Inhaled pulmonary vasodilators are not associated with improved gas exchange in mechanically ventilated patients with COVID-19: A retrospective cohort study

Abstract

Purpose: Measure the effect of inhaled pulmonary vasodilators on gas exchange in mechanically ventilated patients with COVID-19.

Methods: A retrospective observational cohort study at three New York University Hospitals was performed including eighty-four mechanically ventilated SARS Cov-2 nasopharyngeal PCR positive patients, sixty nine treated with inhaled nitric oxide (iNO) and fifteen with inhaled epoprostenol (iEPO). The primary outcomes were change in P_AO₂:F_IO₂ ratio, oxygenation Index (OI), and ventilatory ratio (VR) after initiation of inhaled pulmonary vasodilators.

Results: There was no significant change in P_AO₂:F_IO₂ratio after initiation of iNO (mean - 4.1, 95% CI -17.3-9.0, P = 0.54) or iEPO (mean - 3.4, 95% CI -19.7-12.9, P = 0.66), in OI after initiation of iNO (mean 2.1, 95% CI-0.04-4.2, P = 0.054) or iEPO (mean - 3.4, 95% CI -19.7-12.9, P = 0.75), or in VR after initiation of iNO (mean 0.17, 95% CI -0.03-0.36, P = 0.25) or iEPO (mean 0.33, 95% CI -0.0847-0.74, P = 0.11). P_AO₂:F_IO₂, OI and VR did not significantly change over a five day period starting the day prior to drug initiation in patients who received either iNO or iEPO assessed with a fixed effects model.

Conclusion: Inhaled pulmonary vasodilators were not associated with significant improvement in gas exchange in mechanically ventilated patients with COVID-19.

Keywords: ARDS; COVID-19; Epoprostenol; Inhaled nitric oxide; Respiratory failure; Ventilatory ratio.