title: Brain blood flow autoregulation and metabolism during halothane anesthesia in monkeys.
abstract: Past studies suggest that halothane causes cerebrovascular dilatation and increased cerebral blood flow (CBF); these properties may be relevant to its use for neurosurgical procedures. We studied CBF autoregulation in monkeys during anesthesia with 66% N2O/33% O2 and with 0.5%, 1.0%, and 2.0% inspired halothane at various cerebral perfusion pressures (CPP) achieved by infusion of trimethaphan camsylate or phenylephrine. CBF was measured by monitoring brain xenon-133 clearance after intra-arterial injection of the isotope in saline. CBF autoregulation was intact during N2O/O2 and during 0.5% halothane/N2O/O2 anesthesia at CPPs ranging from 50 to 100 mmHg, but began to fail at 1.0% halothane. Complete loss of autoregulation occurred during 2% halothane/N2O/O2 anesthesia. Estimated brain O2 consumption fell by 30%, 40%, and 50% during 0.5%, 1.0%, and 2.0% halothane anesthesia, respectively, compared to O2 consumption during N2O/O2 anesthesia (100%).
mesh_terms: D000758:Anesthesia; D000818:Animals; D001921:Brain / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D006221:Halothane / Q000494:pharmacology*; D000882:Haplorhini; D008253:Macaca mulatta; D010101:Oxygen Consumption / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D006221:Halothane