The use of midazolam and flumazenil in locoregional anaesthesia: an overview.

Midazolam is useful as an intravenous supplement to local anaesthesia techniques in producing sedation, amnesia and anxiolysis, and has about five times the sedative potency of diazepam. Considerable interpatient variability exists in dose requirements, especially in elderly patients. The combined effects of local anaesthetics and midazolam may contribute to enhanced haemodynamic effects and changes in the respiratory pattern, impairing ventilation and oxygenation. Flumazenil can be titrated in incremental doses to reverse the residual sedative effects of midazolam, without intrinsic haemodynamic or respiratory effects, but may not fully antagonise the decrease in chemoreceptor sensitivity nor the changes in breathing pattern induced by midazolam. Patients treated with epidural or spinal anaesthesia supplemented with midazolam should be monitored to avoid hypoxaemia risks even after the administration of flumazenil.