Effect of mild hypothermia on coagulatory function and survival in sprague-dawley rats exposed to uncontrolle hemorrhagic shock

Abstract

Background: Acute coagulopathy, hypothermia, and acidosis are the lethal triad ofconditions manifested by major trauma patients. Recent animal studies have reported thathypothermia improves survival in animals subjected to controlled hemorrhagic shock.Purpose: The objective of this study was to investigate the effect of hypothermia oncoagulation in rats subjected to uncontrolled hemorrhagic shock.Subjects and Methods: Thirty-two male Sprague–Dawley rats were randomly dividedinto four groups: normothermia (control, group N), hypothermia (group H), hypothermichemorrhagic shock (group HS), and normothermic hemorrhagic shock (group NS).Hemorrhagic shock was induced by splenic laceration. Capacity for coagulation was measured by rotation thromboelastometry (ROTEM®), and was measured at baseline aswell as the end of the shock and resuscitation periods. Survival was observed for 48 hourspost-trauma.Results: Baseline parameters were not different among the groups. Rats exposed tohypothermia alone did not differ in coagulation capacity compared to the control group.Clot formation time (CFT) and maximal clot firmness (MCF) in group HS decreased asthe experiment progressed. Maximal clot firmness time (MCFt) in groups H and HS wassignificantly prolonged during shock and resuscitation compared with that in group NS.In group NS, MCF did not change significantly, but MCFt was reduced compared withbaseline. Group HS had poor survival when compared with normovolemic groups.Conclusion: Blood clotted less firmly in traumatic hemorrhagic shock, and hypothermiaprolonged clotting. However, clot firmness maximized rapidly under normothermichemorrhagic shock. Hemorrhage would continue for a longer time in hypothermichemorrhagic shock. Survival of hypothermic shock was not significantly differentcompared to that of normothermic hemorrhagic shock.