Association between PaO2/(FiO2*PEEP) ratio and in-hospital mortality in COVID-19 patients: A reanalysis of published data from Peru using PaO2/(FiO2*PEEP) ratio in place of PaO2/FaO2 ratio

Abstract

P/FP [PaO2/(FiO2*PEEP)] is associated with in-hospital mortality in patients with acute respiratory distress syndrome (ARDS). However, to the best of our knowledge, the association between P/FP after 24 hours of invasive mechanical ventilation (IMV) and in-hospital mortality in patients with ARDS due to Coronavirus Disease 2019 (COVID-19) remained unclear. This study aimed to evaluate the relationship between the P/FP after 24 hours of IMV and in-hospital mortality in patients with ARDS due to COVID-19. We reanalyzed previously published data from Peru. Hueda-Zavaleta et al conducted a retrospective cohort study between April 2020 and April 2021 in southern Peru. A total of 200 hospitalized COVID-19 patients requiring IMV were included in this analysis. We used Cox proportional hazard regression models and Kaplan–Meier survival analysis to investigate the effect of P/FP after 24 hours of IMV on in-hospital mortality. We used a restricted cubic spline regression and a two-piecewise Cox proportional hazards model to explore the relationship between P/FP after 24 hours of IMV and in-hospital mortality in patients with ARDS due to COVID-19. Of the 200 patients, 51 (25.50%) died in hospital. The median P/FP was 20.45 mm Hg/cmH2O [interquartile range 15.79–25.21 mm Hg/cmH2O], with a range of 5.67 mm Hg/cmH2O to 51.21 mm Hg/cmH2O. Based on the P/FP ratio, patients were equally divided into 2 groups (low group [P/FP < 20.50 mm Hg/cmH2O] and high group [P/FP ≥ 20.50 mm Hg/cmH2O]). In-hospital mortality was lower in the high P/FP group than in the low P/FP group (12 [12%] vs 39 [39%]; unadjusted hazard ratio [HR]: 0.33, 95% confidence interval [CI]: 0.17–0.63; adjusted HR: 0.10, 95% CI: 0.02–0.47). We also found a nonlinear relationship between P/FP and in-hospital mortality. After adjusting for potential confounders, the HR was 0.67 (95% CI: 0.56–0.79) for P/FP ≤ 22 mm Hg/cmH2O and 1.10 (95% CI: 0.83–1.47) for P/FP > 22 mm Hg/cmH2O. In addition, lymphocytes ≤ 1 × 109/L and acute kidney failure had a higher risk of death. After adjusting for potential confounders, the P/FP after 24 hours of IMV was nonlinearly associated with in-hospital mortality in patients with ARDS due to COVID-19.