2009.01.06 1

Preoperative Assessment

Dr. Greg BrysonHead, Pre-Admission UnitsDepartment of Anesthesiology

22009.01.06

Goals n objectives Understand the role of patient history in

preoperative evaluation Identify risk factors adverse outcomes Recognize limited role of testing in healthy

patients Highlight planning issues for common

preoperative problems

32009.01.06

Resectable vs Operable Resectability is surgical decision making

Does this operation suit the patient’s problem? You folks will be the experts on this subject

Operability is a shared responsibility Will this patient tolerate the given procedure? Will this patient leave the hospital? Return to function?

Anesthesia Critical Care Internal medicine Rehabilitation Family medicine

42009.01.06

Anesthesia is bad for you Unable to protect airway Altered control of ventilation

Diminished response to Raw, CO2, and O2

Altered respiratory mechanics FRC, restrictive chest wall defect

Decreased contractility Decreased conduction Vasodilatation

52009.01.06

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

62009.01.06

Functional capacity and outcome

The ability to do predicts risk Patients who can’t hack the activities of

daily living must be carefully evaluated/optimized before surgery

72009.01.06

Put your clinic on the 3rd floor

Girish M. Chest 2001;120:1147-51

82009.01.06

ACC-AHA 2007 Guidelines

Fleisher LA. Circulation 2007; 116:e418-99

92009.01.06

Pulmonary resection

Slinger PD. J Cardiothorac Vasc Anesth 2000;14:202-11

102009.01.06

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

112009.01.06

ASA class and mortalityASA

Class Vercanti

1970 Cohen 1986

Forrest 1990

Lagasse 2005

I 0.07 0.07 0.00 0.01

II 0.24 0.20 0.04 0.03

III 1.43 1.15 0.59 0.13

IV 7.46 7.66 7.95 0.84

V 9.38 - - 22.02

122009.01.06

Causes of 3-day postop deathSystem implicated % of cases

Cardiovascular 59

Respiratory 25

Renal 22

Sepsis 21

Hematological 12

GI 11

Metabolic 10

Surgical condition 9

CNS 8

Hepatic 6NCEPOD 2002 www.ncepod.org. uk

132009.01.06

Cardiac risks

142009.01.06

Revised Cardiac Risk Index

Risk FactorPrevalence

n (%)Adjusted OR

(95% CI)

High risk surgery 490 (34)

2.6 (1.3 – 5.3)

Coronary artery disease 478 (34) 3.8 (1.7 – 8.2)

Congestive heart failure 255 (18) 4.3 (2.1 – 8.8)

Cerebrovascular disease 140 (10) 3.0 (1.3 – 6.8)

Insulin therapy 59 (4) 1.0 (0.3 – 3.8)

Creatinine > 177 umol/l 55 (4) 0.9 (0.2 – 3.3)

Lee TH. Circulation 1999;100:1043-1049

Validation cohort n = 1422Major cardiac events = 36 (2.5%)

152009.01.06

Revised Cardiac Risk Index

Risk Factor

High risk surgery

History of CAD

History of CHF

History of stroke

Diabetes mellitus

Cr > 177

Risk FactorsEvents

(%)95% CI

0 0.4 0.05 – 1.5

1 0.9 0.3 – 2.1

2 6.6 3.9 – 10.3

3 11.0 5.8 – 18.4

162009.01.06

Preoperative ECG in the elderly

Liu LL. JAGS 2002;

50:1186-91

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Pulmonary risks

182009.01.06

CXR - systematic review

Tests %Abnormal %Change %Events

Routine (8) 21517.4

(2.5–37)

0.5

(0–2.1)

1.2

(0–6.8)

Routine + Indicated

(28)18913

20

(1.4–60)

2.4

(0–5.9)

1.2

(0–8.8)

Results reported as median (range)

Munro J. Health Technol Assess 1997;1:1-62

192009.01.06

What is the risk of postop pneumonia?

Score Risk (%)

0-15 0.2

16-25 1.2

26-40 4.6

41-55 10.8

56 or more 15.9

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

202009.01.06

Spirometry and pulmonary events?

