Anesthesia and perioperative care
loss of consciousness
NEUROMUSCULAR BLOCKADE
No premedication was administered to the patients. All patients were monitored by pulse oximetry, noninvasive monitor of arterial blood pressure, electrocardiography, bispectral index (BIS) monitor, neuromuscular monitor, and carbon dioxide capnography. For the R group, anesthesia was induced with continuous infusion of remimazolam at a rate of 12 mg/kg/hr until loss of consciousness (LoC). Anesthesia was maintained with remimazolam at a rate of 1–2 mg/kg/hr. A target-controlled infusion (TCI) device (Orchestra Base Primea; Fresenius Kabi, France) was used for induction and maintenance of anesthesia with remifentanil (target effect-site concentration: 2.5 ~ 4 ng/ml). For the P group, the same TCI device was used for induction and maintenance of anesthesia with propofol (target effect-site concentration: 3–5 µg/ml) and remifentanil (target effect-site concentration 2.5 ~ 4 ng/ml).Endotracheal intubation was facilitated with rocuronium 0.6 mg/kg, and rocuronium 0.15 mg/kg was additionally administered if required during surgery. Anesthesia was maintained with a BIS value between 40 and 60. Remimazolam and propofol were reduced if the BIS was less than 40 and increased if the BIS was over 60. The goal was to maintain mean arterial pressure between 60 mmHg and 95 mmHg. Ephedrine 5 mg was administered intravenously if the mean arterial pressure was less than 60 mmHg, and remifentanil was increased if the mean arterial pressure was 95 mmHg or more. All patients received 1000 mg of acetaminophen and 0.3 mg of ramosetron intravenously 20 min before the end of surgery. In the ward, intravenous acetaminophen 1000 mg was administered twice. After completion of surgery, sugammadex 2–4 mg/kg was administered intravenously to reverse the neuromuscular blockade. In group R, flumazenil 0.2 mg was injected intravenously when sufficient spontaneous breathing was restored. Extubation was performed when patients with sufficient spontaneous breathing had a BIS score of 90 or higher, opened their eyes, and followed verbal commands. If consciousness was not restored even after 10 min of administering flumazenil, it was considered delayed emergence, and 0.1 mg of flumazenil was repeatedly administered at 60 s intervals up to a maximum of 1 mg. The patient was extubated and transferred to a post anesthetic care unit (PACU). Patients were monitored for 1 h in the PACU and then transferred to the general ward.