Effect of open-lung vs conventional perioperative ventilation strategies on postoperative pulmonary complications after on-pump cardiac surgery: the PROVECS randomized clinical trial

Abstract

Purpose: To evaluate whether a perioperative open-lung ventilation strategy prevents postoperative pulmonary complications after elective on-pump cardiac surgery.

Methods: In a pragmatic, randomized, multicenter, controlled trial, we assigned patients planned for on-pump cardiac surgery to either a conventional ventilation strategy with no ventilation during cardiopulmonary bypass (CPB) and lower perioperative positive end-expiratory pressure (PEEP) levels (2 cm H₂O) or an open-lung ventilation strategy that included maintaining ventilation during CPB along with perioperative recruitment maneuvers and higher PEEP levels (8 cm H₂O). All study patients were ventilated with low-tidal volumes before and after CPB (6 to 8 ml/kg of predicted body weight). The primary end point was a composite of pulmonary complications occurring within the first 7 postoperative days.

Results: Among 493 randomized patients, 488 completed the study (mean age, 65.7 years; 360 (73.7%) men; 230 (47.1%) underwent isolated valve surgery). Postoperative pulmonary complications occurred in 133 of 243 patients (54.7%) assigned to open-lung ventilation and in 145 of 245 patients (59.2%) assigned to conventional ventilation (p = 0.32). Open-lung ventilation did not significantly reduce the use of high-flow nasal oxygenotherapy (8.6% vs 9.4%; p = 0.77), non-invasive ventilation (13.2% vs 15.5%; p = 0.46) or new invasive mechanical ventilation (0.8% vs 2.4%, p = 0.28). Mean alive ICU-free days at postoperative day 7 was 4.4 ± 1.3 days in the open-lung group vs 4.3 ± 1.3 days in the conventional group (mean difference, 0.1 ± 0.1 day, p = 0.51). Extra-pulmonary complications and adverse events did not significantly differ between groups.

Conclusions: A perioperative open-lung ventilation including ventilation during CPB does not reduce the incidence of postoperative pulmonary complications as compared with usual care. This finding does not support the use of such a strategy in patients undergoing on-pump cardiac surgery.

Trial registration: Clinicaltrials.gov Identifier: NCT02866578. https://clinicaltrials.gov/ct2/show/NCT02866578.

Keywords: Cardiac surgery; Cardiopulmonary bypass; Open-lung ventilation; PEEP; Postoperative pulmonary complications; Recruitment maneuvers.

Fig. 1

Patient randomization, follow-up, and analysis populations

Fig. 2

Kaplan–Meier curve of the probability of the primary outcome by postoperative day 7. p = 0.29 (hazard ratio, 0.89; 95% confidence interval, 0.68 to 1.10) by the log-rank test for the between-group difference in the probability of the primary outcome