Bronchoalveolar lavage in suspected COVID-19 cases with a negative nasopharyngeal swab: a retrospective cross-sectional study in a high-impact Northern Italy area

Abstract

COVID-19 diagnosis relies on molecular testing for SARS-CoV-2 via nasopharyngeal swab in the presence of suggestive clinical, radiological and laboratory findings. Since bronchoalveolar lavage liquid (BAL) collected during fibrobronchoscopy may increase test sensitivity compared to nasopharyngeal swabs, it was performed during the 2020 pandemic in clinically or radiologically suspected cases. Our aim was to determine whether clinical features, chest computed tomography (CT) findings or laboratory tests may predict patients testing positive for SARS-CoV-2 at BAL after a negative nasopharyngeal swab. We performed a retrospective cross-sectional study with multivariable analysis of suspected patients who were tested for SARS-CoV-2 at BAL after at least one negative nasopharyngeal swab. Univariable logistic regression for odds ratio and multivariate models was calculated to determine clinical, radiological and laboratory predictors. 32/198 (16%) patients had BAL positive for SARS-CoV-2, while 65/198 tested positive for other pathogens at BAL. Of the 32 patients positive for COVID, 4 had a coinfection at BAL, being thus positive both for COVID as well as for another pathogen while the remaining 105 patients were negative for COVID and other pathogens at BAL. COVID-19 patients had more often highly suggestive CT findings, higher number of involved lobes, more often ground glass opacity of more than 50% of lung parenchyma, and less frequently other radiologically suspected infections. At multivariate model, temperature also predicted BAL positivity. The procedure was well tolerated-with only one desaturation episode-while no healthcare worker was infected. In conclusion, when nasopharyngeal swabs are negative but there is clinical or imaging suspicion of COVID-19, BAL represents a complementary diagnostic tool, particularly in conjunction with suggestive/more extensive lung involvement at CT scan. The procedure did not carry increased risks for patients nor for operators, while allowing to free hospital resources, avoiding unnecessary isolations.

What is the role of bronchoalveolar lavage in the diagnosis of COVID-19?

“…The study of Barberi and colleagues [ 15 ] fits perfectly into this context and may provide further insights on the issue. In this retrospective analysis, 198 subjects with at least one negative NPS underwent RT-PCR on BAL to detect SARS-CoV-2.…”

“…Identifying those patients who may benefit most from BAL testing may also be helpful to reduce unnecessary costs and ensure effective resource allocation, although limited evidence currently exists. In their analysis, the authors found some variables associated with an increased likelihood of BAL positivity, including CT characteristics [ 15 ], but these data are preliminary, and need confirmation on larger prospective cohorts. Further studies are needed to define the role of BAL, and which subgroup of suspected COVID-19 patients represents the optimal population to test with BAL.…”

Infection control in the intensive care unit: expert consensus statements for SARS-CoV-2 using a Delphi method

“…84 However, with growing experience and availability of adequate PPE, the experts agreed that the same diagnostic procedures can be performed in patients with COVID-19 as for other patients. [85][86][87]…”

Low utilisation of bronchoscopy to assess COVID-19 respiratory infection: a multicenter experience

“…11 Barberi et al reported in a cohort of 198 patients with suspected COVID-19 and negative NP swabs, 32 (16%) patients had positive BAL. 12 But multiple case reports and studies have reported lower concordance between NP swabs and BAL. [13][14][15] Patrucco et al reported a sensitivity of NP swabs of 23% in a cohort of 43 patients, as 33 patients with negative NP swabs were subsequently diagnosed with COVID-19 on BAL.…”