PROGNOSTIC VALUE OF THE DOBUTAMINE TEST IN PATIENTS WITH SEPSIS SYNDROME AND NORMAL LACTATE VALUES - A PROSPECTIVE, MULTICENTER STUDY

Objectives: To determine the oxygen supply (Do(2)) and uptake (Vo(2)) responses to a 60-min dobutamine infusion in critically ill septic pat ients without circulatory shock and with normal blood lactate concentr ations. Also, to determine whether these responses would predict outco me. Design: Prospective, cohort study. Setting: Five intensive care un its in university-affiliated, city hospitals. Patients: Fifty critical ly ill patients with sepsis syndrome were studied from April 1990 to A ugust 1991. Interventions: Pulmonary artery catheterization; fluid loa ding if pulmonary artery occlusion pressure was <10 mm Hg; and 10 mu g /min/kg dobutamine infusion for 60 mins. Measurements and Main Results : Cardiac index, Do(2), Vo(2), and oxygen extraction ratio were determ ined immediately before and 1 hr after the onset of the dobutamine tes t. Using receiver operating characteristic curves, responders to the d obutamine infusion were identified by a >15% increase in Vo(2) from th e time immediately before to 1 hr after the onset of the dobutamine te st. We identified 23 responders and 27 nonresponders. Groups differed significantly in age (responders 46 yrs vs. nonresponders 55 yrs) and associated chronic disease (responders one cancer vs. nonresponders si x cancers). Significant changes in responders were: a) cardiac index i ncreased 42.9%; b) systemic vascular resistance decreased 20.7%; and c ) Do(2) increased 39.1% while Vo(2) increased 40.8%, with no changes i n oxygen extraction or blood lactate concentration. Significant change s in nonresponders were: a) cardiac index increased 14.2%; b) Do, incr eased 13.2%; and c) oxygen extraction decreased from 0.26 to 0.22. Lac tate concentration increased significantly by 25.1% in nonresponders. The mortality rate in responders (8.7%) was significantly less than th at rate in nonresponders (44.4%). Conclusions: Most of these septic pa tients without shock or hyperlactatemia responded to dobutamine infusi on in one of two ways: with little increase in Do(2) and no increase i n Vo(2), or with significant increases in both Do(2) and Vo(2). The la tter response is typical of healthy volunteers given dobutamine. Becau se of the calorigenic effect of dobutamine, our results imply nothing about the presence or absence of oxygen supply limitation. Still, pati ents who had increases in Do(2) and Vo(2) had a much higher survival r ate than patients who did not. We speculate that the inability of some patients to respond to dobutamine and the associated higher mortality rate may be related to beta-adrenoreceptor dysfunction.