Cardiac surgery is one of the most commonly performed major operative procedures in the United States. The indications for cardiac surgery include myocardial ischemia and infarction, heart failure, valvular dysfunction, aortic pathology, and surgery for dysrythmias. The management of patients following cardiac surgery requires a multifaceted approach and the involvement of a team of specialists. While the intensivist is often the point person for the management of the patients following open heart surgery, it is essential that the management involve the surgeon, cardiologist, and anesthesiologist, and a wide variety of other health care providers.
Successful postoperative management following cardiac surgery requires a clear understanding of the patient's preoperative conditions and the intraoperative events and management. The goal is to restore the patient's normal physiologic condition and homeostasis. As medical management and interventional cardiology procedures evolve and improve, the patients being referred for cardiac surgery are sicker and more debilitated than they were in the past. This trend is likely to continue in the years to come. Despite these increased challenges facing cardiac surgeons, patient outcomes remain very good in large part due to the postoperative management and ICU care. A systems-oriented approach is often necessary to deal with the multitude of problems facing these patients, and the cardiac system is generally the primary determinant of recovery.1
The goal of hemodynamic management is to maintain adequate oxygen delivery to the tissues and to minimize demands on a heart that has just undergone major surgery. Optimization of cardiac output is essential to maintain function of the brain, kidneys, gut, lungs, and other end organs necessary for optimal recovery. Postoperatively, contractility is almost always diminished, the magnitude of which is often related to the severity of chronic dysfunction, ischemia, and intraoperative events.2
Despite the wide array of patient disease and cardiac procedures, significant similarities exist in patient monitoring, evaluation, and management.2 The majority of patients have continuous monitoring of EKG, pulse oximetry, blood pressure, central venous pressure (CVP) monitoring, and in most instances a pulmonary artery catheter (PAC) for monitoring mixed venous O2 saturation (SvO2), pulmonary artery pressures, and continuous cardiac output. Although the use of a PAC in patients undergoing cardiac surgery has been a topic of some debate,3 it has been common practice to use PACs in almost every patient undergoing cardiac surgery. These modalities allow for measurement of oxygen consumption and mixed venous and arterial oxygen saturation, and an estimation of cardiac output. The goal is to maintain normal hemodynamic values if possible since it has been shown that normal oxygen transport and normal SvO2 (>70%) in the immediate postoperative period can improve outcome.4 Although achieving these targets can be challenging,5–7 adjustments to volume status, afterload, heart rate and rhythm, and cardiac output can help to maximize end-organ oxygen delivery.