The effect of remimazolam combined with low-dose propofol on diaphragmatic function in patients undergoing hysteroscopic surgery: a randomized clinical trial.

BACKGROUND

Propofol frequently induces respiratory depression in hysteroscopy, with diaphragmatic dysfunction being a potential contributing mechanism. This study utilized ultrasound technology to investigate whether remimazolam combined with low-dose propofol can attenuate diaphragmatic dysfunction compared to propofol alone in patients undergoing hysteroscopic surgery.

METHODS

Patients undergoing hysteroscopic surgery were randomized 1:1 to either remimazolam 0.2 mg/kg with propofol 1 mg/kg (RP group) or propofol 2.5 mg/kg alone (P group) for induction. Both groups received sufentanil pretreatment and propofol-remifentanil maintenance. Hemodynamic parameters (mean arterial pressure, MAP; heart rate, HR), respiratory parameters (respiratory rate, RR; pulse oxygen saturation, SpO₂), and diaphragmatic parameters (diaphragmatic excursion, DE; diaphragm thickening fraction, DTF) were compared at specified timepoints: T0 (Baseline): 5 min after entering the operating room; T1: 6 min after administration of the sedative; T2: 5 min after removal of the laryngeal mask airway (LMA); T3: 5 min before discharge from the post-anesthesia care unit (PACU). Adverse reactions, including respiratory/diaphragmatic depression, injection pain, hypotension, and hiccups, were also compared.

RESULTS

Eighty patients completed the final analysis. The RP group showed significantly higher DTF values compared to the P group at T1, T2, and T3 (P = 0.02; P < 0.001; P = 0.030). Additionally, the RP group had a significantly lower incidence of diaphragm dysfunction (P = 0.007), injection pain (P = 0.043), and hypotension (P = 0.048) compared to the P group. Notably, the RP group had a significantly higher rate of spontaneous (assisted) breathing compared to the P group (P = 0.011). However, the incidence of hiccups increased markedly in the RP group compared to the P group (P = 0.044). There were no statistically significant differences between the two groups in terms of respiratory depression, delayed awakening, or dizziness (P = 0.235; P = 1.000; P = 0.136).

CONCLUSION

Compared to propofol, the combination of remimazolam and low-dose propofol can significantly alleviate diaphragmatic dysafunction in patients undergoing hysteroscopic surgery, while preserving spontaneous breathing more effectively. Optimized therapeutic regimens may prevent respiratory complications and accelerate recovery.

TRIAL REGISTRATION: Chinese Clinical Trial Registry, identifier: ChiCTR2500102592, Date: 16/5/2025.