h( .mol)er icar( t ium in b lunt t r a u m a is due to more ser ious large vessel or card iac in ju ry , tReli(,f of tamponad(-, is essent ia l wha t eve r the et iology.

Long- t e rm follow-ul) in 1)atients has led to the d iscovery of occasional left ven t r i cu l a r aneur.vsms. T r i c u s p i d insuft iciency has been observed anywhere from :3 m o n t h s to 24 .x.'ears (4 t ) . Aor t ic im 'on lpe tenee is usua l ly detected mu(:h ear l ie r , wi th in 2 m o n t h s or so. If the I)roblem is no t al)preci- a ted i m m e d i a t e l y , the course m a y be as follows: tim p a t i e n t seems to be progress ing well, when s u d d e n l y h(, develops ven t r i cu l a r f ibr i l la t ion, acu te myoca rd i a l fa i lure or acut(~ col lapse due to rup tu re , u sua l ly a left yen. t r i cu la r a n e u r y s m in the contused area. In 5 of 7 pa t i en t s wi th left yen-. t r i cu la r a n e u r y s m s , ru t ) tu re occur red from 2-90 days a f t e r t r a u m a (32). P a t i e n t s with m y o c a r d i a l con tus ion usua l ly show an unevevitful recovery wi th fol low-up to 16 y e a r s (45).

MAJOR V ESS'EA ~̂

T h e diagnosis of i n j u r y to ma~or v ~ s e l s p a r t i c u l a r l y the aor{a, con t inues to be elusive desp i t e inc reas ing emph&sis. "I h~ i.s due to the fact t h a t t he m e c h a n i s m s poss ib ly leading to i n j u r y a re not full,,, a p p r e c i a t e d . Particular:,," in youn~ people, l h e r e of/on d o e s not a p p e a r to be a n y obvious thorac ic or superf ic ia l ex t e rna l ( , . , d (nce of ser ious t r auma . It has bc..t.n e s t ima t e d thai: in 3t,,,,a of ao r t i c rup tu re s , t he re is m in ima l ex te rna l ev idence of !boracic i n j u r y (56, 6 7 ) . In former, yea r s , fails usua l ly were the m e c h a n i s m

33

FtG. 1 1 . ~ T r a r t s e c t i o n of the aorta . A, admission ehe.st tAP) x-ray shows a widening of the mediastinun~ with a " ' shadow" pro- ceeding toward the apex. B. ao r togram demorts t ra tes the total transection.

leading to rupture. At the present time, 67% are due to automobile accidents. I~ul)ture of the aorta is a catastrophic event with al)proximately 20°-/o surviving the initial injury, but with only 10-15~ surviving long enough to reach the hospital (57, 67). This means that of I00 individuals with a ruptured aorta, at least 20 survive and are available for cure. Fiw~ to 10 are lost en route to a hospital. A1)l)roximately 10-15 then arrive at a major hospital, but because of delays in diagnosis, most of these individuals also succumb.

Complete transections are far more common than tears (38, 57, 67). About 56% are at the l igamentum arteriosum, 16% are in the descending thoracic aorta and 1.0g~ in the ascending thoracic aorta. Occasionally other major vessels may be involved, such as the subclavian or the innominate ar tery (46).

It is distressing in view of the ul t imate low salvage, thai: patients who survive long enough to get to a major hospital do permit time for diagnosis. It has been estimated that the patients who do arrive at an emergency room of a large hospital have a 50:50 chance to survive for at least 48 hours. Some have survived as long as 21 days before catastrophe intervenes (38). Survival is due to the fact that the transection hegins in the tissue of least resistance to impact and decelerative forces, the endothel ium and intima. The advential tissue is extremely strong and will hold for a while. There have been ,reports of survivals anywhere from 4 months to 37 years with diagnoses established as post traumatic aneurysms (36, 67). The survivals for this period of time have been limited entirely to injuries at the liga- men tum arteriosum. In diagnosis, the problem once again is due to the mult iple injuries with the more obvious problems taking I)recedence, to the lack of the classic signs and, most important of all, to the lack of a high index of suspicion on the part of the physician. The expected sign of mas-

34

sire left henmthorax occurs in only about 33% of pat ients (36). A wide nat,- d ias t inum is very frequent , reported in one series to be up to 100% (Fig. 11). But a wide naediastimlm may be difficult to ascertain. Indeed there have been instances of coml)lete t ransect ions in which the medias t inum is not very., grea t ly widened. It is imt)ortant to bear in mind that in only. 1 "a'~ ,.o of pat ients art, there accoml)anying rib fractures. Two w, ry impor tan t signs should aid in sett ing into motion the mach inery :for establishing diagnosis. These are the presence of a systolic m u r m u r and ! yper tens ion in a young individual (36). Both occur in 66% of these c~tse~. On admission this is not detectaMe because these individuals may be bypotensiw~ due to bloc~l loss. However, the next day the blood pressure may rise to above 180-200 ram. Hg (,14). Reduced ar ter ia l pressure in the lower extremit ies relative to tha t in the upl)er is a s ingular ly suspicious sign. Unfor tuna te ly , however, differential pr(,ssures are not often measured. ]2educed or sudd~mly dis. appea r ing femoral pulses are pract ical ly pathognomonic. The diagnosis should be confirmed by aor logral)hy to avoid needless explorat ion, par- t icular ly in pat ients who have other serious injury, such as myocardia l contusion. Facilit ies for performing emergency ao r lography should be available. The risk of the examinat ion is small 'm~d is justifiable in terms of the informat ion sought.

T h e r e have been an encouraging number of successful repairs. In general, it is felt that resection with graft ing of the defect is the best procedure.

M EDIASTINUM

Medias t ina l tmmatomas are a common occurrence (63). T h e y are small, diffuse and insignificant in the vast major i ty of instances. The most dra- marie are those due to aort ic rupture. Other sources for gross henmtomas include rul) ture of small vessels from the aor ta and venous bleeding from fractured thoracic vertebrae. The significance of large hematomas is in the critical differentia] diagnosis of an aortic t ransect ion or rupture .

TI1ACHEOBRONCHIAI.

Tracheobronchia l involvement occurs in 2 - 6 % of blunt chest t r auma (25, 35, 58). The incidence of burst t rachea or bronchus in imnaediale traffic fatali t ies is somewhat higher. In survivor.~ who reach hospitals, the in jur ies fall into two categories. Tile first is ear ly and direct from the t r a u m a episode itself and most often involves a main stem bronchus. "l, tu, second is a relat ively recent complication of I P P V t h e r a p y ~ r u p t u r e of a necrotic area of contused lung or of a residual cyst: Both can lead to potent ia l ly disastrous tension pneumothorax. Otherwise, the two are qui te dissimilar.

Th e presence of severe subcutaneous e m p h y s e m a and pneumomedias t i - n u m with pneumothorax (especially tension) marks the provisional diagnosis of rup tu re of a major-s ized division of the airway. In this in f requent in jury , these signs are not always so obvious. Suspicion usual ly i~ aroused by cont inued massive air leak through a thoracotomy tube, with persis tent

35

pneumomedias t inum and subcutaneous emphysema. Detection is usually after 24--48 hours and sometimes the lesion escapes diagnosis completely. Complete transections produce dramatic discomfort and are easily detected. An occasional transection seals off completely. .Most injuries, however, are only partial. The smaller ones may seal, either to be popped open later by IPPV. or to go on to heal with vaD-ing degrees of stenosis. Lami- nography and bronchoscopy will convert suspicion into documentation. Rarely, bronchography may be required.

The secondary ruptures are most dramatic and constitute the second most common cause of death during therapy (12). The first indication is a com- posite of signs and symptoms of tension pneumothorax, the initial sign being subcutaneous emphysema. ~But tragically these often fail to impn~ss the at tending staff. Crises can be averted by an indwLqling thoracotomy tube in all respirator patients.

Management of transections is operative and as an emergency. These patients are too ill not to be operated. "Conservative" therapy of partial tears has no sound basis. Pr imary repair is uniformly possible and successful. The secondary ruptures are treated as a rule by tube thoracotomy and negative suction with undernvater seal. An occasional case will require operation to close the leak or for resection since the continued I P P V will not permit sealing. Surgical intervention of this nature has much to rec- ommend it and is more desirable than watching a hapless patient chained to a respirator, bubbling large volumes of air ignominiously for days and days.

The true incidence of initial ruptures is not known since most seem to be partial and proceed to heal. Subsequent bronchostenosis is apparent ly unusual, judging from the paucity, of reports.

ESOPHAGUS

Traffic accidents are the least common cause of t rauma to the esophagus ( I7, 36). Even in large series, involvement is rarely mentioned. The damage consists of vertical tears usually at the bend of the tracheal bifurcation, sug- gesting a bursting type of mechanism. A tear in the upper segment is mani- fest¢~ by cerx.'ica] subcutaneous emphysema: lower tears are accompanied by hydrothorax. Explorat ion and primary repair is the t reatment and is urgent, as with any esophageal perforation or tear. Unusual complications such as t raumatic tracheoesophageal fistulas have been reported (523.

DIAPHRAG~f

Injuries to the d iaphragm are not common, about ,~at, j so in survivors and 7% in immediate fatalities (7, 22, 25). Left dome rupture predominates 25:1 (_'27).

Approximately one-half the t raumatic diaphragmatic hernias are due to blunt injury and most of these from automobile accidents. The magnitude of the t rauma apparent ly does not influence the probability of this injury-, since the incident need not be of the massive crushing type. Mult iple

36

rib fractures were present in over 50% ,)f the victims. The p(x,;sibility of ipsilateral ahdominal injury always exists. A posterocentral tear with medial extension is tht, 'most common injury, followed in frequency by avulsion from the anterolateral rib cage. and by rupture of the dome. The tear is usually quite large, permitt ing intrathor}acic displacem,qal of abdominal contents. Diagnosis in the emergency room is dill;cult and almost always missed. Transient paralytic ileus removes the i~q:ortant physical sign of bowel sounds in the chest. At times bowel migrado., occurs later. D~;sl)nea and resth~ssness is att~'ibuted to lhe oft accompanying and more obvious thoracic trauma. The initial x-rays may fail to give a clue (part icularly it the technician neglected to include the diaphragm anti costophr(:qaic sinus). Follow-up films usually are conclusive. Barium swallow is rare'ly indicated, D O M D is usually due to failure to sl?sl)ect possibility of this unusual wen t (1-2% incidence). Except for a rare bowel infarction, no catastrophe de- rives from the rupture. Detection is usually made after 24 hours, some. times m a n y years later. Detection often is incidental at laparotomy for an accompanying intra-abdominal injury.

Operative repair is advised e a r l y . . n o t as an emergency (27), but aftt, r stabilization of the cardiovascular-pulmonary system complex. M(×st inter- ventions are transthoracic, but the transperitoneal route is just as satisfactory. Sirnvle suture closure is all that is.needed in e,arly repairs. The older hernia may require additional material (marlex, fascia lata) to bridge a wide defect. In cases of older injury, a transthoracic al~proach is preferr~~t since these often retain intrapleural adhesions or partial obliteration of the pleural space and decortication m~y be requi red.

COMPLICATIONS AND DEATHS

PULMOXARV.--Complications following initial resuscitation and institution of therapy are usually pulmonary f3, 4, 18. 35): These include pn~,u- monia, empyema, fibrothorax, tension pneunaothorax, atelectasis, aspiration, acute anoxia, respiratory failure and oxygen toxicity (Table 14). Pneumonia frequently becomes superimposed on lung contusions (75). It was the single most common cause of complication (26 of I00 .... 36% witla ,t deaths) in our patients. Cordice and Cabezon reported 7 of 10 patients, with 5 deaths (18). The hemorrhagic necrotic beds are not only vulnerable to infection, but serve as culture media. The earlier dominance of Staph, aureus has given away now to gram.negative microorganisms--E, colt. Pseudomonas aeruginosa and Aerobacter-Klebsiella. Initial "wide spec- t rum" antibiotic coverage suppresses gram-positive organisms preferen- tially. Emerging resistant s t r a in s also are a problem. Contusions which fail to show some indication of resolution within 5-7 days are probably infected Spreading infiltrates (including some to the opposite lung) and temperature elevation mark the subsequent course. Consolidation is unusual and is a late, terminal sign, We have found the estimated A.aDO~ to be of inestimable value in anticipating pneumonia prior to x-r~ay evi- denee. The danger is that pneum~mia will lead to acute respiratory t'ailure in patients who already have respiratory difficulty. In u n co mp l i ca t~ fl,,~:il chest, pneumonia is less f;~'tuent and more prone to ready resolution.

