Hemodynamic Repercussions of Pneumoperitoneum in High-Risk Cardiac Patients

The demonstration of significant hemodynamic changes during pneumoperitoneum raises the question of tolerance of these changes by cardiac patients (see Chapter 25 and Chapter 27 ). In patients with mild to severe cardiac disease, the pattern of change in mean arterial pressure, cardiac output, and systemic vascular resistance is qualitatively similar to that in healthy patients.^{[103] [104] [145] [146] [147] [148]} Quantitatively, these changes appear to be more marked. In a initial study including ASA class III or IV patients, SVO₂ decreased in 50% of patients despite preoperative hemodynamic optimization using a pulmonary artery catheter.^[146] Patients who experienced the most severe hemodynamic changes with inadequate oxygen delivery were patients with low preoperative cardiac output and central venous pressure and high mean arterial pressure and systemic vascular resistance—a profile suggesting depleted intravascular volume. The investigators suggest preoperative preload augmentation to offset the hemodynamic effect of pneumoperitoneum. Intravenous nitroglycerin, nicardipine, or dobutamine has been used to manage the hemodynamic changes induced by increased IAP in selected patients with heart disease.^{[104] [148]} Nitroglycerin was chosen to correct the reduction in cardiac output associated with increased pulmonary capillary occlusion pressures and systemic vascular resistance. The administration of nicardipine may be more appropriate than that of nitroglycerin. Right atrial and pulmonary capillary occlusion pressures are not reliable indices of cardiac filling pressure during pneumoperitoneum. Increased afterload is a major contributor to the altered hemodynamics seen during pneumoperitoneum in cardiac patients. Nicardipine acts selectively on arterial resistance vessels and does not compromise venous return.^[149] This drug is beneficial in case of congestive heart failure.^{[150] [151]} Because normalization of hemodynamic variables does not occur for at least 1 hour postoperatively in certain patients,^{[103] [147]} congestive heart failure can develop in the early postoperative period. Dhoste and associates^[152] did not observe impaired hemodynamics in elderly ASA class III patients, but they used low intraperitoneal pressure (10 mm Hg) and slow insufflation rates (1 L/min). The hemodynamic consequences of pneumoperitoneum are minor in heart transplant recipients with good ventricular function.^{[153] [154]} Laparoscopic adrenalectomy in patients with pheochromocytoma can be successfully managed using a continuous infusion of nicardipine.^{[105] [155]} Several studies suggest that hemodynamic changes during pneumoperitoneum are well tolerated by morbidly obese patients.^{[11] [156] [157]}