Upon ICU admission, COVID-19-induced ARDS patients had higher systemic arterial and central venous ET-1 levels compared to the non-COVID-19 ARDS and non-COVID-19 non-ARDS patients (p < 0.05), yet a normal systemic arterial:central venous (A:V) ET-1 ratio [0.63 (0.49–1.02)], suggesting that pulmonary ET-1 clearance is intact in these patients. This evidence concerns the gene EDN1 and acute respiratory distress syndrome.