Respiratory Pathophysiology of Mechanically Ventilated Patients with COVID-19: A Cohort Study

Abstract

To the Editor:Five to twenty percent of hospitalized patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are admitted to the ICU, with mortality reported between 26% and 61.5% (1-3).Nearly all ICU patients present with respiratory failure, and up to 88% are managed with invasive mechanical ventilation (1-3).Descriptions of the pathophysiological characteristics of coronavirus disease (COVID-19) respiratory failure are limited.Reports of preserved respiratory system mechanics despite severe hypoxemia in early small series have led some investigators to hypothesize that a significant proportion of COVID-19 respiratory failure is not the typical acute respiratory distress syndrome (ARDS) and warrants alternative management (4, 5).A detailed characterization of COVID-19 respiratory failure and its response to established ARDS therapies is needed before rigorous comparisons of established and new strategies can be contemplated.We describe the respiratory pathophysiology of patients with COVID-19 respiratory failure treated with invasive mechanical ventilation at two tertiary care hospitals in Boston, Massachusetts. MethodsPopulation and setting.We studied all adult inpatients with SARS-CoV-2 infection and respiratory failure managed with invasive mechanical ventilation at Massachusetts General Hospital and Beth Israel Deaconess Medical Center between March 11 and March 30, 2020.The studies were granted exemption by the hospital institutional review boards.Informed consent was waived.Clinical management occurred at the discretion of the treating physician.Hospital treatment guidelines recommended ventilation with VTs of ,6 ml/kg predicted body weight, early consideration of prone ventilation for Pa O 2 : FI O 2 , 200, and conservative fluid management.Positive end-expiratory pressure (PEEP) was titrated per institutional protocols and included use of the lower-PEEP/higher-FI O 2 ARDS network table, titration by best tidal compliance, and esophageal manometry (6).Both institutions recommended