Guidelines for Ventilation Should Also be Applied to COVID-19 Pneumonia

Eric Nolley, MD

New data from an investigation comparing the mortality rates of patients who had COVID-19 pneumonia with pneumonia from other causes found the rates to be similar. This study contradicts early suggestions that among the causes of pneumonia, those with pneumonia and acute hypoxemic respiratory failure (AHRF) due to SARS-CoV-2 were at higher mortality risk.

"Proponents of COVID-19 AHRF as a unique respiratory physiology phenotype suggest that strict adherence to low tidal volume ventilation may not be necessary and may even be harmful," investigators stated. "However, if COVID-19 pneumonia leads to physiology typical of classic acute respiratory distress syndrome (ARDS), then evidence-based ARDS treatment strategies, such as low tidal volume ventilation and prone positioning, are the only interventions proven to reduce mortality."

Eric Nolley, MD, Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, and investigators found that patients who were mechanically ventilated for severe pneumonia showed the same rates of mortality, however, patients with COVID-19 pneumonia experienced a longer duration of mechanical venilation before liberation.

Does COVID-19 pneumonia have a unique phenotype?

The primary outcome of the retrospective cohort study was 90-day in-hospital mortality. Secondary outcomes included time to liberation from mechanical ventilation, hospital length of stay, static respiratory system compliance, and ventilatory ratio.

To compare outcomes between COVID-19 pneumonia and pneumonia due to other etiologies, investigators collected clinical, laboratory, and mechanical data from the time of admission and hospital discharge or time of death. For the group with COVID-19 pneumonia, information from March 2020-June 2021 was analyzed, and for non-COVID-19 pneumonia, the team assessed information from July 2016-December 2019.

The study population consisted of adult patients, 18 years and older, who were hospitalized in the Johns Hopkins Healthcare System for pneumonia and required mechanical ventilation within the first 2 weeks after admission.

Guidelines for Mechanical Ventilation in Patients with Pneumonia

Results from 1846 patients with pneumonia were included in the analysis. Among the 719 patients with COVID-19 pneumonia, 61.5% were men, the average age was 61.8 years, and 64% were in a minoritized racial group while 35.2% were white.

Of the 1127 patients with non-COVID-19 pneumonia, 52% were men, the average age was 60.9 years, 40.7% belonged to a minoritized racial group, and 58.1% were white. Before adjustment, analyses indicated that patients in the COVID-19 group had higher 90-mortality, as well as a longer duration of time on mechanical ventilation, and lower compliance compared with the non-COVID-19 group.

However, the propensity score-matched analyses showed that both groups had an equal mortality risk within 90 days, and similar respiratory compliance and ventilatory ratio. Although, lower rates of liberation from mechanical ventilation were observed in patients with COVID-19 pneumonia when compared with those with non–COVID-19 pneumonia.

Additionally, investigators reported that they also had somewhat lower rates of being discharged from the hospital alive at 90 days, but the difference was not statistically significant.

"In this study, mechanically ventilated patients with severe COVID-19 pneumonia had similar mortality rates as patients with other causes of severe pneumonia but longer times to liberation from mechanical ventilation," the team wrote. "Mechanical ventilation use in COVID-19 pneumonia should follow the same evidence-based guidelines as for any pneumonia."

The study "Outcomes Among Mechanically Ventilated Patients With Severe Pneumonia and Acute Hypoxemic Respiratory Failure From SARS-CoV-2 and Other Etiologies" was published in JAMA.