37

- - - . _

TABI_,E I,I.

; \ . - - - ' l ' i + o l I A c i c "l'It,xt: .xIA (',).~I l'l . lt' .Xl'h')XS l 7~.1 [ ) xI'IEN T.'¢, i

( ' o M I'LI+'ATIONS N o PER ('HNI" 1)!I;I~

F ) n e u m o n i t is 25 :t(; 4 l d m l ) y e m a I 1 tt A l e l { ~q a s i .~ :: 3(; 46 () T e n s i o n P N ' I ' ~ 4 (; 1 S u c t i o n h y l . ~ ) x i a : I 1 1 l l e ~ / ) i r a [ o r y f a i l u r e 10 14 ---" S e p t ic t . 'm i a 3 -1 - - 1) i..<~ e m i n a t (.~ [ i n t r a v a s c u l a r

t h m m l . ~ ) s is :t .I - - ":

: M a j o r < s e g m e n t a l o r l o b a l ) . TS( . '< ' onda ry t o " ' t )h : )w-ou! '" + o n r e s p i r a t o r ~ . • ;1 n t r a ! r a c h e a l g, u c | [Oll i llg'. -" l n c h M ( u t o n t ) n e u m o n i t ~ s .

[ ~ , . - - M OI¢T,X I.I.~'Y I-{.A T E

("ATEG,H'IY ~ O PER CH.~'T TOTALS PF:II ( ' E x ' r

T h o r a c i c S 1 t [ m nu~ ~ia t e I I

t ) t t l t l l o n a t r v a r t e r y t e a r I

l - I o s p i { a l i z a t i o n ,r I() P n o t ~ r n o n i t b, .1 T e n s i o n l " N i ' 1 S. u ( : ' / i on h} ~,,~xia I A o r t i c r u p t u r e 1

N o n t h o r a c i c 12 17 : \1 | 20 28

The sequen t , : of events to t e r m i n u s has become classic. T h e Imtient with a nu;derat~, contus ion is in a s tabi l ized, l~resumably t"ot~trolled s ta te on the resp i ra to r , wi th a roduced inpu t of .t0-.507:~ oxygen. Cons t e rna t i on envelol)S the staff', as the infi l t rate, inst+,ad of resolving, b(,ein~,, _ to st)read. T h e t e m p e r a t u r e risps. Tho pa t ien t " d o e s n ' t look as go()d." T h e Pao:. drol)s and the A.aDO~, which had decl ined, rises again (Fig. 12). T h e oxygen input is increasod. Cul tu res , sensitivitic, s a re rechecked and ant ib io t ics arc again m a n i p u l a t e d . T h e inf i l t rate s p r e a d s first t h r o u g h o u t the lobe, then the lung and then sDill.a ov(,r into the c(-mtralaterat lung (v,'hich had been "sup t )o r t ing" the pati~:,nt}. I n t r a t r a c h e a l suct ion yie lds a re scanty . T h e oxygen i np u t is --~r+. . . 100 ~>, the, P a o : drops to 70. 60 50, 40 m m Hg: the

. [ o ' .. A - a I ) o . l e v e l s o u t a t 5 0 0 - 6 0 ( . ) r a m . F ~.. A c u t e r e s p i r a t o . r v f a i l u r e , e x i s t s .

D a y s ,~o b y . O x , , , g ~ , n t o x i c i t y g r a d u a l l y i n c r e a s e s (81) T h e l u n g s a r e c o n s o l i -

d a t e d into a rubbery , still" mass. I:~espiratory, then mixed me tabo l i c acidosis su|:u:,rv~:,nes. T h e h e a r t slows and quits.

Tens ion : l m e u m o t h o r a x o c t ! i t s with a l a r m i n g f r equency in lung contusion pa t ients . ~3,.-'e have seen this p rob lem in 4 pat ients . T w o factors a re significant: p n e u m o n i a and the resl)irat~>r. T h e lung responds to contus ion p n e u m o n i a by d e v e l o p m e n t of weak sImts due to cystic, necro t ic changes. T h e resist ive i n t r a - a tveo la r tens ion is lost. In a lung n o r m a l l y imperv ious to reasonable posi t ive p ressure su rges from the re sp i ra to r , these weak areas rul) ture. A qui+:-scent t h o r a c o t o m y tube sudden ly e r u p t s into frantic' b u b b l i n g . T h i s p a t i e n t is f o r t u n a t e . . I f the tube had been removed, acu te respi rator~¢, and circulatorv,. ¢,o. tla f~s.+:." --e ¢x.cu r . ~ "

3 8

800

6 0 0

A-a DO 2 4 0 0

mm HO

CO 2

mmHg

Pa

pH

200

0

50

30

I0

7 7 0

7'.50

H.B., 37 ?

F L A I L , LUNG CONTUSION

I I I I I I I I I I I I I HI rll I I I

I I I I I [ I l r l l l U I I J I I II I I ~ _ 1 I J I I

7 30 ~ . . . . . . . . . . • _ _ . _ ' ' " III I _ II I i "z I ' • I ' ! v T •

DAY 1 2 3 4 5 6 7 8

F16. 12 .~ [~ l eva t e ( l A-al)o,2 dec l ined in i t i a l ly , but ro.~ a f t e r the 5 th d a y d u e to d e v e l o p m e n l 0 [ [)TlVL! IlloI1 i~l.

Ateloc tas i s is a cons tan t ly r ecu r r ing problem due to inefficient clearance of the a i r w a y and to /;he ~(,ndency of damaged p a r e n e h y m a to collal)se, p robab ly because of loss of su r f ac t an t . P a t c h y a reas of a te lec tas i s a re s t a n d a r d f ea tu res of the d a m a g e d lung. Fa i lu re to p u r s u e vigi lant f requvnt suct ion leads t(-) s egmen ta l and t hen lobar collapse,.

Usua l ly , the pa t i en t is p rogress ing well. I n t r a v e n o u s a l i m e n t a t i o n is dis- con t inued , and oral feedings a re begun. An inf la ted .nasotraciaea] or t rache- os tomy tube cuff is not coml)let~:dy 1)rot~,ctive and, as he eats, occasional a sp i r a t i on may. occur. More common ly , the a sp i r a t e is f rom contcnt~ of a d i la ted , p a r a l y t i c s tomach , the d e v e l o p m e n t of which has escaped notice. In a m a r g i n a l p a t i e n t acute anox ia f rom prolong(:,d sue i ion ing is a cons tan t threa t . T h e nu r se mus t be a d e p t , dec'isive and s t r i c t l y l imed in this procedure. T h e cr i t ical pati~mt can to le ra te sopa ra t i ,m from the " m o t h e r " resl)irat()r for only a brief l)ericd. T h e a sp i r a t i ng c a t h o t e r sucks a i r more easi ly t han secret ions. In a few seconds, the p r eca r ious ly m a i n t a i n e d Pao~ can be p rec ip i tous ly dep le ted . \Ve have thus /()st 1 1)at ient

Acute r e s p i r a t o r y fa i lure is gene ra l ly associa ted wi th advanced e m p h y - sema or the, neona ta l r~,spiratory dis(,as: ~, syndr t )me. Mort, r ecen t ly the problem has been reeognizod as a leading compl ica t ion in o the r criseS such

39

as shock from nrmthorae ic t r a u m a . T h e morphologic mechan i s m has heen descr ibed as a sch.rc~sing alvetditis. Oxygen t~xicitv frnm prnl,.mg~,d admin - i s t ra t ion ~,f high c ,mcen t ra t e s Imve been impl ica ted . Th i s l}roblem has emerged as a re la t ively new syndr~mu* in the y o u n g pa t i en t with chest t r a u m a . T h e i n d i c tmen t s inc lude l )neumoni l i s supurinll)¢~sed on lung contus i tm and lm~longed resp i ra t t , r t h e r a p y with h~gh oxygen inl)ut. T h e in- evi table p a t t e r n emerges when the imtimat canno t t)e t aken off the respirator, much ]t,ss to le ra te a reduced oxygen c~,ncentra t i .n .

3Iana~,mcnt (TaMe 1 5 ) . - - T h e r e is no object ive evidence ft~r or aga ins t "prol~hylactic" ant ib io t ic t h e r a p y in severe blunt ches t t r a u m a . Cmatamina- t ion is a rea l i ty by the t ime the p a t i e n t a r r ives in the hnslfital . ~I'~ be sure, infec t ions per se have not developed, bu t the p recond i t i ons a re ideal. T h e p r inc ip le of a specific, l a b o r a t o r y - d o c u m e n l e d an t ib io t i c for a specific mi- c roo rgan i sm is most p e r t i n e n t in t r a u m a . Meth ic i l l in 12 G m . / d a y (or o the r pen ie i l l i nase - re s i s t an t drug) is advised, unti l cu l t u r e and sensi t iv i t ies are avai lable . In the hus t le nf the ~'rnergency room, s p u t u m cu l tu re is often fl~r- got ten. It is even nlorq i m p o r t a n t to get Luken ' s tube cu l tu res of in t ra- t r achea l secre t ions u n d e r asept ic condi t ions . We rou t ine ly obta in culture.,; eve ry ,IS hours du r ing t la~ acu te per iod and da i ly witJa serim.ls problems. S m e a r s a re of ten helpful , and an t ib io t ics are s t a r t ed accordingly , since cu l tu r e repor t s often requi re 48 hours. S t r i c t asepsis is r igidly enforced for suct ioning. \V h en ev e r l ,ossibh ,, pa r t i a l isolfilion should be imposed to protect the t r a u m a patient f rom those in the in tens ive (-are uni t with clinical infections. Airb~~rne and cross c o n t a m i n a t i o n (l)erstmnt,1 car r ie rs ) and un- s te r i le e q u i p m e n t art, 1)rincilml sources of infect ion. E m e r g e n c e of gram- nega t ive bac ie r i a s eco n d a r y to suppress ion of g ram-pos i t ives is ano the r .

E m p y e m a is r~,lativelv unusua l , occur r ing in about 1% of ma jo r non- p e n e t r a t i n g thorac ic t r auma . T h e s e are se~'ondary to tmounmnia , occur r ing in a sma l l e r g roup due to infec t ion of hemothoraces . T h e r a p y is control of lmeumon i t i s and p r o m p t evacuatim~ of i n t r a p l e u r a l flui~t with ccmaplete re- expans ion of the col lapsed lung. Rep( ,a t t ho racen te s i s invites infect ion. T u b e thorac¢~orny is the only surc., safe and effective methc~d preventativ,: , technic and the best initial t r e a t m e n t for eml~yt'naa (Tab le 15).

F i b r o t h o r a x is re la t ively unusua l , a l t h o u g h an inc idence as high as 12% has been re rmr ted (7. 18). E a r l y decor t i ca t ion is recommended, pre fe r ab ly d u r i n g the s ame hospi ta l s tay . T h e p rocedu re is s impler , less t r a u m a t i c to the lungs and far more effective than a de layed proc~.~cture. Tensicm pneu- m o t h o r a x is best t r ea ted by an t i c ipa t ion , with a decnmpress ion t h o r a c o t o m y tube. In chronic cases with r e p e a t blow-¢mts, more t h a n one tube is requ i red . It. shou ld be borne in mind t h a t a tension pneunao thorax m a y be due to a r e s p i r a t o r blow-ou t of a p rev ious ly sealed t racheobronclaia] laceration. T h e fa i lu re of p r o m p t re-expans i rm and seal sugges ts the need for ope ra t ive in te rven t ion . : e i the r for the p r i m a r y t r a c h e o b r o n c h i a | t ea r or the secondary : blow-out. In e i ther s i tua t ion , a t ight seal is urgent , e i the r by p r i m a r y c losure or lobectomy. S e g m e n t a l resect ion is i l l-advised. S i n c e the p a t i e n t will con t inue to be on the resp i ra to r , a p rofuse a i r leak is l ikely to occur f rom the raw surface.

