The effect of remimazolam versus propofol on respiratory depression for non-intubated general anesthesia: a randomized controlled trial

BACKGROUND: This randomized controlled trial aimed to compare the respiratory safety profiles of remimazolam versus propofol during non-intubated general anesthesia. METHODS: This single-center, randomized controlled trial investigated 200 female patients undergoing Open Excision of Benign Breast Nodule (OEBN) under non-intubated general anesthesia. Participants were randomly assigned to receive either remimazolam or propofol for anesthesia induction and maintenance, combined with remifentanil. We employed the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale for continuous sedation monitoring. The primary endpoint was the incidence of respiratory depression. Secondary outcomes encompassed: postoperative recovery quality, sedation success rate, frequency of respiratory depression episodes, requirement for airway interventions, and occurrence of adverse events (including hemodynamic instability and procedure-related complications). RESULTS: Of 200 randomized participants, 173 completed all study procedures and were included in the final analysis (Group R: n = 87; Group P: n = 86). The remimazolam group exhibited superior respiratory safety profiles compared to the propofol group, with a lower incidence of respiratory depression (89.7% vs 97.7%, p = 0.031) and a significantly reduced requirement for airway interventions (all p < 0.05). Furthermore, remimazolam predominantly induces mild respiratory depression (73.6%), whereas propofol is more frequently associated with severe respiratory suppression (44.2%). Regarding adverse events, Group R demonstrated markedly lower rates of injection pain (0% vs 39.5%, p < 0.001), hypotension (29.9% vs 46.5%, p = 0.024), and bradycardia (18.4% vs 44.2%, p < 0.001). Patients receiving remimazolam (Group R) demonstrated significantly superior hemodynamic stability compared to the propofol group. CONCLUSION: Although both remimazolam and propofol demonstrated a high incidence of respiratory depression, remimazolam was associated with milder respiratory suppression and a reduced need for airway interventions during OEBN with non-intubated general anesthesia. Additionally, it offers better hemodynamic stability and fewer adverse events, making it a safer alternative for such procedures. CLINICAL TRIAL REGISTRATION: ChiCTR2400089826.