7 October 1972 S.A. MEDICAL JOURNAL

*Intravenous Hyperalimentation1493

G. C. BAKER; M.B. CH.B., F.C.S. (S.A.), F.R.CS. EDIN. AND R. F. WILSON, M.D., F.A.C.S., Department ofSurgery, Wayne State University School of Medicine, and Detroit General Hospital, Detroit, Michigan, USA

SUMMARY

Intravenous hyperalimentation may be useful in the careof the seriously ill, surgical patient. Our experience of thistechnique in 30 patients is discussed, with particularreference to the problems encountered. The introductionof the catheters, glucose intolerance, polyuria, and infec­tion, have been our commonest problems. Close super­vision by trained personnel is essential to recognize andovercome these problems.

s. Afr. Med. l.o 46, 1493 (1972).

In most surgical cases the metabolic consequences oftrauma are not critical. The weight 'loss and negativenitrogen balance are usually reversed within a few days,as soon as activity of the gastro-intestinl'\l tract is resumedand sufficient calories and protein are taken by mouth.However, in the severely traumatized patient, or whencomplications develop, the negative nitrogen balance maycontinue for several weeks, or longer. If a disorder ordysfunction of the alimentary tract is also present, theweight loss due to depletion of body protein and fat maybe considerable. Excessive weight loss may increase themorta'1ity rate significantly. Lawson' found that an acuteloss of 30 % of body weight within 30 days in severely illsurgical patients proved uniformly fatal. Cahill' andMorgan et al.' observed that the rapid loss of approximate­ly one third of total body protein, even in normal indi­viduals, could be lethal.

In an effort to reduce the loss of protein and weight inpatients who require intravenous therapy for more thana few days, a technique of intravenous hypera-limentationwith protein and hypertonic glucose solutions has beendeveloped.' The underlying principle is to supply a con­stant 24-hour infusion of protein (for wound healing andrepair) and carbohydrates (for calories and for their pro­tein-sparing effect). There are, however, many potentialpitfalls in intravenous hyperalimentation and close super­vision by trained personnel is essential. Such cases shouldpreferably be treated in a Special Care Unit, or on a wardwhere such supervision is ava.I1able.

The purpose of this article is to present some of theproblems recently encountered during the use of intra­venous hyperalimentation in 30 critically ill, or injured,patients for an average of 23 days per patient, 108 daysbeing the longest.

PATIENT SELECTION

The most common indication was a gastro-intestinal fis­tula (16 patients) after surgery for gunshot wounds, blunt

* Date received: 29 February 1972.

trauma, carcinoma of the colon, irradiation, and Crohn'sdisease. Of the 16 fistulae, 11 involved the small bowel,3 the stomach, 1 the duodenum, and 1 the small boweland colon. The next most common cause was prolongedileus (8 patients) associated with postoperative sepsis aftersurgery for gunshot wounds, blunt trauma, pancreatitis,and adhesive intestinal obstruction.

PREPARATION OF FLUID

As we have not had more than 4 patients on hyperali­mentation at anyone time, we have preferred to useindividually prepared solutions rather than those preparedby the bulk method, which is used by Dudrick.' We haveused the Cutter Polynute pack which consists of a bottlecontaining 410 ml of 50% dextrose which is added to 590mI of 7% protein hydrosylate; vitamins and electrolytesare added as required. This mixture makes a solutioncontaining approximately 1 calorie per ml.

Sepsis from contaminated solutions is always a possi­bility, but we have had no proven infection from thehyperalimentation fluid itself. The risks of such infectionare minimized by using careful sterile technique in a quietcorner of the pharmacy and by storing the prepared fluidat 4·C. If the fluid is contaminated, it loses its crystal­clear appearance after 2 weeks' storage, and is discarded.Electrolytes and vitamins are added on the day the solu­tion is sent to the ward. An extra bottle is always keptavailable on the ward in case the prescribed amount offluid is used before the next day's supply has arrived.

