First, determine the type and urgency of the proposed surgery. Low-risk procedures do not need further evaluation given low risk of complications, even in the highest risk patient. Emergency surgeries should not be delayed for “medical clearance.”
For all other surgeries, the clinician should assess the patient for active heart conditions that could delay surgery. These include decompensated heart failure (CHF), unstable coronary syndromes (myocardial infarction [MI] within 30 days, unstable or severe angina), significant arrhythmias, and severe valvular disease (severe aortic or mitral stenosis).
If no “red flag” features are found, the patient’s functional status should be assessed. Patients who have symptoms with activities of less than four metabolic equivalents (METs) have poor functional capacity and an increased risk for perioperative cardiovascular events. One MET is defined as the energy expenditure for sitting quietly. For the average adult this is equivalent to oxygen consumption of 3.5 mL/kg body weight per minute. 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 one flight of stairs. If the patient cannot perform these activities, then it is important to determine if they are limited by dyspnea or cardiovascular disease which may require further workup. The ability to accomplish these activities without symptoms correlates with moderate or greater functional capacity and a lower perioperative risk.
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 myocardial infarction. The 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 based upon three factors: clinical predictors, functional capacity, and surgery-specific risks.
Determine whether your patient has angina and if so, find the frequency, precipitating factors, and response to rest and nitroglycerin. Especially, worrisome are increasing occurrence at lower levels of provocation and slower response to nitroglycerin. Examine the electrocardiogram (ECG) for evidence of prior MI or ongoing ischemia. If prior cardiac catheterizations or coronary revascularizations have been performed, obtain the reports. Successful revascularization within 3 years confers a low risk; the presence of drug-eluting stents presents unique challenges as described below.
Inquire for CHF symptoms now or in the past, for example, exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, cough, or peripheral edema. If prior evaluations of cardiopulmonary function such as cardiac catheterization or echocardiography have been performed, obtain the results.
Dysrhythmias and cardiac devices
Ask about palpitations, syncope, or other symptoms of arrhythmias, or whether arrhythmias been documented on prior ECGs or ambulatory monitoring. Examine current and old ECGs for high-grade atrioventricular block, symptomatic ventricular arrhythmias associated with structural heart disease, or supraventricular tachycardias at uncontrolled rates. If the patient has a pacemaker or defibrillator, determine the type and model, date of implantation, and when the battery life and performance were last interrogated.
Valvular and congenital heart disease
The presence of intracardiac shunts or valve abnormalities may require endocarditis prophylaxis. Obtain the results of the most recent echocardiogram, if one has been done. Look especially for evidence of severe valvular heart disease (e.g., aortic stenosis) that might require intervention before proceeding with elective noncardiac surgery.
The presence of symptomatic cerebrovascular disease (transient ischemic attack or stroke) is associated with an increased risk for perioperative cardiovascular morbidity including stroke. Ask if there have been prior evaluations or interventions performed on the carotid or peripheral arteries and obtain the results if these tests have been performed.
Record any symptoms of current pulmonary disease and ask if there have been pulmonary complications after previous surgeries. Ask if patients with known lung disease have had pulmonary function testing (PFT) and if so, obtain the results. Record the use of bronchodilators for asthma or obstructive lung disease including the strength, frequency of use, and response to rescue inhalers.
Postoperative pneumonia is the third most common complication among surgical patients leading to increased length of stay, costs, and morbidity . A postoperative pneumonia risk index indicates that the type of surgery, age, functional status, weight loss, chronic obstructive pulmonary disease, general anesthesia, impaired sensorium, cerebral vascular accident, blood urea nitrogen level, transfusion, emergency surgery, long-term steroid use, smoking, and alcohol use are additive risk factors for developing postoperative pneumonia . The risk for postoperative respiratory failure can be estimated . Postoperative lung expansion, selective postop nasogastric tube use, and use of short-acting neuromuscular blockade may help reduce pulmonary risk .
A history of deep venous thrombosis or PE perioperatively or without provocation is associated with an increased risk for perioperative deep vein thrombosis/PE. Inquire whether studies for thrombophilia (e.g., factor V Leiden mutation, lupus anticoagulant, or deficiency of antithrombin III, and protein C or S) were performed and obtain the results if possible.
Assessment of Bleeding Risk from History
The best predictor of bleeding is history of prior postoperative bleeding. A negative history assures you that the patient is not at increased risk for bleeding in the absence of antiplatelet and/or antithrombotic medications. If concerns arise from the history, a laboratory evaluation may be indicated. Screening tests (e.g., PT/INR, PTT, platelet count) in a patient with a negative history are not helpful; these tests do not predict bleeding risk.
Personal and familial coagulation disorders
Ask about excessive bleeding with dental extractions, surgery, or childbirth or if there is a family history of excessive bleeding in those circumstances. Ask patient about the problems with heparin-induced thrombocytopenia or other heparin allergies.
Platelet and vessel disorders
Determine whether the patient experiences gingival bleeding, epistaxis, menorrhagia, hematuria, melena, or excessive bleeding or bruising at venipuncture sites or from minor cuts and whether they have noticed petechiae, spontaneous bruising, or bruises larger than a silver dollar with minor trauma.
