重型颅脑损伤亚低温治疗中脑氧代谢的变化

背景亚低温对重型颅脑损伤患者的治疗作用已被人们所认识,但其机制尚需进一步证实.目前对于重型颅脑损伤后及亚低温治疗过程中脑组织氧代谢状态的改变,尚未见到相应报道.目的观察重型颅脑损伤患者亚低温治疗过程中的脑氧代谢变化规律,揭示亚低温治疗的作用.设计以患者为观察对象的析因设计.单位天津市环湖医院亚低温治疗中心.对象选择1998-08/2000-01在天津市环湖医院亚低温治疗中心就诊的重型颅脑损伤患者13例.男11例,女2例;年龄18-65岁.脑挫裂伤并硬膜下血肿6例,硬膜外血肿1例,蛛网膜下腔出血4例,弥漫性轴索损伤2例;保守治疗7例,手术清除血肿同时行内/外减压术6例.方法所有患者在亚低温治疗室内应用体温调节毯进行全身降温,同时给予冬眠肌松合剂(生理盐水500 mL+氯丙嗪100 mg+异丙嗪100 mg+卡肌宁400 mg)持续静滴.采用Neurotrend-7TM多参数监测系统持续监测脑组织氧分压、二氧化碳分压、pH值及脑温,比较治疗前后指标的变化.并对患者脑氧代谢与格拉斯哥昏迷量表(总分15分,正常为15分,分数越低意识障碍程度越深)及格拉斯哥预后评分进行相关性分析.主要观察指标持续监测脑组织氧分压、二氧化碳分压、pH值及脑温.结果13例患者均进入结果分析.①脑氧代谢的变化趋势氧分压亚低温后18 h明显高于降温前[(2.23±1.29,1.29±0.57)kPa,t=2.449,P＜0.05].二氧化碳分压亚低温后6 h明显低于降温前[(7.32±0.92,7.75±1.07)kPa,t=2.446,P＜0.05].pH值达低温时明显高于降温前[(7.06±0.15,6.83±0.20),t=5.164,P＜0.05].颅内压达低温时明显低于降温前[(2.03±1.01,2.57±0.93)kPa,t=2.948,P＜0.05].脑灌注压亚低温后6 h明显高于降温前[(9.40±1.80,7.80±1.59)kPa,t=2.365,P＜0.05].②重型颅脑损伤患者脑氧代谢与格拉斯哥预后评分的相关关系二氧化碳分压在低温24 h时的数值与格拉斯哥预后评分呈负相关(r=-0.699,P＜0.05).治疗前后脑氧代谢指标的变化与格拉斯哥预后评分呈正相关.结论脑氧代谢持续监测安全、有效,有利于早期发现重型颅脑损伤后脑组织缺氧及酸中毒.亚低温治疗能有效缓解重型颅脑损伤后的脑组织缺氧及酸中毒,从而改善患者预后.

Changes of cerebral oxygen metabolism during mild hypothermia treatment of severe brain injury

BACKGROUND: The therapeutic effect of mild hypothermia in the treatment of severe brain injury has been recognized in spite of the poor understanding of its mechanism. Until now, no reports have been available to describe the changes in cerebral oxygen metabolism following serious brain and during mild hypothermia treatment.OBJETCIVE: To observe the patterns of cerebral oxygen metabolism changes during mild hypothermia treatment for severe brain injury, and explore the mechanism of the therapeutic effect of mild hypothermia.DESIGN: A clinical observation of factorial design.SETTING: Mild Hypothermia Treatment Center of Tianjin Huanhu Hospital.PARTICIPANTS: From August 1998 to January 2000, 13 patients with severe brain injury were treated in Mild Hypothermia Treatment Center of Tianjin Huanhu Hospital, including 11 males and 2 females aged 18-65 years. Diagnosis of brain contusion and laceration with subdural hematoma was established in 6 cases, epidural hematoma in 1 case, subarachnoid hemorrhage in 4 cases and diffuse axonal injury in 2 cases. Of these cases 7 were treated with conservative therapy, and 6 with internal/external decompression after surgical hematoma removal.METHODS: A blanket for controlling the body temperature was applied to induce whole-body hypothermia in the patients in the mild hypothermia treatment room with continuous intravenous infusion of chlorpromazine (100 mg), promethazine (100 mg) and atracurium besilate (400 mg) administered in 500 mL normal saline. Neurotrend-7TM multi-parameter monitoring system was used to for monitoring the dynamic changes of cerebral PO2,PCO2, pH and brain temperature to evaluate their changes after treatment.The correlation between cerebral oxygen metabolism and the scores of Glasgow Coma Scale was analyzed.MAIN OUTCOME MEASURES: Dynamic changes of cerebral PO2,PCO2, pH and brain temperature.RESULTS: All the 13 patients entered the final analysis. Eighteen hours after hypothermia, the PO2 [(2.23±1.29) kPa] was obviously increased in comparison with that before hypothermia [(1.29±0.57) kPa, t=2.449, P ＜ 0.05], and PCO2 exhibited significant decrease at hypothermia 6 hours to (7.32±0.92) kPa from the pre-treatment level of (7.75±1.07) kPa (t=2.446, P ＜ 0.05). Significant elevation of pH and descension of intracranial pressure occurred upon the achievement of hypothermia [7.06±0.15 vs 6.83±0.20 for pH, t=5.164, P ＜ 0.05;(2.03±1.01) vs (2.57±0.93) kPa for intracranial pressure, t=2.948, P ＜ 0.05].Six hours after hypothermia, the cerebral perfusion pressure was obviously higher than that before hypothermia [(9.40±1.80) vs (7.80±1.59) kPa, t=2.365,P ＜ 0.05]. PCO2 was found inversely correlated with Glasgow Outcome Scale (GOS) scores at 24 hours of hypothermia (r=-0.699, P ＜ 0.05). The variations of cerebral oxygen metabolism indices before and after mild hypothermia were positively correlated with GOS scores.CONCLUSION: Dynamic monitoring of cerebral oxygen metabolism is safe and effective, and may help in early detection of cerebral hypoxia and acidosis following severe brain injury. Mild hypothermia treatment can effectively alleviate hypoxia and acidosis following severe brain injury to improve the prognosis of the patients.