McAlister FA. Am J Resp Crit Care Med 2005;171:514-7

Variable Odds Ratio P Value

Age > 65 5.9 <0.001

Cough Test 3.8 0.01

NG Tube 7.7 <0.001

GA > 2.5 hrs 3.3 0.008

Abnormal CXR 1.80 (0.41-7.85)FEV1<1000 6.51 (1.36-30.6)

212009.01.06

Renal risks

222009.01.06

Risk factors for renal failure

Kheterpal S. Anesthesiology 2007;107:869-70

232009.01.06

Risk factors for renal failure

Kheterpal S. Anesthesiology 2007;107:869-70

242009.01.06

What tests would you order?

252009.01.06

Preop bloodwork in the elderly?

Risk Factor OR (95% CI)

ASA Class > II 2.55 (1.6 – 4.2)

Surgical Risk 3.48 (2.3 – 5.2)

Dzankic S. Anesth Analg 2001; 93(2):301-8

262009.01.06

NHS - Routine preoperative tests

“…produce a wide range of abnormal results, even in apparently healthy individuals.”

“..the clinical importance of these abnormal results is uncertain.”

“…lead to changes in clinical management in only a very small proportion of patients and for some tests virtually never.”

Munro J Health Technol Assess 1997;1:1-62

272009.01.06

Big picture… Information from history provides most

predictive value Preoperative assessment is not about

ordering tests Preoperative assessment is about talking

to patients Consult if unsure or unusual condition

282009.01.06

Some Caveats… Trials reflect elective surgery

Acute illness should influence choice of tests Trials don’t reflect your staff guy

Some tests ordered as part of a larger workup Some habits are hard to break

Be reasonable Get an INR on someone taking coumadin Get an ECG in a guy with a pacemaker

Refer to testing directive if in doubt Appendix M in the Periop Navigator

292009.01.06

Trouble spots Some patients cause more trouble in the

OR than others.Anesthesiologist looks pissed offSurgeon upset case cancelled$#!t runs down hill

These issues can be worked around if communicated in advance

302009.01.06

A is for Airway Misadventures in airway management are

leading cause of anesthesia-related morbidity/mortality Past history of airway problems Head and neck trauma Head and neck masses Morbid obesity Short chin (think Joe Clark)

Easily dealt with, but requires planning

312009.01.06

Fasting is about the airway Regurgitation and aspiration of gastric

contents under anesthesia can make a bad airway day worse.

Increased morbidity/mortality with solid, acidic gastric contents

Ottawa Hospital Fasting Guidelines 8 hour fast for solids 3 hour fast for water

Ranitidine 90 min preop to increase pH in those with reflux

322009.01.06

B is for Breathing Chronic, stable pulmonary disease is

something to be worked around Acute decompensation should be fixed

preopWheezing asthmatic Increased SOB in COPDProductive cough with fever

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C is for Circulation/Clopidogrel

Artang R. Am J Cardiol 2007;99:1039–43

342009.01.06

D is for Device/Defibrillator Pacemakers

Electrocautery may inhibit pacing If pacemaker dependent, reprogram to VOO Use bipolar cautery, if possible Short bursts if monopolar required

AICDs Electrocautery may cause defibrillation Must be turned off in monitored environment Sign of badness

352009.01.06

E is for Electrolytes Euvolemia is expected Beware the patient with

GI pathology Diuretics Malignancy

These numbers will usually get you cancelled K+ less than 2.7 or greater than 5.5 Na+ less than 120 or greater than 150 Ca + + less than 1.0 or greater than 3.0

362009.01.06

F is for Family History Malignant hyperthermia

Autosomal dominant, variable, 1:50000 Disordered calcium handling by skeletal muscle TO, acidosis, rhambdomyolysis,hyperkalemia…

Atypical plasma cholinesterase Autosomal recessive, 1:3000 Unable to metabolize succinylcholine 10 minute drug now lasts hours.

Friend of a friend

372009.01.06

G is for G$d D#mn Anticoagulants 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) Beware drug eluting stents ASA is OK for most procedures

Don’t drown folks with FFP Octaplex 40 units for average adult Vitamin K 1-2 mg (plus time) often enough

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H is for Held Medications NPO does not mean hold medications In general, keep patients on the medications

they take every day, in particular… Antianginals Antihypertensive Antiarrythmics Puffers Steroids Narcotics

392009.01.06

Withholding preop medications

% 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

Bronchodilator 16 15

Steroids 19 17

NCEPOD 2002 www.ncepod.org. uk

402009.01.06

Summary Patients not expected to be perfect Patients expected to be at “their best” More talk…less test Poor functional capacity is trouble Shared care Trouble starts when they leave the OR