INTRODUCTION OF THE INTRAVENOUSCATHETER

The subclavian vein is the site of choice for the intra­venous catheter. Usually this vein can be entered withoutdifficulty, by using the standard technique of Wilmore andDudrick: It is important to have the patient's completecooperation while the catheter is being inserted. The footof the bed should be elevated to distend the subclavianveins. A scrupulously sterile technique is vital. Some ofthe problems which may occur with the introduction orlater management of the intravenous catheter include pneu­mothorax, incorrect positioning, puncture of the subcla­vian artery, catheter embolism, and air embolism.

Pneumothorax (2 patients): This can be minimized byexperience and by suction on the needle during its intro­duction. The needle kept close and parallel to the medialthird of the clavicle, is directed toward a point just be­hind the sternoclavicular junction. A radiograph of thechest is taken after the procedure to exclude a pneumo-

1494 S.-A. MEDIESE TYDSKRIF 7 Oktober 1972

thorax and to confirm the position of the tip of thecatheter.

Incorrect positioning of the catheter (2 patients): On 2occasions the tip of the catheter was found in the internaljugular vein; in each instance the catheter was reposi­tioned under fluoroscopy.

Puncture of the subclavian artery (4 patients): The sub­clavian artery was entered on 4 occasions, but the needlewas withdrawn without after-effect. If needle and syringeare kept parallel to the floor, the chances of entering theartery are reduced.

Catheter embolism (none): The catheter should neverbe withdrawn while the needle tip is subcutaneous. Bothneedle and catheter should be withdrawn as a single unit.Although we have had no such complication in our series,catheter embolism does occur and is a serious problem.

Air embolism (none): The tubing was disconnected acci­dentally 3 times in this series because the catheter andconnecting intravenous tubing were not taped and proper­ly secured; each time it was noticed immediately and therewere no adverse effects excepting a temporary shortnessof breath. However, 1 patient, not in this series, died inour hospital as a result of air embolism through thecatheter when the LV. tubing was disconnected.'

Air embolism is more likely to be fatal when the patientis sitting up, because the lower venous and intrathoracicpressures allow a greater volume of air to be sucked intothe vein. If air embolism does occur: the patient shouldbe placed on his left side with his legs elevated, and anattempt should be made to aspirate the air by advancingthe catheter, or a needle, into the right ventricle. Wesuture and tape all LV. connections, and cover the punc­ture site and the first connection with adherent plasticsquares. This has the added advantage of sealing off thewound, especially in patients with tracheostomies.

INFUSION OF FLUID

Initially, pumps were used with in-line micropore filtersof 22 fLm; however, certain problems arose with theseinstruments. They were: (i) overheating and failure of thepumps; (ii) variation in flow rate; (iii) erosion of the tub­ing by the pump; and (iv) rupture of the tubing when itkinked and was completely obstructed.

Because of these problems, we have used simple grav­ity infusion without a pump and have been satisfied thatthe infusion rate can be kept relatively constant by check­ing the drip chamber every 15 - 30 minutes. There hasbeen no increased infection rate since the miUipore filterswere discontinued.

GLUCOSE TOLERANCE

The amount of fluid given, initially, is about I 500 ­2000 ml/day, depending on the patient's age and weight.The volume is then gradually increased by 200 - 300 ml/day up to 3 - 4 litres, and on occasion, up to 6 litres/day.

Insulin is given only if the glucose spill in the urine is3+ or 4+, or if the blood glucose levels exceed 200 mg/

100 ml. It is important to remember that 4+ glycosuriadenotes a spill of 2 % or more and is, therefore, particu­larly dangerous. Glucose intolerance was unusual if theincrease in I.V. hyperalimentation was gradual, but didtend to occur in 4 groups of patients: diabetic patients,septic patients, elderly patients, and in patients soon afterthey had suffered trauma.

