THE CONTRASTING EFFECTS OF DOBUTAMINE AND DOPAMINE ON GASTRIC-MUCOSALPERFUSION IN SEPTIC PATIENTS

To test the hypothesis whether or not dobutamine or dopamine infusion increases gastric mucosal perfusion, a prospective randomized crossove r trial was conducted on 10 septic patients in the intensive care unit of a university hospital. Systemic hemodynamic, oxygen transport, and gastric perfusion assessed by gastric intramucosal pH and laser Doppl er flowmetry were measured at baseline and after administration of dob utamine or dopamine (5 mu g/kg/min). Both increased oxygen transport I n response to dobutamine, gastric mucosal blood flow increased (+32 +/ - 14% from baseline; p < 0.05), gastric tonometered PCO2 and gastric a rterial PCO2 difference decreased (58 +/- 7 versus 52 +/- 7 mm Hg; p < 0.05; 16.8 +/- 7.0 versus 10.5 +/- 7.2 mm Hg; p < 0.05), and intramuc osal pH increased (7.23 +/- 0.05 versus 7.29 +/- 0.06; p < 0.05), In r esponse to dopamine, gastric mucosal blood flow decreased (-28 +/- 8% from baseline; p < 0.05), gastric tonometered PCO2, gastric-arterial P CO2 difference, and calculated intramucosal pH were unchanged (58 +/- 7 versus 61 +/- 9 mm Hg, ns; 16.8 +/- 7.0 versus 18.9 +/- 8.4 mm Hg, n s; 7.24 +/- 0.05 versus 7.21 +/- 0.06, ns). We speculated that despite an oxygen transport increase, dobutamine and dopamine have affected d ifferently gastric mucosal perfusion in septic patients.