The Cerebral Functional, Metabolic, and Hemodynamic Effects of Desflurane in Dogs

Abstract

The effects of 0.5-2.0 MAC (3.6-15%) desflurane on cerebral function, metabolism, and hemodynamics and on systemic metabolism and hemodynamics were examined in dogs. Desflurane produced a significant dose-related decrease in cerebral vascular resistance from 1.53 +/- 0.21 mmHg.ml-1.min.100 g at 0.5 MAC to 0.50 +/- 0.03 mmHg.ml-1.min.100 g at 2.0 MAC desflurane. This was accompanied by an increase in cerebral blood flow (CBF) from 61 +/- 7 ml.min-1.100 g-1 at 0.5 MAC to 78 +/- 3 ml.min-1.100 g-1 at 1.5 MAC desflurane. At 2.0 MAC desflurane CBF was 52 +/- 2 ml.min-1.100 g-1 but was associated with a decrease in mean arterial pressure (MAP) to 43 +/- 2 mmHg. When MAP was increased to 73 +/- 3 mmHg with phenylephrine, CBF increased to 87 +/- 3 ml.min-1.100 g-1 at this concentration. At 0.5 MAC desflurane, intracranial pressure (ICP) was 15 +/- 5 mmHg, higher than normal, but did not change significantly with increasing concentrations of desflurane. Increasing concentrations of desflurane initially produced on the EEG the common pattern sequence of increasing depth of anesthesia with decreasing frequency and increasing amplitude progressing to burst suppression and then at 2.0 MAC desflurane to regular attenuation with interruption by periodic polyspiking, a pattern similar to that seen with isoflurane. At both 1.5 and 2.0 MAC the EEG pattern initially observed at that concentration changed to one with faster background activity with time.(ABSTRACT TRUNCATED AT 250 WORDS)