Effects of two mechanical ventilation strategies during cardiopulmonary bypass on perioperative mechanical power: a prospective observational study

Background and aimCardiac surgery requiring cardiopulmonary bypass (CPB) is associated with a high rate of postoperative pulmonary complications (PPCs). Mechanical power (MP) represents energy per breath multiplied by respiratory rate and conversion factor (0.098), resulting in J/min. This prospective observational study aimed to investigate the effects of two ventilation strategies applied during CPB on MP and their association with PPCs.MethodsIn this prospective observational study, ventilation during CPB was managed according to routine clinical practice. Ventilation was discontinued after full CPB flow in Group 1 (n = 125), while low-tidal volume ventilation (3 mL/kg) was maintained in Group 2 (n = 120). Mechanical power was measured before CPB (T1), after CPB (T2), and in the intensive care unit (T3). Patients were monitored for PPCs for 7 days postoperatively.ResultsMP, the primary endpoint of the study, did not differ significantly between the two ventilation strategy groups at any measured time point. In a secondary exploratory analysis, MP values were higher at T2 and T3 in patients who developed PPCs (T2: 8.54 ± 0.32 vs. 7.78 ± 0.19 J/min, p = 0.041; T3: 8.67 ± 0.33 vs. 7.82 ± 0.19 J/min, p = 0.029).ConclusionThe two ventilation strategies applied during CPB did not significantly affect the primary outcome, mechanical power. Higher post-CPB MP values were observed in patients who developed PPCs, although this finding was exploratory.