Mezrow C K, Midulla P S, Sadeghi A M, Gandsas A, Wang W, Bodian C, Shing H H, Zappulla R, Dapunt O E, Griepp R B
Department of Cardiothoracic Surgery, Neurosurgery, and Biomathematical Sciences, Mount Sinai Medical Center, New York, NY 10029, USA.
J Thorac Cardiovasc Surg. 1995 May;109(5):925-34. doi: 10.1016/s0022-5223(95)70318-7.
Although hypothermic circulatory arrest and low-flow cardiopulmonary bypass are routinely used for surgical correction of congenital cardiac anomalies, use of long durations of arrest, often required for more complex repairs, raises serious concerns about cerebral safety. Searching for an intraoperative assessment that can reliably predict cerebral injury, we have found an excellent correlation between changes in quantitative electroencephalography intraoperatively and immediately postoperatively after prolonged hypothermic arrest, and neurologic and behavioral evidence of cerebral injury. After epidural placement of four recording electroencephalographic electrodes and baseline neurologic/behavioral and electroencephalographic assessment, 32 puppies were randomly assigned to one of four groups: hypothermic controls in which cooling to 18 degrees C was followed immediately by rewarming, 30 minutes of hypothermic circulatory arrest at 18 degrees C, 90 minutes of arrest at 18 degrees C, and 90 minutes of low-flow cardiopulmonary bypass at 25 ml/kg per minute at 18 degrees C. An electroencephalogram was recorded at baseline, after cooling, during rewarming, and at 2, 4, and 8 hours after the start of rewarming, as well as before the operation and 1 week after the operation. Postoperative neurologic and behavioral outcome was assessed 24 hours after cardiopulmonary bypass and daily for 1 week by means of a graded scale in which 0 is normal and 12 and 13 indicate severe neurologic injury (coma and death). Thirty animals survived the experimental protocol: two animals in the 90-minute hypothermic arrest group died before neurologic evaluation could be completed, and the remainder exhibited various degrees of neurologic and behavioral impairment, more severe on day 1 than on day 6. No animal in the remaining groups had a significant neurologic deficit. Quantitative electroencephalographic analysis shows marked differences between the 90-minute arrest group and the controls in the percent electroencephalographic silence during rewarming and at 2 hours, and in the percent recovery of baseline power at 2, 4, and 8 hours. At 2 hours after the start of rewarming, a correlation between electroencephalographic amplitude and neurologic/behavioral score on day 1 was carried out, which predicts with great certainty (p < 0.00001) that if electroencephalographic power at this time is less than 500 microV2, overt neurologic injury will subsequently become apparent. In addition, a significant shift from higher to lower frequency in the day 6 postoperative electroencephalogram compared with baseline occurs only in the 90-minute arrest group.(ABSTRACT TRUNCATED AT 400 WORDS)
尽管低温循环停止和低流量体外循环常用于先天性心脏畸形的手术矫正，但对于更复杂的修复手术通常需要较长时间的停循环，这引发了对脑安全性的严重担忧。为寻找一种能够可靠预测脑损伤的术中评估方法，我们发现长时间低温停循环术中及术后即刻定量脑电图的变化与脑损伤的神经学和行为学证据之间存在极好的相关性。在硬膜外放置四个记录脑电图电极并进行基线神经学/行为学和脑电图评估后，32只幼犬被随机分为四组：低温对照组，先冷却至18摄氏度然后立即复温；18摄氏度下30分钟的低温循环停止组；18摄氏度下90分钟的停循环组；以及18摄氏度下每分钟25毫升/千克的90分钟低流量体外循环组。在基线、冷却后、复温期间、复温开始后2、4和8小时以及手术前和手术后1周记录脑电图。在体外循环后24小时评估术后神经学和行为学结果，并在1周内每天通过分级量表进行评估，其中0表示正常，12和13表示严重神经损伤（昏迷和死亡）。30只动物存活至实验方案结束：90分钟低温停循环组中有两只动物在神经学评估完成前死亡，其余动物表现出不同程度的神经学和行为学损伤，第1天比第6天更严重。其余组中没有动物有明显的神经功能缺损。定量脑电图分析显示，90分钟停循环组与对照组在复温期间和2小时时脑电图静息百分比以及2、4和8小时时基线功率恢复百分比方面存在显著差异。在复温开始后2小时，进行了脑电图振幅与第1天神经学/行为学评分之间的相关性分析，结果非常确定地预测（p < 0.00001），如果此时脑电图功率小于500微伏²，随后将出现明显的神经损伤。此外，与基线相比，仅在90分钟停循环组中术后第6天脑电图出现从较高频率到较低频率的显著转变。（摘要截断于400字）
