Preoperative Evaluation

1. Preoperative Evaluation B. Wayne Blount, MD, MPH Professor, Emory

2. 67% of consultations were for preoperative evaluation. In 12% of cases, the findings of the consultation resulted in a significant change in perioperative management; in 7%, surgery was delayed; a decision was made to cancel surgery altogether in 2% of cases. • Mollema, et al (2000) Neth J Med 56:7

3. Why Preoperative Evaluation? • 10 percent of the United States population undergoes non-cardiac surgery annually. • Over 8 million have known CAD or cardiac risk factors. • Over 50,000 will suffer a perioperative myocardial infarction. (0.2%)

4. “The purpose of preoperative evaluation is not to give medical clearance, but rather to perform an evaluation of the patient’s current medical status; make recommendations concerning the evaluation, management, and risk of cardiac problems over the entire perioperative period; and provide a clinical risk profile that the patient, primary physician, anesthesiologist, and surgeon can use in making treatment decisions…” Kim A. Eagle, FACC, Chair, ACC/AHA Task Force on Practice Guidelines for Perioperative Cardiovascular Evaluation for Noncardiac Surgery

5. What are You Really Being Asked to Do? • Assess risks of anesthesia • Assess the risks of the procedure • Manage “complicated” medical problems • Predict the future

6. General Considerations • Limit number of recommendations • Focus on critical problems • Be specific about drugs, dosage and intervals • Don’t ask the surgeon to think

7. Misconceptions • Advise on type of anesthesia • General, local or spinal • Change ongoing treatment plans • Initiate diagnostic work-ups • If not in-patient doc, manage perioperative problems

8. Steps to Preoperative Evaluation** • Surgical Risk Factors • Patient Risk Factors • Preoperative Testing • Perioperative Management

9. Risk: Type of ProcedureACC/AHA Guidelines • High risk (reported risk of adverse cardiac event >5%) • Emergency surgery • Aortic procedures • Peripheral vascular surgery • Prolonged surgical procedures associated with large volume shifts or high EBL • ‘A’ Rec

10. Risk: Duration of Anesthesia Reilly, et al. (1999) Arch Int Med 159:2185 Percent Complications Duration (hours)

11. Risk: Type of ProcedureACC/AHA Guidelines • Intermediate Risk (reported cardiac risk < 5%) • Carotid endarterectomy • Head and neck surgery • Intraperitoneal and Intrathoracic • Orthopedic surgery • Prostate surgery • ‘A’ Rec

12. Risk: Type of ProcedureACC/AHA Guidelines • Low risk (reported cardiac risk < 1%) • Endoscopic procedures • Superficial procedures • Cataract surgery • Breast surgery • ‘A’ Rec

13. Steps to Preoperative Evaluation • Surgical Risk Factors • Patient Risk Factors • Preoperative Testing • Perioperative Management

14. Patient Factors** • Exercise Capacity • Medication use • Obesity • Age • Labs EKG CXR PFT

15. Who’s at Risk : ‘B’ Rec** • Recent MI ( < 30 days) • Valvular heart disease • CHF • Unstable angina • Diabetes

16. Patient Factors: Exercise Tolerance

17. McPhail, et al (1988) J Vasc Surgery 7:60 • Patients able to achieve 85% of their maximal predicted heart rate had a 6% cardiac complication rate, whereas patients unable to achieve 85% MPHR had a 24% rate of complications (p = 0.04) • Patients who had a positive stress test but achieved > 85% MPHR had fewer cardiac complications.

18. 1 MET: the oxygen consumption (VO2) of a 70 kg, 40 y.o. man at rest…3.5 cc/kg/minDuke Activity Status Index < 4 METS:> 4 METS: Baking Ice skating Slow dancing Moderate cycling Golfing with a cart Walking 4 mph Playing a musical instrument Heavy housework Walking 2 – 3 mph Skiing

19. Exercise Capacity • 4 METs - • Two level blocks without symptoms • One flight of stairs with two bags of groceries Poor exercise capacity: < four level blocks or two flights of stairs Complications: Total: 20% vs 10% Cardiac: 10% vs 5% Pulmonary: 9% vs 6% (not statistically signif.)

