A Retrospective Analysis of the Effects of TIME on Compliance and Driving Pressures in Acute Respiratory Distress Syndrome: The TIMED Study

Abstract Background: The evolution of compliance and driving pressure in acute respiratory distress syndrome (ARDS) and the effects of time spent on noninvasive respiratory support prior to intubation has not been well studied. We conducted this study to assess the effect of the duration of noninvasive respiratory support prior to intubation (i.e., 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: Retrospective analysis of prospectively collected data from one university-affiliated academic medical center, one a rural magnet hospital, and three suburban community facilities. A total of 589 patients were included: 55 COVID-19 positive, 137 culture positive, and 397 culture negative patients. Static compliance and driving pressure were calculated at each 8-hour ventilator check. Results: Days of pre-intubation noninvasive respiratory support was associated with worse compliance and driving pressure but did not moderate any trajectory. COVID-19 positive patients showed non-statistically significant worsening compliance by 0.08-units per ventilator check ( p = .241), whereas COVID-19 negative patients who were either culture positive or negative patients showed statistically significant improvement (0.12 and 0.18, respectively; both p < .05); a statistically similar but inverse pattern was observed for driving pressure. Conclusion In contrast to non-COVID-19 ARDS, COVID-19 ARDS was associated with a more ominous trajectory with no improvement in static lung 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.