Speed of reversal of midazolam‐induced respiratory depression by flumazenil ‐ a study in patients undergoing upper G.I. endoscopy

Abstract

Intravenous midazolam was given to 17 patients coming to upper G.I. endoscopy. All patients had an ear oximeter and calibrated induction plethysmograph attached to record oxygen saturation and minute volume continuously. Midazolam induced significant depression of respiration. Following removal of the endoscope, a new base line was obtained before giving intravenous flumazenil in an attempt to reverse the sedative and ventilatory effects of midazolam. When 0.5 mg of flumazenil was given over 20 s, followed by 0.1 mg every minute, up to a total of 1.0 mg, all patients were apparently awake in under 2 min. Although the flumazenil had clearly reversed the sedative effects of midazolam, the ventilatory effects were largely uninfluenced. The implications are discussed.

Sedative and ventilatory effects of midazolam infusion: effect of flumazenil reversal

“…29 In contrast, we found that flumazenil was effective in reversing some components of midazolam-induced ventilatory depression (e.g., the decrease in VT). Analogous to the finding of Gross et al, t4 flumazenil did not reverse the depressant effects of midazolam on the CO2 response curve.…”

Guidelines for sedation in gastroenterological endoscopy

“…The antagonistic effect for respiratory depression induced by midazolam appears within 120 s after the i.v. injection of flumazenil, which immediately attenuates or eliminates respiratory depression . The underlying problem in using flumazenil is that re‐sedation may occur because this drug has a shorter duration of action than midazolam.…”

“…The underlying problem in using flumazenil is that re‐sedation may occur because this drug has a shorter duration of action than midazolam. Because of the above mechanism, patients may awaken temporarily and then spontaneously lose consciousness again . A study compared flumazenil and a placebo given immediately and 30 min after the examination in 50 cases undergoing upper GI endoscopy under sedation with midazolam.…”

“…In endoscopy for the elderly, when patients request the use of a sedative and there are no specific grounds for refusing this request, there is no reason to hesitate, but it is necessary to monitor the patients during and after the examination more cautiously than in the case of non-elderly patients. [69][70][71] Furthermore, attention should be paid to aspiration, delayed recovery and falls as a result of suppressed biological protective reflexes. 72 In short-duration endoscopy, avoidance of using a sedative and/or an analgesic should be considered.…”

“…injection of flumazenil, which immediately attenuates or eliminates respiratory depression. [69][70][71] The underlying problem in using flumazenil is that re-sedation may occur because this drug has a shorter duration of action than midazolam. Because of the above mechanism, patients may awaken temporarily and then spontaneously lose consciousness again.…”