The effects of midazolam and sufentanil sedation on middle cerebral artery blood flow velocity in awake patients.

Abstract

Midazolam and sufentanil are commonly used for sedation. Cerebrovascular effects of low-dose midazolam have not been studied previously, and cerebrovascular effects of sufentanil remain controversial. Forty ASA I and II patients were studied preoperatively. These patients were given midazolam (20 or 40 micrograms/kg) or sufentanil (0.1 or 0.2 micrograms/kg) i.v. Transcranial Doppler recordings of middle cerebral artery mean blood flow velocity (Vm) were recorded before administration of the study drug and for the 5-min investigation period. Mean arterial pressure, heart rate, and end-tidal CO2 remained constant during the investigation and did not vary between treatment groups. Vm decreased 17 to 21% with both midazolam doses (p < 0.05), returning to baseline within 5 min. Vm did not change with either sufentanil dose. These results suggest that midazolam decreases cerebral blood flow (CBF) by increasing cerebral vascular resistance (CVR). The low sedative doses of sufentanil used in this study did not affect Vm over 5 min in unanesthetized patients.