Treatment usually relies on aggressive diuretic therapy, although care must be taken to avoid dehydration, which may result in hypotension during the induction of anesthesia. Hypokalemia can result from diuretic therapy and is especially deleterious to patients who are taking digitalis. In addition to diuretics and digitalis, treatment often includes the use of preload-and afterloadreducing agents. Optimal use of these drugs and correction of CHF may be aided by consultation with a cardiologist. It is preferable to continue the usual regimen of cardioactive drugs throughout the perioperative period.
Postoperative CHF frequently results from excessive administration of intravenous ﬂuids and blood products. Other common postoperative causes are myocardial infarction, systemic infection, pulmonary embolism, and cardiac arrhythmias. The cause of postoperative heart failure must be diagnosed because, to be successful, treatment should be directed simultaneously to the underlying cause. Postoperative diagnosis of CHF is more difficult than preoperative diagnosis because the signs and symptoms of CHF are not specific and may result from other causes. The most reliable method of detecting CHF is chest radiography, in which the presence of cardiomegaly or evidence of pulmonary edema is a helpful diagnostic feature.
Acute postoperative CHF frequently manifests as pulmonary edema. Treatment of pulmonary edema may include the use of intravenous furosemide, supplemental oxygen, morphine sulfate, and elevation of the head of the bed. Intravenous aminophylline may be useful if cardiogenic asthma is present. Electrocardiography, in addition to laboratory evaluation, including arterial blood gas, serum electrolyte, and renal function chemistry measurements, should be obtained expediently. If the patient’s condition does not improve rapidly, she should be transferred to an intensive care unit.
Arrhythmias Nearly all arrhythmias found in otherwise healthy patients are asymptomatic and of limited consequence. In patients with underlying cardiac disease, however, even brief episodes of arrhythmias may result in significant cardiac morbidity and mortality.
Preoperative evaluation of arrhythmias by a cardiologist and anesthesiologist is important because many anesthetic agents and surgical stress contribute to the development or worsening of arrhythmias. In patients undergoing continuous electrocardiographic monitoring during surgery, a 60% incidence of arrhythmias, excluding sinus tachycardia, are reported (201). Patients with heart disease have an increased risk of arrhythmias, most commonly ventricular arrhythmias (201). Patients without cardiac disease are more likely to develop supraventricular arrhythmias during surgery. Patients taking antiarrhythmic medications before surgery should continue taking those drugs during the perioperative period. Initiation of antiarrhythmic medications is rarely indicated preoperatively, but consultation with a cardiologist is recommended for patients in whom arrhythmias are detected before surgery.
Patients with first-degree atrioventricular (AV) block or asymptomatic Mobitz I (Wenckebach) second-degree AV block require no preoperative therapy. A pacemaker is appropriate in patients with symptomatic Mobitz II second-or third-degree AV block before elective surgery (202). In emergency situations, a pacing pulmonary artery catheter can be used. Before performing surgery on patients with a permanent pacemaker, the type and location of the pacemaker should be determined because electrocautery units may interfere with demand-type pacemakers (203).