Comparison of Pulmonary Gas Exchange According to Intraoperative Ventilation Modes for Mitral Valve Repair Surgery via Thoracotomy With One-Lung Ventilation: A Randomized Controlled Trial

Objective: Impaired pulmonary gas exchange after cardiac surgeries with cardiopulmonary bypass (CPB) often occurs, and the selection of mechanical ventilation mode, pressure-controlled ventilation (PCV) or volume-controlled ventilation (VCV), may be important for preventing hypoxia and improving oxygenation. The authors hypothesized that patients with PCV would show better oxygenation, compared with VCV, during one-lung ventilation (OLV) for mitral valve repair surgery (MVP) via thoracotomy. Design: Randomized controlled trial. Setting: University teaching hospital. Participants: Sixty patients in each group. Interventions: MVP was performed using thoracotomy with OLV by PCV or VCV. Measurements and Main Results: Arterial partial pressure of oxygen (PaO2) and fraction of inspired oxygen (FIO2) were measured before anesthesia induction (T0), at skin incision (T1), after administration of heparin (T-2), at 30 minutes after CPB weaning (T3), just before departure from the operating room to the intensive care unit (ICU) (T4), and 1 hour after ICU admission (T5), and PaO2/FIO2 ratio was calculated. Peak inspiratory pressure (PIP) and mean inspiratory pressure (P-mean) were recorded at T1, T2, T3, and T4. No significant difference was noted in the PaO2/FIO2 ratio between the groups at any measured point. PIP in the PCV group at all measured points was lower than that in the VCV group (T1, p < 0.001; T2, p < 0.001; T3, p < 0.001; T4, p = 0.025, respectively). P-mean was not different between the two groups at any measured point. Conclusions: PCV during OLV in patients undergoing MVP via a thoracotomy with OLV showed lower PIP compared with VCV, but this did not improve pulmonary gas exchange. (C) 2014 Elsevier Inc. All rights reserved.