D e a t h from a s p i r a t i o n can corne as a t ragic etad to an o therwise b r i l l i an t resuscitative effort. Nasogastric decompression and vigilant nursing care

40

c _ - - . . J , _ • . . . . , . _ i

T A B L E 1 5 . - - - U R G E N T PROBI.F.MS Dt..RI,' N'(, ~ I A N / t G E M H N T

A. Thoracic Flai l

Img

S t l | ) e u | il ll(,~tlS

Increased air leak {chc~t tube}

Bleeding (chest tube}

[ )u lmonary t~h'm:t

B. Card iovascu la r Tae!~year~tia

l~radyeardia

Ar , 'hythmias

ttylx~tenskm shock

W I l Y

Segmenl nol sl abi I iz~n I Patient nol in cycl,, Patient is hylx~xic

Atelectasis Pl l eUI l lO i |l(}l 'a N " B l o w - o u l " with ten~ion

l J n t ? t l I t l f ) { } l 0 r t t X

Mis~ed traeheol~ronchial rupture

M isse.~l esoDhageal laeera l ion

Chest tttbe t)o ! I It, m i xup Tension ]~lleurllo{ |lorax M issed I racheoln'onchial

r t l p l u r e

Major vexsel

Acute myoeardi,,tl failure: overhydra / ion

Hypox ia : l.lypovoh.nl ia ~ sep~i:; Apl)rchension lsehemia; hunI×}n:~de

Cant usion; ischemia : failure

Hypovo lemia : hyi'x3xi:a; ll~yocard ial cent usion: delayeu:| aort.ie rul)turL:,

\VIIAT To 1)o Adjnst r~,spiralor pressure Nm'c(,t ic or muscle relaxtmt C'ht~:k for cause ~atelectasi~, respi-

r a lh l r I ' t l l lCl io l l , ~vofS~tllill/g A-ial_'o,,).

lncr~>- (),2 inlml Suct~0n ×. ray confi |'|ll;ttl it1|1 X-ray : ,:beck chest iulm "l'rocar relict; x-ray; chest l u l w

X-rat','; b ronchoscopy; lJhmiRram.,,; surgery

(..;aslrogratin ,.wallow: stlrgl~rry ("hc~,k a::l(t correcl

• ~ . t ' t " ;1 [ ) O ' . ' e

S f2~r 3 ] ) 0 V t

X - r a y ; t r a n - d ' w , t , : , Iorlo! ,~rt l l l l ; surgery

X-ray : -':C{;. adjust respiralm'; liigilalis; diuretic.,

X-ray : adiusl re.sl:,irator: C V P and ten! tlaid load; x-ray; sedat ion

Check and em'rt~.'l hyl .Jxia: hyi×)- volemia; I.,;C(.I: x-ray t,.iuprel

As above, digitalis

la'luid~ nnd whole Mood ; check lml- llmnar'y stalus" x-ray; I:~C(;; aori og raln

are the mainstays of prevention. Acute anoxia is prevented b y s t r i c t ad- i~erence to suction technics as outlined. Acute respiratory failure can be treated effectively only by n(~t, permitt ing it to dev¢,h:)p. The important factors include sul)pression of lmeumonit is , avoidance of excessive oxygen concentrations and meticulous care in use of the respirator.

Subcutaneous emphy sema is a dramatic and distressing development. It is almost alway's due t() an air leak under t e n s i o n ~ p l e u r a l tear or tracheobronchial injury, Trea tment is direcled at the source. Patients on the resp, rator often will not sh.ow a Imeumothorax. Insertion of a Chest tube into the affected side, nevertheless is mandatory. Pneumomedias t inum is not infrequently present with a tension pneumothorax. If the pericardium had been lacerated, Imeumopericardium may also occur. Again, therapy is directed at the source by effective closed tube thoracotomy and negative suction.

CalzD]OVaSCUt, a m ~ T h e early complications are due to D O M D and i.n, elude failure, arrhythmias and cardiac arrest or rupture seconda~, to car. diac injury. Severe hypoxia from noncardiac sources can cause arrest. Late compl icat ions are du.e to myocardial c, mtusion<~ (traumatic infarct) and to valve leaflet ruptures. W e have considered that patients, who, days after the injury, require digital ization, probably have a contusion, rather than some nebulous myst ic myocardial assault. Inappropriate flui'd therapy may cause overload, especial ly i n o lder Imt ients. Again, s o m e pre-existing fault

41

most likely exists, such as contusion or ischemia from other sources. La te l~rol)lems include l )ost t ramnatic aneurysms and valvular insufficiency, most of which require operat ive correction.

MlSCFA, LANI,:OUS.~HypovoIemia and shock are early COml)lications and most often are due to nonthoracic injuries. A failing hematocr i t later on in the c o u p e may be due to (!) dilutiona] fluid theral)y; (2) cont inued blood loss ( re t roper i toneal most common) ; (3) fresh source (stress ulcer) ; or (4) in t ra thorac ic crises (delayed aort ic rupture , intercostal vessel). Renal shutdown (8% incidence) secondary to hypovolemia has been reported. Hemodialys is is recommended (6).

Sep t icemia occurred in 3 of our I)atients with 1 death. Likely, it was more common but not detected because of failure of sufficient and correct blood sampl ing for culture.

Vent i la tory insufficiency af ter recovery has not proved a serious late complication, except in pat ients with pre-existing chronic lung disease. The young pa t ien t is completely rehabil i tated.

DISSEMINATED INTRAVASCULAR THROSIBOSIS ( D I T ) . ~ T r a u m a is p resumed to be accompanied by in t ravascular phenomena. Documen ta t ion is scanty since a search is not made as a rule. We have observ(xt this probl(,nl in 3 pat ients (12). The syndrome is due to inapl)roI)riate act ivation of clott ing mechan i sms with subsequent in t ravascular fibrin deposits and deplet ion of coagulat ion precursors. Bleeding of unexpla ined origin is the p r imary overt clinical m a n i f e s t a t i o n ~ t h e t racheostomy site, l)etechial hemorrhages , undue bleeding from a vein puncture. The late signs are due to organ failure, secondary to major vascular thrombosis. The pa t ien t may demons t ra te a falling hematoer i t , for no discernible reason. A low platelet c()unt provides a s imple and ready clue. P ro th rombin tittle is reduced and fibrinogen is depleted. As lysis takes place, p lasminogen levels may decline. Our pat ients had pneumonias and the infection may well have been a contr ibut ing factor. A survey of 10 other pat ients with chest t r auma revealed thrombocy- topenia and decreases in clottable protein. Before an advanced stage is reached or prior to in tervening sepsis the diagnosis can be established by s imple laboratory tests, including hematocr i t , l)latelet count, 1)rothrombin t ime and es t imate of elottable protein.

Since the problem is one of in t ravascular thrombosis, initial therapy requires full heparinizat ion. Caut ion and careful watch are essential since the pa t ien t may have a l)otential, la tent bleeding problem from an in jury site. Hepa r in is shor t -act ing and effects can be an tagonized with pro tamine sulfate.

VENTILATORS

N u m e r o u s ventilators are available commercial ly . While there are dis- t inguishing characteristics between them, the ventilators have certain c o m -

m o n functions: (1) either to assist or to control venti lat ion (total take- over) and (2) restoration of pulmonary function in order to mainta in a normal P,~O~ and P.~co::. Ideal characteristics are listed in Table 16. T h e

42

T A B L E 16.~RESPIRATORS: IDEAL CIIAr{ACTgt,USTt('S

1. CAI 'ACITY:

'2 (.,ON I I{C. LS:

3. MONI I(.I~S:

• !, MI':CHAN1CS:

Wide range of tidal volume (2(R)-2(100 co . ) l)rc.,ssure (lelivery to overcome hicrensed ztir~,',qly r(,.-ii~tltllct~ ~Ilr|

reduced thorax (~oml)lhmce (0-90 cm. l l-:O) Adjustnble cycl ing rate ( Io 50-G0/mh~. } Minimal nlechanienI dead space Full range of 02 del ivery (20-100%} With simple adjus tabi l i ty I.-)olivery of lOOt';, humid i ty ;at patient'S; It mper~llure :\ssistor, controller, or both Variable insl) i ratory flow tale mid mSl)ml,ory-explr l l lor } ratio T ida l volume, tleli'very, in lermi t lent or conlinuous Temperature at the insl) i r tdory line l r~spiratory i))'e~,~;-~tire, conti l lUotls Alarm sys(em, p~lrticuhu'ly in vo lume. l imi l ing r(,,s'pirators Reliable, safe, ease of operation l n i e rmi l l en t nel)~li-zalion of medica l ions Gas in take through single en t ry port to I)drmit use of a filter l:teliable valves, pneunmt ic o r mechanica l Las t ly steriliz,qhle Mol)ile; ease of ns.~eml:)ly and disassembly

most critical aspect is not tho hardware but the software. It is far more impor t an t tha t the l)ersonnel be thoroughly famil iar with Ol)eration of the vent i la tors than concerned about part icuJar charactcrmtlc,, of any given ventilator.

CLASS|FICATION

I. VOLUSIE-LIMITING/PRISSSUI¢E VARIABLE (Emerson, E n g s t r S m ) . - - I n s p i - rat ion ends when a pre-set volnme has been delivered from a piston bellows or bag to the patient . Wi th a decrease in comI han(c,, the delivered tidal volume would decrease sl ightly when compared to the next group of ventilators. A nomogram is available for which loss of volume due to eom- t)ressibility of the gas can be de termined and app rop r i a t e ad jus tments can be made (62). The advan tage is tha t for pract ical purposes a pre-set tidal volume would be delivered regardless of the lung- thorax compliance. The re is a pop-off device which can be set to various pressures, usual ly to a level well above those normal ly existing in clinical pressure l imit ing machines.

II. PRESSURE-LIMITING/VOLUME VARIABLE (Bird, B e n n e t t ) . ~ I n s p i r a t i o n ends when a pre-set pressure is reached regardless of the tidal volume delivered to the patient . T he n u m b e r registered on the respi ra tor does not represen t alveolar pressure but machine pressure only. Decrease in compliance or increase in a i rway resistance resulks in no increase of pressure delivered to the pa t ien t but there, is marked reduct ion of the. deliverc~l tidal volume. It is necessary, therefore, to ad jus t the pressure set t ings in order to assure del ivery of a required tidal volume. Conversely, delivered pressures are decreased in instances of increasing compliance. Both groups of vent i la tors may be assistors or controllers or a combinat ion of both. Most pneumat ica l ly dr iven respi ra tors can be uti l ized as assistors or controllers or as a combination, whereas many of the electr ical ly dr iven sys tems are control lers only. T h e re .p l ra to r s described here are p r imar i ly for use out-

43

side the operating room. (For exhaust ive review, see Mush in et nl. [54], and He irominus [34] ).

C t ! A R A C T E R I S T I C S OF C O M M E R C I A L L Y AVAILABLE R E S P I R A T O R S ( T a b l e 17.) N o at tempt is made to discuss all features of the commercia l ly available respirators. The choice essential ly is l imited to those with which the individual is most familiar. T h e highest success rate will be obtained when the operator uses that respirator with which he is well acquainted. In our hands, the Bird Mark 7 (pressure l imit ing) , with flow and mixing cartridges, and the Emerson (volume l imit ing) , postoperative respirators have stood up well through thousands of hours of use.

]X'IONITORING.~I. Inspired oxygen concentration s . ~ T h i s is monitored by a B e c k m a n D2 or other analyzer. The delivered oxygen concentration is checked by the nurse at least once within 6 hours of inst itution of therapy

T A B L E 1 7 . ~ C L A S S I F I C A T I O N AND E S S E N T I A L FEATURE.q OF

C O M M O N L Y U S E D RESPIRATOI{S IN T I l E U .....

N A 3I E

Bird Ma rk 7

Bird M a r k 8

Bird Mark 6

B e n n e t t Pr ,- ')

B e n n e l t M a I

E m e r s o n Post Op

E n g s t r 0 m 200

tMr Shields Rt_-~piralor

O h i o N ~

VOL U 51 E- l ,I 311Tt:D P R|::SS U RI-~-

AND 1.131 ITED

VARI,kBI.E VARIABLE

X

X

X

X

X

X

X

X

X

K z S ?" z, ,. d 7.. ~

X X X

X X X X

X X X

X X X X

X X X

X X

X

X X X

X X X

C N ¢\11 ::' ;\

C N A I I ::: A"

C N A 11 ':; A

1 (X)% 60-9{}':'i; h N

h N All A X X

All h H X X

h H All X u

C N A I 1 A X

All u X X

X

X I

X X 1

X 1

X 4

3

X 5

X 2

X 4

* - - F l o w and M i x i n g Cartr idge A l l - - V a r i a b l e O2 from 2 0 - 1 0 0 % 02

h - - H ea *, e~ t C ~ C o l h H ~ H u m i d i f i e r u~Ul/ra.~-3nic

A ~ A e r o s o l Drug Nebul izmr N ~ N e b u l i z e r

Modif ied from

Expense l ~ U n d e r Sl ,tX)O 2---$1,000-- 2.000 3~ 2 ,o00- 3.000 4 - - 3 ,000- 4,000 5--- 4 ,000+

T a b l e by Dr. P. Safar , C l in i ca l A n e s t h e s i a - - R ~ s p i r a l o r y T h e r a p y 1/19.)o, F. A. I)a%s Co., P h i l a d e l p h i a

44

and on any occasion that the patient demonstrates signs of hypoxia. T h e oxygen concentrat ion is regulated to the m i n i m u m required to mainta in a normal arterial Pao~ (65). A Pao: in the 60--70 ram. Hg range is acceptable as high oxygen concentrations lead to pu lmonary damage. It mus t be era. phasized, however, that "the brain gets soft before :.he lungs get hard" and, if necessary,"high~r oxygen concentrat ions must b~: used to assure an adequate Pao~.

