A Retrospective Analysis of the Effects of Time on Compliance and Driving Pressures in ARDS

BACKGROUND: The evolution of compliance and driving pressure in ARDS and the effects of time spent on noninvasive respiratory support prior to intubation have not been well studied. We conducted this study to assess the effect of the duration of noninvasive respiratory support prior to intubation (ie, noninvasive ventilation [NIV], high-flow nasal cannula [HFNC], or a combination of NIV and HFNC) on static compliance and driving pressure and retrospectively describe its trajectory over time for COVID-19 and non–COVID-19 ARDS while on mechanical ventilation. METHODS: This is a retrospective analysis of prospectively collected data from one university-affiliated academic medical center, one rural magnet hospital, and 3 suburban community facilities. A total of 589 subjects were included: 55 COVID-19 positive, 137 culture positive, and 397 culture-negative subjects. Static compliance and driving pressure were calculated at each 8-h subject-ventilator assessment. RESULTS: Days of pre-intubation noninvasive respiratory support were associated with worse compliance and driving pressure but did not moderate any trajectory. COVID-19–positive subjects showed non-statistically significant worsening compliance by 0.08 units per subject-ventilator assessment (P = .24), whereas COVID-19–negative subjects who were either culture positive or negative showed statistically significant improvement (0.12 and 0.18, respectively; both P < .05); a statistically similar but inverse pattern was observed for driving pressure. CONCLUSIONS: In contrast to non–COVID-19 ARDS, COVID-19 ARDS was associated with a more ominous trajectory with no improvement in static compliance or driving pressures. Though there was no association between days of pre-intubation noninvasive respiratory support and mortality, its use was associated with worse overall compliance and driving pressure.