Experience with the cerebral function monitor during deliberate hypotension

Forty-five healthy patients (30 aged 15-46 yr and 15 aged 58-82 yr) undergoing various types of plastic surgery were studied during deliberate hypotension produced by a combination of ganglion- and beta-blockade, halothane, head-up tilt and positive end expiratory pressure. A Cerebral Function Monitor was used to assess the adequacy of cerebral perfusion. Cerebral activity did not undergo any significant change if the systolic arterial pressure was decreased gradually and maintained at approximately 60 mm Hg at heart level. However, a rapid decrease in pressure may depress cerebral activity in a reversible manner.