FIG, 1 3 . ~ P r c . ~ . ' s u r e - l i m i l i n g / v o l u m e v a r i a b l e r ~ p i r a t o r ( B i r d M a r k 7} with a, l l achment~ a'~

e m p l o y ~ t for c o n t i n u o u s I P P V .

W

i STERILE WATEm

TUBE.

~¢NALAT ION VALVE

• . •

SWIVEL

IV TUBE (TO LARCE NEBULIZER

FLOW ACCELERATOR CA~RIDGE

INSP IP~ATOR TIME FLOW RATE CONTROL

.. AIR NIX ~

• .. EXPIRATORY TIME / CON'IY~OL FOR APNY.~

- " LARGE NEB~LLZER ~ -

A

COPPER SPONGE ~ ' * - ' - - . ~ - ~

i'" " W 2 1

?" •

LL NE~F/L[ZER "

"&J i' • ~ . . . . ~• ji• :,•i! '

• , : - i ~ : ~ , i •

• : •:~ •~•~ :••: ~,ii:~i •j~!i:~i•~ :~!•~iii J: - : i . . , : . L '~"~,?'~!':.~:~.i, :~ J,~J~.

45

ACID-BA~E [¥'tLu4TIOI~ DIA,~RA)'~

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . f . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . -* . . . . . . . . . . . . . . . . . . . . . . . ~ . . . . . . .

v a - . . . . . . . . . . . . . . . . . . ~ - - L ~ _~ _1_ ~ . . . . . ! _ ~ _ _ ..... T .

77;":':'-:'~"~ ,pc~,~ a~ ~ , , , " - . . . . } --t---'-~ *t '-- t . . . . , . . . . . . . . . . . . . -* ... . . . . ~ ... . . . . . . . . . . . . . ]- #" . . . . . . . . . . . ] ' - 7 "-] . . . . . ' ~,-~ ~ k 1 L : J ~ . . . . . . b - - 4 - . . . . . . . . ~ . . . . . . . . I .~ -

7~: . . . . . __.,, [ I 11 l a lo ~ 117 ..... T - - ~ . . . . F" . . . . "1' . . . . [ " i [ I l i

7 , F - - ~ ~ ~ i : - - : T - - - F - , ~ - T . . . . 7 - - ~ . . . . ~ - - - F . . . . J - - - V - T - - - T ] I -

~ ,' } } I i I • o,~ , " ' ~ , " ' I l ~ a , ! i , t ! , I I ! t t l , ~: <;, c " "~ ~ I I I ~, ! ! I I ! I ~ i i I I I I . . . . . . . . . . . -'t-" - - 4 - - - ' . . - - - - - , ~ . . . . . }. . . . . . b - - - - b , . . . . . ~; . . . . . + . . . . . . . . . ~, . . . . . . . . . . ~ - - - - - t - - - - * ['

. . . . . . . . . . . . . . . l MEC ONV[ ~S!~T4BOL I f C C~ON [: N T f ~C T C= ¢. ~:a ..~ £ ~ 3 ~ a, a, .~ ., ~ ~ .r . ' .~ , . ~ . ~ . , , .

/ I / / / L / / / / M / I . 5 5 ~

5 0 - -

4 5 - -

4 0

0 30

.~ 25

20

g~ ~ / E . I G N T = "7"o K ~ | o

/ /

}

PA' I IENT '~. NA~E, .to.

15

10

ll/,

0

p ~

IM + } n ~ / t 15~ I ~ : 0 a * I 'a

k ~ , %

12"6 100 80 63 50 4~ 32 2.5 20 16 6 3 ~11 I 0 12 5 16 . '~ 1 5 3Z ,1~ ~0 T T T -i" T T "I" "i" T T

Ft(~ 1 4 . - - M o d i f i e d I ) a v e n l x } r t n o m o g r a m used in c x m j u n e t i o n with r e s p i r a t o r t h e , ' a p y . I 'Hood gazes and pl-! a n a l y s e s arc- r lone on a r t e r i a l (A) s a m p l c ~ . I f a n o t h e r , ;ource is used . it m u s t be s p ~ i i i e d . T h e O:~ c * m c e n t r a t i o n is obtnint.~! f r o m a n a n a l y z e r ( se t t ings o n the r e s p i r a t o r a re notoriotL.dy i naecu rn t e~ . T h e A - a l ) o 2 is ca l cu l a l t~ | f r o m the f o r m u l a in T a b l e 6 . 1 L T h e tota l CO:: con t en t is o b l a l n e d f r o m the n o m o g r a m : T h e p H tabsci~sa} of 7.32 is t r a c e d u p w a r d s to the indiea/¢~l Poe,, {30 r a m . H g l i s o p l e t h ~ i n d i c a t e d b y " , 2 " . T h e p a t i e n t s h o w s a ba se defici t a n d {~.s inr.lieatcwl b y the l oca t i on in the spec i f i ed q u a d r a n t ) is in m e | - d m l i e aeidosis~r~-..-spira- t o r y alkalosLs {Poe2 of 30 r o w . H g ) . "17o d e t e r m i n e how m u c h e x o g e n o u s b a s e is r~uBtired to co r rec t the def ic i t , the tht~}relic CO2 c o n t e n t (CT} is o b t a i n e d as i n d i e a t ~ t . "Phe t h e o r e t i c CO2 c o n t e n t ~27 m M . / l , . ) is subtract¢~] f r o m the a c t u a l CO2 e t m t e n t (17 m M . / I , . ) , g i v in~ a neg.al ive v a l u e ( , -11 m M . / L . ), i n d i c a t i n g the pn~-senee of a ba.,;e {|elicit. T h e d a t a d e m o ~ , q r a t e two p rob- len~-~: {1 } a n exct~,s ively e l e v a t e d O~ g r a d i e n t { n o n B a l for 54}~[, irt, q) i red O:~ s h o u l d not exceed 2,5--30 ram. t . lg) , a n d {2) a c o m b i n e d m e t a L ~ l i c a c i d o s i s a n d r e s p i r a t o r y a l k a l o s i s . S i n c e the

4 6

2. Ven t i la t ion v o l u m e . ~ T h e delivered tidal and minu te volumes are moni tored preferably on a continuous, or at least an in t e rmi t t en t basis. Recordings shouht be done as often as a pa t ient ' s pu lmona ry c i rcumstance or problems in managemen t require: general ly, every ,! hours.

3. Compli~tncc... Measuremen t s of tim coml)liance provide iml)ortant informat ion relative to l )uhnonary s ta tus and the manag , ,ment of rosl)irator therapy . Unde r the usual clinical circumstances, thtl c)n(t i t ions f(~r accu- rat(, nleasurem(mt ()f static coml)liances are not l)osslbh' Tim l)eak insl)ira- tory mach ine pressure required to deliver the measure(l expired tidal volume is noted and by dividing tidal volume by the pressure, a value of "effective compl iance" is :)btained. The normal range is between 40 and 50 e c . / c n l , o f w a t e r l : l r o s su r e ( 9 ) . Sequent ia l effective compliance measure- ments are of par t icu lar value in denot ing a trend of change.

4. A l a r m . - - A potent ia l ly serious problem with respect to the vontilat()rs, especially dur ing continuous vent i la t ion, are unrecognized leaks in the system or accidental disconnection occurring in some par t of the respirat(w a t t a c h m e n t to the patient. Death has resulted from sqch mishaps. \Vith pressure- l imit ing devices, leaks are t~asily diagnose(t since the respi ra tor remains in the insl)irator t)haso since th( • 1)re-set l)ressure is not reached. On the o ther hand, with volunlo-]imiting machine oh,ctronic alarms, acti- vated by a drop in the de]ivy,red t)ressuro, are manda to ry . Those alarms. however, do have a drawback in tha t (m some machines they are switched off (luring periods of in t ra t rachea] suction b y the nurse, who af terwards fails to tu rn them on again. Sore(, a la rm devices are t empora r i ly switched off for vary ing d(:,lay times, and dur ing this period, suction may be carried out. Since this ('an be done by 1)rossing a delay button, these machines have the advantage in tha t the alarm need not b(, switched off complet(qy. Howew:,r. no a la rm sys tem replaces critical moni tor ing of the l)atient by skilled t rained nurses at the bedside 24 hours a day (Fig. 131).

5. B lood gas and otller m e a s u r e m e n t s . - The single most impor t an t guide with respect to correct managemen t of pat ionls on resp i ra tory the rapy is blood gases. T h e r e are a n u m b e r of sat isfactory machines for analysis, the two most common being the Rad iome te r or the IL.* Arterial blood gases and pH should assume l)recisely the same role as other almost routine labora tory work in pu lmonary patients . The service should be available on a 24-hour basis. Since ad jus tments to the ventilator~ are made on the basis of the results obtained by the blood gas analysis, thei r accuracy is vital. Credibi l i ty is the responsibil i ty of the physician.

The technic for obtaining ar ter ia l samples is simple. T h e necessity for fundamenta l care and correctness in obtaining samples to assure val idity

*Instrumentat ion Laboratory, Inc., Blood Gas Machine.

arterial P02 is 100 ram. Hg, tile input is rtxtuctwt tt~ maintain a range of 7t)-84) ram. l~g Po:,. Exogenous base is required to correct the deficit. The total deficit in mEq. is calcutat~M by multiplying the conversion factor (uplwr right of nomogram) by the previously obtained deficit of - -11 mM. /L .

(1) Total deficit: 17.5 ~K --11 = ~192. CPhe conversion factor is lmsed on the patient.~ extra- cellular fluid volume.)

A deficit in excel,; of --2 mEq. /L . , k~. |×~dy weight is corrected. (2) Base required: one-haft of --!92i or 86 m.Eq.

,t7

of the analysis is emphasized. Samples are taken from the femoral, brachial or radial ar tery in rotation. Heparinized glass syringes.are used. The samples are obtained under anaerobic conditions: a 22-gauge neede for femoral and a 25-gauge for radial or brachial punctures. If more than 3 or 4 samples are required in a 24-hour period, an intra-arterial indwelling needle or cannula is inserted which may be left in as long as 3 days. After the sample is obtained, the syringes should be capped or sealed and put into a beaker of ice lest the Pao: drop 2 ram. Hg per minute.

The sliP sent with the blood sample to the !a[mratory must contain the fob lowing information: (1) the inspired oxygen concentration or input into the respirator: (2) whether ventilation is spontaneous or controlled: and (3) the patient 's temperature. The result can be obtained quickly, at the most within 15 minutes.

The data should be charted on an acid-base nomogram either of the Davenport or Siggaard-Andersen type. We have modified a Davenport nomogram with additional spaces for recording the following: sampling time, nature of sample-arterial or mixed venous, Pao.~. Pace: , arterial pH, calculated A-aDo._., CaCO:, both actual and theoretical (Fig. 14).

PHYSIOLOGIC EFFECTS

INTRATHORACIC DYNAMICS.--The normal physiologic events during resl)i- ration cannot be duplicated by any mechanical device, including positive and negative phasic respirators. The respirator does not restore, pulmonary function by reinstitution ()f normal dynamic events within the intact chest under atmospheric conditions. It is capable of impr.oving abnormal ventilation during t rauma or other lung problems. The r~_,spirator, as c o n v e n -

t ionally used, induces almost a direct reversal of the normal dynamic rela- tionships of pressure gradients resl)onsibie for natural breathing. During inspiration, the negative intrathoracic pressure beconaes Imsitive, reaching its maximum at end-inslfiration. Dur ing the expiratory l)hase, the pr~>ssure decreases to resting level, reacbing its lowest point at the end ()f th~ post- expiratorw_ phase. In short, the gradient, which exists b(~tw~'~.t:.n~ relative nega._ t ivi ty and relative l'msitivity is abolished and the principle of ventilation with the respirator is base;d on a positive-zero relationship entirely.

