DOPEXAMINE IMPROVES LIVER OXYGENATION DURING CRYSTALLOID RESUSCITATION FROM EXPERIMENTAL HEMORRHAGIC-SHOCK

Objective: To evaluate the effects of dopexamine administration on hem odynamic variables and tissue oxygen tensions during crystalloid resus citation from hemorrhagic shock. Design: Randomized, control trial. Se tting: An animal laboratory at a university center. Subjects: Twelve p iglets, mean weight 22 kg. Interventions: The animals were anesthetize d and bled to a state of hemorrhagic shock and resuscitated, using a c rystalloid solution infused at a rate of similar to 2.6 mL/min/kg (tot al amount 208 mL/kg), Cardiac output and mean arterial pressure (MAP) were measured as indicators of volume filling during the 20- to 30 min resuscitation period and during the follow-up period until 80 mins fr om the start of resuscitation. Dopexamine was administered by infusion at 6 mu g/kg-min from the start of volume replacement (dopexamine gro up, n = 6), The rest of the animals (control group, n = 6) were given volume replacement only. Measurements and Main Results: Systemic oxyge n transport variables were calculated, Tissue oxygen tensions were con tinuously recorded from the liver, conjunctival layer, and via subcuta neous and transcutaneous electrodes in the abdominal region. MAP decre ased from 119 +/- 2 (SEM) to 44 +/- 2 mm Hg and cardiac output decreas ed by 77% during the shock period, During resuscitation, cardiac outpu t was restored in both groups, MAP increased close to the baseline dur ing the early resuscitation period and decreased slowly during follow- up, Oxygen delivery remained at 46% of baseline, whereas systemic oxyg en consumption was restored during resuscitation in both groups. Liver tissue oxygen tension increased well above baseline during resuscitat ion in the dopexamine group, and liver tissue oxygen tension was signi ficantly higher then in the control group, After 60 mins of resuscitat ion, the liver oxygen tension decreased to control group values, None of the other tissue oxygen tensions showed any differences between gro ups. Conclusions: Dopexamine administration during crystalloid resusci tation from hemorrhagic shock was well tolerated and resulted in signi ficant and specific, although transient, improvement in liver oxygenat ion.