Diabetics

Three diabetics were treated in this series. In general,they were much more difficult to control, due to fluctuat­ing levels of blood sugar, glycosuria and osmolar diuresis.Smoother control was obtained by adding ID - 30 units ofregular insulin to C1ch litre of solution, immediately beforeuse, rather than by giVlOg it subcutaneously, as indicatedby urine testing. One diabetic was managed for 41 daysby this technique and gained 3,63 kg. Fructose has beenadvised by some authors: and this may be helpful; how­ever, it is more expensive, requires more elaborate pre­paration, and after several days may have no advantageover glucose:

Septic Patients

Septic patients often develop significant hyperglycaemiaand glycosuria even on as little as 150 - 200 g glucose perday. Two patients with intra-abdominal abscesses deve­loped high blood glucose with urine spill, and they re­quired insulin to control the hyperglycaemia. As soon asthe pus was drained, the blood glucose returned to normallevels, and insulin was no longer necessary.

Elderly Patients

One must be particularly careful about glucose intoler­ance in the elderly.]· They develop hyperglycaemia readily,but may have only minimal spill-over into the urine; there­fore, serial blood glucose determinations are particularlyimportant in this group. Because of this tendency to hyper­glycaemia, the rate at which the LV. hyperalimentationcan be increased in this group, should usually be muchslower than in younger individuals.

Trauma

During the first 2 - 4 days after trauma, a temporaryglucose intolerance is common." We prefer to wait untilthis phase is over and the patient fully stabilized beforestarting I.V. hyperalimentation. If it is considered impor­tant to start early, insulin may be necessary. Furthermore,the changing glucose tolerance will require daily altera­tion of insulin, and extremely careful monitoring. In thesecircumstances we would advise subcutaneous, regular in­sulin given according to the blood levels and the urinespill.

POLYURIA

Not uncommonly, large volumes of urine may be excretedwhile the patient is on LV. hyperalimentation, and espe-

7 October 1972 S.A. MEDICAL JOURNAL 1495

cially during the first few days. It is extremely importantto recognize the problem and differentiate between thepossible causes, which include: hyperosmolar diuresis,fluid overload, and the mobilization of fluid.

Osmolality studies of the serum and urine may be ofvalue in diagnosing the cause of the polyuria, but thenecessary instruments are not available at most hospitals.

Hyperosmolar Diuresis

We have had 6 patients who developed urine outputsexceeding 150 rnI/hour when blood sugar levels rose above300 mg/lOO m!. All 6 patients responded to a slowing ofthe infusion and/or an addition of insulin. No patientdeveloped coma, although I reCi:nt patient, seen in an­other hospital, did develop coma. This patient was a fe­male diabetic with an intestinal fistula, a sequel to surgeryfor intestinal obstruction caused by abdominal radiation.She was given LV. hyperalimentation, but because thesupervision was not good enough, the fluid loss was notadequately recorded, and coma ensued. When she wentinto coma, she was grossly dehydrated with a blood glu­cose of I 500 mg/lOO ml and a serum sodium of 162 mEq/L. She needed more than 12 litres of fluid in the next 24hours, large doses of insulin, and careful monitoring ofthe electrolytes, before she regained consciousness andwas stabilized.

Fluid Overload

Additional fluid is usually required at the beginning ofI.V. hyperalimentation because of the initial osmotic diu­resis. This is given through another infusion site, to avoidconfusion and prevent contamination of the subclaviancatheter. As the volume of I.V. hyperalimentation fluidincreases, the additional fluid must be tapered off to pre­vent fluid overload which can -result in an excessive urineoutput.

Mobilization of Previously Administered Fluid

We have noted that patients with moderately severetrauma, or sepsis, often require large amounts of fluid fortheir successful resuscitation. Much of this fluid is usuallymobilized as an increased urine output, between the secondand fifth days after injury. When trauma and sepsis aremost severe this mobilization of fluid may be delayed. IfI.V. hyperalimentation is started during or just beforethis fluid mobilization, the resultant polyuria may exceed5 - 6 litres/day for several days.

