Pleural fluid characteristics of patients with COVID-19 infection

IntroductionPleural effusions are known to occur in many cases of COVID-19. Data on typical characteristics of COVID-19-associated pleural effusions are limited. The goal of this project was to characterize the pleural fluid from patients with COVID-19.MethodsWe retrospectively collected electronic medical record data from adults hospitalized at a large metropolitan hospital system with COVID-19 infection who had a pleural effusion and a thoracentesis performed. We assessed pleural fluid characteristics and applied Light's criteria.ResultsWe identified 128 effusions from 106 unique patients; 45.4% of the effusions had fluid/serum protein ratio greater than 0.5, 33.9% had fluid/serum lactate dehydrogenase (LDH) greater than 0.6, and 56.2% had fluid LDH greater than 2/3 of the serum upper limit of normal. Altogether, 68.5% of effusions met at least one of these three characteristics and therefore were exudative by Light's criteria. The white blood cell (WBC) differential was predominantly lymphocytic (mean 42.8%) or neutrophilic (mean 28.7%); monocytes (mean 12.7%) and eosinophils (mean 2.5%) were less common.ConclusionWe demonstrate that 68.5% of pleural effusions in patients with COVID-19 infection were exudative and hypothesize that COVID-19-associated pleural effusions are likely to be exudative with WBC differential more likely to be predominantly lymphocytic. The pleural fluid characteristics associated with COVID-19 infection were assessed in 128 effusions from 106 unique patients; 68.5% of effusions met at least one of the three Light's criteria and therefore were exudative. Elevated LDH was notable. The white blood cell differential was predominantly lymphocytic (in 60.9% of effusions) or neutrophilic (30.5%). image