Time course of central venous-to-arterial carbon dioxide tension difference in septic shock patients receiving incremental doses of dobutamine

Purpose To assess the time course of the central venous–arterial carbon dioxide tension difference (∆PCO 2 )—as an index of the carbon dioxide production (VCO 2 )/cardiac index (CI) ratio—in stable septic shock patients receiving incremental doses of dobutamine. Methods Twenty-two hemodynamically stable septic shock patients with no signs of global tissue hypoxia, as testified by normal blood lactate levels, were prospectively included. A dobutamine infusion was administered at a dose of up to 15 μg/kg/min in increments of 5 μg/kg/min every 30 min. Complete hemodynamic and gas measurements were obtained at baseline, and at each dose of dobutamine. Results Dobutamine induced a significant dose-dependent increase of CI from 0 to 15 μg/kg/min ( P