Limiting Dynamic Driving Pressure in Patients Requiring Mechanical Ventilation*

Abstract

Objectives: Previous studies reported an association between higher driving pressure (∆P) and increased mortality for different groups of mechanically ventilated patients. However, it remained unclear if sustained intervention on ∆P, in addition to traditional lung-protective ventilation, improves outcomes. We investigated if ventilation strategies limiting daily static or dynamic ∆P reduce mortality compared with usual care in adult patients requiring greater than or equal to 24 hours of mechanical ventilation. Design: For this comparative effectiveness study, we emulated pragmatic clinical trials using data from the Toronto Intensive Care Observational Registry recorded between April 2014 and August 2021. The per-protocol effect of the interventions was estimated using the parametric g-formula, a method that controls for baseline and time-varying confounding, as well as for competing events in the analysis of longitudinal exposures. Setting: Nine ICUs from seven University of Toronto-affiliated hospitals. Patients: Adult patients (≥18 yr) requiring greater than or equal to 24 hours of mechanical ventilation. Interventions: Receipt of a ventilation strategy that limited either daily static or dynamic ∆P less than or equal to 15 cm H2O compared with usual care. Measurements and Main Results: Among the 12,865 eligible patients, 4,468 of (35%) were ventilated with dynamic ∆P greater than 15 cm H2O at baseline. Mortality under usual care was 20.1% (95% CI, 19.4–20.9%). Limiting daily dynamic ∆P less than or equal to 15 cm H2O in addition to traditional lung-protective ventilation reduced adherence-adjusted mortality to 18.1% (95% CI, 17.5–18.9%) (risk ratio, 0.90; 95% CI, 0.89–0.92). In further analyses, this effect was most pronounced for early and sustained interventions. Static ∆P at baseline were recorded in only 2,473 patients but similar effects were observed. Conversely, strict interventions on tidal volumes or peak inspiratory pressures, irrespective of ∆P, did not reduce mortality compared with usual care. Conclusions: Limiting either static or dynamic ∆P can further reduce the mortality of patients requiring mechanical ventilation.