20. Functional Capacity in METS • 10 METS : Excellent • 7 – 10 METS : Good • 4 - 6 METS : Moderate • < 4 METS : Increased risk for cardiopulmonary complications

21. Risk: Patient FactorsMajor Clinical Predictors ACC/AHA Guidelines ** • Unstable coronary syndromes • Decompensated CHF • Significant arrhythmias • Severe valvular disease

22. Risk: Patient FactorsIntermediate Clinical PredictorsACC/AHA Guidelines • Mild angina pectoris • Prior MI • Compensated or prior CHF • Diabetes mellitus • Renal insufficiency

23. Risk: Patient FactorsMinor Clinical PredictorsACC/AHA Guidelines • Advanced age • Abnormal ECG • Rhythm other than NSR • Low functional capacity • History of CVA • Uncontrolled HTN

24. Pulmonary Risks • Complications • Hypoventilation • Pneumonia • Atelectasis • Occur in about a third of patients • Accounts for half of perioperative mortality

25. Who’s at Risk** • Smokers • COPD • Obesity • Age > 70 • Thoracic surgery • Upper abdominal surgery • Anesthesia > 2 hours

26. PFTs : ‘B’ Rec • No improvement over clinical eval • Where the money is: • Decreased breath sounds • Prolonged expiratory phase • Rales, rhonchi, wheezes • PFTs for unexplained dyspnea after good clinical eval

27. Risk Assessment : ‘C’ Rec • FEV1 > 2L, probably safe • FEV1 between 1 and 2L, increased risk • FEV1 < 1L, high risk

28. Risk Management** • Quit smoking • Bronchodilator therapy • CPT (including incentive spirometry) • Early treatment of bronchitis • Early mobilization

29. CXR : ‘C’ Rec • Abnormalities not well associated with post-operative risk • 0.1% affected management • Routine use not recommended • 2 exceptions • > 60y • Suspected cardiac or pulmonary disease

30. Steps to Preoperative Evaluation • Surgical Risk Factors • Patient Risk Factors • Preoperative Testing: • Who • How • Perioperative Management

31. Cardiac Testing: Resting ECG** • Class I (definite indication) • Recent ischemic symptoms • Major / intermediate clinical predictors and high or intermediate risk procedure • Class II (probably warranted) • Asymptomatic diabetics • History of cardiac revascularization • Asymptomatic man > 45 yo or woman > 55 yo • Prior hospitalization for cardiac causes • Class III (not indicated) • Asymptomatic patient; low risk procedure

32. Risk: Type of ProcedureACC/AHA Guidelines • High risk (reported risk of adverse cardiac event >5%) • Emergency surgery • Aortic procedures • Peripheral vascular surgery • Prolonged surgical procedures associated with large volume shifts or high EBL • ‘A’ Rec

33. Risk: Type of ProcedureACC/AHA Guidelines • Intermediate Risk (reported cardiac risk < 5%) • Carotid endarterectomy • Head and neck surgery • Intraperitoneal and Intrathoracic • Orthopedic surgery • Prostate surgery • ‘A’ Rec

34. Risk: Patient FactorsMajor Clinical Predictors ACC/AHA Guidelines ** • Unstable coronary syndromes • Decompensated CHF • Significant arrhythmias • Severe valvular disease

35. Risk: Patient FactorsIntermediate Clinical PredictorsACC/AHA Guidelines • Mild angina pectoris • Prior MI • Compensated or prior CHF • Diabetes mellitus • Renal insufficiency

36. Echocardiography • Class I (definite indication) • Current or poorly-controlled CHF unless prior studies have documented severe ventricular dysfunction • Class II (probably warranted) • Prior CHF and no recent evaluation • Dyspnea of unknown etiology • Evidence of significant valvular disease • Class III (not indicated) • Routine testing of ventricular function in asymptomatic patients without a prior history of CHF

37. Need for non-cardiac surgery emergency O. R. elective N Y Recurrent S/sx? Recent cardiac revascularization ? N Y Recent cardiac evaluation? Favorable result? N Unfavorable result or change in sx? • Clinical Predictors ACC/AHA Guidelines

38. Labs : ‘C’ Rec • CBC • Asymptomatic anemia <1% prevalence • Surgically significant anemia is even lower • Mortality for surgery with expected blood loss • Hct >12  1.3% • Hct < 6  33% • Remainder of CBC not useful (wbc,plt)

