Central and regional hemodynamics during crystalloid fluid therapy after uncontrolled intra-abdominal bleeding

Objective: To study the effect of graded crystalloid fluid resuscitation on central hemodynamics and outcome after intraabdominal hemorrhage. Methods: Ten minutes after a 5-mm long laceration was produced in the infrarenal aorta, 32 pigs were randomized to receive either no fluid or Ringer's solution in the proportion 1:1, 2:1, or 3:1 to the expected amount of blood lost per hour (26 mL kg(-1)) over 2 hours. The hemodynamics were studied using arterial and pulmonary artery catheters and four blood flow probes placed over major blood vessels. Results: During the first 40 minutes after the injury, the respective blood flow rates in the distal aorta were 39% (no fluid), 41% (1:1), 56% (2:1), and 56% (3:1) of the baseline flow. Fluid resuscitation increased cardiac output but had no effect on arterial pressure, oxygen consumption, pH, or base excess, Rebleeding occurred only with the 2:1 and 3:1 fluid programs, Survival was highest with the 1:1 and 2:1 programs. Conclusions: Crystalloid fluid therapy improved the hemodynamic status but increased the risk of rebleeding. Therefore, a moderate fluid program offered the best chance of survival.