亚低温对新生猪缺氧缺血脑损伤振幅整合脑电图变化的影响

Influence of mild hypothermia treatment on amplitude integrated electroencephalogram in newborn pigs with hypoxic-ischemic brain damage

目的研究亚低温对新生猪缺氧缺血性脑损伤(HIBD)振幅整合脑电图变化的影响,旨在用振幅整合脑电图这种无创性的检查方法判断亚低温的疗效.方法34头5～7 d的新生猪随机分为四组:常温正常组(n=7)、低温正常组(n=9)、缺氧缺血(HI)常温组(n=9)和HI低温组(n=9).采用双侧颈总动脉阻断和机械通气吸入6%的氧气制备HIBD模型.HI后2 h,低温组采用选择性头部亚低温治疗(维持鼻咽温度35℃±2℃,肛温36.0℃±2℃).常温组维持肛温在39℃左右.采用脑功能监测仪连续监测HI及亚低温后不同时间振幅整合脑电图振幅波谱带的变化,分析aEEG各种波形出现的比例.结果正常新生猪aEEG表现为连续正常电压(CNV),HI24 h后HI常温组连续低电压(CLV)、爆发-抑制(BS)、平台(FT)比例较缺血前明显增高(P<0.05),亚低温治疗组CLV、BS、FT比例增高的程度小于HI常温组(P<0.05),HI后6 d亚低温治疗组恢复至CNV的比例大于HI常温组(P<0.05).结论亚低温可明显降低HI后严重aEEG异常波形(CLV,BS和FT)出现的比例,证实亚低温有神经保护作用.

ObjectiveThis study examined the effect of mild hypothermia on amplitude integrated electroencephalogram (aEEG) recordings in neonatal pigs with hypoxic-ischemic brain damage (HIBD) and investigated the role of aEEG in the assessment of the effect of mild hypothermia on HIBD. Methods Thirty-four 5-day-old piglets were randomly divided into four groups: a Normal control group (normal temperature, n = 7), a Hypothermic-control group (n = 9), a Normothermic hypoxic-ischemic (HI) group (n = 9) and a Hypothermia-treated HI group (n = 9). HIBD was induced by a temporary occlusion of both carotid arteries, followed by mechanical ventilation with low concentration of oxygen (FiO_2 = 0.06) for 30 minutes. The nasopharyngeal and rectal temperature maintained at 35℃±2℃ and 36.0℃±2℃ respectively by head cooling in the two hypothermia-treated groups. The aEEG was recorded before HI and 15 mins, 2 hrs, 12 hrs, 24 hrs, 48 hrs, 72 hrs and 6 days after HI.Results The normal piglets presented with continuous normal voltage (CNV). The incidence of abnormal waves reflecting the severity of brain damage, continuous low voltage (CLV), burst-suppression (BS) and flat tracing (FT), significantly increased 24 hrs after HI. The incidence of three abnormal waves in the Hypothermia-treated HI group was significantly lower than that in the normothermic HI group. A significant difference was also observed in the incidence of CNV between the two groups 6 days after HI. Conclusions The incidence of CLV, BS and FT recorded by aEEG decreased significantly after mild hypothermia treatment, suggesting that mild hypothermia has a neuroprotecive effect against HIBD.