Dobutamine in the treatment of depressed cardiac function: a study in patients with ischaemic heart disease during the early post-operative period.

Dobutamine was administered by intravenous infusion to 10 patients with ischaemic heart disease who had a low cardiac output syndrome following abdominal surgery. The dosage of dobutamine started from 2.5 mcg kg-1 min-1 and was increased stepwise to 5, 7.5, 10, 12.5 and 15 mcg kg-1 min-1. Cardiac index increased significantly from 2.05 +/- 0.32 to 3.03 +/- 0.61. min-1 min-2 with 15 mcg kg-1 min-1. Heart rate was unchanged with 7.5 mcg kg-1 min-1 but increased significantly from 97.7 +/- 18.5 to 126.1 +/- 21.5 beats. min-1 with 15 mcg kg-1. min-1. Stroke index increased significantly from 21 +/- 4.4 to 25.4 +/- 5.1 ml m-2. beat-1 with 7.5 mcg kg-1 min-1. Pulmonary wedge pressure fell significantly from 14 +/- 2.9 to 9.1 +/- 2.4 mmHg with 2.5 mcg kg-1 min-1. Mean arterial pressure showed no significant change. No side effects were observed in these patients. We conclude that in patients with depressed cardiac function dobutamine at low doses of 2.5 mcg kg-1 min-1 decreases afterload and filling pressures. At the average doses of 5 - 7.5 mcg kg-1 min-1 stroke index and cardiac index are increased. At higher doses of 10 - 15 mcg kg-1 min-1 heart rate and cardiac index increase while stroke index fails to increase further.