A randomised crossover trial of post-operative cognitive and psychomotor recovery from benzodiazepine sedation: effects of reversal with flumazenil over a prolonged recovery period.

OBJECTIVE

To study the post-operative cognitive and psychomotor recovery from midazolam conscious sedation, after reversal with the benzodiazepine antagonist flumazenil over a prolonged recovery period.

DESIGN

A prospective, double-blind, randomised, crossover trial.

SETTING

Out-patient Sedation Department, Newcastle Dental Hospital and School

METHOD

Eighteen patients, ASA I or II, received midazolam on two separate occasions to undergo equivalent dental treatment. Following treatment patients were reversed with intravenous flumazenil or saline (placebo) at alternate appointments. Assessment of mood and cognitive function was undertaken using a highly sensitive and specific computerised battery of cognitive tests administered by telephone. Cognitive and psychomotor tests were administered prior to sedation and every hour for 6 hours post reversal.

RESULTS

Results indicated no significant effect of flumazenil on simple reaction time and choice reaction time but did show a trend of reversing the effects of midazolam on numeric working memory and word recognition.

CONCLUSION

The cognitive and psychomotor effects of the sedation were not fully reversed by flumazenil. Cognitive impairments were still present up to 6 hours post-reversal, despite patients appearing clinically more alert. This has important implications for treatment protocols and discharge instructions.