Preoperative medical screening strives to estimate the patient's risk for, and minimize the occurrence of, perioperative medical complications, without unnecessarily delaying surgery or causing undue morbidity or expense. To appropriately counsel the surgeon and patient, your history, physical examination, and other studies should assess the risks for myocardial infarction (MI), arrhythmias, heart failure, endocarditis, stroke, pulmonary insufficiency, venous thrombosis and pulmonary embolism (PE), hemorrhage, diabetic acidosis, renal or hepatic failure, and, in the immunocompromised host, infection. When needed, you must make recommendations to minimize these risks by specific preoperative evaluations or treatments or with specific perioperative management strategies. The consultant, surgeon and patient must balance the risks of proceeding directly to surgery against the risks of delaying a necessary procedure.
First, determine the type and urgency of the proposed surgery and the patient's age and functional capacity. Ask, if your patient can climb a flight of stairs comfortably. Patients who have symptoms with activities of less than four metabolic equivalents (METs) have poor functional capacity and an increased for perioperative risk for cardiovascular events. One MET is defined as the energy expenditure for sitting quietly. This is equivalent to an oxygen consumption of 3.5 mL/kg body weight per minute, for the average adult. Activities that correlate with 4 to 5 METs of activity include mopping floors, cleaning windows, painting walls, pushing a power lawnmower, raking leaves, weeding a garden, or walking up 1 flight of stairs. Walking 4 miles (6.4 km) per hour or cycling 10 miles (16 km) per hour on level ground constitutes 5 to 6 METs of activity. The ability to accomplish these activities without symptoms correlates with moderate or greater functional capacity and a lower perioperative risk. If the patient cannot perform these activities, what are the symptoms that limit them?
Find out, if complications have occurred with previous operations. Then focus the history and physical examination upon the specific areas of concern as outlined below.
Assessment of Cardiovascular and Pulmonary Risk from History
The most frequent cause of nonsurgical perioperative morbidity and mortality is acute MI. The patient's current history is the best method of risk assessment. The American College of Cardiology and the American Hospital Association have published guidelines for perioperative cardiovascular evaluation [Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovasculoar evaluation for noncardiac surgery—executive summary. J Am Coll Cardiol. 2002;39:542–553 [PubMed: 11823097]. The recommendations are based upon three factors: clinical predictors, functional capacity, and surgery specific risks.
Pneumonia is a not infrequent postoperative complication. A multifactorial risk assessment tool has been published which predicts the risk for pneumonia. The derivation and validation cohorts were a large veterans population so applicability to other populations is not known [Arozullah AM, Khuri SF, Henderson WE, et al. Development and validation of a muiltifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Ann Intern Med. 2001;135:847–857 [PubMed: ...