EDN1 and COVID-19: COVID-19-induced ARDS patients had higher systemic arterial and central venous ET-1 levels upon ICU admission compared to the non-COVID-19 ARDS and the non-COVID-19 critically ill patients [2.66 (2.11–4.14) pg/mL vs. 1.59 (0.85–2.54) pg/mL and 1.12 (0.89–1.72) pg/mL, respectively] (Figure 1A; p < 0.05 and p < 0.001; respectively).