Gastrointestinal Diseases

 GOAL

• Determine presence of comorbid disease that increases surgical morbidity and mortality.

• Reduce risk and optimize pt’s condition.

The Healthy Patient

Should have screening history and physical exam.

• Simple preoperative questionnaires are useful

• Determine exercise tolerance and reason for intolerance

• Routine laboratory tests in healthy pts are of little value 

CARDIAC RISK ASSESSMENT

Cardiac complications are most important cause of perioperative morbidity and mortality.Risk can be estimated by adding up the number of risk factors (Table 11-1). Class II pts should receive noninvasive cardiac testing (e.g., dipyridamole- thallium testing or dobutamine stress echocardiography; see Chap.118) for vascular surgery.Class III or IV pts should receive treatment to reduce risk prior to elective surgery.

Physical Examination

Evaluate for uncontrolled hypertension, signs of CHF (jugular venous distention, rales, S3), previously unknown heart murmurs, carotid bruits.Inspect for pallor, cyanosis, poor nutritional state.

Laboratory

Examine ECG for evidence of previous MI (Q waves) or arrhythmias. Inspect CXR for signs of CHF (e.g., cardiomegaly, vascular redistribution, Kerley B lines).Additional testing is dictated by specific underlying cardiovascular disease and nature of the planned operation.See Fig.11-1 for  clinical predictors of increased perioperative risk of MI, CHF, or death and approaches to preoperative evaluation. 

Specific Cardiac Conditions CORONARY ARTERY DISEASE (CAD)

Consider postponing purely elective operations for 6 months following an MI.Pts with stable CAD can be evaluated per algorithm in Fig.11-1.Surgical risk is generally acceptable in pts with class I–II symptoms (e.g., able to climb one flight carrying grocery bags) and in those with low risk results from noninvasive testing.For those with highrisk results or very limited functional capacity, consider coronary angiography. Perioperative beta-blocker therapy reduces incidence of coronary events and should be included in medical regimen if no contraindications. 

HEART FAILURE

This is a major predictor of perioperative risk.Regimen of ACE inhibitor and diuretics should be optimized preoperatively to minimize risk of either pulmonary congestion or intravascular volume depletion postoperatively. 

ARRHYTHMIAS

These are often markers for underlying CHF, CAD, drug toxicities (e.g., digitalis), or metabolic abnormalities (e.g., hypokalemia, hypomagnesemia), which should be identified and corrected.Indications for antiarrhythmic therapy or pacemakers are same as in nonsurgical situations (Chap.125). Notably, asymptomatic ventricular premature beats generally do not require suppressive therapy preoperatively. 

VALVULAR DISEASES

Those portending surgical risk are advanced aortic or mitral stenosis (Chap.119), which should be repaired, if severe or symptomatic, prior to elective surgery.Ensure adequate ventricular rate control in mitral stenosis with atrial fibrillation (using beta blocker, digoxin, verapamil, or diltiazem).Endocarditis prophylaxis is indicated for operations associated with transient bacteremias (Chap.85). 

HYPERTENSION

Control elevated pressure preoperatively (Chap.122), especially using beta blocker if possible, which should be continued perioper  atively.If pheochromocytoma is a possibility, surgery should be delayed for evaluation because of high anesthetic risk. Perioperative beta blockers reduce risk of cardiac complications in pts with two or more of the following risk factors: age _ 65 yrs, hypertension, current cigarette use, diabetes mellitus, and total cholesterol _ 240 mg/dL. 

PREOPERATIVE PULMONARY EVALUATION

Table 11-2 shows risk factors for postoperative pulmonary complications. Chronic obstructive pulmonary disease (Chap.133) increases risk fourfold. Risk increases with thoracic operations.Laparoscopic abdominal surgery is low risk. Preoperative pulmonary function testing (Chap.130), especially simple spirometry with FEV1, is indicated prior to lung resection surgery. Cigarette smoking should be stopped 8 weeks before elective surgery. Chronic obstructive pulmonary disease and asthma should be vigorously treated. Postoperative lung expansion, deep breathing exercises, and pain control reduce complications in pts with chronic pulmonary disease.