Limiting Dynamic Driving Pressure in Patients Requiring Mechanical Ventilation

Abstract

Objectives: Previous studies reported an association between higher driving pressure (ΔP) and increased mortality for different groups of mechanically ventilated patients. However, it remained unclear if sustained intervention on ΔP, in addition to traditional lung-protective ventilation, improves outcomes. We investigated if ventilation strategies limiting daily static or dynamic ΔP 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 ΔP 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 ΔP greater than 15 cm H2O at baseline. Mortality under usual care was 20.1% (95% CI, 19.4-20.9%). Limiting daily dynamic ΔP 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 ΔP 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 ΔP, did not reduce mortality compared with usual care. Conclusions: Limiting either static or dynamic ΔP can further reduce the mortality of patients requiring mechanical ventilation.