CARDIOVASCULAR SYSTE~I.~The subatmospheric intrathoracie pressure during . . . . normal inspiration creates a faw)rable pressure gradient b(.t~, .v(.:n~e the peripheral w~nous circulation and the r i , ~ ~ide of the hear{ or the central venous system. This gradient is abolished by the respirator induced inspiratory positive pressure. There is progressive impedance to venous return w i t h diminished diastolic filling and reduced cai'diac output. There is elevation in pulm(mary arterial pressure, increase in pulmonary vascular rt~istance, and increase in" right ~,entricular work. Pu lmonary capillary ft(w,, is reduced, I P P V can be considered to be a series of minor Valsalva maneuvers.. During expiration and in the immediate postexpiratory,pause phase, the pulmona~" arterial pressure falls, there is a decrease in right ventrieular work, with improvement of left ventrieular filling and increase in cardiac output. Under ordinary circumstances, these effecLs are modified by an increase in the venomotor tone, thus restoring the normal pressure

48

gradient between the peripheral venous system and the right atrium, Venomotor compensation, however, may not occur in patients with poor vascular reactivity, hypovoh:,mia or central nervous system depression. It has been demonstrated that the effects on blood flow can be considerably modified by the ratio of inspiration to expiration phase and by the postexpiratory-pause. Induced expiratory negative pressure.,, based on experi- mental studies, i have been recommended as causing thq ha s t disturbance to blood flow (191 70). Negative pressure adds an incre{na~nt of complexity, however, and may be deleterious if not applied correcllv: namely, in the postexpiratory pause. Clinical experience has demonstrated that the sim- pler device, in termit tent positive pressure only, is quite satisfactory and that positive-negative phasing equipment presents no real practical ad. vantages.

L U N G S ( N O R ~ I A L ) . ~ ' - [ ~ h e longer the inspiratory phase and the lower the inspiratory flow rate. the less is the anaount of pressure required to move a designated tidal volume into the lungs. This setting results in the best distribution of inspired gases to the lungs but also causes the greatest interference to venous return and cardiac output. \Vith shorter, inspi ratory phase and a more rapid inspiratory flow rate. a greater pressure is required to deliver a designated tidal volume. There is less disturbance to cardiac out- p:ht. On the other hand; the evenness of gas talking within the lungs is somewhat impaired. Therefore, a balance must be achieved between impai rment with blood flow and interference with in t rapulmonary gas distribution. These factors are idealized by establishing an inspiratory-expiratory ratio of 1:2 or 1:3. Other problems exist. Atelectasis appears when a constant tidal volume is delivered. The incidence appears to be related to the inspired oxygen concentration, the length of time on I P P V and whether or not periodic hyperinflation is used (08). Compliance decreases, and there appears to be a decrease in surfaetant related in part to the oxygen concentration input and perhaps to I P P V itself (55).

Effects of dead space also must be considered. Under norrnal circumstances, anatomic and ptiysiologic dead space are approximately equiva- lent, During positive pressure ventilation, however, the physiologic dead space increases due to enlarged airway and conversion of normal alveolar units to dead space units.*: The changing of normal units into dead space uzlits therefore affects the venti lat ion/perfusion ratio. If the physiologic dead space increases disproportionately to the tidal volume, alveolar ventilation will be impaired, It is therefore important that the ratio of tidal volume to dead space be measured and .not simply the tidal volume alone.

~ATIENT MANAGEMENT

Management may fall into two b r o a d categories: (1~ the c h e s t injured " ~ h "

patient requiring IPPV~t only and (2) patients requiring continuous I P P V + (Table 1,8).

~A dead space uni t is one ~n which vent i la t ion occurs, but no perfusion. "; IPPV1 : in termi t tent , noncontinuoct~ $ I P P V = eontinuou_~.

49

T A B L E 18.~IRE;SI'II~ATOR ~.IANAGEMENT IN 13Lt'NT CIIEST "i'ItAV.'qA

C R I T E R I A

A. Uon_servalivt.---I ppx, q ~C'ategory 1 )

U s u a l l y fewer than 5 f racture , , M m i n m l lo no llail , m i n i m a l s p l i n t i n g A d e q u a t e cough ing Im,,, i l ,h .. a b i l i t y to rai,;e

se*'relion., I10| imlm~red S m a l l to no ehe,,! contu . , ion ln'e,-ent M e n t a l l y a h , r t ~ n o as~ociate,! head i n j u r y N o pre-existin.~ lung ~li,.e.'~s~, COOlmrative. ab le to lake I I ' P V t Gal i : f fac tory Pao 2 with or wi thou l na.,,al 0 2

II. Aet ive-- - I I q ' V ¢ Cate tzory 2 )

Pat tents w h o .,,how deter iora l ion fro,n eon ,m~ 'a l i r e ~ roup

U s u a l l y mort . l h an 5 fraeture.~ F l a i l i n g or s p l i n t i n g Inadequale c o u g h wi th retainesl secretion,; I-urge lumz contu~ion-~, c o s t o c h o n , l r a l

s;ep;~ rat ions Pre-, ,xi ,a ing l u n ~ ~1 i,,ea,,e N o n c o o i ~ , r a t i ~ e . unahh , to l ake 1 I ' i"\ '~ A,,, ,tmiah'd head mh~ry wi th .-,lul~)r or ¢onm i l.x'l~xia wi th adde~l na~al ()._, A ri-~ixa~ l ' a c u , R e s p i r a t o r y rat~, nf :~.5-t. per m i n u t e A~,,oeiatt.~l injurie-; requir ing h q m r o t o m y

l ' ~ sS l 'N r lA t . FI;AI" I "RH.'-;

Vilal sign.,, SeriaI h h ~ , ! ga',,.',

ln terco- . ta l Idock .Nl:n,mal c|o.v~ (,f na rco t ic-, N a - a l O.. if in'lw,~l,.~l l - lumid l ty via h u m i d l i i e r and h :df - face h .m ( 'he-q l~hY',ical l l m r a p y an, l l I ' l 'V t -*dt,qunlt. hvd , ' a t i on alltl Ido(,,I sr)hunv ('h~ .~,I x-ray

Vi ta l siml-; ~er ia l I~lood ga,,e-, .~q'ial × - r ay che-,t Na,-ot rachea l m t u b a t ion ( 'ont ro l l t~ l ven t l l a l J<~ll ]n~lfi: , ,I ().. cone. t.nou~zh to in. , I . l r l , ;Idl'tllh||O

l'ao..: 70-f~O ram. I~R P;n',~,: 32-3t ; m m itR pH: 7.4~t--7.4~;

H y d r , a m n and Idoo, I. if re~luire, I C |u~ t I~hy'~ical Ih,.'r;qLv. ,-ucl r a n . ~'I~'. N ;t-t~ga~',l rlc f i l l ~i' A d t ~ | l h ' l t t ' ¢lOst"~, l i ; t l ' t ' o l [t "~- "rrat 'ht~,qtonLv when ¢'ot~X,.l"litql|

I P P V , . n T h i s category includes pat ients with tile fo l lowing characteristics. (a) blunt chest trauma with usual ly tess than 5 f rac tured ribs: (b) min ima l degree o f s l ) l i n t i n g or flailing: (el abil ity to mainta in sat isfactory Pao., and Pace., with nasal oxygma only: (e) a mwmai ~r somewhat alka- lotto pH: (f) none to a small lung contusion: (g) menta l l y al~,rt with,rot head injuries: (h) no pre-exis t ing lung disease: (i) a reslfiratory rah' und~,r 30 per minute .

Arterial blood gases drawn on admiss ion usual ly n,voa] s~me hypoxia. hypocarbia with a P a c e : of less than ,10 and a pH which is normal or s l ight ly e levated. Added oxygen is given via a nasal catheter sufficiently to raise' the Pao: to acceptable levels. F lows of over 5 t , . / m i n , a r e not used. d u e to the compl ica t ion of intragastric d is tent ion which results in added imlmir- merit to venti lat ion. Fo l lowing adminis trat ion of nasal oxygen for about 15-30 minutes , blood gases are checked again.

Vital s igns are monitored at fn ,quent intervals. T hos e indicating hypoxia inc lude rise or fall in pulse rate or arterial pressure, usual ly a rise in both; cyanosis , which is a late sign: an increase in respiratory rate ovvr 30 per minute: a change in the level of consciousness . In terms of mechanical work of breathing in normal people , the rate of lung oxygen uti l izat ion is a p p r o x i m a t e l y 0 .5-1.0 ml. per L. of venti lat ion. Oxygen requirement rises dramat ica l ly in patients with severe chest injury. Phys ica l signs are often unrel iable and may lead to a false sense of security. Therefore . serial blood gases are absolute ly essential and should be n,corded on an acid-base n o m o g r a m as described previously. This has proved to be the only effective m e a n s to evaluate a patient's progress.

50

~: N I T

~-2:; ~glf~S ,MIAPTOR

OOLLECTIOI~ gAG

NAS~TRIC TU~E

i;,~}i

, ' 1} : , : ,

-.>.--:

RE~EIIVOIR TUBING

" S T ~ B I E "

! . . , ,

. . . . . . , . , - ! ~ 4 i : ~ ' : ' : ~ . . . . .

'riIB£ FI~O'M NEBULIZER

'BULIZER

] : I t ; . ]5.~Set-llp use~t for h u m i d i f i e d o x y g e n t h e r a p y w i t h n a s o h ' a c h e a l i n t u b a t i o n . S t e r i l e d i s t i l l e d w a t e r is s u p p l i e d to the n e b u l i z e r via an i n t r a v e a n u s set ,

Intercosta l nerve block is an e x t r e m e l y effective, valuable and much neglected procedure in m a n a g e m e n t of rib fractures. Any t(:~chnics which cause added l imitat ion to chest mot ion and vent i lat ion are contraindicated. Furth( ,rmore, intercostal blocks are preferable to tile use of large doses of narcotics.

E l i m i n a t i o n of secret ions is ex t rem e ly vital. S ince the mucus often is thick and viscid and difficult to remove, it is ess(,niial to keep the secre- t ions as thin as I)ossibh,. This can be achieved in two ways. One is by mainta ining adequate hydrat ion of the patient and the se~?ond by adminis tra- tiol) of we l l -humidi f ied oxygen-enr iched air to the patient. A sui table hu- midif ier with plast ic hose a t tached to a half-faced tent is super ior to placing the pat ient in an oxygen tent. In the latter s i tuat ion oxygen concentrat ion cannot be control led. T h e pat ient cannot be a t tended to adequate ly by e i ther the nurs ing or the professional staff'.

In this group of patients , I P P V , is adminis tered at intervals as required. depending on the cl inical stratus. The procedure genera l ly is to adminis - ter it every 4 - 6 hours and to ut i l ize a bronchodi lator medication, as a nebul izer i tse l f m a y give rise to bronehospasm. Micronepl~rin, 5 drops to 5 co. of s ter i le dist i l led water, is recommended . If bronchosp~Lsm is severe. aminophy l l in , 5 co. with 5 drop-s of micronephr in in a nebul izer has proved

51

highly effective. Isuprel is not recommended because of possible deleterious side effects.

Narcotics may be utilized, but with caution since they depress ventilation, part icularly in large dosages. Small dosages given intravenously are, on the other hand, highly effective including Demerol. 12.5-25.0 rag., or morphine, 2.5-5.0 rag. Pain relief is dramatic with minimal respiratory depression. The intravenous administrat ion is essential because the correct dosage can be given and the drug is effective in a very short time. Pheno- thiazines generally are not desirable, due to the fact that they have a tendency to produce thick secretions.

Measurement of lung volumes is extremely helpful in assessing progress. A single breath vital capacity of less than twice the normal tidal volume of the patient, or a vital capacity of 15 cc./kg, body weight or less indicate inadequate maintenance of progress and the need for active treatment.

I t is preferable if possible {o monitor these patients in the intensive care unit where they can receive appropriate attention 24 hours a day. Pat ients with a few fractured ribs, minimal flail and small contusions usually respond well to this conservative regimen. On the other hand, some of these individuals do become fatigued and demonstrate progressive deterioration of function which is evidenced by physical signs and in particular by blood gas changes. Daily x-rays are important with respect to determining presence or absence of pneumothorax or the development of complications such as atelectasis and /o r pneumonitis. Lung contusions are best diagnosed by calculating the A-aDo: gradient which often precedes x-ray appearance of change by at least 12-24 hours.

