Acute effects of almitrine infusion on pulmonary haemodynamics in normal man.

The aim of the study was to assess haemodynamic and ventilatory effects of almitrine infusion in normal subjects. Five males aged 19-49 years were studied using a floating catheter technique. The investigation consisted of three consecutive periods, lasting 20 min each. During the first one, the subject was allowed to settle down and baseline measurements were made. During the second period, a total dose of 0.33 mg X kg-1 of almitrine was infused over 20 min. During the third period, postinfusion effects were observed. Almitrine produced the expected increase in minute ventilation that was entirely due to that in tidal volume. Haemodynamic changes consisted of an increase in pulmonary vascular resistance and pulmonary arterial pressure. As there was no concomitant change in cardiac output or wedge pressure, the increase in pulmonary vascular resistance was apparently due to constriction of pulmonary muscular arteries. Pulmonary vasoconstrictor effects of almitrine were of short duration and were already tapering off before completion of the infusion, so that pulmonary arterial pressure was back to the baseline value 10 min after the infusion was completed.