Comparison of Pressure-Controlled and Volume-Controlled Ventilation During One-Lung Ventilation in Thoracic Surgery:...

Background: One-lung ventilation (OLV) is commonly required during thoracic surgery and is associated with significant changes in respiratory mechanics and hemodynamics. The optimal ventilation mode during OLV remains controversial. This trial compared pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) with respect to respiratory mechanics and gas exchange during OLV. Methods: In this single-blind randomized trial, 40 adult patients undergoing thoracic surgery requiring OLV were allocated to receive either PCV or VCV in two groups. During OLV, patients in the PCV group were ventilated with pressure adjustment to achieve a target tidal volume (VT) of 6 mL/kg, while the VCV group received a fixed VT of 6 mL/kg. Respiratory and hemodynamic parameters were recorded every 15 minutes, and arterial blood gas analysis was performed every 30 minutes. Results: Mean airway pressure (P-mean) during OLV was significantly lower in the PCV group compared with the VCV group (P < 0.05), while dynamic compliance (C-dyn) was significantly higher in the PCV group (P < 0.05). Expiratory VT was also higher in the PCV group (P < 0.05). Mean arterial pressure was consistently higher in the PCV group during OLV (P < 0.05). No significant differences were observed between the two groups in arterial oxygenation indices (P > 0.05). Conclusion: PCV improved respiratory mechanics during OLV in thoracic surgery by reducing P-mean and increasing C-dyn, without improving gas exchange. These findings reflect short-term intraoperative physiological differences and should not be extrapolated to postoperative clinical outcomes.