[Effects of halothane, isoflurane and sevoflurane on renal function in dogs under infra-renal aortic cross-clamping.].

BACKGROUND AND OBJECTIVES Infra-renal aortic cross-clamping is associated to renal effects. This study aimed at analyzing halothane, isoflurane and sevoflurane effects on renal function of dogs submitted to infra-renal aortic cross-clamping. METHODS This study involved 30 mixed-breed dogs randomly distributed in three groups, according to equipotent anesthetic doses (0.75 MAC) of inhaled anesthetics: GH (n = 10) - 0.67% halothane; GI (n = 10) - 0.96% isoflurane; and GS (n = 10) - 1.8% sevoflurane. All animals were submitted to infra-renal aortic cross-clamping for 30 minutes. Renal parameters were evaluated at control (C), 15 (Ao15) and (Ao30) minutes after aortic cross-clamping, and 15 (DAo15) and 30 (DAo30) minutes after aortic unclamping. RESULTS Free water clearance was significantly lower in GI and GS as compared to GH (p < 0.05) after aortic unclamping. Urinary output, sodium urinary excretion and sodium clearance have significantly increased during aortic cross-clamping, while urinary osmolarity has decreased in all groups (p < 0.05). Renal vascular resistance and filtration fraction have increased during aortic cross-clamping in GS only, while sodium fractional excretion increased in GH and GI (p < 0.05). All renal parameters had returned to control levels after aortic unclamping, with the exception of urinary osmolality which has remained below control levels in all groups (p < 0.05). Renal vascular resistance and filtration fraction have remained higher in GS, followed by renal blood flow and PAH clearance decrease (p < 0.05). CONCLUSIONS In dogs under our experimental conditions, 0.75 MAC of halothane or isoflurane, but not 0.75 MAC of sevoflurane, have minimized renal vascular resistance increase, which is the major infra-renal aortic cross-clamping effect.