RESUMO
BackgroundThe coronavirus disease 2019 (COVID-19) pandemic raised concern for exposure to healthcare providers through aerosol generating procedures, such as bronchoalveolar lavage (BAL). Current society guidelines recommended limiting use of BAL to reduce operators risk for infection, yet data on the infection rate for providers after BAL is sparse. Since March 2020, our institution used a modified protocol to perform over 450 BALs on intubated COVID-19 patients. We therefore sought to describe the subsequent infectious risks to providers associated with BAL. MethodsFifty-two pulmonary and critical care providers (faculty and fellows) at our tertiary-care, urban medical center were surveyed. Survey participants were asked to provide the number of BALs on COVID-19 patients they performed, the number of weeks they cared for intensive care unit (ICU) patients with COVID-19, and the results of any SARS-CoV-2 testing that they received. Participants were asked to assess the difficulty of BAL on intubated COVID-19 patients as compared to routine ICU BAL using a numeric perceived difficulty score ranging from 1 (easier) to 10 (harder). ResultsWe received forty-seven responses from fifty-two surveyed (90% response rate), with 2 declining to participate. Many respondents (19/45, 42%) spent >5 weeks on an ICU service with COVID-19 patients. The number of BALs performed by providers ranged from 0 to >60. Sixteen of the 35 providers (46%) who performed BALs underwent at least one nasopharyngeal (NP) swab to test for SARS-CoV-2, but none were positive. Twenty-seven of the 35 providers (77%) who performed BALs underwent SARS- CoV-2 serology testing, and only one (3.7%) was positive. Respondents indicated occasionally not being able to follow aerosol-minimizing steps but overall felt BALs in COVID-19 patients was only slightly more difficult than routine bronchoscopy. DiscussionAt a high-volume center having performed >450 BALs on intubated COVID-19 patients with aerosol-limiting precautions, our survey of bronchoscopists found no positive NP SARS-CoV-2 tests and only one positive antibody test result. While the optimal role for COVID-19 BAL remains to be determined, these data suggest that BAL can be safely performed in intubated COVID-19 patients if experienced providers take precautions to limit aerosol generation and wear personal protective equipment.
RESUMO
Some patients infected with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) develop severe pneumonia and the acute respiratory distress syndrome (ARDS) [1]. Distinct clinical features in these patients have led to speculation that the immune response to virus in the SARS-CoV-2-infected alveolus differs from other types of pneumonia [2]. We collected bronchoalveolar lavage fluid samples from 86 patients with SARS-CoV-2-induced respiratory failure and 252 patients with known or suspected pneumonia from other pathogens and subjected them to flow cytometry and bulk transcriptomic profiling. We performed single cell RNA-Seq in 5 bronchoalveolar lavage fluid samples collected from patients with severe COVID-19 within 48 hours of intubation. In the majority of patients with SARS-CoV-2 infection at the onset of mechanical ventilation, the alveolar space is persistently enriched in alveolar macrophages and T cells without neutrophilia. Bulk and single cell transcriptomic profiling suggest SARS-CoV-2 infects alveolar macrophages that respond by recruiting T cells. These T cells release interferon-gamma to induce inflammatory cytokine release from alveolar macrophages and further promote T cell recruitment. Our results suggest SARS-CoV-2 causes a slowly unfolding, spatially-limited alveolitis in which alveolar macrophages harboring SARS-CoV-2 transcripts and T cells form a positive feedback loop that drives progressive alveolar inflammation. This manuscript is accompanied by an online resource: https://www.nupulmonary.org/covid-19/ One sentence summarySARS-CoV-2-infected alveolar macrophages form positive feedback loops with T cells in patients with severe COVID-19.
