Effects of epinephrine, norepinephrine, or the combination of norepinephrine and dobutamine on gastric mucosa in septic shock

Objectives: To compare in the same patient with septic shock, respective effects of epinephrine, norepinephrine, and the combination of norepinephrine and dobutamine (5 μg/kg/min) on systemic hemodynamic parameters and gastric mucosal perfusion using gastric tonometry and laser-Doppler flowmetry techniques. Design: Prospective, controlled, randomized, crossover study. Setting: University hospital intensive care unit. Patients: Twelve patients with septic shock. Interventions: Each patient received in a random succession epinephrine, norepinephrine, and norepinephrine plus dobutamine. Dosages of epinephrine and norepinephrine were adjusted to achieve a mean arterial pressure between 70 and 80 mm Hg. A laser-Doppler probe and a tonometer were introduced into the gastric lumen. Measurements and Main Results: The increase in gastric mucosal perfusion detected by laser-Doppler flowmetry was higher with epinephrine and the combination of norepinephrine and dobutamine than with norepinephrine alone (p < .05). In addition, the ratio of gastric mucosal perfusion (local oxygen delivery) to systemic oxygen delivery was increased after norepinephrine plus dobutamine as compared with norepinephrine alone and epinephrine (p <.05). Although values of intramucosal pH and gastroarterial PCO₂ tended to be higher with norepinephrine plus dobutamine compared with those obtained with norepinephrine and epinephrine, differences were not statistically significant. Conclusions: For the same mean arterial pressure in patients with septic shock, our study showed that administration of epinephrine increased gastric mucosal perfusion more than norepinephrine administration alone. Addition of dobutamine (5 μg/kg/min) to norepinephrine improved gastric mucosal perfusion. This result could be explained by a vasodilating effect of dobutamine on gastric mucosal microcirculation.