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

Abstract

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.

Keywords: ARDS; driving pressures; noninvasive ventilation; respiratory failure; static compliance.

Fig. 1.

Unadjusted (A and C) and adjusted (B and D) estimated static compliance (A and B) and driving pressure (C and D) across subject-ventilator assessments; estimates were adjusted for body mass index and biological sex. Although the statistical models were estimated using static compliance or driving pressure at all available subject-ventilator assessments, in these figures, the number of subject-ventilator assessments was truncated at 40 given that 95% of culture-negative subjects had ≤ 42 subject-ventilator assessments. Shaded areas represent 95% CI.

Fig. 2.

Time to in-hospital mortality (A) and time to hospital discharge censored at in-hospital mortality (B) stratified by subjects with or without COVID-19. Shaded areas represent 95% CI.