g. l. bryson, md, frcpc, msc department of anesthesiology the ottawa hospital – civic campus...

G. L. Bryson, MD, FRCPC, MScDepartment of AnesthesiologyThe Ottawa Hospital – Civic

Campus

Preoperative Assessment

Risk assessment and management

Department of AnesthesiologyCivic Campus

Objectives

• Perioperative morbidity and mortality• You can’t avoid what you can’t anticipate

• Preoperative testing• Less than you’d expect

• NPO guidelines• Problems


Preoperative assessment

• Just like the rest of medicine…• History• Physical• Laboratory


An approach to preoperative evaluation

• What’s wrong with the patient?• Is the patient is good as they can get?• If not, does it have to be better pre-op?• Getting to the OR is less than half the job.• Anticipate postoperative problems, then plan.


Anesthesia is bad for you• Unable to protect airway

• Aspiration• Obstruction

• Altered control of ventilation• Diminished response to CO2 and O2

• Altered respiratory mechanics FRC, restrictive chest wall defect

• Myocardial depression• Decreased conductivity • Vasodilatation• Immune suppression


The Killing Fields

• Getting patients out of the OR is easy• Getting patients home is another matter• Postoperative course complicated by:

• Increased O2 demand• Myocardial ischemia/infarction• Respiratory depression / VQ mismatching• Hemorrhage • Fluid and electrolyte shifts • Hypercoagulable• Protein catabolism


Causes of 3-day postop mortality

System implicated % of cases

Cardiovascular 59

Respiratory 25

Renal 22

Sepsis 21

Hematological 12

GI 11

Metabolic 10

Surgical condition 9

CNS 8

Hepatic 6

NCEPOD 2002 www.ncepod.org. uk


Functional capacity predicts outcome

• Postoperative cardiac deaths confined to those with VO2Max < 3 METS

Older P. Chest 1999;116:355-62

• Inability to climb 2 flights of stairs 82% PPV (97% specific) for postoperative CV/RS complications

Girish M. Chest 2001;120:1147-51 • Self-reported exercise tolerance < 2 flights of

stairs doubled risk of complications following non-cardiac surgery (20% v 10%)

Reilly DF. Arch Intern Med 1999;159(18):2185-92


ASA Physical Status Classification

Class Description I Healthy II Systemic disease no functional limitation III Systemic disease with functional limitation IV Systemic disease with functional limitation

constant threat to life V Moribund unlikely to survive 24 hrs

with or without surgery E Emergency procedure


ASA class and mortality

ASA Class

Vercanti 1970

Marx 1973

Cohen 1986

Forrest 1990

I 0.07 0.06 0.07 0.00

II 0.24 0.40 0.20 0.04

III 1.43 4.3 1.15 0.59

IV 7.46 23.4 7.66 7.95

V 9.38 50.7 - -


Revised Cardiac Risk Index

Risk Factor Cardiac EventsCrude Data

Adjusted OR(95% CI)

High risk surgery 18/490 (4%)

2.6 (1.3 – 5.3)

CAD 26/478 (5%) 3.8 (1.7 – 8.2)

CHF 19/255 (7%) 4.3 (2.1 – 8.8)

CVD 10/140 (7%) 3.0 (1.3 – 6.8)

Insulin therapy 3/59 (5%) 1.0 (0.3 – 3.8)

Cr > 177 3/55 (5%) 0.9 (0.2 – 3.3)

Lee TH. Circulation 1999;100:1043-1049


Revised Cardiac Risk Index and Cardiac Events

Risk Factors Cardiac Events (%) 95% CI

0 0.4 0.05 – 1.5

1 0.9 0.3 – 2.1

2 6.6 3.9 – 10.3

3 or more 11.0 5.8 – 18.4



Risk Factor PointsType of Surgery

AAA 15

Thoracic 14

Upper Abdominal 10

Neck 8

Neurosurgery 8

Age

> 80 years 17

70 – 79 years 13

60 – 69 years 9

Functional Capacity

Totally dependent 10

Partially dependent 6

Weight Loss > 10% in past 6 mo

7

COPD 5

11 others worth 4

Points Pneumonia (%)

0 – 15 0.24

16 – 25 1.18

26 – 40 4.6

41 – 55 10.8

> 55 15.8

Arozullah AM. Ann Intern Med 2001;135:847-57.

