Medical Consultation and Preoperative Evaluation

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					Medical Consultation and Preoperative Evaluation

Diane Doerner MD PhD
University of Washington Medical Center

Ten Commandments for Effective Consultations
• Determine the question being asked

1. Determine the question being asked.
2. Establish the urgency of the consult. 3. Gather primary data.

4. Communicate as briefly as possible. 5. Make specific recommendations.
Goldman, L et al. Arch Int. Med (1983), 143: 1753

Ten Commandments for Effective Consultations
• Determine the question being asked

6. Provide contingency plans.
7. Understand your role in the process. 8. Offer educational information.

9. Communicate recommendations directly. 10. Provide appropriate follow-up.
Goldman, L. et al. Arch Int. Med (1983), 143: 1753

• One study looking at patterns of consultation among internists showed that 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

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. • The economic burden of these complications has been estimated at more than $20 billion annually.

“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

Steps to Preoperative Evaluation
1. Surgical Risk Factors 2. Patient Risk Factors 3. Preoperative Testing 4. Perioperative Management

Case 1
• A 74-year old man is referred to you for preoperative evaluation prior to undergoing a right total hip replacement. He is severely limited due to his osteoarthritis and can ambulate only limited distances in the home. His medical history is notable for CAD, for which he underwent an uncomplicated 3-vessel CABG 2 years ago. He has been symptom-free since. He has mild HTN and chronic renal insufficiency with a creatinine of 2.0 at baseline. Other than his CABG, he has no surgical history. His current medications include aspirin and lisinopril, 10 mg daily. His vital signs are notable for a BP of 140/87, HR 88. Examination is essentially normal.

– What are his surgical and medical risk factors?

Risk: Type of Procedure
ACC/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

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

70 60 50

Percent Complications

40 30 20 10 0
0 - 3.9 4 - 7.9 8 - 11.9 12 - 15.9 16 +

Duration (hours)

Risk: Type of Procedure
ACC/AHA Guidelines

• Intermediate Risk (reported cardiac risk < 5%)
– – – – – Carotid endarterectomy Head and neck surgery Intraperitoneal and Intrathoracic Orthopedic surgery Prostate surgery

Risk: Type of Procedure
ACC/AHA Guidelines

• Low risk (reported cardiac risk < 1%)
– – – – Endoscopic procedures Superficial procedures Cataract surgery Breast surgery

Case 1
• A 74-year old man is referred to you for preoperative evaluation prior to undergoing a right total hip replacement. He is severely limited due to his osteoarthritis, and can ambulate only limited distances in the home. His medical history is notable for CAD, for which he underwent an uncomplicated 3-vessel CABG 2 years ago. He has been symptom-free since. He has mild HTN and chronic renal insufficiency with a creatinine of 2.0 at baseline. Other than his CABG, he has no other surgical history. His current medications include aspirin and lisinopril, 10 mg daily. His vital signs are notable for a BP of 140/87, HR 88. Examination is essentially normal.

– What are his surgical and medical risk factors?

Steps to Preoperative Evaluation
1. 2. 3. 4. Surgical Risk Factors Patient Risk Factors Preoperative Testing Perioperative Management

Patient Factors: Exercise Tolerance

• McPhail, et al (1988) J Vasc Surgery 7:60
– 100 patients requiring vascular reconstructive surgery were evaluated preoperatively with treadmill testing or arm ergometry. – 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.

