Early vs Late Intubation in COVID-19 Acute Respiratory Distress Syndrome: A Retrospective Study of Ventilator Mechanics, Computed Tomography Findings, and Outcomes

Abstract

Introduction: As the management of COVID-19 has continued to evolve, the question as to whether delaying intubation is beneficial or harmful for patients with COVID-19 induced hypoxic respiratory failure has yet to be answered. Early reports suggested that patients may benefit from early intubation during a period of severe hypoxia;later management shifted towards delaying intubation as much as possible using non-invasive ventilation. Additionally, the pathophysiologic implications of timing of intubation are poorly understood, including the potential for pulmonary vascular thrombosis and intussusceptive angiogenesis. This study examines the differences in outcomes and respiratory mechanics between subjects who are intubated earlier versus later in their COVID-19 disease course. Study Design and Methods: Retrospective single-center cohort study of subjects intubated for COVID-19 ARDS between March and June 2020. Patients were stratified by time to intubation: 30 subjects were intubated 4-24 hours after presentation and 24 subjects were intubated 5-10 days after presentation. Data regarding baseline characteristics, hospitalization, ventilator mechanics and outcomes were extracted and analyzed. 10 clinically available CT scans for these patients were manually reviewed to identify evidence of pulmonary vascular thrombosis and intussusceptive angiogenesis. Results: Median time from symptom onset to intubation was significantly different between the Early and Late Intubation Cohorts, with the latter being intubated later in the course of their illness (7.9 days vs 11.8 days;p=0.04). The Early Intubation Cohort had a lower mortality rate than the Late Intubation Cohort (6% vs 30%, p < 0.001) without significantly different ventilator mechanics at the time of intubation. However, the Late Intubation Cohort was noted to have higher dead space ratio (0.40 vs 0.52;p = 0.03). On review of CT scans, the Late Intubation Cohort also had more segments with dilated and tortuous peripheral vessels on imaging (2 segments vs 5 segments). Interpretation: As our approaches to treatment of COVID-19 continue to evolve, the decision of timing of intubation remains paramount. While non-invasive ventilation may allow for delaying intubation, it is possible that there are downstream effects of delayed intubation that should be considered.