Incidence 1.5%

30-day mortality 21%

Risk factors for postoperative pneumonia


Preoperative testing

• Routine preoperative testing isn’t helpfulMunro J. Health Technology Assessment 1997;1(12)

• Testing should “follow” history and physical• Like most testing, it’s most helpful when you don’t

know what the answer is.• OMA-GAC statement• http://gacguidelines.ca/pdfs/tools/Ontario%20Preoperative%20Testing

%20Grid.pdf

• Elective versus emergency patient


OMA-GAC recommendations

http://gacguidelines.ca/pdfs/tools/Ontario%20Preoperative%20Testing%20Grid.pdf


TOH fasting guidelines

• For elective surgery:• NPO solids at 2400• Unlimited water until 3 hours preop

• For urgent surgery:• NPO solids a minimum of 6 hours• NPO clear fluids 3 hours• Modified by urgency of surgery

• All usual medications given, except• Anticoagulants, oral hypoglycemics, MAOIs• Insulin and glucose require physician order


Withholding preoperative medication

% of patients in whom drug was withheld

Drug Class All surgeries Non-emergency

Anti-anginal 27 22

Anti-arrhythmic 25 20

Anti-hypertensive 34 33

Thyroid 43 31

Bronchodilator 16 15

Steroids 19 17

NCEPOD 2002 www.ncepod.org. uk


Valvular or congenital heart disease

• Stenotic lesions intolerant of changes in preload/afterload

• RL shunts aggravated by hypoxia & SVR • Important to understand the plumbing

• Preoperative echocardiogram helpful • Anticoagulation issues• SBE prophylaxis

• www.americanheart.org/Scientific/statements/1997/079701.html


Subacute bacterial endocarditits

• Oral / dental surgery• Ampicillin 2000 mg (50 mg/kg) IV 60 min pre-op• Cefazolin 1000 mg (25 mg/kg) IV 60 min pre-op• Clindamycin 600 mg (20 mg/kg) IV 60 min pre-op

• Gastrointestinal, genitourinary• As above, plus• Gentamicin 1.5 mg/kg IV 60 minutes pre-op • Vancomycin 1000 mg (20 mg/kg) IV 60 minutes

pre-op, if penicillin-sensitive• Repeat Ampicillin 6 hours post-op if high-risk

pathologyhttp://circ.ahajournals.org/cgi/content/full/96/1/358


Pacemakers and AICDs

• Pacemakers• Should be evaluated preoperatively• If pacemaker dependent, reprogram to VOO• Rate adaptive functions may need to be disabled• Use bipolar cautery, if possible• Short bursts if monopolar required

• AICDs• Must be turned off preoperatively• in monitored environment


Anticoagulation• Normal coagulation expected preoperatively• Neuraxial hematoma & surgical hemorrhage

• Coumadin held for 5 days• INR less than 1.4• LMWH held for 24 hours • UFH held for 6 hours• Fancy antiplatelet drugs withdrawn (7 days)• ASA is OK for most procedures

• Vitamin K needs a day• Don’t drown folks with FFP


I think that’s a blood thinner• Clopidogrel (Plavix) • Abciximab (RheoPro) • Eptifibatide (Integrilin) • Low molecular weight heparins

• Dalteparin (Fragmin)• Enoxaparin (Lovenox)• Nadroparin (Fraxiparin)• Tinzaparin (Innohep)

• Fondaparinux (Arixtra)• Ximelagatran (Exanta)


Summary

• Preoperative assessment must identify and anticipate perioperative problems

• Getting to the OR is the easy part• Communication is essential• Fasting should not exclude hydration or

medication• Laboratory testing should be individualized


The surgeon is a carnivorous beast. It’s happy only when there is fresh meat on the table. Ross Kerridge MD, FRCA

Newcastle, AustraliaAt WCA Montreal 2000

Questions??


Case 1

• 64 yr old male scheduled for hemicolectomy for colon ca. Past history includes:• Diabetes x 15 years (on insulin)• CVA 3 years ago• Stable CCS 3 angina• He takes diltiazem, hctz, and plavix

• What is his risk of cardiovascular event?• What preoperative tests would you order?• What preop instructions would you give?


Revised Cardiac Risk Index

Risk Factor Cardiac EventsCrude Data

Adjusted OR(95% CI)

High risk surgery 18/490 (4%)

2.6 (1.3 – 5.3)

CAD 26/478 (5%) 3.8 (1.7 – 8.2)

CHF 19/255 (7%) 4.3 (2.1 – 8.8)

CVD 10/140 (7%) 3.0 (1.3 – 6.8)

Insulin therapy 3/59 (5%) 1.0 (0.3 – 3.8)

Cr > 177 3/55 (5%) 0.9 (0.2 – 3.3)



Risk of cardiac morbidity?



AHA ACC guidelines for cardiac evaluation prior to noncardiac surgery


What about ß-blockers?

