Effect of a Low vs Intermediate Tidal Volume Strategy on Ventilator-Free Days in Intensive Care Unit Patients Without ARDS: A Randomized Clinical Trial.
Writing Group for the PReVENT Investigators None., Simonis FD., Serpa Neto A., Binnekade JM., Braber A., Bruin KCM., Determann RM., Goekoop G-J., Heidt J., Horn J., Innemee G., de Jonge E., Juffermans NP., Spronk PE., Steuten LM., Tuinman PR., de Wilde RBP., Vriends M., Gama de Abreu M., Pelosi P., Schultz MJ.
ImportanceIt remains uncertain whether invasive ventilation should use low tidal volumes in critically ill patients without acute respiratory distress syndrome (ARDS).ObjectiveTo determine whether a low tidal volume ventilation strategy is more effective than an intermediate tidal volume strategy.Design, setting, and participantsA randomized clinical trial, conducted from September 1, 2014, through August 20, 2017, including patients without ARDS expected to not be extubated within 24 hours after start of ventilation from 6 intensive care units in the Netherlands.InterventionsInvasive ventilation using low tidal volumes (n = 477) or intermediate tidal volumes (n = 484).Main outcomes and measuresThe primary outcome was the number of ventilator-free days and alive at day 28. Secondary outcomes included length of ICU and hospital stay; ICU, hospital, and 28- and 90-day mortality; and development of ARDS, pneumonia, severe atelectasis, or pneumothorax.ResultsIn total, 961 patients (65% male), with a median age of 68 years (interquartile range [IQR], 59-76), were enrolled. At day 28, 475 patients in the low tidal volume group had a median of 21 ventilator-free days (IQR, 0-26), and 480 patients in the intermediate tidal volume group had a median of 21 ventilator-free days (IQR, 0-26) (mean difference, -0.27 [95% CI, -1.74 to 1.19]; P = .71). There was no significant difference in ICU (median, 6 vs 6 days; 0.39 [-1.09 to 1.89]; P = .58) and hospital (median, 14 vs 15 days; -0.60 [-3.52 to 2.31]; P = .68) length of stay or 28-day (34.9% vs 32.1%; hazard ratio [HR], 1.12 [0.90 to 1.40]; P = .30) and 90-day (39.1% vs 37.8%; HR, 1.07 [0.87 to 1.31]; P = .54) mortality. There was no significant difference in the percentage of patients developing the following adverse events: ARDS (3.8% vs 5.0%; risk ratio [RR], 0.86 [0.59 to 1.24]; P = .38), pneumonia (4.2% vs 3.7%; RR, 1.07 [0.78 to 1.47]; P = .67), severe atelectasis (11.4% vs 11.2%; RR, 1.00 [0.81 to 1.23]; P = .94), and pneumothorax (1.8% vs 1.3%; RR, 1.16 [0.73 to 1.84]; P = .55).Conclusions and relevanceIn patients in the ICU without ARDS who were expected not to be extubated within 24 hours of randomization, a low tidal volume strategy did not result in a greater number of ventilator-free days than an intermediate tidal volume strategy.Trial registrationClinicalTrials.gov Identifier: NCT02153294.