CONTINUOUS I P P V (,CATEGORY 2 ) . ~ T h i s includes patients wi(h critical chest injury (or disease): (1) whose respiratory status has deteriorated; (2) patients with a significant flail with multiple fractured ribs and a significant lung contusion; (3) patients in whom (a) coughing is entirely ineffective; (b) respirator rate is greater than 30 per mifiute: (c) hypoxia is unresponsive to increased oxygen by half face tent or nasal oxygen catheter: (d) the Paco: may have become elevated; (e) neurologic signs exist such as depressed sensorium or coma: and (f) undue fatigue is prominent.

3[aintenance .~The following points are vital: (I) Nasotracheal tube must be firmly fixed to the patient with a marker to emible the nursing staff to ascertain any movement from its .original position. (2) Gastric decompression, is mandatory with plastic nasogastric intubation "through the other nostril to vent the stomach of swallowed air, which always occurs with IPPV. The tube is at tached to a plastic enema bag held about 2 feet above the level o f the patier, t's head to permit escape of air and collection of gastric juice which is returned to the patient. Tube patency must be ascertained hourly. (3) Remot,al o[ secretions: suction is carried out under sterile conditions, including disposable gloves and 22-inch long plastic catheters ( # 10 or 14 French) with a side arm. The catheters are used for one suction period only. Sterile normal saline for the suction catheters is supplied in I00 cc. plastic water bottles which are used for a period of 8 hours only and replaced with fresh bottles. Instruction of nurses in suction technics is critical, with constant checks. One hand is kept.sterile, while the other is

52

used to undo the plastic cap at the back of the swivel, handle tile wash bottle, etc. Suctioning should always ,be as brief as pt~,sible. The catheter can partially obstruct the tube. Suctioning precipitously reduces P,o~, in- ducing acute hypoxia. The actual suctioning period is limited to 5 seconds. The catheter is removed from the nasotracheal tube, and the patient is ade- quately reventilated before suctioning is repeated. There is no set timetable. The procedure is done at least hourly but more frequel tly when necessary. (4) Cuff inflation: The cuff is inflated with air at a ~rcssure just sufficient to obtain the seal with a small leak, at end-inspiratior. It is preferable to make respirator adjustments rather than permit excessive cuff pressure on tracheal mucosa. Deflation is not done regularly, but only once or twice a day. Strict at tention to the proper degree of inflation of the cuff is in professional hands. Hour ly deflation and inflation by different sets of hands increases risk of improper cuff pressures.

INITIAL CONTROL: ESIERGENCY ROOM.~These patients are usually hypoxic with rapid, shallow, ineffective ventilation and a small tidal voIume. Fur- thermore, they are restless, in pain and emotionally distraught. Assisted ventilation generally is introduced first. The Bird Mark 7 with flow and mixing cartridges and maximum inspired oxygen Concentration is used. High inspiratory flow rates and usually pressures of ,¢:5-35 cm. water are established. More may be necessary. Narcotics are given intravenously as noted above. Once intubation and I P P V have been instituted, it is essential to check regularly for the possibility of a pneumothorax. A closed tube thoracotomy on the injured side should be performed to ser~,e ms a vent whether or not a pneumothorax is present, Not infrequently the patient reacts t6 nasotracheal intubation by bucking and coughing. This can be handled by instillation of 2-3 cc. of 4% Xylocaine through the nasotracheal tube or by a nebulizer. \Vith these procedures, it has been noted that the patient 's tidal volume can be stepped up. By opening the expiratory time for apnea on the Bird respirator, ventilation can be controlled within a relatively short peried of time. Control of ventilation is absolutely essential in order to stop flail and to stabilize the chest wall (Table 19). Rarely a patient requires a muscle relaxant.

Blood gases constitute the single most impor tant tool for the management of a patient on the respirator. These are repeated within 15 minutes after institution of IPPV. When the patient 's evaluation has been com- pleted and he is considered to be in a relatively stabilized 'state, he is moved to the intensive care unit or to the operating room, i f ,nece~ary. Emphasis is placed strongly on establishing control of the patient 's ventilatory status before he is moved from the emergency room.

INTENSI%~E CARE UNIT.~It is desirable to maintain a large t ida l volume and to use the lungs as pneumatic splints. The volume delivered is generally 1,200-1,500 cc. with a respiratory control set at 6-8 breaths per minute. In the Bird Mark 7, pcwered by oxygen with the flow cartridge in the fully open pc~sition, the oxygen concentration delivered to the patient is approximately 93%. The nasogastric tube is checked for patency with frequent aspiration of air. Gastric contents are returned to the stomach unless there is an indication for continuous gastric suction. A f t e r several

53

i . . , . , , J , J i , , . . , , , , , , , . , . , , i . . , _ , , ,

T A B I . L 19---C().~1.~mx F~ESI'IRATOR I)I¢OI~LE,MS AND HAZARt)S

| ~ROIII.t; M

1 {(~,pir,,~ Ior r , ,main~ in, in~I-firalary phase

|{t~piratc~r cych:-~ on and off r ap i ( l l y

| {esp irotor out of ph;cse wi th pat i ent

}:{EASO N

l , eak in .~ystenl: fa i lure to reach pl ' t ' , s (q ]ll'{.':-;:',llre a. la. ,aking cuff b, Broken cuff (*. l~;)o,,e r~:..Slfirah)r o r h o s e

COIIll(~'I ion

l ' r [ - .se l p r e s s n r e r e a r h ~ t r a p i d l y ~lue 1o ol~stru(:lion to gas ttow a. Pat ient buck ing and c o u g h i n g on

tulle b. Se( 'rel ions c. ( . )hstrucl ion Io n a s o t r a c h e a l lul~e d. T u b i n g from respirator io pa-

t ient kinM,(t, t )hwked wi th l ice "|'OO l l l l lCh s u t m t m o , q ) h e r i c ¢insl)ira-

Io ry ) I}re'sstu'e requi re ( ! tO I:rip l}la( 'hi l l ( . ~ o n

M:u:'hine cycle'; on i m m m t i a t e l y fol- l owing exp ira t ion

Too s low a I }ow r a ( e f i ) r l)aliell t ~ ins | l i t;It |el l [()o Iollg

REM EI)Y

a. lnlb~te p i lo t l.ndloon b. |{(,pl:we lul)e c. C 'heck s y s l e m f r o m swivel to

l't~ I )i ra [(Jr d. I{eph lce tube

h. Su(' l ion '~ 4" ' ,. ce. o x y | o c a i n e inje~_'led (lowtl naso t r :u :hea l /tlb(.~ or nebl, l iztul 1o the pal ten t

b. . 'Suet ion c. I r r iga l ion and s u e i i o n replace

t tl| m d. U n k i n k . dra in tul) ing

Increase s e n s i t i v i t y on machine

l ) e c r e a s o s e n s i l i v i l y on m a c h i n e

]ll(?rtqls¢~ I | o w . incr(?;~so |)rt~silr(_- to keep u p v,'ilh i ) a l i en t ' s in- s p i r a l o r y pattern of ven l i l a - l ion: s ~ l a t i m ~

*Pr(,,s-~ure-|imiting. v o l u m e variable maehin(~s.

days the ca the ter may he removed, if the patient is conscious. Repeat checks are required in the ew:mt that gastric distenti<m recurs.

One of the great advantages of ut i l iz ing respirator therapy rather than fixed s tabi l izat ion equi lmlent is that the lmtient can be turned frequently. Turn ing the pat ient on tlm flail s ide is avcdded, due i() the double fractures, T h e te~:hnic of vibration and percussion of the ch~,st is carried Otlt hourly together with suctioning, T h e suctim~ing, however, is uti l ized as often as necessary. Great care mus t I m ex~,r,,is~,d in suct ioning, lmrt icularly in lmtients who are ex tremely hypox ic so thal they are not Off the resl)ira- for for an undue period of time.

Blood gas m e a s u r e m e n t s are repeat(,d as often as indicated during inspiration of a known oxygen concentratima. It is not u n c o m m o n to find that the P a c o : is quite low. It is not desirable to I)ermit a lkalos i s for a long period, due to shift ing o'f the oxygen (tissociatim~ curve to the left, witt~ l)ossihle i m p a i r m e n t in cardiac contract i l i ty with reduced output. Further- more, a marked degree of respiratory alkalos is renders weaning from the venti lator difficult. To correct for this, dead space is l)laced into tho sys tem between the expiratory valve and the patient. Init ial ly, the dead sl)ace is increased by approxiri)alely 100 ec. and blood gas tests are rep(,ated after 15 minutes . T h e dead space then is a l tered so that the Paco~ is mainta ined at a level of 34 -36 ram. Hg. A n o m o g r a m is available for predict ing the dead space required to bring the Pacoe to a desired level. In general , Pao._, is ma in ta ined at 70--90 ram. I-.Ig and the pFI at 7.40-7.46.

Since: infect ions are so common, Luken's tube spec imens of intratracheal tube secret ions are taken under s ter i le condit ions and sent for cultures and

54

sensitivity every 48 hours. Bronch(~dilators are administered 4 times daily. or more often, if dictated by the (h,gree af br(mchospasm. Proce(tur(.s including adjustm(,nts, patient ('are and gas analysis are carried out as frt,- quently as required in or(h)r t~) insure that th(, adjustments art, correct.

'1'he effective coml)liance is (h,termint.d along with adjustments for necessary input of x, olume of air. This (in additi(m to blo~,d gases) is the mast valuable indicator of tla(, state of the lung. A l)rogrt, ssixoly dt,('rea~in~ rom- l)liance is indicative of a wors~,ning situaticm and i~ r ) m m o n with contusion, pneumonia, secretions and atelectasis.

Initially" feeding is intravenous. Fluids, subsequently, are given by naso. gastric tube. On('e the lube has been remm'(,d, fluids can be giv(,n by mouth and may include any form which is suitable in a liquid stat~,, avoiding fruit juices. It must be remembered that an inflate(t cuff is no guarantee against ast)iration.

WEANING PATIENT FROM THE I~ESPIRATOR

i This is a most critical step and should be executed 0nly." by trained, ex-

perienced personnel. Readiness is bas(,d on the patient 's physiologic and clinical state. The criteria in genera] are as follows: (1) Pao: of greater than 250 ram. Hg on 100'~ :, O:: (2) Paco~ of less than 55 ram. Hg on the respirator; (3) tidal volume of l0 cc./kg, body weight; (,1) reasonable stability of the chest wall: (5) radiologic evidence of resolution of pulmonary contusion: and (6) reduction in A-aDo=. In flails, as a rule, at least a 10-day period ~s requi red t)efore weaning is begun.

The first and mosl vital st(q) is to explain to the pafi(,nt in detail what is to be done i~nd what he can exl)ect. Most patients have become quite ac- customed ,~¢ the resl)irator. A tr(mlen(lous am(rant of anxiety can occur when ~(., pat ient is taken off. Loss of this important sul)l)ort on which he has;JI~'ome so depend(,nl may be terrifying. All ess(mtials shoul(t l)e pre- pared and readily at hand: suitable humidifier (we prefer an Ohio) with the ability to sul)ply varying O~ concentrations, 1)lastic hosing, Briggs Adaptor with reservoir tubing. The insl)ired oxygen concentration delivered to the patient is s()mewhat higher than that receiv(,d on the respirator. The flow also is about twice the patient 's estimated minute volume on the resl)i- rater, to prevent rebreathing. The (.lead space is limited to tubing from the adapter to the nasotracheal tube, about 10-20 co. ('Fable 20).