Mangano Poldermans

Treated Control Treated Control

Patients 99 101 59 53

In-hospital mortality 1(1) 2 (2) 2 (3) 9 (17)

In-hospital death/mi 2 (2) 4 (4) 2 (3) 18 (34)

Post-discharge PCM* 16 (17) 32 (32) 8 (14) 14(32)

Mangano DT. NEJM 1996;335(23):1713-20Wallace A. Anesthesiology 1998;88(1):7-17

Poldermans D. NEJM 1999;341(24):1789-94Poldermans D. Eur Heart J 2001;22(15):1353-8.


An aspirin an day…

Neilipovitz DA. A&A 2001;93:573-80

Outcome ASA % No ASA %

MI 2.71 4.61

CVAt 1.12 1.69

CVAh 0.59 0.37

GI bleed 0.76 0.35

Wound bleed 7.71 5.58

All adverse events 12.89 12.90

Mortality 2.05 2.78

QALY 14.79 14.72


ASA and perioperative hemorrhage

Antiplatelet Trialists’ Collaboration. III. BMJ 1994;308:235-48Pulmonary Embolism Prevention Trial. Lancet 2000;355:1295-302

ATC III PEP

Bleed Control Treated Control Treated

Fatal 0 0.05 0.2 0.2

Major 0.4 0.7 2.4 2.9

Wound 5.6 7.8 3.9 4.4


Case 2

• A 45 yr old male is scheduled for TURP.• He has hypertension, atrial fibrillation, and

had a mechanical aortic valve placed 4 years ago.

• He takes metoprolol and coumadin.• What investigations?• What instructions?


Coumadin and thrombosis

IndicationAnnual Risk

TreatedAnnual Risk

UntreatedRisk

Reduction

Atrial fibrillation 2.3 % 7.4% 67%

Aortic valve 1.9% 12.3% 85%

Mitral valve 4.7% 22.2% 79%


Who needs special care with coumadin?

• DVT < 3 months ago• History of recurrent DVT• Arterial thromboembolism < 3 months ago• Mechanical prosthetic heart valves• Tissue prosthetic heart valves + embolism• Thrombophilia (lupus ac, Factor V - L, C&S)• Atrial fibrillation + embolism


Coumadin withdrawal plan

• Day -5. Stop coumadin.• Day -3. Dalteparin 200 u·kg-1 sc.• Day -2. Dalteparin 200 u·kg-1 sc.• Day -1. Dalteparin 100 u·kg-1 sc.• Day 0. Check INR pre-op• Day +1. Is surgical blood loss controlled?

Restart coumadinDalteparin 200 u·kg-1 until INR

>2.0


Subacute bacterial endocarditits

• Oral / dental surgery• Ampicillin 2000 mg (50 mg/kg) IV 60 min pre-op• Cefazolin 1000 mg (25 mg/kg) IV 60 min pre-op• Clindamycin 600 mg (20 mg/kg) IV 60 min pre-op

• Gastrointestinal, genitourinary• As above, plus• Gentamicin 1.5 mg/kg IV 60 minutes pre-op • Vancomycin 1000 mg (20 mg/kg) IV 60 minutes

pre-op, if penicillin-sensitive• Repeat Ampicillin 6 hours post-op if high-risk

pathologyhttp://circ.ahajournals.org/cgi/content/full/96/1/358


Case 3

• 45 yr old female for lumbar spinal fusion• Uses “some percocets” for pain control• Smokes 1.5 packs per day


Smoking is bad for you

• 6x increase in pulmonary complications• Need to stop > 4 weeks preop

Bluman LG. Chest 1998 Apr;113(4):883-9

• 3x increase in wound complications following breast surgery

Sorensen LT Eur J Surg Oncol 2002 Dec;28(8):815-20

• 2x increase risk of bony non-unionAndersen T. Spine 2001 Dec 1;26(23):2623-8


Smoking cessation works

Cessation Control

n 56 52

Age 66 64

Pack years 35 37

Wound 3 (5%) 16 (31%)

Reoperation 2 (4%) 8 (15%)

Any complication 10 (18%) 27 (52%)

Moller AM. Lancet 2002;359:114-7


Narcotic tolerance

• Important to document just how much narcotic patients are taking preoperatively

• Previous intake must be accommodated in perioperative care

• If patient takes 2 percocets 6 x day• 60 mg oxycodone = 90 mg morphine• 90 mg morphine po = 22.5 mg morphine IV• Adjust PCA settings accordingly


Regional anesthesia and outcome

Rodgers A.BMJ 2000;321:1–12

g. l. bryson, md, frcpc, msc department of anesthesiology the ottawa hospital – civic campus...

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