Circulating endothelin-1 concentrations in acute respiratory failure.

To elucidate the pathophysiologic role of endogenous endothelin (ET)-1 in acute respiratory failure, we measured plasma immunoreactive ET-1 levels in 13 patients with acute respiratory failure, and compared those with hemodynamic and respiratory parameters. The mean plasma ET-1 levels (10.7 +/- 5.0 pg/ml) in 13 patients with acute respiratory failure at the time of hospital admission were about sevenfold greater than those of healthy subjects (1.5 +/- 0.5 pg/ml, n = 16). Plasma ET-1 levels positively correlated with right atrial pressure (r = 0.626), systolic pulmonary arterial pressure (r = 0.726), mean pulmonary arterial pressure (r = 0.591), and the resistance ratio (pulmonary vascular resistance/systemic vascular resistance) (r = 0.658). They also showed correlations with peak airway pressure (r = 0.588), mean airway pressure (r = 0.607), and airway resistance (r = 0.756). Stepwise multiple regression analysis confirmed the significance of these observations. Our data suggest that raised circulating ET-1 levels may partly contribute to the development of pulmonary vasoconstriction and bronchoconstriction associated with acute respiratory failure.