Effect of protective ventilation throughout the intubation period on perioperative oxygenation in patients undergoing MIDCABG: a randomised controlled trial

Introduction Minimally invasive direct coronary artery bypass grafting (MIDCABG) requires prolonged one-lung ventilation (OLV), increasing postoperative pulmonary complications (PPCs) risk. We investigated whether protective lung ventilation (PLV) throughout intubation benefits MIDCABG patients.Methods In this single-center randomized study, MIDCABG patients received PLV (low tidal volume of 6–8 mL·kg−1, PEEP of 6 cm H2O, alveolar recruitment maneuvers) or conventional mechanical ventilation (CMV, tidal volume of 8–10 mL·kg−1, without PEEP or maneuvers) from tracheal intubation to extubation. The primary outcome was perioperative oxygenation, assessed by the PaO2/FiO2 ratio.Results Sixty patients (n = 30 per group) were enrolled. Compared with CMV, PLV improved PaO2/FiO2 ratios (mean difference at OLV60: 34.56 mmHg; 95% CI: 11.78–57.33; p < 0.01), shortened median durations of postoperative mechanical ventilation (median difference: −4.5 h, 95% CI: −8.5 to −0.5; p = 0.013) and hospital stay (median difference: −3.0 days, 95% CI: −5.0 to −1.0; p = 0.019). PLV also reduced driving pressure, airway pressure and intrapulmonary shunt during OLV (all p < 0.05). Desaturation occurred in 23.3% of CMV patients and 13.3% of PLV patients (p = 0.506). Hemodynamic parameters were generally comparable between groups, except for lower MPAP and PVRI in the PLV group during OLV and after ICU admission (p < 0.05). The incidence of PPCs did not differ between groups.Conclusions In patients undergoing MIDCABG, PLV applied throughout intubation improved perioperative oxygenation and shortened the duration of postoperative mechanical ventilation and hospital stay, but did not reduce PPCs.Clinical trial registration ChiCTR1900022005