One patient ran a complicated course, after perforatingand bleeding from a postbulbar ulcer. He required 2 ope­rations, and then developed a lateral duodenal fistula.When I.V. hyperaIimentation was started, he mobilizedlarge quantities of fluid and sodium. His urine output roseto 5 -7 litres/day for 7 days, and his weight fell by 15 kgbefore his urine output decreased to normal levels. A: reviewof his chart showed that he had failed to mobilize pre­viously administered fluid.

ELECTROLYTES

The daily requirement of electrolytes will vary, dependingupon the urine and gastro-intestinal losses, and must beadjusted accordingly. No single fluid preparation is suit­able for all patients. The level of serum sodium andbicarbonate must be watched carefully, especially if thereis excessive fluid loss from a gastro-intestinal fistula. Theneed to increase the intake of sodium and fluid must berecognized whenever there are decreasing levels of urine­sodium. If adequate fluid and sodium are not given, whenurine sodium concentrations fall below 20 - 40 mEq/L thepatient may become dehydrated, hypotensive, and oliguric.

INFECTION

Ideally, patients should be free of sepsis before they arestarted on I.V. hyperalimentation. If a patient does spikea temperature once LV. hyperalimentation has begun, andno other cause is evident, a blood culture should be taken,the catheter removed, and cultures taken from the cathetertip and the fluid in the tubing. If LV. hyperalimentationis considered essential for the patient, another LV. cathe­terization is started at another site.

The problem is much more difficult when the patient isseptic before the I.V. hyperalimentation is started. A wn­tinued febrile course may be due to (i) the underlyingsepsis; (if) an infected sleeve thrombus around the cathe­ter; (iii) infection at the site of insertion in the skin andsubcutaneous tissue; or (iv) contaminated fluid. If there isdoubt about the origin of the continued fever, it may bewise to switch to 10% dextrose and watch the patient care­fully; if there ig no improvement, the catheter should beremoved.

We have had 2 positive blood cultures for Candida. Bothcases had been on large doses of multiple antibiotics for along time, and Candida was grown from all orifices. Thecatheter was removed in each case. One patient's infectionimproved rapidly without further therapy. The otherpatient, however, died in spite of treatment with Ampho­tericin B. He was on I.V. hyperalimentation for only 3days. Ellis and Spivaku recommended that the centralvenous catheter be removed as soon as candidiasis isproved by blood culture. If blood culture the following dayis positive for C. albicans, Amphotericin B should begiven. If blood culture is negative, drug therapy will notbe necessary.

HOW LONG SHOULD I.V. HYPERALIMEN­TATION BE USED?

I.V. hyperalimentation may be discontinued when thepatient is taking sufficient calories by mouth and is gain­ing weight. If a fistula is present and the underlying cause(e.g. distal obstruction, or foreign body) is unlikely to bereversed without surgery, one should not persist with I.V.hyperalimentation. Although the fistula flow usually re-

1496 S.-A. MEDIESE TYDSKRIF 7 Oktober 1972

duces dramatically when LV. hyperalimentation is estab­lished, surgery to correct the defect should be performedas soon as the surrounding skin improves, and nitrogenbalance is restored.

CONCLUSIONS

LV. hyperalimentation is an important modern adjunct tothe care of critically ill surgical patients. Many problemsmay arise with its use, but these can usually be avoidedby careful attention to detail and close supervision. A mal­nourished patient is unlikely to be able to heal his woundsbetter than one who is in positive nitrogen balance bymeans of LV. hyperalimentation.

History 01 Medicine

This study was supported by the Detroit General HospitalResearch Corporation.

REFERE CES

!. Lawson, L. J. (1965): Brit. J. Surg., 52, 795.2. Cahill, G. F. jnr (1970): New Engl. J. Med., 282, 668.3. Morgan, A., Filler, R. M. and Moore, F. E. (1970): Med. C1in.

