Investigation into isoprenaline resistance in patients with obstructive lung disease

12 patients with chronic obstructive lung disease have been studied in an investigation regarding the causes of resistance to isoprenaline. The effects of repeated intravenous doses of 10 µg isoprenaline were assessed by cross over comparison before and after infusions of isoprenaline and a placebo; the infusions lasted for 35 to 40 min and the amount of isoprenaline infused was 0.5 µg/min. Total resistance, thoracic gas volume (whole-body plethysmography) and heart rate (ECG) were measured. No decrease in bronchospasmolytic or positive chronotopic effects on single isoprenaline injections could be demonstrated after prolonged infusions of isoprenaline.