When the patient is removed fro n~ the respirator, the initial period of spontaneous breathing is carefully observed for indirations of mild respiratory distress, which always dew:,lops. The other sign which is carefully looked for is recurrence of the flail. If the latter does occur, the patient is reat.taehed to the respirator and weaning is deferred for another 1)('tied of at least a week. If the flail does not occur, the length of time for development of signs and symptoms of" respiratory difficulty are noted. Blood gases are drawn at this period. If the blood gases are within, acceptable limits (no hyi)oxia and no-to-slight hypercarbia) , a period of about half the length of time it took for the distress to develop is selected as the initial time period off the respirator. For example, if the patient was able to remain off

55

, • . , . . , J , , , . , , , m ,

T A B L E 2 0 . - - \ V E A N I N G P A T I E N T H t O M l t I 'S t ' I I :ATOR

A. PATIENT OlilENTATIt/N

T h i s is s i n g l e mos t imlxwtant step, Expla in in deuul : T h e e q u i p m e n t

T h e c h a n g e o v e r W h a t to expt~t

R e a s s u r a n c e t~'fore, d u r i n g , after-----con-~ant

B . I NIIICATIONS

On respirator: l'ao._," 250+ ram. t lg on 100% O2 P a t h 2 : 5 0 n u n . I tg \" l ) /~r l ' : 11.6 Thorax reasonably slable Stable vital s igns

C. PREPARkTIONS

E q u i p m e n t for inh:flation (see text) t t i g h h u m i d i t y source 02 Iiigher than tim! on r t~piralor T h o r o u g h clearanee o f a i ~vay T h o r o u g h c l earance of pharynx l)el lale cuff (if no excess secretions)

~'l" M I'TO 5I

Pulse rate or Arterial pressure or S wea t i n g Rt_~pi ra t ions t )yspnea Flai l recurrence

D, *X~0NtTOaINC

PATIIOL(RIY

HYlmxia Hy|xgxia A n x i e t y : hypoxia Hyl-~xia : a n x i e t y H y I x~ x i a Ins tabi l i ty

|/t:.~t En Y

Back on respirator l',ack on r ,~pirator Reassure: rexpirator Respirator: reassure Back on respiralor Bacll on respirator

D e t e r m i n a n t s :

E . PERIOD OFF F{I.2St'IRITOR

(1) L e n g t h of t ime to first s ign of r t~pi ra tory d i s t r ~ s {Diaphoresis: dyspnea; tlail: tachyl.mea}

(2) E v i d e n c e of p h y s i o l o g i c rcNfiratory ,siatu~: P a o 2 : 8 0 Into. I-tg; P a c o 2 : 4 5 ram. Hg: pH: 7.:~(;

13) T ime off respirator in each hour: !,~ of (1) if t2) is O K

F . PROGRESSION

R e d u c e inspirtw! O2 Extend t ime off reNfiralor When 4.5 m i n . / h r . , extend

to a few hours w i lh IPPVj

( ; . |~XTUB.tTION

Pa¢~2 ok on 40"/, 0"2 PaCo2:45 n l n l . ] l~ pH: 7.36

for 30 minutes, then the initial weaning period for institution of tho pro- gram would be 15 minutes off the respirator at hourly intervals. The weaning process is performed only from 8:00 a.m. to 8:00 p.m. during which t ime the full complement of staff is available. All patients are kept on the respirator (luring the night.

Based on blood gases and the clinical signs, the t ime off the respirator is extended and the oxygen concentration reduced as rapidly as tolerated by

A n o , o x y g e n o r the patient. ~,Vhen 45:Tninutes of spontaneous breathing o n - , . / o

less is possible, a furtlier period of spontaneous breathing is al lowed for a number of hours with intermit tent I P P V treatments via the tracheostomy or nasotraclieal tube for 15 minutes every 4 hours. If the patient progresses well, then the period is extended for 4-24 hours. If the patient's status and blood gases are satisfactory, extubation is carried out. It is emphasized that extubation should not be performed at night or over the weekend when there is only a minimal staff present. Fol lowing extubation, high humidi ty is administered via ultrasonic or other suitable humidifier via a face tent for 48-72 hours with sufficient nasal oxygen to maintain an acceptable Pao=. Peric~lic I P P V treatments together with chest physiotherapy are given as

56

ind ica ted to raise secre t ions and to encourage coughing in o rde r to p r eve n t a te lectas is .

T h e over-all per ied r equ i red for successful wean ing of a pa t i en t with a flail ches t var ies cons iderab ly . T h e sho r t e s t t ime is abou t 7-10 days . T h e longes t has been as much as 4-5 weeks. E a c h of our 70 pa t i en t s has been successfu l ly weaned.

NASOTRACHEAL INTUBATION

E n d o t r a c h e a l i n t u b a t i o n was i n t roduced by S i r Wi l l i am M c E w e n in 188I. Over the y ea r s s e n t i m e n t has f luc tua ted for and aga ins t this pro- cedu re which in i t ia l ly was l imi ted to anes the s i a and for brief per iods im- m e d i a t e l y following anes the t i c . R e c e n t l y the m a t t e r has been reviewed in ch i ld ren as well as in adu l t s (2, 43, 50). T o n k i n and H a r r i s o n noted a r a t h e r s ignif icant n u m b e r of compl ica t ions (71). We have recen t ly reviewed a ser ies of 225 of our own pa t i en t s (2). T h e r e was a 2.4% inc idence of severe

t l a ryngea l compl ica t ions and 4.6% modera t e .* In 9a::,o t he re were none. T h e r e were no ins tances r)t' pe r fo ra t ion or of stenosis. I n t u b a t i o n s were m a i n t a i n e d from a few to over 300 hours wi th mos t in the 48-200 h o u r range.

T h e a d v a n t a g e s of na so t r achea l in tuba t ion as an ini t ial p rocedu re a re as follows: (1) i n s t i t u t i on of rap id and effective vent i la t ion : (2) e n h a n c e d use of t ime avai lable for pa t ien t , eva lua t ion and in i t i a t ion of resusc i ta t ive p rocedures : (3) a d e q u a t e suct ioning: and (4) avo idance of u n t o w a r d ex- pe r iences with e m e r g e n c y t r acheos tomy . T h e safe d u r a t i o n of i n t u b a t i o n is somewha t in d ispute , bu t we have noted m i n i m a l or no l a ryngea l d a m a g e with in tuba t ion as long as 6 (lays. On the o the r hand , in severe ches t t r a u m a whe re it is qu i t e l ikely t h a t ass is ted ven t i l a t ion m a y be prolonged, elect ive t r a e h e o s t o m y is r e c o m m e n d e d , usua l ly wi th in 4 8 - 7 2 hours . N a s o t r a c h e a l i n t u b a t i o n is p re fe r red to o ro t rachea l i n tuba t ion since the l a t t e r is m u c h m o r e unco mf o r t ab l e for the p a t i e n t and gives rise to h igher inc idence of l a ryngea l compl ica t ions .

T e c h n i c . ~ T h e l a rge r nostr i l is selected and ,~,r'a"..,o c o c a i n e . i s app l i ed with cot ton sticks. T h i s assis ts in reduc ing inc idence of epis taxis on pass ing the tube. A wel l - lubr ica ted tube" is pushed t h r o u g h the nose w i thou t force in to the n a s o p h a r y n x . T h e tube size selected for an adu l t u sua l ly is 7.5 or 8.0 ram. T h e p h a r y n x is c lea red of any foreign ma te r i a l (mucus, blood) by suct ion. Oxygen is a d m i n i s t e r e d t h rough the a d j a c e n t nostr i l via a ca the te r . T h e neck is extend¢,d a t the a t l an to -occ ip i t a l joint , p rov ided no associa ted t r a u m a con t r a ind i ca t e s this posi t ioning. A smal l pil low is placed u n d e r the sboulders ; the head is held in mid- l ine posit ion: At this point , while l i s ten ing to the b r e a t h sounds , the tube is i n t roduced f u r t h e r in to the nasopl~arynx and as the p a t i en t inspires , it is i n t r o d u c e d in to the t r achea , In the vas t m a j o r i t y of ins tances , bl ind naso t r achea l i n tuba t ion is successful on the first a t t e m p t wi th m i n i m a l d iscomfor t . T h e p resence of .a tube in the t r a c h e a is confirmed~by (1) cough and (2) b r ea th sounds t l f rough ttae

*Severe---Mucosal ulcerat,:ons and pronounced edema; Modera te - -Minor erosiotm and edema.

57

"FABLE 21.~Co.~iMo.w PROBLEMS AND HAZARIiS A S S O C I A T E D WIT}I ] N T U B A T I O N

|)RO~t I..I~ M

A. N a ~ ) t r a c h e a l l )ur ln,~ l n t u b a t . ) n l . C)l)st ruct io i~

,qoeret ions K i n k i n g o f tubo Ovi, r in lhl t ion cu l t l n l u b a l i o n r ight l l l l l t r l s l l , i l l

l i ronch l ls 2 - \cc iden ia l exi l i |~, l I io l l ;i. ~)r*., • thro; i l 4. Asp i r a t ion

Folh) l i . )ng I n ttt bat ton 1. I atryngit i ,~

'2. }|o;ir'-i(, voice

Su| ~ lo t t l c t.Moma w i l h i.l|)~; t I-tlcl Jrin

-1. A s p i r a t i o n

It. 'I'ro¢|i(,o-~tOllly D u r i n g Intl, tba t :gn I. C)I)<i I-uct lo l l 2, I lernbrrh;i.~e :1. l.)ish.)dgi~)tq~l ,1. lilfex:t iorl 5. l ) i l a t i on of t r a c h e a (;. ' | ' r a c b o ~ o t i h a g e a l . Ir i lcho(i-

t)lt 't lHt I fist tl I~l Af tc ' r l"~Xtlal)a.twm

T r : t c l l ( ~ l enos i.,;

I~EM EIW

:kdt~luale h y d r a t i o n , humi~l i ty & ~u('tion t~,eplace t u b e Inf la te pilo,~ I)alloon with ju,~t ent)ut:h a ir to o b t a i n a

seal (tilling m,q)ir ; i lory l)h.a,;e m t l y 4 t ' t l i l i i f i O l l ; i n l | x - x ' i l y t o il~4-,t~, "z, tulw~, I x i s i l i on

Vigih~nce. corrt~ct iiq~ing of tube , prc~'elat reslh,ssnt,~, 1.~)cal tint.~|ht, I h?.,~ l%x~! via tlil-~(')Zil,,ll'i(r ILlbc'; rtothirlg l ). (). exc(,pI 1-1-2().

i c e chips

H i g h I m m i d i l y viii ne tmlizer ,w u l l r a , o n i c im, I t~alf-face telal for .1,q--7:2 hour.-,

As above. If Ix.'r~ists for 24 ht)ut=-, tht:,n in, l i teel ,)r (liteel laryngo~('~)I)y

| : ,arly: |is above phl~ Meraid-~: vil~ilanee %Vor~e: l ~ e i n t u b a ( e : Irach(~)~t<mLv ln i t i ld |). (). f luids water o n l y . ~ i f ,'fm,qh occur,; fr(~l via

N. ( ; . tulle tmti l l;irynge;ll (-())nl)ei(',rice inlm'!

A,; for N T tul,es ( [ / ' h t l r l g P tllbO: heilloM;~,si'~; chock c();Igul:iti~m st.iiu~ "Firm fixalion; vii;ilanct, SI'twar l-lIll| ('llllllre; <lilt ibiolic,~ U~e longer lull(, Mi l f ima l air in cuff. Sl/ 'J t ' I ~lsel)li,it ~u('tion (echni('~:

s u r g e r y

|{eintuI~ate if v'(~tuh'e~]: s u r g e r y

L , _ _ - , , _ - - : . . . . . . . . ,

tube. If the first a t t e m p t is not suc('(,ssful, .the head is rf)tated to the sial(. of the nostri l bc, ing use(t; and the pr(w('dure is tried again. In .qt)°,; ()t" instances, blind intubati(m can be carried out, In the rest. lbe gl~ttis is vis- ual ized with a laryngoscope and sl)rayed with ltwal anes ihet ic . Und,,r di rec( vision then intubation is , 'a l l ied out. Intrav(:.nous barbituratt,s and musc le relaxa~3ts to achieve intubation are pr(,ferably avoided and rarely m, eessary. After the patient is connected to the respirat()r. (he cuff is inflated. Enough, air is introduced to obtain an air t ight seal in tlie inspir,.atory 1)has(' of ven- t i lation. A high oxygen com'entrat ion is del ivered to the pat ient fol lowing a few cyc les of venti lat ion. Th e .position of the tube is checked careful ly by auscultation_ to e n s u r e that it is not down the right main s tem bronchus. X-ray conf irmation is a must as soon after ~ intubation as condit ions permit .

