NLRP3 and COVID-19: The purpose of this study is to contextualize vascular features and NLRP3 expression along the vascular wall in lungs of fatal cases of “COVID-19 ARDS” and “non-COVID-19 ARDS” (as compared to lungs from non-COVID-19 non-ARDS subjects) to ascertain if the NLRP3 inflammasome pathway is COVID-19 (SARS-CoV-2 infection) specific or arises from respiratory distress (and associated clinical maneuvers such as MV).