Background: The peak inspiratory pressure (PIP) is crucial in mechanical ventilation with supraglottic airway device (SAD). Pressure-controlled ventilation volume-guaranteed (PCV-VG), delivering a preset tidal volume with the lowest required airway pressure, is being increasingly used during general anesthesia. In this study, we compared respiratory mechanics and circulatory parameters between volume-controlled ventilation (VCV) and PCV-VG in elderly patients undergoing laparoscopic surgery using the laryngeal mask airway supreme (LMA).
Methods: Eighty participants scheduled for laparoscopic surgery were enrolled in this prospective, randomized clinical trial. The participants were randomly assigned to receive VCV or PCV-VG. PIP, dynamic compliance (Cdyn) and mean inspiratory pressure (Pmean) were recorded at 5 min after induction of anesthesia (T1), 5 min after pneumoperitoneum(T2), 30 and 60 min after pneumoperitoneum (T3 and T4). Data including other respiratory variables, hemodynamic variables, and arterial blood gases were also collected. The difference in PIP between VCV and PCV-VG was assessed as the primary outcome.
Results: PIP was significantly lower at T2, T3, and T4 in both groups compared with T1 (all P < 0.0001), and it was significantly lower in the PCV-VG group than the VCV group at T2, T3, and T4 (all P < 0.001). Cydn was decreased at T2, T3, and T4 in two groups compared with T1 (all P < 0.0001), but it was higher in PCV-VG group than in VCV group at T2, T3, and T4 (all P < 0.0001). There were on statistically significant differences were found between the groups for other respiratory and hemodynamic variables.
Conclusion: In elderly patients who underwent laparoscopic surgery using an LMA, PCV-VG was superior to VCV in its ability to provide ventilation with lower peak inspiratory pressure and greater dynamic compliance.
Keywords: Elderly patients; General anesthesia; Laparoscopic surgery; Laryngeal mask airway; Mechanical ventilation.