The marked cardiovascular changes associated with pregnancy, labor, and delivery often cause preg-nant patients with heart disease (2% of parturients) to decompensate during this period. Although most pregnant patients with cardiac disease have rheumatic heart disease, an increasing number of parturients are presenting with corrected or palli-ated congenital lesions. Anesthetic management is directed toward employing techniques that mini-mize the added stresses of labor and delivery. Specific management of the various lesions is discussed else-where. Most patients can be divided into one of two groups. Patients in the first group benefit from the falls in systemic vascular resistance caused by neur-axial analgesia techniques, but usually not from overzealous fluid administration. These patients include those with mitral insufficiency, aortic insuf-ficiency, chronic heart failure, or congenital lesions with left-to-right shunting. The induced sympathec-tomy from spinal or epidural techniques reduces both preload and afterload, relieves pulmonary con-gestion, and in some cases increases forward flow (cardiac output).
Patients in the second group do not benefit from a decrease in systemic vascular resistance. These patients include those with aortic stenosis, congenital lesions with right-to-left or bidirectional shunting, or primary pulmonary hypertension. Reductions in venous return (preload) or afterload are usually poorly tolerated. These patients are bet-ter managed with intraspinal opioids alone, systemic medications, pudendal nerve blocks, and, if neces-sary, general anesthesia.
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