Haemodynamic effects of phentolamine in chronic obstructive pulmonary disease.

Ten patients with chronic obstructive pulmonary disease without complicating cor pulmonale were studied by right and left heart catheterization. Respiratory and haemodynamic observations were made during a control period and during the infusion of phentolamine. Phentolamine produced a significant reduction in mean pulmonary artery pressure from I8 8 mmHg to I3 I mmHg, right ventricular end-diastolic pressure from i 8 mmHg to o*i mmHg, and left ventricular end-diastolic pressure from 8 2 mmHg to I -9 mmHg. The mean brachial artery pressure, cardiac index, and pulmonary vascular resistance were essentially unchanged. It is concluded that the haenodynamic response of the patients to phentolamine cannot be explained by a single mechanism. Multiple actions of the drug must be considered, including active pulmonary vasodilatation, and