Kuo Jinn-Rung, Lin Chia-Li, Chio Chung-Ching, Wang Jhi-Joung, Lin Mao-Tsun
Section of Neurosurgery, Department of Surgery, Chi-Mei Medical Center, Yung-Kang City, Tainan, Taiwan.
Intensive Care Med. 2003 Sep;29(9):1567-73. doi: 10.1007/s00134-003-1854-4. Epub 2003 Jun 19.
To evaluate the effects of hypertonic (3%) saline in heatstroke rats with circulatory shock, intracranial hypertension, and cerebral ischemia.
Urethane-anesthetized rats were exposed to a high ambient temperature of 42 degrees C until mean arterial pressure and local cerebral blood flow (CBF) in the corpus striatum began to decrease from their peak levels, which was arbitrarily defined as the onset of heatstroke. Control rats were exposed to 24 degrees C.
Extracellular concentrations of glutamate and lactate/pyruvate ratio (cellular ischemia markers), and glycerol (a cellular injury marker) in the corpus striatum of rat brain were assessed by intracerebral microdialysis methods. Striatal PO(2), temperature, and local CBF were measured with a combined OxyLite PO(2), thermocouple, and OxyFlo LDF, respectively. The values of mean arterial pressure, cerebral perfusion pressure, and striatal CBF and PO(2) in rats treated with 0.9% NaCl solution after the onset of heatstroke were all significantly lower than those in normothermic controls. In contrast, the values of intracranial pressure, brain temperature, and extracellular concentrations of glutamate, glycerol, and lactate/pyruvate in the corpus striatum were greater. Intravenous infusion of hypertonic (3%) saline solution either "0" time before the start of heat exposure or right after the onset of heatstroke significantly attenuated the heatstroke-induced arterial hypotension, intracranial hypertension, decreased cerebral perfusion, and cerebral ischemia and damage and resulted in prolongation of survival time.
Our results strongly suggest that the experimental heatstroke syndromes can be effectively prevented and treated by hypertonic saline.
评估高渗（3%）盐水对中暑伴循环性休克、颅内高压和脑缺血大鼠的影响。
用乌拉坦麻醉大鼠，使其暴露于42℃的高环境温度下，直至平均动脉压和纹状体局部脑血流量（CBF）开始从峰值水平下降，这被任意定义为中暑发作。对照大鼠暴露于24℃环境。
采用脑内微透析法评估大鼠脑纹状体中谷氨酸的细胞外浓度、乳酸/丙酮酸比值（细胞缺血标志物）和甘油（细胞损伤标志物）。分别用组合式OxyLite PO₂、热电偶和OxyFlo激光散斑血流仪测量纹状体PO₂、温度和局部CBF。中暑发作后用0.9%氯化钠溶液治疗的大鼠，其平均动脉压、脑灌注压、纹状体CBF和PO₂值均显著低于正常体温对照组。相比之下，颅内压、脑温度以及纹状体中谷氨酸、甘油和乳酸/丙酮酸的细胞外浓度更高。在热暴露开始前“0”时间或中暑发作后立即静脉输注高渗（3%）盐溶液，可显著减轻中暑诱导的动脉低血压、颅内高压、脑灌注减少以及脑缺血和损伤，并延长存活时间。
我们的结果强烈表明，高渗盐水可有效预防和治疗实验性中暑综合征。
