Hemodynamics of intravenous nitroglycerin during aortic clamping.

Anesthetic management and dosage schedules of vasodilators have not been standardized in many studies of aortic cross clamping (CCL). For this reason, 25 consecutive patients with arteriosclerotic disease of the aorta were studied, all having received the same anesthetic management. Six patients who received nitroglycerin during the cross clamp period, at a dosage of 0.25 micrograms/kg/min, were compared with 19 who underwent CCL without the drug. Contractility was maintained in the nitroglycerin group, but not in the other group. Despite a low cardiac index in both groups, peripheral blood flow was adequate only in the nitroglycerin group. Intrapulmonary shunt was higher in the nitroglycerin group, but it did not significantly decrease the Pao2. Nitroglycerin infusion seems to be helpful in maintaining pre-CCL contractility and adequacy of peripheral blood flow.