Initial resuscitation volume in uncontrolled hemorrhage: Effects on organ function

Conventional resuscitation of hypovolemia due to hemorrhage has consisted o f aggressive fluid administration. Recent studies have suggested that surgi cal control of bleeding before fluid resuscitation might improve early surv ival. The effects of limited resuscitation on organ function have not been assessed in these studies. We developed a model of moderate intraperitoneal hemorrhage designed to evaluate long-term end-organ function after various resuscitation protocols. Male Sprague-Dawley rats underwent ketamine anest hesia, followed by placement of femoral artery and vein lines. Intraperiton eal hemorrhage was induced by division of distal branches of the ileocolic artery and vein. After 5 minutes of bleeding, the animals were randomized t o one of three resuscitation groups: Group 1 received no fluid resuscitatio n before surgical control of the hemorrhage; Group 2 received 0.5 mt of lac tated Ringer's solution (LR) every 5 minutes for a mean arterial pressure ( MAP) of less than 80 mm Hg; Group 3 received 2.0 mt of LR every 5 minutes f or a MAP of less than 80 mm Hg. In all three groups, after 20 minutes, the bleeding was surgically controlled. All rats were then resuscitated with LR to a MAP of 80 mm Hg. The intravascular lines were removed, and the rats w ere allowed to recover from anesthesia and were returned to animal holding. On the 7th day, survivors were sacrificed, and their blood was assayed for hematocrit and serum levels of bilirubin, alanine aminotransferase, urea n itrogen, and creatinine. Kidneys, lungs, and liver were harvested for micro scopic examination. Survival was lower in Group 2 than in the other groups (90%, 60%, and 100%, respectively; P = 0.04), but all deaths occurred withi n 3 hours of hemorrhage and were due to either hypovolemia or anesthetic co mplications. No histologic abnormalities were identified in the livers of t he animals that survived, but pulmonary atelectasis and mild-to-moderate re nal tubular necrosis were identified uniformly. No histologic differences c ould be discerned between the groups. Hematocrit and indices of liver and r enal function were similar in all groups, and no animal developed organ dys function. In this model of moderate uncontrolled intraperitoneal hemorrhage , the volume of fluid resuscitation, or the absence of resuscitation, had a n inconsistent effect of 7-day survival and did not influence function or h istologic appearance of the liver, lungs, or kidneys 7 days after hemorrhag e.