[Effects of halothane, isoflurane and sevoflurane on cardiovascular responses to infrarenal aortic cross-clamping: experimental study in dogs].

BACKGROUND AND OBJECTIVES Infrarenal aortic cross-clamping is associated to cardiovascular effects. This study aimed at analyzing the effects of halothane, isoflurane and sevoflurane on cardiovascular function of dogs following infrarenal aortic cross-clamping. METHODS Thirty mongrel dogs were randomly divided in three groups, according to equipotent (0.75 MAC) inhaled anesthetic doses: GH (n = 10) - 0.67% halothane; GI (n = 10) - 0.96% isoflurane; and GS (n = 10) - 1.8% sevoflurane. All dogs were submitted to infrarenal aortic cross-clamping for 30 minutes. Hemodynamic parameters were measured at control (C), at 15 (Ao15) and 30 (Ao30) minutes of aortic cross-clamping, and immediately (DAo) and 15 (DAo15) minutes after aortic unclamping. RESULTS In all groups, infrarenal aortic cross-clamping significantly increased mean blood pressure, right atrial pressure, cardiac index, stroke volume index, left ventricular work index and right ventricular work index. Pulmonary artery pressure significantly increased during cross-clamping in GI and GS groups while pulmonary capillary wedge pressure significantly increased in GH and GI groups. After aortic unclamping all hemodynamic parameters have returned to control levels with the exception of cardiac and stroke volume indices which remained high, followed by systemic vascular resistance index decrease. There have been no significant differences among groups in studied attributes, except for heart rate which was always lower in GH group as compared to other groups during and after infrarenal aortic cross-clamping. CONCLUSIONS In dogs under our experimental conditions, equipotent concentrations (0.75 MAC) of inhalational halothane, isoflurane and sevoflurane have not attenuated cardiovascular responses to infrarenal aortic cross-clamping.