Dopamine and intestinal mucosal tissue oxygenation in a porcine model of haemorrhage

Haemorrhage is associated with intestinal mucosal hypoxia and impaired gut barrier function. Dopamine increases oxygen delivery to the intestinal mucosa and may thus counteract haemorrhage-induced mucosal hypoxia. Jejunal mucosal tissue oxygen tension (mucosal P-O2) and jejunal oxygen saturation of mucosal microvascular haemoglobin (mucosal Hb(O2)) were measured in 14 anaesthetized pigs. Seven animals served as controls (group C) and seven received continuous infusion of dopamine 16 mu g kg(-1) min(-1) (group D) while 45% of blood volume was removed in three equal increments. Resuscitation was performed using shed blood and fluid. Mean arterial pressure and systemic oxygen delivery decreased significantly during haemorrhage and returned to baseline after resuscitation in both groups. Mucosal PO2 decreased from 4.4 to 1.7 kPa after haemorrhage (P<0.01) and further to 1.5 kPa after resuscitation (P<0.01) in group C whereas group D showed an increase from 3.9 to 5.9 kPa after the start of the dopamine infusion (P<0.05), but no significant difference from baseline after haemorrhage (2.3 kPa) (ns) or resuscitation (3.1 kPa) (ns). Mucosal Hb(O2) decreased from 52 to 32% after haemorrhage (P<0.05) and increased to near baseline (37%) (ns) after resuscitation in group C whereas group D showed no significant changes from baseline (54 %) throughout the experiment. Comparison between groups showed higher mucosal PO2 and Hb(O2) values for group D animals after the start of the dopamine infusion (P<0.05 each), after the first two steps of haemorrhage (P<0.01 each) and after resuscitation (P<0.05 each). We conclude that i.v. dopamine 16 mu g kg(-1) min(-1) improved tissue oxygenation of the small intestinal mucosa during moderate haemorrhage and subsequent resuscitation.