Effects of almitrine and oxygen on ventilation and gas exchange in patients with chronic respiratory insufficiency.

Effects of a new respiratory stimulant almitrine on lung ventilation and gas exchange were studied in 15 patients suffering from chronic respiratory insufficiency. The variables examined were measured during 4 consecutive periods lasting 30 min each. During the first period initial data were collected. From the second period to the end of the investigation, oxygen, 1.5 1/min, was administered. During the third phase, almitrine was infused at a dose of 0.33 mg/kg. Administration of oxygen increased arterial oxygen tension without change in lung ventilation. Infusion of almitrine increased minute ventilation by 27%. The increase in VE was entirely due to increase in tidal volume. There was a significant rise in arterial oxygen tension and decrease in carbon dioxide tension. Hyperventilation and improvement in blood gases were still observed 30 min after the infusion was completed. It is suggested that almitrine increases minute ventilation in patients with respiratory failure receiving oxygen.