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Attending Version:

Preoperative Evaluation; created by Dr. Meg Lieberman

Objectives:

  1. Be able to identify patients at significant risk for perioperative cardiac morbidity.
  2. Identify patients who are candidates for empiric beta blockade, vs. stress imaging and/or invasive management.
  3. Be able to list 3 patient-related and 4 procedure-related risk factors for post-operative pulmonary complications.
  4. Identify 3 interventions that have been shown to reduce the incidence of post- operative pulmonary complications.
  5. Describe principles of perioperative medication management.

References:

1. Eagle KA, Berger PB, Calkins H, et al.,ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery—executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery) J Am Coll Cardiol 2002;39:542-53.

2. Lee TH, Marcantonio ER, Mangione CM, et al, Derivation and Prospective Validation of a Simple Index for Prediction of Cardiac Risk of Major Noncardiac Surgery.Circulation 1999;100:1043-9.

3. Lindenauer PK, Pekow P, Wang K, Perioperative Beta Blocker Therapy and Mortality After Major Surgery.NEJM 2005;353:349-61.

4. Poldermans D, Bax JJ, Schouten, J,Should Major Vascular Surgery Be Delayed Because of Preoperative Cardiac Testing in Intermediate-Risk Patients Receiving Beta-Blocker Therapy With Tight Heart Rate Control?J Am Coll Cardiol 2006; 48:964-9.

5. Smetana GW, LawrenceVA, Cornell JE, et al. Preoperative Pulmonary Risk Stratification for Noncardiothoracic Surgery: Systematic Review for the American College of Physicians. Ann Intern Med 2006;144: 581-W122.

Goals of Preoperative Medical Consultation:

  1. Address known problems: .“Optimize” the patient prior to surgery, or advise against it.

2. Detect previously unknown problemswhich are likely toaffect surgical morbidity

(“Routine screening”)

Excessive screening studies result in a surplus of false positives, unnecessary expense, and anxiety for patient and clinician alike.

Frequently Indicatedfor Routine screening (all except minor procedures):

Hemoglobin (anemia can be occult; highly correlated with mortality)(Lancet,348:1055-60)

EKG in men >45 & women >55

Creatinine in everyone > 50

Not indicated on a routine basis: platelets, coags, glucose, electrolytes, LFT’s,

urinalysis, pulmonary function tests

CARDIAC EVALUATION:

Twowidely accepted algorithms for risk assessment:

ACC Guidelines: Highly patient-specific, procedure-specific (Figure1) (1)

Revised Cardiac Risk Index (RCRI): Easy to remember; no need to download/print

More useful in outcomes-based research

1. High-risk surgical procedures: Intraperitoneal, Intrathoracic, Supra-inguinal Vascular

2. History of ischemic heart disease: MI, +Stress Test, Current “typical” chest pain,

Nitrate use, Q waves on EKG

3. History of congestive heart failure: Pulmonary edema, PND, Bilateral rales, S3,

Pulmonary vascular redistribution on CXR.

4. History of cerebrovascular disease: TIA or stroke

5. Preoperative treatment with insulin

6. Preoperative creatinine > 2.0 mg/dL

Risk of Major Cardiac Event (MI, Pulmonary edema, VFib, Cardiac arrest,

completeheart block):

Risk Factors Risk

0 0.4%

1 0.9%

2 6.6%

3 + 11% (2)

Perioperative Beta Blockers:

Not for everyone! Risks outweigh benefits in low risk individuals.

Should be used: When 2 RCRI risk factors, or known CAD (3)

In current beta blocker users, or independent indications for their use

When noninvasive testing is indicated but unfeasible or unavailable

Benefits closely linked to heart rate control: Goal HR = 60, if tolerated.(Circulation114:I344-9)

Ideally start 3 days preoperatively. If necessary, can use Atenolol 5 mg IV/5min. in pre-op area; repeat after 10 min if tolerated to goal HR = 60.

Figure 1

Stress Imaging:

Valuable in the management of high-risk patients, since negative predictive value is excellent, but positive predictive value is poor. Thus, most useful in reassuring us when a patient thought to be at high risk is found to have a negative study.

