ABSTRACT
Objective To investigate the pathophysiological features of rat hemorrhagic shock under high temperature conditions.Methods A total of 128 SD rats were assigned to high temperature group and normal temperature group according to the random number table,with 64 rats per group.Rats in high temperature group were pretreated at 342 for 12 h,and in normal temperature group were kept at 25℃.Hemorrhagic shock models in rats were produced by withdrawing 40％ of the total blood volume via the femoral artery.Parameters of the two groups were measured including blood electrolytes (Na +,K +),plasma osmotic pressure,liver function [aspartate aminotransferase (AST),alanine aminotransferase (ALT)],kidney function [creatinine (CREA)],arterial blood gases (pH,PO2 and PCO2) and cardiac function [heart rate (HR),cardiac output (CO),cardiac index (CI) and DO2].Animal survival time and survival rate were detected.Results Before shock,high temperature group versus normal temperature group showed higher detections of Na+ concentration [(142.3 ± 2.2) mmol/L:(139.1 ±1.5) mmol/L],plasma osmotic pressure [(304.8 ± 4.7) mmol/L:(300.0 ± 1.9) mmol/L],HR [(462 ±30) times/min:(402 ± 44) times/min],CO [(0.892 ± 0.190) L/min:(0.713 ± 0.090) L/min] and CI [(0.0030±0.0006)L·min-1 · cm-2:(0.0023 ±0.0002)L· min-1 · cm-2] (P＜0.05).After shock,normal temperature group showed further increased concentrations of Na + and K + and significantly enhanced AST,ALT and CREA compared to normal temperature group (P ＜ 0.05).After shock,CO,CI and DO2 in high temperature group were decreased by 63％,63％ and 69％ respectively compared to those before shock,but less decrease was observed in normal temperature group.Rat survival rate and survival time were significantly reduced in high temperature group compared to normal temperature group (P ＜ 0.05).Conclusion Pathophysiological changes of hemorrhagic shock in rats under high temperature are mainly manifested as impaired cardiac function,significantly increased concentrations of Na + and K + and significantly shortened survival time.