Single-dose intravenous remimazolam reduces risk of post-cesarean shivering and promotes postoperative recovery: a randomized double-blind controlled trial

Post-cesarean shivering under combined spinal-epidural anesthesia (CSEA) is highly prevalent, which can cause to maternal discomfort, increase oxygen consumption, interfere with vital sign monitoring, and potentially lead to adverse cardiovascular and respiratory events. Remimazolam, a novel ultrashort-acting benzodiazepine, has been shown to reduce postoperative shivering in general anesthesia. This study aims to evaluate the prophylactic effect of remimazolam on post-cesarean shivering under CSEA and its impact on maternal recovery quality.

A prospective randomized double-blind placebo-controlled trial was conducted on 140 singleton full-term parturients (aged 24-40 years, ASA physical status Ⅱ, BMI ≤35 kg/m²) undergoing elective cesarean section under CSEA in our hospital from June to December 2025. They were randomly assigned to a remimazolam group (Group Remimazolam, receiving a single intravenous injection of remimazolam 0.2 mg/kg immediately after delivery and umbilical cord clamping, n=70) and a control group (Group Control, n=70, receiving an equal volume of normal saline). The incidence of moderate-to-severe shivering within 90 min after neuraxial anesthesia [assessed using the Bedside Shivering Assessment Scale (BSAS)]. quality of recovery on postoperative days 1 and 2 [measured by the 15-item Quality of Recovery (QoR-15) scale, covering 5 dimensions: emotional state, psychological support, physical comfort, physical independence, and pain], Observer's Assessment of Alertness/Sedation (OAA/S) scores within 90 min after drug administration, and intraoperative adverse reactions (hypotension, bradycardia, nausea. vomiting and dizziness) were compared between the 2 groups.

There were no statistically significant differences in baseline characteristics between the 2 groups, including age, body weight, gestational age, primipara ratio, anesthetic block level, intraoperative blood loss, or operative duration (all P>0.05). ① For the primary outcome, the overall incidence of moderate-to-severe shivering in Group Remimazolam was 27.1% (19/70), significantly lower than that in Group Control [55.7% (39/70), P<0.001]. Remimazolam reduced the risk of moderate-to-severe shivering by 62% compared with the risk in the Group Control (HR=0.38, 95%CI: 0.22 to 0.67, P=0.0004). During the 0-30 min period, the incidence of moderate-to-severe shivering was significantly lower in Group Remimazolam than in Group Control (10.0% vs 25.7%, P=0.027). ② For secondary outcomes, the QoR-15 total score on postoperative day 1 was 126 (124, 128) in Group Remimazolam, which was significantly higher than that in the Control group [116 (115, 118), P<0.001]; on postoperative day 2, the Remimazolam group scored 141 (140, 143), which was significantly higher than that in the Control group [133 (130, 135), P<0.001]. Group Remimazolam showed significantly higher scores in the dimensions of emotional state, psychological support, and physical comfort (all P<0.001), whereas there were no statistically significant differences between the 2 groups in the dimensions of physical independence or pain (P>0.05). The OAA/S score at 15 min after drug administration in the Remimazolam group was 5(4, 5), which was lower than that in the Control group [5 (5, 5), P=0.004], and returned to the level of the control group after 30 min (P>0.05). No significant differences were observed in the incidence of bradycardia, hypotension, nausea, vomiting or dizzines between the 2 groups (all P>0.05).

A single intravenous dose of 0.2 mg/kg remimazolam administered immediately after delivery during cesarean section under CSEA can significantly reduce the risk of moderate-to-severe post-cesarean shivering by 62%, also improve the quality of maternal recovery on postoperative days 1 and 2 (particularly in the dimensions of emotional state, psychological support, and physical comfort). The regimen produces only mild, reversible intraoperative sedation without increasing the risk of adverse reactions.