[Value of vasodilators in decreasing the afterload during infrarenal abdominal aorta cross-clamping].

Adverse effects of aortic crossclamping (A. C. C.) have been shown by a retrospective study and a literature review. A. C. C. results in increased afterload with ensuing left ventricular function alteration and low cardiac index (C. I.). 15 P. T. S. sustaining an operation with A. C. C. below the renal arteries were studied. A Swan-Ganz catheter was positioned with recording of pressures, including radial artery pressure and repeated cardiac output determinations. Prior to A. C. C., vascular filling and nitroprusside (N. P.) infusion improved hemodynamic conditions. Increase of C. I. (1.8 to 2.8 l/mm-1/m2) was observed with important decrease in peripheral vascular resistance (from 2,346 to 1,425 dyne/s-1/cm-5), pulmonary capillary pressure was lowered slightly and heart rate as well as mean arterial pressure remained stable. During A. C. C., rate of N. P. infusion was increased to maintain stable arterial pressure. Hemodynamic improvement observed prior to A. C. C. was maintained.