Long-term delayed emergence after remimazolam-based general anesthesia: a case report

Background: Remimazolam is an ultra-short-acting benzodiazepine anesthetic that is antagonized by flumazenil, and it is typically expected to be applied in anesthesia with the purpose of ensuring early postoperative recovery. We report a case of long-term delayed emergence with re-sedation even after three times of flumazenil administration.

Case presentation: A 71-year-old man was scheduled for a robotic-assisted laparoscopic radical prostatectomy for prostate cancer. We used remimazolam for anesthetic induction and maintenance. The intraoperative bispectral index (BIS) was 30-50. Flumazenil was administered as patient emergence was delayed after surgery; however, re-sedation was observed. This finding persisted till 12 h after surgery, and the patient awakened on postoperative day 2.

Conclusions: Remimazolam is a short-acting anesthetic, but long-term delayed emergence with re-sedation may occur even after flumazenil administration. Anesthesia using remimazolam requires anesthesia management that takes into account the individual differences in sensitivity and metabolism, with BIS as the indicator.