Has the patient ever had a blood transfusion or received procoagulant factor replacement at surgery? If so, determine when, which type of blood product, and the approximate volume of transfusion. Remember that patients will confuse reinfusion of autologous blood for an allogenic transfusion.
Assessment of Metabolic Risk: Diabetes, Renal, and Hepatic Insufficiency
Metabolic abnormalities are assessed so that they can be controlled preoperatively and managed through the perioperative period.
Glucose intolerance, hyperglycemia, and diabetes
Screen for symptoms of diabetes by asking about polyuria, polydipsia, or weight loss. Ask about a personal history of diabetes mellitus; ask women about gestational diabetes. If the patient is known to have diabetes, assess the use of oral hypoglycemic agents and control. If the patient uses insulin, record the types, schedule, and doses. Determine the frequency and severity of hypoglycemia and whether hypoglycemia unawareness is likely.
Ask about any history of kidney disease and, if present, determine the stage and whether the patient has ever required dialysis.
Inquire about a history of liver disease, the etiology, and severity. Determine whether the liver disease is compensated or decompensated; look for signs of advanced disease such as ascites, encephalopathy, portal hypertension, or GI bleeding. Assess hepatic synthetic function with albumin, bilirubin, and PT/INR only if liver disease is suspected from history.
Biologic capacity declines with age, but it has been difficult to identify age as an independent risk factor for surgery. Comorbidities play a large role in surgical outcomes in the elderly, and operative mortality among octogenarians was substantially higher than patients aged 65 to 69 .
Ask about a family history of adverse reaction to anesthesia (e.g., malignant hyperthermia), deep venous thrombosis or PE, bleeding problems, diabetes mellitus, elevated cholesterol, hypertension, or heart disease.
Most chronic medications can be continued through the perioperative period. The exceptions are nonsteroidal anti-inflammatory drugs and oral hypoglycemic agents which should be held prior to surgery. All unnecessary medications should be discontinued. The risks and benefits of perioperative use of aspirin, thienopyridines, and warfarin need to be individually assessed balancing thrombosis and bleeding risk.
Review the patient’s medications, to see, if they are taking cardiac, antiarrhythmic, or antihypertensive medications. Most drugs are continued except diuretics and ACE inhibitors.
The AHA/ACC 2009 focused update on perioperative beta blockade, recommended that beta blockers be continued in patients undergoing surgery who are already receiving them. Beta blockers titrated to heart rate and blood pressure are recommended for patients undergoing vascular surgery who are at high cardiac risk and for patients whose preoperative assessment identifies CAD or high cardiac risk (more than one clinical risk factor) who are undergoing intermediate risk surgery [6, 7].
Use of statins also has been associated with decreased perioperative cardiac events and can be considered in patients with clinical risk factors.
Drugs affecting hemostasis
It is important to ask directly about the drugs that affect hemostasis or increase the risk for thromboembolism, for example, nonsteroidal anti-inflammatory drugs, antiplatelet agents (including aspirin, clopidogrel, or ticlopidine), anticoagulations (warfarin, anti-Xa, and direct thrombin inhibitors), oral contraceptives, and estrogens.
An increasing number of patients have coronary stents and are receiving dual antiplatelet therapy. Chest guidelines recommend deferring surgery for at least 6 weeks after placement of a bare metal stent and for at least 6 months after placement of a drug-eluting stent whenever possible. For those requiring surgery sooner, dual antiplatelet therapy should be continued perioperatively . For patients who receive a drug-eluting stent and who must have procedures that mandate stopping thienopyridine therapy, aspirin should be continued if at all possible, and the thienopyridine should be restarted as soon as possible after the procedure.
Determine when, how much, for what reason, and for how long the patient took the corticosteroid. Steroid-induced adrenal suppression may persist for up to a year after even relatively short courses of corticosteroids in doses above 10 mg/d. If this has occurred, coverage with stress doses of steroids starting just before surgery and continuing for 48 to 72 hours is advised.
Knowledge of a patient’s habits will help you be alert for problems in the perioperative period such as drug or alcohol withdrawal.
Has the patient been using alcohol or illicit or addicting drugs? If so, which drugs and when was the last time they were used? Drug withdrawal should be anticipated in the postoperative period if addicting drugs, including alcohol, were used recently.
Does the patient smoke? If so, how many cigarettes daily? Quitting smoking for at least 8 weeks prior to surgery is optimal; however, a recent systematic review of five perioperative trials demonstrated that a preoperative smoking cessation intervention reduced a broad composite outcome of any postoperative complication compared with standard care. Preoperative smoking cessation interventions were positively associated with long-term (12 months) self-reported smoking cessation .
Mechanical and Positioning Risks
Patients with rheumatoid arthritis may have cervical spine instability that can result in serious or fatal injury at the time of endotracheal intubation. Also, determine if the patient requires particular care in positioning to avoid excessive pressure on deformed limbs.