To assess the effects of different doses of dopamine, norepinephrine, and epinephrine on the splanchnic circulation in patients with septic shock.Design
Prospective, randomized, open-label study.Setting
A 31-bed, medicosurgical intensive care unit of a university hospital.Patients
Convenience sample of 20 patients with septic shock, separated into two groups according to whether (moderate shock group, n = 10) or not (severe shock, n = 10) dopamine alone was able maintain mean arterial pressure >65 mm Hg.Interventions
Dopamine was progressively withdrawn and replaced successively by norepinephrine and then epinephrine (the order of the two agents was randomly determined) to maintain mean arterial pressure constant (moderate shock) or to increase mean arterial pressure above 65 mm Hg (severe shock).Measurements and Main Results
Systemic circulation (pulmonary artery catheter) and splanchnic circulation (indocyanine green dilution and hepatic vein catheter) and gastric mucosal Pco2 (gas tonometry) were measured during dopamine (moderate shock only), norepinephrine, and epinephrine administration (both groups). Data were analyzed with nonparametric tests and are presented as median [percentiles 25–75]. In moderate shock, cardiac index was similar to dopamine and norepinephrine (3.1 [2.7–3.8] vs. 2.9 [2.7–4.1] L/min·m2, p = nonsignificant) but greater with epinephrine (4.1 [3.5–4.4]p < .01 vs. dopamine and norepinephrine). Splanchnic blood flow was similar with the three agents (732 [413–1483] vs. 746 [470–1401] vs. 653 [476–1832] mL/min·m, p = nonsignificant). The gradient between mixed-venous and hepatic venous oxygen saturations was lower with dopamine than with norepinephrine and epinephrine, but the Pco2 gap was similar with the three agents. In severe shock, cardiac index was higher, but splanchnic blood flow was lower, with epinephrine than with norepinephrine (4.6 [3.7–5.3] vs. 3.4 [3.0–4.1] L/min·m2, p < .01 and 860 [684–1334] vs. 977 [806–1802] mL/min·m2, p < .05, respectively). Epinephrine increased the mixed-venous and hepatic venous oxygen saturation gradient but did not alter Pco2 gap.Conclusions
Dopamine and norepinephrine have similar hemodynamic effects, but epinephrine can impair splanchnic circulation in severe septic shock.