Effect of dobutamine on pulmonary gas exchange in patients with severe heart failure

Twenty patients (two female, 18 male, mean age 57±11 years) with severe heart failure NYHA IV (7 coronary artery disease, 13 congestive cardiomyopathy) were treated with 8·8±l·7μg .kg−1. min−1 of dobutamine. Pulmonary gas exchange was analysed by withdrawal of blood samples from a central venous catheter and a radial artery canula. Dobutamine increased SvO2 from 58·7±11·2% to 72·2±6·3% (P=0·0001) and decreased avDO2 from 7·7±2·45 Vol% to 4·97±1·34 Vol% (P=0·0001). PaO2 and PaCO2 were not changed. Qs/Qt increased slightly from 91±8·3% to 11·3±6·4% (P=0·035). Cardiac index increased by 51% (P=0·0001), pulmonary capillary wedge pressure decreased by 28% (P=0·0001). In patients with severe heart failure, dobutamine improved haemodynamics without detrimental effects on arterial oxygen concentration.