[The effect of O2 therapy on mixed venous concentration of endothelin-1 in chronic obstructive pulmonary disease]

Pulmonary hypertension (PH) is an important factor in the prognosis of cases of chronic obstructive pulmonary disease (COPD), and endothelin-1 (ET-1) is a major factor in the development of PH in COPD. Oxygen (O2) therapy improves the prognosis of COPD by suppressing the development of PH. We therefore assessed the correlation of PH and ET-1, and the effect of O2 therapy on the plasma ET-1 concentration. In COPD patients, the plasma ET-1 level in mixed venous blood, but not in arterial blood, was negatively correlated with mixed venous O2 tension and positively correlated with pulmonary vascular resistance. No such correlation, however, was observed in the case of plasma HANP or plasma BNP. O2 administration significantly suppressed the plasma ET-1 level. This level in mixed venous blood was thought to serve as a marker of PH in COPD. and O2 administration decreased the plasma ET-1 level in mixed venous blood. It consequently attenuated PH.