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Prognostic value of the dobutamine test in patients with sepsis syndrome and normal lactate values: a prospective,
B Vallet1, C Chopin, S E Curtis
1Department of Critical Care Medicine, University of Lille, France.
Objectives:
To determine the oxygen supply (DO2) and uptake (VO2) responses to a 60-min dobutamine infusion in critically ill septic patients without circulatory shock and with normal blood lactate concentrations. Also, to determine whether these responses would predict outcome.
Design:
Prospective, cohort study.
Setting:
Five intensive care units in university-affiliated, city hospitals.
Patients:
Fifty critically ill patients with sepsis syndrome were studied from April 1990 to August 1991.
Interventions:
Pulmonary artery catheterization; fluid loading if pulmonary artery occlusion pressure was < 10 mm Hg; and 10 micrograms/min/kg dobutamine infusion for 60 mins.
Measurements And Main Results:
Cardiac index, DO2, VO2, and oxygen extraction ratio were determined immediately before and 1 hr after the onset of the dobutamine test. Using receiver operating characteristic curves, responders to the dobutamine infusion were identified by a > 15% increase in VO2 from the time immediately before to 1 hr after the onset of the dobutamine test. 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 six cancers). Significant changes in responders were: a) cardiac index increased 42.9%; b) systemic vascular resistance decreased 20.7%; and c) DO2 increased 39.1% while VO2 increased 40.8%, with no changes in oxygen extraction or blood lactate concentration. Significant changes in nonresponders were: a) cardiac index increased 14.2%; b) DO2 increased 13.2% and c) oxygen extraction decreased from 0.26 to 0.22. Lactate concentration increased significantly by 25.1% in nonresponders. The mortality rate in responders (8.7%) was significantly less than that rate in nonresponders (44.4%).
Conclusions:
Most of these septic patients without shock or hyperlactatemia responded to dobutamine infusion in one of two ways: with little increase in DO2 and no increase in VO2, or with significant increases in both DO2 and VO2. The latter response is typical of healthy volunteers given dobutamine. Because of the calorigenic effect of dobutamine, our results imply nothing about the presence or absence of oxygen supply limitation. Still, patients who had increases in DO2 and VO2 had a much higher survival rate 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.