Regional blood flow redistribution in preterm piglets with hemorrhage and resuscitation

Acute hemorrhage in premature infants occurs as the result of obstetrical complications, birth trauma, or operative procedures. This study evaluates the response of the preterm piglet to acute hemorrhage and resuscitation. Piglets delivered by Caesarean section 7-14 days preterm underwent acute arterial/venous hemorrhage (20 cc/kg). At 0, 15, and 60 min after hemorrhage, hemodynamic parameters and regional blood flows (reference organ technique) were measured. Animals were then resuscitated with shed blood (20 cc/kg), crystalloid (60 cc/kg), or colloid (dextran 40, 20 cc/kg) with study parameters obtained 30 min later (statistical analysis by ANOVA). Significant decreases in blood pressure (BP) and cardiac output (CO) occurred after hemorrhage. BP and CO were reestablished to near control levels following resuscitation with blood and crystalloid. Dextran failed to return BP to baseline; however, it resulted in CO 1.7 x control. Heart and CNS blood flow were not significantly influenced by hemorrhage; however, dextran increased flows to these organs significantly above control levels. In the kidney and small bowel, flows decreased significantly following hemorrhage; blood and crystalloid restored flows to near baseline, while dextran resulted in flows significantly greater. In summary, the preterm piglet responds to hemorrhage with maintenance of blood flow to the heart and brain and significantly decreased flows to the kidney and small intestine. Flows following resuscitation with blood and crystalloid are comparable to those in control. Dextran resuscitation resulted in flows significantly greater than baseline; this response might be detrimental with ongoing hemorrhage and/or prolonged ischemia.