N. Amer., 54, 1367.4. Dudrick, S. J., Wilmore, D. W., Vars, H. M., and Rhoads, J. E.

(1968): Surgery, 64, 134.5. W.lmore, D. W. and Dudrick, S. J. (1969): Arch. Surg., 98, 256.6. Lucas, C. E. and Irani, F. (1969): New Engl. J. Med., 281, 966.7. Durant, T. M., Long, J. and Oppenheimer, M. J. (1947): Amer,

Heart J., 33, 269.8. Miller, M., Drucker, W. R., Owens, J. E., Craig, J. M. and Wood­

ward, H., jnr (1952): J. Clin. Invest., 31, 115.'9. Bonerjee, S. (1958): Indian J. Med. Res., 46, 269.

10. Dudrick. S. J. (1971): Manual of Preoperat;ve and Posloperllli\'eCare, 2nd ed., p. 102. Philadelphia: W. B. Saunders.

I!. Ross, H., JohnslOn, I. D. A., Welborn, T. A. and Wright, A. D.(1966): Lancet, 2, 563.

12. Ellis, C. A. and Spivak, M. L. (1967): Ann. Intern. Med., 67, 51!.

The Role of the Merino in Medicine *

P. C. BELONJE AND L. P. VOSLOO, Faculty of Agriculture, University of Stellenbosch, Stellenbosch, CP

SUMMARY

A brief account is given of man's earliest associationwith sheep and the subsequent development of the fine­woolled merino in Spain. This is followed by a concisehistory of the origins of the South African and Australianwool industries.

S. Afr. Med. J., 46, 1496 (1972).

The sheep has long been regarded as a valuable supplierof the needs of man. Apart from the more obvious pro­ducts such as meat, wool, and skins, the intestines areused either as sausage casings, or as catgut for surgery,musical instruments, and tennis and squash racquets.Lanolin, or wool-fat, is used as a base for medicinal andcosmetic creams, in certain petroleum products, as arust inhibitor, and even as a growth stimulant for plants.One product has taken some time to gain general accep­tance; Hippocrates suggested about 400 BC that sheep­skins should be used as mattresses for recumbent patients,but only recently have special medical sheepskins beenprepared in South Africa and Australia for this purpose.

Although there are many different types of sheep, themerino, with a total of about 930 milliOll, is numericallyprobably the most important, and the purpose of this

* Date received: 8 March 1972.

article is to give a brief history of this woolled sheep andits interesting association with man.

From archaeological evidence it appears that the sheepwas first domesticated about 8000 years ago in Babylonia.The domestic sheep (Ovis aries) originated from 2 wildtypes, the moufflon (Ovis musimon), and the argali (Ovispoli: Marco Polo's sheep). The wild moufflon is still tobe found on the islands of Corsica and Sardinia, and theargali inhabits the mountainous regions of central Asia.Although it is only a small animal, the argali has 'enor­mous horns, in fact, the Guinness Book of Records claimsthat the longest horns (190,5 cm) found on any wild ani­mal, came from an argali ram.

During early domestication the sheepskin was usedfor clothing, and this in time led to the selection ofwoollier types of animals, which rendered a garment notonly softer and more comfortable, but also with superiorinsulating properties. This progressed even futher, andby 4000 BC the first woollen materials had been woven.It was natural for a close association to develop betweenman and the provider of his material comforts, and thisis borne out by early written history. The Bible forinstance, mentions the sheep no less than 493 times, thefirst mention being in Genesis IV, v,erse 2: 'and Abelwas a keeper of sheep, but Cain was a tiller of theground'. Furthermore, the sheep was used not only as asacrificial gesture, but often symbolically, with GaG asthe Shepherd, as it occurs in Psalm 23: 'The Lord is myShepherd; I shall not want'.