Assessing mortality differences across acute respiratory failure management strategies in Covid-19

Abstract

Purpose: Prolonged observation could avoid invasive mechanical ventilation (IMV) and related risks in patients with Covid-19 acute respiratory failure (ARF) compared to initiating early IMV. We aimed to determine the association between ARF management strategy and in-hospital mortality.

Materials and methods: Patients in the Weill Cornell Covid-19 registry who developed ARF between March 5 - March 25, 2020 were exposed to an early IMV strategy; between March 26 - April 1, 2020 to an intermediate strategy; and after April 2 to prolonged observation. Cox proportional hazards regression was used to model in-hospital mortality and test an interaction between ARF management strategy and modified sequential organ failure assessment (mSOFA).

Results: Among 632 patients with ARF, 24% of patients in the early IMV strategy died versus 28% in prolonged observation. At lower mSOFA, prolonged observation was associated with lower mortality compared to early IMV (at mSOFA = 0, HR 0.16 [95% CI 0.04-0.57]). Mortality risk increased in the prolonged observation strategy group with each point increase in mSOFA score (HR 1.29 [95% CI 1.10-1.51], p = 0.002).

Conclusion: In Covid-19 ARF, prolonged observation was associated with a mortality benefit at lower mSOFA scores, and increased mortality at higher mSOFA scores compared to early IMV.

Keywords: Acute respiratory failure; Covid-19; Mechanical ventilation.

Fig. 1

Exclusionary cascade. This figure illustrates the identification of our cohort at risk for intubation.

Fig. 2

SOFA score distribution by ARF management strategy. This figure illustrates the distribution of modified SOFA score by ARF management strategy (intubation strategy). The purple corresponds to patients in the early IMV group, green to the intermediate group, and grey to the prolonged observation group. Overlapping distributions are presented by a mix of colors. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Hazard ratio for in-hospital mortality comparing the prolonged observation strategy to the early invasive mechanical ventilation strategy by modified SOFA score. This figure plots the adjusted hazard ratio for mortality comparing the prolonged observation strategy versus the early IMV strategy as a function of the modified SOFA score. The shaded grey areas are the point-wise 95% confidence intervals.