Study population and design
This was a pilot prospective observational cohort study at Washington
University/ Barnes Jewish Hospital in St. Louis, MO between Aug 2020 and
March 2021. This study was conducted according to the Declaration of
Helsinki principles (as revised in 2013) and was approved by the
Washington University Institutional Review Board (protocol #
202006151). Adult subjects with COVID-19 related pneumonia diagnosed by
nasopharyngeal SARS-CoV-2 RT-PCR who required endotracheal intubation
and mechanical ventilation for ARDS were considered for the study.
Informed consent was obtained from the legally-authorized
representative. ARDS was defined according to the Berlin criteria (9).
We collected demographic and clinical variables of interest from the
electronic health records including age, gender, race, weight, body mass
index, comorbidities, prior use of immunosuppressive medications,
treatments administered, BAL and laboratory results and relevant
outcomes (mortality, duration of ventilation and length of stay in the
hospital). Subjects were enrolled if they had undergone bronchoscopy
with BAL performed for clinical reasons, most commonly to rule out
bacterial pneumonia. Immune response markers and cycle threshold (Ct)
SARS-CoV-2 RT-PCR were obtained from the subjects’ plasma and BAL fluid.
We excluded intubated subjects who did not undergo planned clinical
bronchoscopy and those subjects who we could not obtain informed consent
in sufficient time to analyze / store the fresh samples.