The DECREASE-II study recently demonstrated that noninvasive testing offers no benefit over beta blockers alone in intermediate risk patients(1-2 RCRI risk factors). (4)

Cardiac Catheterization/Revascularization:

Beneficial preoperatively only if otherwise indicated (in non-operative setting) – CARP trial

(NEJM351:2795-2804).

What else is useful in reducing perioperative cardiac risk?

Perioperative normothermia: Cardiac event rate 1.4% (vs. 6.3%) in patients kept warm in OR.

(JAMA 277: 1127-34).

Clonidine: reduced perioperative ischemia and mortality out to 2 years, but no decrease in

incidence of MI. (Anesthesiology101: 284-93).

Valvuloplasty? Valve stenting? In a few selected candidates

PULMONARY EVALUATION: Remains a clinical art

Pre-op Chest Radiography – Useful only in patients >50 yoa who have known cardiopulmonary disease, or are undergoing high risk surgery. Pre-op CXR’s do not predict post-op pulmonary complications with any greater accuracy than the history & physical exam.

Pulmonary Function Testing – Also trumped by physical exam, as a general rule. Useful only prior to CABG, lung resection, and in setting of unexplained pulmonary symptoms.

Patient-Related Risk Factors for Post-operative Pulmonary Complications (PPC’s)

Grade A: Advanced age,ASA class >2, functionally dependent, COPD, CHF

Grade B: Impaired sensorium, abnormal chest exam, cigarette or alcohol use, weight loss

NOT Risk Factors: Stable asthma, obesity, diabetes. (Insufficient data for sleep apnea)

Procedure-Associated Risk for PPC’s:

Grade A: AAA repair, thoracic, abdominal, neuro, vascular, head&neck surgery, prolonged

or emergent procedures

Grade B: Perioperative transfusion

Risk Reduction: Regional anesthesia whenever possible; neuraxial lower risk than general

Avoid long-acting neuromuscular blockers

Shorter procedures when possible

Postoperative lung expansion maneuvers

Smoking cessation useful only if done 2mos. prior to surgery; otherwise

risk of PPC’s > current smokers.(MayoClinProc.64:609-16)

Optimize COPD/Asthma patients with bronchodilators & antibiotics if

exacerbating. Benefits of systemic steroids preoperatively exceed risks

when peak flow < 80% of baseline. (Mayo Clinic Proc 64:609-16).

PERIOPERATIVE MEDICATION MANAGEMENT

Stop the drug if it: Increases surgical morbidity, interacts with other perioperative drugs, or

is not essential.

Continue the drug if: Withdrawal is likely to harm the patient, or if drug is associated with

reduction in surgical morbidity.

Drugs to Continue: Beta blockers, central alpha agonists (e.g., clonidine), anticonvulsants, antipsychotics, allopurinol, colchicine, inhaled beta agonists/anticholinergics, steroids, opiates, H2 blockers, PPI’s, statins (growing body of evidence, cf..J.Vasc.Surg.39:967.)

Drugs to Stop: ACE inhibitors/ARB’s (intraoperative hypotension)

Diuretics (electrolyte abnormalities, arrhythmias)

Niacin, fibrates (myopathy)

NSAID’s (renal failure, GI bleeds)

Oral contraceptives, HRT (thrombogenic)

Alpha blockers

Oral hypoglycemics

Herbs to Stop: Garlic, Gingko, Ginseng, Ginger, Grapeseed Extract, Fish Oil, Vitamin E,

Feverfew (perioperative bleeding)

Kava, Valerian, St. John’s Wort, Hops, Passion Flower (oversedation)

Antiplatelet Drugs: Continue in:

Procedures low risk for bleeding (cataracts, dental, dermatologic)

Patients at high risk for thrombosis (CABG, peripheral vascular)

Steroids: Prednisone >20 mg for > 3 weeks Assume adrenal suppression

Any dose < 3 weeks, or 5 mg for any durationLikely normal HPA axis

“Stress Doses:” Moderate illness: Hydrocortisone 50 mg bid

Major surgery, severe illness: Hydrocortisone 100 mg. q8h.

Taper by 50% / day to previous dose.

Proceed With Caution: SSRI’s (impair platelet aggregation)

Thyroid replacement (OK to hold x 5 days; IV dose =0.8 x p.o. dose)

SERM’s – Case-by-case basis; discuss with Oncology

Antiparkinsonians: Avoid withdrawal syndrome by tapering (if

possible) pre-op and resuming ASAP post-op.