COMPLICATIONS ( T a b l e 211 ) .~ l l anagemen t . - - : - (1 ) Acc identa l extubat ioni T h e chief deterrent to extubat ion is (a) constant vigi lance to prev(,nt or correct loosening and m o v e n w n t and (b) ('ontrol of Dat!ent restle:~sness. If due to reasons o(]:er tha 0 |Wpoxia, judic ious use of ,analges ics , sedai ives or hand restraints are indicated. (2) Sore throat: Th i s is compla ined of on occasions, X y l o c a i n e viscol)aste or some other local an.esthetic drug given oral ly and held in the pharyn× for a few minutes prior to swal lowing has worked very we l l . ( 3 ) Epis taxis : This has occurred very infrequent ly and

58

has never been a ser ious probh*m. (4) Excor ia t i (m of the nostr i ls : If the nasa | mucous m e m b r a n e or the skin adja('c, nt t(~ the tub(* b,.,com¢,s ~:~(h,ma- tous or infect~:,d, cultur( ,s art, tak(*n and a su i tab le local an t ib io t i c a;)l)li~'d to the area. Thi s also has b(:en a very tar(, occt2rr~,n('t ~. (5) Suc t ion ing : In- ab i l i ty to introduct~ t h(~ suct ion cath~q~,r all th(, way d,~wn the naso t r achea l tube indicat,~s t rouble which m a y be du(" to (a) too large a suc t ion tube. (b) i n a d e q u a t e lubri(. 'ation of th, ' suc'tion tub(:, (wotqn~,,.with sl( ' r i le salin~ • solves this) or (el obs t ruc t ion (tu¢* to s~.crvti,,ns. W(,!h.,ve examined all of our naso t r achea l tubes fol lowing r ,xtubati(m and hay(, boon imt)r(,ss~,d by a lack of inst) issated secre t ions and hay(* nev(,r had to ('hang(, a tube for this reason. (6) Over inf la t ion of the cuff.

E.x'tubation.--This al)i)lic's only to those i)ati(~nts in whom the flail is m i n i m a l an(t.wt~(~r(, ~xtubati()n is l~()ssiblo withot~t t ra(,h(,ostomy. (1) Loss of voice and la ryngi t i s : T h i s (~ccurs in ]0()ff~ of pa t i en t s and is tr(,at~*d by a d m i n i s t v r i n g high h u m i d i t y usua l ly with an ultras(mitt or twat(,d humidi - t ier for a per iod of 48-~~ h()urs and cons tan t vigilance. Indir( ,ct l a r y n g o s c o p y is ind ica ted if hoars,*n(,ss l~ersists f(~r l(mg(,r than 24 h~)urs. (2) Subglo t t i c e d e m a and obs t ruc t ion : \Ve have had 3 ins tances in :the pas t 315 naso- tracb(,al intut)at i (ms 'wh(:,re, usua l ly 4S-_00 hours f(fllowing c.xtubati(m, acut(!, obs t ruc t ion has oc('urr(,d, n(*cessitating t r acheos tomy . In all cas(~s. obs t ruc t ion was du(, . to a thick(,n(,d m~,mbra~le s i t ua t ed sup(,r ior to the h,vtq of th(- ct~ff on the nasotracht~al tube. Fol lowing traclwost(~my in all cast=s. it was pos,sible to r(,movb th¢* t rach( ,os tomy tub(!, wi th in a l)(~riod of 5-7 d a y s and no fur th( , r c()mt)licalions occurr(~d in a follow-ul) l)orio(t of long~,r t.han 6 months .

TRACHEOSTOMY

"Fracheos tomy is n(~ver p e r f o r m e d as an ~,m(,rg(,ncy. Nasotrach(~al in tuba- t ion is car r ied out and thbn tracbe()st(wny is don(, on an (d(~(:tiv(, basis in thc- ol)( ,rating room u n d e r stc, rih, condi t ions. Furt)l~,rmor(,. th(: [)erforman(*(, ()f the tracheos(omy is a lways done with the pa t i en t ' s ven t i l a t ion u n d e r com- l)]ete control and with a p a t e n t a i r w a y via the nasoI:rach(,a] tube, Sultabh: pre,medit:at ion is g(,n(::,rally order(,d. A g(~n(,r~d am~sth(,{:ic is avoided if possible, a l t hough thor(, in no hes i t ancy t(:) use it when r(,quircd. A superf ic ia l c6rvical block is c, xecutcd by in!(,cling 10 ('c'. ,..~f 1 °" Xvlo(al~ e a long th(, . - . / : 1 ' ) . _

pos te r io r bo rde r of' e"ath" s t e rnoc le idomas to id m u s c l e . Addi t iona l l(~'al in- I

• ~ T • Ib f i l t ra t ion with ] % XylocaJne is car r ied out when needed. D u r i n g i)orform- a n t e of the t racheost ( )mv, the l )a t ient is ven t i l a t ed bv the resp i ra to r , ,~ hJch was b rough t wi lh him e i the r from the e m e r g e n c y room or from the in ten- sive care unit l T h e surgical p rocedu re is rout ine. T h e disse.ction is ca r r i ed out u n d e r a calm, re laxed a t m o s p h e r e . Large ','e~qels a r e avoidbd and hemo- s tas is is effect ively m a i n t a i n e d . Fol lowing mobi l iza t ion of th¢~ t rachea , a segment of ~,,.t l eas t two r ings is r(mlovi~d in an el l ipse in o rde r to p e r m i t easy i n t roduc t ion of the t r a c h e o s t o m y . t u b e and to e n s u r e aga ins t u n d u e necrosis. A t the t ime the inc lsmn is m a d e in to the t r achea , |.he cuff or t~he naso t r achoa l tube is usua l ly r u p t u r e d and this then can be wi thd rawn . T h e

. s~ I v e l . I t i s e x - tr~iehcostomv tube then is connec ted to a 15 ram. M6rch - v ' -

59

t remely important to maintain active suction throughout the procedure as required. A few cc. of 1 go Xylocaine can be instilled if there is any coughing.

I~IAINTENANCE.--The basic respiratory management of the pat ient with a tracheostomy is exactly that of management on a nasotracheal tube. An ordinary sterilized red rubber catheter may be used for suction purposes. Provided the level of consciousness is adequate and no paralyt ic ileus exists, oral feedings may be instituted with a fluid or a soft diet. It is impor tant to keep the tracheostomy tube in tim midline at all times. Lat- eral displacement may cause erosion of the tracheal wall with tracheoesophageal perforation or erosion of arteries. Fixation is achieved by placing 2 or 3 layers of Reston self-adhesive sponge plastic material on skin pre- pared with tincture of Benzoin. Two pieces of tracheostomy tape, approxi- mate ly 10 inches long, are placed beneath and then tied over the short piece of green plastic Bird tubing running from the exhalatiot~ ,~'.illve or the Y of the respirator to the M6rch swivel.

CO,MPLICA'rIo~'s.~A. [ n t u b a t i o n . ~ ( l ) Obstruction of the tracheostomy tube due to inspissated secretions: This should never occur and is caused by inadequate humidi ty from the respirator. (2) Hemorrhage: Small amounts may be initiated by frequent and rough suctioning. Large amounts should be viewed with alarm as indicating a possible erosion of a large vessel or a sign of disseminated intravascular thrombosis. (3) Tube dislodgment, either to the exterior or into the neck tissues: This can be prevented by attention to the tension of the tracheostomy tape. When it occurs during the first 24 hours of tracheostomy, it is a potentially dangerous situation. A spare sterile tracheostomy tube should be available at the patient 's bedside for instant use. All the necessary equipment for reintubatioi~ should b,, available in the intensive care unit. (4) Infection. (5) Dilation o t , ' trachea: I r i s not uncommon to find that progressively larger amounts of ai~ are necessary to obtain an airt ight seal. If this occurs ;+ is probably preferable to change over to a different kind of tracheostomy tube, or use a double cuffed tube with al ternat ing filling. (6) Tracheoesophageal and tracheo- pleural fistulas. (7) Too long, too short, or the wrong kind of tube.

B. E x t u b a t i o n . ~ T r a c h e o s t e n o s i s is an ever-increasing problem following the prolonged tracheostomy with positive pressure ventilation. The site of the stenosis may be at the stoma itself or at the site of the cuff. Difficulties in extubation have been noted due to tracheostomy complications and to respi rator problems.

SUMMARY

Major blunt chest t rauma is a multifaceted, complex problem with rising incidence, deficiencies in emergency care, inadequate comprehension of dynamics and of pathophysiology, inordinately delayed or missed diagnoses, controversies in and complications deriving from management. "Pile major problem of flail chest is greatly complicated by accompanying lung contusion. Interference with the mechanical component of function result from flail, intrapleural collections, loss of ventilable lung tissue and parenchymal d a m a g e disturbances in effective alveolar ventilation. Impair-

60

ment of the many components of lung function result in abnormal i t ies in ~ ' / 0 manifes ted by low Pao : and increased A - a D o : . Cur ren t thesis indi- cates the fundam~nta l defect is physiologic shunting.

Pa thodynamics are poorly understood and have been inad~,quately stud- ied. Most disser tat ions ( including our own) are based on extrap(:,lations of relatively unre la ted exper imenta l conditions, inductiv~ hypothet ical r(,a- soning and biologic tamper ing with physical laws. In t|li: context, it appears

. ~ m c its d i sseminat ion . thoracic cage injury is due to dir~ct impa.".t force Most in t ra thoracic injuries are the result of secondary phenomena gener- ated ei ther from the direct impact or the envi ronment of the accid~,nt.

Clinical percept ion s tands as the sol~i~ sure way of rapid, a~rcurate assessment of l i fe- threatening components of thoracic in jury and of pa t ien t progress dur ing therapy. Radiology and laboratory tests arc, supt)lemental anti confirmatory, except in special situat~ions. Delayed or missed diagnoses are due to lack of, ¢~r faulty, perception. The s ingular laboratory aid is the Pao,_, and calculation of A-aDo:. Shock is not often due to a purely thoracic injury. Significant hypovolemia suggests a complicatin/,, nonthoracic problem, such as long bone or l)elvic fracture or intra-abd~.~minal catastrophe. Emergencies are relative, except those due to a crippled card iopulmonary system which requires irnm(~diate rest i tut ion and stabilization.

A st~p-by-stel) protocol execut~,d with dr3liberate, p rogrammed tension by teach effort will insure, the immedia te saving of lives. A clear a i rway is achieved by. prompt eradicat ion of secretions and blo(Jd and bv. n~s~tgttacheal" •

i n t u b a t i o n . Tracheos tomy in the hospital is an elective procedure and never performed as an e m e r g e n c y . Until the extent of chest pathology can be dis- cerned, respira tor suppor t with 100r~ oxygen should be inst i tuted and continued. Resp i ra to r m a n a g e m e n t should b~e in the hands of skilled, experi- enced professionals, funct ioning as members of a team. The respi ra tor does n o t reconst i tute normal ventilation. A flail is Stabilized and alveolar ventilation improved. Arterial blood gases and the es t imated A-aDo~ are, the best guides for respi ra tor and other technical ad jus tments . For pa t ien t adjustments , the best guide is clinical judgment , which in tu rn is sharl)ened by relentless pursui t anti tenacity. Evacuat ion of air or blood or both by large tube thoracotomy is vital. Externa l stabil ization ~)f the flail segment should be l imited to on-the-site and in- t ransi t oT)erations. I P P V with the lungs as pneumat ic splints is the preferred in-hospital procedure, Flails uncompli- cated by lung contusion are uniformly ('ontrolh~d. Not all flails requ~'r,o respi ra tor support . It is wise to inst i tute I P P V , how~,er, until the magnitude of the instabil i ty can be ascertained.

Lung contusions are the problem, giving rise to the major i ty of complications, par t icular ly pneumonia . If not arrested, p rogre~ ive ly inc rea . s ing O.~ concentrat ions are required over long periods of time. T h e spreading pneumoni t i s culminates in acute resp i ra tory failure. This, coupled with prolonged O, therapy, may convert the lungs into a rubbery functionless mass. Relat ively new problems related to gram-negat ive pneumonias and to the respi ra tor have emerged. In a well-organized a n d run t r auma service, lives may be saved only to be lost to acute respi ra tory failure and re.,spirator genera ted cornplication~O.., toxicity and lung rupture, Since these complications are iatrogenic, they can be prevented.

6T

ACK NO'WLEDGSIENT

Tho assistanco ,ff Nan Briggs anti hlary Sav,,la in the l)r,,paration of this manuscript is gratefully ackn,,wh,dgod.

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:i2 t ~ , l a n c y , I,'1. l . ." T r a u m a t i c left v e n t r i c u l a r aneur)' , , ,m. ( ' a r* t iac thromtx, x-,is foi lowii lg an . eu r~ .~mee tomy, Am. J . C~irdio], 20:42/5. 196"7.

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major blunt chest trauma

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