Effects Of Controlled Hypothermia On Outcome After Traumatic Hemorrhagic Shock In Pigs

Objective: Extensive preclinical evidence suggests that controlled hypothermiacan protect tissues from ischemia-reperfusion injury, reduce organ damage, andimprove survival. In the current research, we assessed the effects of controlledhypothermia on haemodynamic parameters, coagulation capacity, pathologicalchanges of small intestine and survival during haemorrhagic shock (HS) and fluidresuscitation, in a pig model of traumatic haemorrhagic shock with multiple intestinalperforations.Methods: Pigs (n=16) were randomized to two groups: a controlled hypothermiagroup (n=8,34～36℃) and a normothermia group (n=8,38～39.5℃). Traumatichaemorrhagic shock was induced using multiple intestinal perforations. Pulseindicator continuous cardiac output (PICCO) was used to monitor haemodynamicchanges. Coagulation capacity was measured using thrombelastography (TEG) atbaseline as well as during resuscitation periods. Small intestine conventional H&Estaining examination were observed. The small intestine were examined forpathological changes72h after HS. Survival was documented for72h post-resuscitation.Results:（1）At3h and4h after resuscitation, the heart rate(HR), extravascularlung water index (EVLWI) in the controlled hypothermia group were significantlylower than those in the normothermia group（P＜0.05). There were no significantdifferences between the two groups in the mean arterial pressure(MAP), cardiacouIput index(CI), Global End-diastolic Volume Index(GEDVI)，and lactate（P＞0.05).（2）Analyses of thromboelastometry during hypothermia showed significantdifferences for reaction time (R) and alpha angle ()（P＜0.05), but not for maximalamplitude (MA)（P＞0.05). Rewarming reversed the coagulation changes induced by hypothermia. Controlled hypothermia affects haemodynamic parameters and thecoagulation system but does not worsen outcomes in a pig HS model.（3）Conventional pathology revealed：pathological injuries were significant lower inthe controlled hypothermia groups than that of normothermia.(4)Mortality in the hypothermic HS group was low, there were significant differencesin mortality between the groups (mortality=2/8controlled hypothermia vs5/8normothermia, P＜0.05).Conclusions:（1）The hemodynamics and coagulation dynamics indices don’tworsen in hemorrhagic shock pigs under controlled hypothermia.（2）Controlled hypothermia can inhibit inflammatory reaction.（3）Controlled hypothermia can significantly increase the survival rate of traumatichemorrhagic shock.