DIABETES

Remember, CBG’s are not the only issue perioperatively. Be sure to address cardiac risk stratification & possible end-organ disease (nephropathy, hypertension, peripheral vascular disease.)

Most inpatients require basal insulin, even when NPO – they are likely to be insulin resistantdue to stress of illness / surgery. The few individuals who are truly “diet controlled” as outpatients may be treated initially with sliding scale insulin alone while in the hospital.

Hold oral hypoglycemics A.M. of surgery; resume when taking p.o. well.

Check HbA1c in all diabetics on admission to assess the efficacy of outpatient regimen.

When possible, schedule surgery early in the morning.

Insulin-requiring patients: Give 1/3 – ½ of usual total A.M. insulin as long-acting, and cover with SSRI as needed. If surgery scheduled for late in the day, add D5 ½ NS

Optimal Glycemic Control??? Thoughts on this are evolving….

2005 ADA recommendations (non-critical patients): Fasting <110 mg/dl

2 hr pp< 180 mg/dl

CASE STUDY

You are called by the Neurosurgery Service to perform a preoperative evaluation of a 74 year old diabetic Navajo man with rheumatoid arthritis who sustained an atlantoaxial dislocation. The patient speaks little English, but the family informs you that he was in his usual state of health until he looked upwards several days ago and suddenly felt like his head was falling off.

At baseline, his activity is limited to ambulating slowly indoors, holding on to furniture. The family does not think he has experienced any chest discomfort, SOB, edema, orthopnea or PND. He sleeps on two pillows at night. He has not reported any fever, chills, or digestive disturbances, and they have not heard any cough.

PMH: RA MEDS: Glyburide 10 mg. daily NKDA

DM-II Enalapril 10 mg. daily

Htn Methotrexate 10 mg. weekly P/S: Resides with daughter

Mild Asthma Flomax 0.4 mg. daily Denies EtOH, Tob

Remote CVA

EXAM: Thin elderly male. T 98.8 HR 96 R 18 BP 163/92

HEENT: Symmetric, anicteric, mucous membranes moist NECK: Unable to examine due to bulky brace extending to torso THORAX: Also limited, but CTA CV: RRR S1S2 w/o m/g/r

ABD: Scaphoid, NT, NABS< w/o HSM EXT: Bony deformities c/w longstanding RA, no C/C/E NEURO: Alert, moving all extremities, nonfocal.

LAB: Hgb.-11.6 WBC-6.7 Plt.-167 Na–129 K–4.8 Cl–99 HCO3-20 BUN-40 Cr-2.0

Gluc. - 160

EKG: SR, 98, no diagnostic abnormality

PCXR: Poor quality due to overlying hardware and hypoinflation, but no gross abnormalities

QUESTIONS

1. According to the ACC guidelines, what cardiac intervention is indicated?

a. Echocardiogram

b. Stress imaging

c. Perioperative beta blockade

d. No further intervention

Answer: b - stress imaging This gentleman has two intermediate predictors for cardiac morbidity (diabetes and renal insufficiency), and he is anticipating a moderate risk procedure. Since his exercise capacity is poor, stress imaging is indicated. (As an aside, an echo-cardiogram was also performed since it was so difficult to perform an adequate physical exam.)

2. What is his risk level according to the Revised Cardiac Risk Index?

a. Low

b. Medium

c. High

Answer: b – medium Two revised cardiac risk factorsare present. Beta blockers are indicated. (According to the DECREASE II study, stress imaging is not likely to result in any additional benefit in moderate risk patients, as long as beta blockers are titrated to a HR of 60.)

3. What is his most significant risk factor for postoperative pulmonary complications?

a. diabetes

b. asthma

c. age

d. immobilization

Answer: c – ageis byfar the most significant patient related risk factor for PPC’s. Stable asthma is not a risk factor.

4. Which medication(s) should be held on the day of surgery?

a. glyburide

b. enalapril

c. Flomax (tamsulosin)

d. all of the above

Answer: d – all of the above. ACE-inhibitors and alpha blockers are associated with intra-operative hypotension, and sulfonylureas should be discontinued to avoid hypoglycemia while NPO.