The influence on renal function of halothane (0.9%) in O2 and of halothane, plus increasing concentrations (20, 40 and 60%) of N2 or N2O, was determined in 23 dogs. Halothane produced significant reductions in cardiac output and mean arterial pressure (MAP), which were not significantly further altered by addition of any concentration of N2 or N2O. Halothane in O2 caused marked reductions in urine flow rate and para-aminohippurate clearance (C(PAH)), inuline (C(In)), and osmolar (C(OSM)) clearances, and significantly reduced free water clearance (C(H2O)) and renal blood flow (RBF). Urine osmolarity and renal vascular resistance (RVR) were significantly elevated by halothane-O2. Addition of N2O produced further concentration-related reductions in urine flow rate, C(H2O), and RBF. N2O increased C(OSM), urine osmolarity, and C(In) but did not further alter C(PAH) or RVR. Addition of N2 caused no further changes in urine flow rate, C(PAH), C(In), C(OSM), RBF, urine osmolarity, or RVR. Maintenance of halothane (0.9%) in O2 for 140 minutes in 5 dogs caused no further changes in renal function after the initially observed alterations. These data demonstrate that N2O supplementation potentiates the antidiuresis produced by halothane and suggests that one mechanism involved may be stimulation of antidiuretic hormone release.
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine