Systemic and microcirculatory effects of dobutamine in patients with septic shock

Purpose

The aim of this study was to characterize the cardiovascular responses to dobutamine and their predictors. Our hypotheses were that dobutamine mainly produces tachycardia and vasodilation and fails to improve the microcirculation of patients with septic shock.

Materials and Methods

Systemic hemodynamics and sublingual microcirculation were evaluated with dobutamine (0, 2.5, 5.0, and 10.0 μg kg^− 1 min^− 1) in 23 patients with septic shock.

Results

Dobutamine increased heart rate, cardiac index, and stroke volume index (SVI). Mean blood pressure was unchanged, and systemic vascular resistance decreased. Individual responses were heterogeneous. Stroke volume index increased in 52% of the patients. These patients showed lower changes in mean blood pressure (3 ± 16 mm Hg vs − 10 ± 6 mm Hg, P < .05) and higher increases in cardiac index (1.47 ± 0.93 L m^− 1 m^− 2 vs 0.20 ± 0.5 L m^− 1 m^− 2) than did nonresponders. Changes in SVI significantly correlated with echocardiographic left ventricular ejection fraction (r = 0.55). In the whole group, perfused capillary density remained unchanged (14.0 ± 4.3 mm/mm² vs 14.8 ± 3.7 mm/mm²), but improved if basal values were 12 mm/mm² or less (9.1 ± 4.3 mm/mm² vs 12.5 ± 4.8 mm/mm²).

Conclusions

Dobutamine produced variable hemodynamic effects. Systolic dysfunction was the only variable associated with increases in SVI. Finally, dobutamine only improved sublingual microcirculation when severe alterations were found at baseline.