[Perioperative physiological and cognitive functions following oral premedication with 3.75 mg midazolam in operations with retrobulbar anesthesia].

UNLABELLED: The number of surgical procedures performed as day surgery has significantly increased in recent years. Therefore, a safe and short postoperative recovery period has become increasingly important. The aim of the present study was to investigate perioperative cognitive and physiological function after oral premedication with low-dose midazolam (3.75 mg), especially during the postoperative period.

METHODS

Forty-seven men (age > 69 years, weight 50-90 kg) scheduled for elective cataract surgery under retrobulbar anaesthesia (RBA) were included in the study. The patients were randomly assigned to either group 1 (n = 28), receiving 3.75 mg midazolam p.o. (Dormicum), or group 2 (n = 19), receiving a placebo orally 30 min before RBA. We measured the following parameters: sedation (modified Glasgow coma scale); anxiety (visual analogue scale); numerical and verbal memory (digit span and reproduction of previously presented words); concentration (Revisions test of Stender/Marschner). To identify depression of ventilation, pulse oximetry and nasal end-tidal PCO2 were monitored intraoperatively.

RESULTS

After premedication with 3.75 mg midazolam, patients were significantly more sedated (P < 0.01) and systolic blood pressures were significantly reduced (P < 0.05); 30 min after midazolam premedication only concentration was significantly (P < 0.05) decreased. The results of the other cognitive functions did not differ. No differences in cognitive and physiological functions between and groups could be found 2 h after the operation (293 +/- min after premedication). Intraoperatively, there were no significant differences in end-tidal PCO2 and oxygenation between the groups. In both groups anxiety and blood pressure were significantly higher pre- than postoperatively.

CONCLUSION

Oral administration of low-dose midazolam (0.049 +/- mg/kg) seems to be appropriate for premedication before ambulatory surgical procedures in elderly patients. In the interest of patient safety, standardised oral premedication with 3.75 mg midazolam may not be sufficient for some of the patients.