1 MET: the oxygen consumption (VO2) of a 70 kg, 40 y.o. man at rest…3.5 cc/kg/min
Duke Activity Status Index

< 4 METS:
Baking Slow dancing Golfing with a cart Playing a musical instrument Walking 2 – 3 mph

> 4 METS:
Ice skating Moderate cycling Walking 4 mph Heavy housework Skiing

Risk: Patient Factors Major Clinical Predictors
ACC/AHA Guidelines

• Unstable coronary syndromes • Decompensated CHF • Significant arrhythmias • Severe valvular disease

Risk: Patient Factors Intermediate Clinical Predictors
ACC/AHA Guidelines

• Mild angina pectoris • Prior MI • Compensated or prior CHF • Diabetes mellitus • Renal insufficiency

Risk: Patient Factors Minor Clinical Predictors
ACC/AHA Guidelines

• • • • • •

Advanced age Abnormal ECG Rhythm other than NSR Low functional capacity History of CVA Uncontrolled HTN

Case 1
• A 74-year old man is referred to you for preoperative evaluation prior to undergoing a right total hip replacement. He is severely limited due to his osteoarthritis, and can ambulate only limited distances in the home. His medical history is notable for CAD, for which he underwent an uncomplicated 3-vessel CABG 2 years ago. He has been symptom-free since. He has mild HTN and chronic renal insufficiency with a creatinine of 2.0 at baseline. Other than his CABG, he has no other surgical history. His current medications include aspirin and lisinopril, 10 mg daily. His vital signs are notable for a BP of 140/87, HR 88. Examination is essentially normal.

– What are his surgical and medical risk factors? – What preoperative testing is indicated?

Steps to Preoperative Evaluation
1. Surgical Risk Factors 2. Patient Risk Factors 3. Preoperative Testing:
• • Who How

4. Perioperative Management

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

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

Need for non-cardiac surgery elective

emergency N Y
Recurrent S/sx?

O. R.

Recent cardiac revascularization ? N
Recent cardiac evaluation? N

Y Favorable result? Unfavorable result or change in sx?

Clinical Predictors

ACC/AHA Guidelines

Clinical Predictors
Major Clinical Predictors? Intermediate or Minor Clinical Predictors?

Further evaluation

Exercise Tolerance?

Poor Exercise Tolerance: < 4 METS

Good Exercise tolerance: > 4 METS

Minor or No Clinical Predictors

Poor Exercise Tolerance: < 4 METS

Good Exercise tolerance: > 4 METS

High risk procedure

Intermediate or low risk procedure

Non-invasive cardiac testing High risk
Further evaluation

Low risk

O. R.

Intermediate clinical predictors Poor Exercise Tolerance: < 4 METS Good Exercise tolerance: > 4 METS

High risk procedure

Intermediate risk procedure Low risk procedure

Non-invasive cardiac testing High risk Further evaluation
Low risk

O. R.

Preoperative Stress Testing:**
Major clinical predictors? N Y Further evaluation

2 or more of the following: * Intermediate clinical predictors * Poor exercise tolerance < 4 METS * High risk surgery Y Patient ambulatory and can exercise?

N

O.R.

** Test ONLY if outcome will impact management

Patient ambulatory and can exercise?
N
Bronchospasm? Second degree AV block? Theophylline dependent? Valvular dysfunction?

Y
Male, normal ECG at rest?

N
ETT Echo or Perfusion scan

Y
ECG ETT

Y

N

Prior symptomatic arrhythmia? Poor Echo window? Extreme blood pressure?

Hx Arrhythmias? N Severe HTN?

Pharmacological Echo or Perfusion Scan Persantine or Adenosine Perfusion Scan

Y Further evaluation

N
Dobutamine Echo or Perfusion Scan

Y

Perioperative Management: Percutaneous Intervention (PCI)
• No randomized trials have demonstrated benefit of balloon angioplasty or stenting in decreasing cardiac risk before non-cardiac surgery. • Posner KL, et al (1999) Anesth Analg 89:553
– Retrospective cohort study comparing patients undergoing preoperative PTCA, patients with known CAD that did not undergo PTCA preoperatively, and normal controls (no known CAD). – No reduction in early postoperative MI or death in patients who underwent PTCA. – Study was not controlled for severity of CAD, differences in medical management between the groups, or comorbidity.

