Reply to Cherian et al. : Positive Bubble Study in Severe COVID-19 Indicates the Development of Anatomical Intrapulmonary Shunts in Response to Microvascular Occlusion

Reynolds et al provide a response to the discussion of Cherian et al on their research letter. The medical community's knowledge of coronavirus disease (COVID-19) and its impact on the pulmonary system is evolving rapidly; they believe this kind of open, iterative dialogue is critical to informing their approach to patient care. In their letter, Cherian et al suggest that transpulmonary bubble transit in hepatopulmonary syndrome (HPS) is solely due to abnormal pulmonary arteriovenous connections. Reynolds et al believe that pulmonary capillary dilation is a significant cause of hypoxemia that is specific to COVID-19 respiratory failure. They do, however, acknowledge that they cannot rule out arteriovenous connections or intracardiac shunt.