Electrical impedance tomography-based evaluation of regional lung ventilation according to ventilation strategy during cardiopulmonary bypass in minimally invasive cardiac surgery: a prospective randomized controlled trial.

Background: Despite the potential benefits of minimally invasive cardiac surgery (MICS), cardiopulmonary bypass (CPB) during MICS can cause pulmonary complications. However, the optimal ventilation strategy for the left lung under CPB during MICS remains unclear. Thus, this study aimed to evaluate differences in postoperative pulmonary ventilation and complications according to ventilation strategy during MICS. Methods: This prospective, randomized controlled trial included 60 patients who underwent MICS with one-lung ventilation. They were randomly assigned to either the non-ventilation (NV) group, in which ventilation was halted during CPB, or the ventilation (V) group, in which ventilation at a tidal volume of 5 mL/kg was maintained during CPB. Electrical impedance tomography (EIT) monitoring was performed immediately after surgery to evaluate differences in regional ventilation and ventilation heterogeneity. Results: The V group exhibited better ventilation homogeneity across the entire lung (0.5±0.1 Conclusions: Ventilation of the left lung during CPB in MICS showed better ventilation homogeneity and ventilation of the left posterior lung area, but did not result in differences in early complications, including respiratory issues. Therefore, the necessity of left lung ventilation during CPB in short surgeries with a CPB time of <90 min is unclear. Trial Registration: The clinical research was registered at ClinicalTrials.gov (ref. No. NCT04985513).