Rationale: Evidence from observational studies suggests that driving pressure is strongly associated with pulmonary injury and mortality, regardless of positive end-expiratory pressure (PEEP) levels, tidal volume, or plateau pressure. Therefore, it is possible that targeting driving pressure may improve the safety of ventilation strategies for patients with acute respiratory distress syndrome (ARDS). However, the clinical effects of a driving pressure-limited strategy for ARDS has not been assessed in randomized controlled trials.Objectives: To evaluate the feasibility of testing a driving pressure-limited strategy in comparison with a conventional lung-protective ventilation strategy in patients with ARDS and a baseline driving pressure of ≥13 cm H2O.Methods: This was a randomized, controlled, nonblinded trial that included 31 patients with ARDS who were on invasive mechanical ventilation and had a driving pressure of ≥13 cm H2O. Patients allocated to the driving pressure-limited strategy were ventilated with volume-controlled or pressure-support ventilation modes, with tidal volume titrated to 4-8 ml/kg of predicted body weight (PBW), aiming at a driving pressure of 10 cm H2O, or the lowest possible. Patients in the control group were ventilated according to the ARDSNet (Acute Respiratory Distress Syndrome Network) protocol, using a tidal volume of 6 ml/kg PBW, which was allowed to be set down to 4 ml/kg PBW if the plateau pressure was >30 cm H2O. The primary endpoint was the driving pressure on Days 1-3.Results: Sixteen patients were randomized to the driving pressure-limited group and 15 were randomized to the conventional strategy group. All patients were considered in analyses. Most of the patients had mild ARDS with a mean arterial oxygen tension/fraction of inspired oxygen ratio of 215 (standard deviation [SD] = 95). The baseline driving pressure was 15.0 cm H2O (SD = 2.6) in both groups. In comparison with the conventional strategy, driving pressure from the first hour to the third day was 4.6 cm H2O lower in the driving pressure-limited group (95% confidence interval [CI], 6.5 to 2.8; P < 0.001). From the first hour up to the third day, tidal volume in the driving pressure-limited strategy group was kept lower than in the control group (mean difference [ml/kg of PBW], 1.3; 95% CI, 1.7 to 0.9; P < 0.001). We did not find statistically significant differences in the incidence of severe acidosis (pH < 7.10) within 7 days (absolute difference -12.1; 95% CI, -41.5 to -17.3) or any clinical secondary endpoint.Conclusions: In patients with ARDS, a trial assessing the effects of a driving pressure-limited strategy using very low tidal volumes versus a conventional ventilation strategy on clinical outcomes is feasible.Clinical trial registered with ClinicalTrials.gov (NCT02365038).
Keywords: acute respiratory distress syndrome; artificial respiration; driving pressure; tidal volume; ventilator-induced lung injury.