Association Between Early Invasive Mechanical Ventilation and Day-60 Mortality in Acute Hypoxemic Respiratory Failure Related to Coronavirus Disease-2019 Pneumonia

Abstract

Objectives: About 5% of patients with coronavirus disease-2019 are admitted to the ICU for acute hypoxemic respiratory failure. Opinions differ on whether invasive mechanical ventilation should be used as first-line therapy over noninvasive oxygen support. The aim of the study was to assess the effect of early invasive mechanical ventilation in coronavirus disease-2019 with acute hypoxemic respiratory failure on day-60 mortality.

Design: Multicenter prospective French observational study.

Setting: Eleven ICUs of the French OutcomeRea network.

Patients: Coronavirus disease-2019 patients with acute hypoxemic respiratory failure (Pao₂/Fio₂ ≤ 300 mm Hg), without shock or neurologic failure on ICU admission, and not referred from another ICU or intermediate care unit were included.

Intervention: We compared day-60 mortality in patients who were on invasive mechanical ventilation within the first 2 calendar days of the ICU stay (early invasive mechanical ventilation group) and those who were not (nonearly invasive mechanical ventilation group). We used a Cox proportional-hazard model weighted by inverse probability of early invasive mechanical ventilation to determine the risk of death at day 60.

Measurement and main results: The 245 patients included had a median (interquartile range) age of 61 years (52-69 yr), a Simplified Acute Physiology Score II score of 34 mm Hg (26-44 mm Hg), and a Pao₂/Fio₂ of 121 mm Hg (90-174 mm Hg). The rates of ICU-acquired pneumonia, bacteremia, and the ICU length of stay were significantly higher in the early (n = 117 [48%]) than in the nonearly invasive mechanical ventilation group (n = 128 [52%]), p < 0.01. Day-60 mortality was 42.7% and 21.9% in the early and nonearly invasive mechanical ventilation groups, respectively. The weighted model showed that early invasive mechanical ventilation increased the risk for day-60 mortality (weighted hazard ratio =1.74; 95% CI, 1.07-2.83, p=0.03).

Conclusions: In ICU patients admitted with coronavirus disease-2019-induced acute hypoxemic respiratory failure, early invasive mechanical ventilation was associated with an increased risk of day-60 mortality. This result needs to be confirmed.

Keywords: acute hypoxemic respiratory failure; coronavirus disease 2019; critically ill; invasive mechanical ventilation; mortality; noninvasive oxygen support.

Figure 1.

Flowchart. AHRF = acute hypoxemic respiratory failure, COVID-19 = coronavirus disease 2019, GCS = Glasgow Coma Scale, IMV = invasive mechanical ventilation, LOS = length of stay.

Figure 2.

Standardized differences of variables used to generate the propensity score before and after proportional-hazard model weighted by inverse probability (IPTW). Propensity scores ranged from 0.01 to 0.92 and from 0.02 to 0.97 in the no early invasive mechanical ventilation (IMV) and in the early IMV groups, respectively, with 93.8% in the region of common support (0.02–0.92). All the covariates in the planned propensity score were kept in the final model. After applying IPTW, all covariates in the planned propensity score had weighted standardized differences below 10%, which is in favor of an equilibration of the covariates between the subgroups and ensures the exchangeability at baseline for these confounders. ACE = angiotensin-converting-enzyme inhibitors, SOFA = Sequential Organ Failure Assessment.

Figure 3.

Effect of early invasive mechanical ventilation on ICU death of patients in the main cohort and in different subgroups (sensitivity analyses).