special subjects
Preoperative Evaluation
Patient Risk Factors
). Use of these tools not only allows uniformity in interpreting surgeons' outcomes data but also contributes to better shared decision-making and informed consent for patients and family members ( More Information ). Older age is associated with decreased physiologic reserve and greater morbidity if a complication occurs. However, chronic disorders are more closely associated with increased postoperative morbidity and mortality than is age alone. Older age is not an absolute contraindication to surgery. Cardiac risk factors dramatically increase surgical risk. Perioperative cardiac risk is typically assessed using the American College of Cardiology/American Heart Association's Revised Cardiac Risk Index ( see Figure: Algorithm for risk stratification for noncardiac surgery ). It considers the following independent predictors of cardiac risk: History of coronary artery disease (CAD) History of heart failure History of cerebrovascular disease Diabetes requiring treatment withinsulin Serum creatinine (2.0 mg/dL) Risk of cardiac complications increases with increasing risk factors: No risk factors: 0.4% (95% confidence interval 0.1 to 0.8%) 1 risk factor: 1.0% (95% confidence interval 0.5 to 1.4%) 2 risk factors: 2.4% (95% confidence interval 1.3 to 3.5%) ≥ 3 risk factors: 5.4% (95% confidence interval 2.8 to 7.9%) A high-risk surgical procedure (eg, vascular surgery, open intrathoracic or intraperitoneal procedure) also independently predicts a high cardiac perioperative risk. Patients with active cardiac symptoms (eg, of heart failure or unstable angina) have a particularly high perioperative risk. Patients with Unstable angina have about a 28% risk of perioperative myocardial infarction. In patients with stable angina, risk is proportional to their degree of exercise tolerance. Patients with active cardiac symptoms thus require thorough evaluation. For example, the cause of heart failure should be determined so that perioperative cardiac monitoring and treatment can be optimized before elective surgery. Other cardiac testing, such as Preoperative care should aim to control active disorders (eg, heart failure, diabetes) using standard treatments. Also, measures should be taken to minimize perioperative tachycardia, which can worsen heart failure and increase risk of myocardial infarction; for example, pain control should be optimized and beta-blocker therapy should be considered, especially if patients are already taking beta-blockers. Coronary revascularization should be considered for patients with unstable angina. If a heart disorder cannot be corrected before surgery or if a patient is at high risk of cardiac complications, intraoperative and sometimes preoperative Pulmonary Artery Catheter (PAC) Monitoring may be advised. Sometimes the cardiac risk outweighs the benefit of surgery. In such cases, a less invasive procedure may provide or serve as a bridge to definitive treatment (eg, tube cholecystostomy for cholecystitis) and decrease morbidity and mortality. *Active clinical conditions include unstable coronary syndromes, decompensated heart failure, significant arrhythmias, and severe valvular disorders. †See the ACC/AHA ‡Clinical risk factors include coronary artery disease, history of heart failure, history of cerebrovascular disease, diabetes mellitus, and preoperative creatinine > 2.0 mg/dL. ACC = American College of Cardiology; AHA = American Heart Association; HR = heart rate; MET = metabolic equivalent. Adapted from Fleisher LA, Beckman JA, Brown KA, et al: ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery; a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.Fleisher LA, Fleischmann KE, Auerbach AD, et al Incidental bacterial infections discovered preoperatively should be treated with antibiotics. However, infections should not delay surgery unless prosthetic material is being implanted; in such cases, surgery should be postponed until the infection is controlled or eliminated. Patients with respiratory infections should be treated and have evidence that the infection has resolved before receiving inhalational anesthesia. Viral infections with or without fever should be resolved before elective surgery is done, especially if a general anesthetic is going to be used. Fluid and electrolyte imbalances should be corrected before surgery. Hypokalemia, hyperkalemia, hypocalcemia, and hypomagnesemia must be corrected before general anesthesia to decrease risk of potentially lethal arrhythmias. Dehydration and hypovolemia should be treated with IV fluids before general anesthesia to prevent severe hypotension on induction—blood pressure tends to fall when general anesthesia is induced. Overview of Undernutrition and obesity increase the risk of postoperative complications in adults. Nutritional status is assessed preoperatively using history, physical examination, and laboratory tests. Severe nutritional risk factors include the following: A body mass index < 18.5 kg/m2or a history of unintentional weight loss > 10% of body weight over 6 months or 5% over 1 month Suggestive physical examination findings (eg, muscle wasting, signs of specific nutritional deficiencies) Low serumalbuminlevels (< 3 g/dL without evidence of renal or hepatic dysfunction) It is important to ask whether weight loss was intentional, because Involuntary Weight Loss may reflect a catabolic state refractory to nutritional repletion, suggesting serious underlying pathology such as cancer. ; half-life 3 to 5 days). Preoperative and perioperative nutritional support with the aid of a dietitian to prevent and treat specific nutritional and electrolyte deficiencies is most likely to improve outcomes in patients whose histories of weight loss and protein levels indicate severe undernutrition ( More Information ). In some cases, surgery can be delayed so patients can receive nutritional support, sometimes for several weeks (eg, in chronically undernourished patients, to help prevent the refeeding syndrome). ) increases perioperative mortality risk because such patients have increased risk of cardiac and pulmonary disorders (eg, hypertension, pulmonary hypertension, left ventricular hypertrophy, heart failure, coronary artery disease). Obesity is an independent risk factor for Deep Venous Thrombosis (DVT) and pulmonary embolism; preoperative venous thromboembolism prophylaxis is indicated in most obese patients. Obesity also increases risk of postoperative wound complications (eg, fat necrosis, infection, dehiscence, and abdominal wall hernias). 1.Bilimoria KY, Liu Y, Paruch JL, et al: Development and evaluation of the universal ACS NSQIP surgical risk calculator: A decision aid and informed consent tool for patients and surgeons.J Am Coll Surg217(5):833-42.e423, 2013. doi:10.1016/j.jamcollsurg.2013.07.385 2.Weimann A, Braga M, Harsanyi L, et al: ESPEN guidelines on enteral nutrition: Surgery including organ transplantation.Clin Nutr25:224–244, 2006. doi: 10.1016/j.clnu.2006.01.015 