ĐÁNH GIÁ SỰ AN TOÀN CỦA CHẾ ĐỘ THÔNG KHÍ HỖ TRỢ LÊN NGƯỜI BỆNH ĐƯỢC GÂY MÊ TOÀN THÂN QUA MẶT NẠ THANH QUẢN

Abstract

Introduction: Modern anesthesia machines are now equipped with supported ventilation modes such as SIMV and PSV. These modes not only help maintain spontaneous breathing and compensate for inadequate tidal volumes, but also provide more physiologically favorable ventilation compared to controlled ventilation. However, no study has been specifically designed to evaluate the safety of combining SIMV and PSV - applied sequentially according to different stages of anesthesia – compared to the traditional approach of controlled ventilation. Objective: To evaluate the safety of supported ventilation in patients undergoing general anesthesia with a laryngeal mask airway (LMA), compared to controlled ventilation. Methods: A randomized controlled clinical trial was conducted on 60 adult patients undergoing general anesthesia with LMA between August 2024 and May 2025. Participants were randomly assigned into two groups: the PSV group (pressure supported ventilation) and the VCV group (volume controlled ventilation). The primary outcome was the incidence of perioperative respiratory complications. Ventilatory parameters—including leak fraction, peak airway pressure, respiratory rate, dynamic compliance, and end-tidal CO₂ (EtCO₂) - as well as hemodynamic variables (mean arterial pressure and heart rate), were recorded at multiple perioperative time points to compare the safety characteristics between groups. Results:. The incidence of perioperative respiratory complications was lower in the PSV group than in the VCV group (0% vs. 3.33%), although the difference was not statistically significant (p>0.05). Leak fractions were comparable between groups (1.91% vs. 2.11%; p = 0.65). EtCO₂ levels were significantly higher in the PSV group at the end of surgery and prior to LMA removal (37.9 mmHg vs. 35.4 mmHg; p = 0.001, and 37.2 mmHg vs. 35.6 mmHg; p = 0.015, respectively). Hemodynamic variables including mean arterial pressure and heart rate were similar between groups at all perioperative time points. Conclusion: Supported ventilation during general anesthesia with LMA demonstrated safety comparable to that of controlled ventilation. Respiratory parameters shifted toward more physiologic values when spontaneous breathing was preserved, though these changes remained within acceptable limits and required no intervention throughout the perioperative course