Case 1
• A 74-year old man is referred to you for preoperative evaluation prior to undergoing a right total hip replacement. He is severely limited due to his osteoarthritis, and can ambulate only limited distances in the home. His medical history is notable for CAD, for which he underwent an uncomplicated 3-vessel CABG 2 years ago. He has been symptom-free since. He has mild HTN and chronic renal insufficiency with a creatinine of 2.0 at baseline. Other than his CABG, he has no other surgical history. His current medications include aspirin and lisinopril, 10 mg daily. His vital signs are notable for a BP of 140/87, HR 88. Examination is essentially normal.

– What are his surgical and medical risk factors? – What preoperative testing is indicated? – What measures would you initiate preoperatively to optimize his risk?

Steps to Preoperative Evaluation
1. Surgical Risk Factors 2. Patient Risk Factors 3. Preoperative Testing:
• • Who How

4. Perioperative Management

Perioperative Management: Beta-Blockers
Poldemans D, et al (1999) NEJM 341:1789
– 112 patients identified to be at increased cardiac risk (positive dobutamine Echo) preoperatively were randomized to treatment with bisoprolol or placebo. – Cardiac complications and cardiac death was significantly less in the treatment group (p=0.02):
• Bisoprolol • Placebo 3.4 % 17.0 %

Wallace A, et al (1998) Anesthesiology 88:7
– 200 patients undergoing general surgery were randomized to 7 day treatment with Atenolol or placebo. – Patients treated with Atenolol had significantly fewer episodes of ischemia by continuous monitoring (p=0.03)

Perioperative Management: Cardiac Devices
• Pacemakers:
– Current generated through use of electrocautery can interfere with function of implantable devices: • Temporary reset to a VVI mode • Increase in pacing rate due to activation of rate-responsive sensor • Failure to sense or capture

Recommendations: *Obtain information preoperatively regarding the pacer manufacturer, model
and serial number, battery status, and most recent interrogation. *If the pacer is programmed in a rate-responsive mode, this feature should be inactivated preoperatively. *If a patient is pacer-dependent, temporary reset to a non-sensing mode preoperatively may be indicated. *Operative techniques to minimize stray current (short electrocautery strokes, placement of electrocautery grounding pad away from pacer pocket).

Perioperative Management: Cardiac Devices
• Implantable Defibrillators:
– Can fire due to activation by stray electrical current from electrocautery use – Must be programmed OFF preoperatively and then reactivated postoperatively – Place defibrillator patches intraoperatively – Telemetry monitoring is indicated postoperatively until the AICD has been reactivated.

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

Perioperative Management of Selected Drugs:
Drug Beta-blockers
Clonidine Calcium channel blockers

Preoperative Continue including day of surgery (DOS)
Continue including DOS Continue including DOS

Long NPO period Substitute IV form
Substitute transdermal form Substitute IV form for arrhythmia.

ACEI

HTN (-) CRI: Continue on DOS. CHF or CRI: Hold on DOS Hold on DOS

Substitute Hydralazine / NTP Use IV diuretic prn

Diuretics
Oral contraceptives and HRT

Hold 4-6 weeks preop for Hold 4-6 weeks preop for surgery with high risk of surgery with high risk of thrombosis. thrombosis.

Case 2
• A 60-year old woman is referred to you for preoperative evaluation prior to undergoing a right femoral-popliteal bypass procedure. She develops symptoms of claudication at about 1 block but states she can walk 2 blocks if need arises. Her medical history is otherwise notable for obesity, hyperlipidemia and type II diabetes, diagnosed 6 years ago and well controlled on oral medications. ROS is significant for infrequent atypical CP. Her current medications include glucophage and atorvastatin and cilostazol. Her vital signs are normal. Examination is only remarkable for a cool right lower extremity with a non-palpable dorsalis pedis pulse. Cardiopulmonary examination is normal and there are no bruits. – What are her surgical and medical risk factors? – What preoperative testing is indicated? – What measures are needed perioperatively?

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.

THANKS


				
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