PULMONARY VASODILATATION AND AUGMENTATION OF RIGHT VENTRICULAR-FUNCTION FOLLOWING TERBUTALINE INFUSION IN SEVERE CHRONIC PULMONARY-DISEASE

Twenty patients with a median age of 61 years and a median forced expired volume in 1 s (FEV1) after bronchodilatating therapy of 0.55 1 were studied in order to measure the effect of intravenous terbutaline on bronchial tone, cardiac function, pulmonary haemodynamics, gas exchange, and oxygen transport capacity during rest and in 10 patients during exercise. Terbutaline infusion during rest resulted in an increase in heart rate from 84 to 103 beats min-1 (P < 0.01), a decrease in mean systemic arterial pressure from 95 to 80 mmHg (P < 0.02), an unchanged mean pulmonary arterial pressure (18 mmHg), an increase in cardiac index from 2.89 to 3.86 1 min-1 m-2 (P < 0.01), an increase in right ventricular ejection fraction from 45 to 53% (P < 0.01), an increase in left ventricular ejection fraction from 63 to 67% (NS), an unchanged arterial oxygen tension, and an increase in calculated oxygen delivery from 533 to 638 ml O2 min-1 m-2 (P < 0.01). During exercise terbutaline infusion resulted in an increase in heart rate from 108 to 120 beats min-1 (P < 0.05), a decrease in mean systemic arterial pressure from 117 to 106 mmHg (P < 0.01), a decrease in mean pulmonary arterial pressure from 29 to 22 mmHg (P < 0.01), an increase in cardiac index from 4.53 to 4.64 min-1 m-2 (NS), an unchanged arterial oxygen tension, and an increase in the calculated oxygen delivery from 834 to 856 ml O2 min-1 m-2 (NS). It was concluded that terbutaline augments right ventricular function: increases right ventricular ejection fraction and decreases right ventricular end-diastolic volume, and further decreases pulmonary vascular resistance without decreasing arterial oxygen tension, and increases oxygen delivery in patients with chronic pulmonary disease during rest and exercise.