Low-dose midazolam infusion for oculoplastic surgery under local anaesthesia

Abstract

Purpose. Oculoplastic surgery with infiltration of local anaesthesia at the operative site performed as a day-case procedure is both efficient and cost-effective. Patients considered unsuitable for this because of fear or apprehension may, however, benefit from per-operative conscious sedation. We sought to study the efficacy and safety of this using midazolam, a water-soluble benzodiazepine. Method. We have performed a controlled clinical trial comparing the effect of a low-dose intravenous infusion of midazolam (0.2 mg/ml of normal saline at a rate of 1 mg/h) with saline placebo on 48 subjects undergoing oculoplastic surgery with local anaesthesia. Patients were given pre- and post-operative questionnaires assessing, amongst other factors, anxiety levels, pain, degree of reported amnesia and psychomotor recovery. Results. Using the low-dose midazolam infusion no adverse cardiorespiratory reactions occurred. Patients receiving midazolam reported remembering significantly less about their operation than controls (p = 0.04) and showed significantly lower state-anxiety after their operation than before (p < 0.02). This change was not noted in the placebo group. There was no significant difference in the psychomotor performance of patients given midazolam compared with controls 2 h after surgery. Conclusions. A low-dose continuous infusion of midazolam can be used to safely provide effective anxiolysis and conscious sedation with good psychomotor recovery during oculoplastic procedures in a day-case setting.