39. Steps to Preoperative Evaluation • Surgical Risk Factors • Patient Risk Factors • Preoperative Testing: • Who • How • Perioperative Management

40. Perioperative Management: Beta-Blockers Poldemans D, et al (1999) NEJM 341:1789 • Cardiac complications and cardiac death was significantly less in the treatment group (p=0.02): • Bisoprolol 3.4 % • Placebo 17.0 % Wallace A, et al (1998) Anesthesiology 88:7 • Patients treated with Atenolol had significantly fewer episodes of ischemia by continuous monitoring (p=0.03)

41. Beta Blockers • Beta Blockers should be given perioperatively to patients with known ischemic heart disease undergoing vascular surgery or who have previously taken beta blockers A Rec • Beta blockers generally are not recommended for patients with low to moderate risk B Rec

42. Beta Blockers • Long-acting better than shorter-acting ones • Better when titrated to pulse of < 65 bpm; Rec B • More effective when started at least 30 days prior to surgery AND continued thru hospital stay; Rec C • Fewer MIs, but more CVAs • Need to do a risk analysis using Revised Cardiac Risk Index (RCRI). Use beta-blockers in pts with scores of > 3.

43. RCRI • 1 Point each for : • High Risk Surgery • Ischemic Heart Disease • Cerebrovascular Disease • Renal Insufficiency • Diabetes

44. Perioperative Beta-blockade to Prevent 1 Death • NNT = 33 with RCRI Score of 4 + • NNT = 62 with RCRI of 3 • NNT = 227 with RCRI of 2 • NNT = 864 with RCRI of 1 • NNK = 504 with RCRI of 1 • Lindenaur. Perioperative Beta-Blocker…. NEJM 2005;353:349-61. • POISE Study Grp. Lancet;May 13, 2008

45. When to stop Aspirin (general indication) 14 days Aspirin (TIA / CVA / MI) 7 days NSAIDS 3-7 days Cox II inhibitors -------- Clopidogrel (Plavix) 4-7 days Persantine 7 days Coumadin variable Herbal remedies 14 days (Gingko, Ginseng, Garlic, Feverfew) Perioperative Management:Blood Thinners

46. Perioperative Management of Selected Drugs:

47. Preoperative management of diabetics: • General anesthetic produces relative insulin hyposecretion and resistance due to changes in neuroendocrine balance (increased production of ACTH, catecholamines, GH, and glucagon). • Postoperative factors such as inability to eat or absorb oral medications, use of steroids, hyperalimentation or tube feeds can affect glycemic control. • Perioperatively: • Assess glycemic control preoperatively. • Oral hypoglycemics can generally be continued up until the time of surgery but should not be taken on the morning of the procedure. Metformin should be held for 48 hours postoperatively, and then restarted only if renal and hepatic function are stable. • The dose of intermediate and long-acting insulins should be reduced on the night prior to surgery. • For long or complicated procedures in patients requiring insulin, intravenous insulin should be used in the immediate perioperative period. For short procedures, it may be possible to either delay the use of morning insulin, or use a fraction of the normal dose of intermediate-acting insulin.

48. Risk Management • Monitor for perioperative ischemia • Repair severe aortic stenosis first • Treat CHF aggressively preoperatively • Postpone non-emergent procedures for at least 6 months after an MI

49. Summary • Pre-op eval is not “clearance” • Determine risks, then minimize • Let surgeon, anesthesia do the “clearing” • Screening Labs/Tests rarely useful • Should be driven by suspicions from eval/hx • Perioperative beta blockers decrease mortality: ‘A” Rec. Cochrane

50. Links Articles • http://www.acc.org/clinical/guidelines/perio/update/periupdate_index.htm • http://www.aafp.org/afp/20040415/poc.html • http://www.americanheart.org/presenter.jhtml?identifier=1960 • Smetana, Gerald W. in: http://uptodateonline.com/utd/content • Flood C &Fleisher L. AFP2007;75:656-65. • forms • http://www.aafp.org/afp/20040415/pocform.html • http://uptodateonline.com/utd/content/image.do?imageKey=prim_pix/preop_pa.gif