RESUMEN
OBJECTIVE: To test whether dopexamine hydrochloride, by its beta 2-adrenoreceptor and dopaminergic 1 (DA1) and dopaminergic 2 (DA2) agonistic properties, can improve oxygen consumption (VO2) in hyperdynamic patients with septic shock. DESIGN: Prospective, single-cohort study. SETTING: ICU, university hospital. PATIENTS: Twenty-nine postoperative, hemodynamically stabilized, hyperdynamic patients with septic shock. INTERVENTIONS: Short-term application (30 min) of dopexamine hydrochloride at a dose of 2 microgram/kg/min. MEASUREMENTS: Complete hemodynamic profile with O2 transport-related variables at baseline, 30 min after starting the dopexamine infusion, and 30 min after stopping the infusion. MAIN RESULTS: The dopexamine infusion resulted in significant increases in cardiac index (17%) (p<0.001) and O2 delivery (DO2) (16%) (p<0.001). VO2 increased slightly but significantly about 4% (p<0.001) by respiratory gas exchange measurements and 9% (p<0.001) by cardiovascular Fick calculations. The O2 extraction ratio decreased about 8% (0.001). CONCLUSIONS: The addition of dopexamine hydrochloride at a dose of 2 microgram/kg/min resulted in significant increases of DO2 and to a lesser extent VO2. Much of the global DO2 increase was not utilized, because O2 extraction ratio decreased. Direct calorigenic effects of dopexamine and an increase in myocardial VO2 likely account for a large portion of the increase in global VO2. Whether any of the VO2 increase reflects improvement in regions of jeopardized tissue oxygenation remains to be clarified before the definite value of this drug in septic shock can be established.
