Maciel Carolina B, Morawo Adeolu O, Tsao Ching Y, Youn Teddy S, Labar Douglas R, Rubens Elayna O, Greer David M
*Department of Neurology, Yale-New Haven Hospital, Yale School of Medicine, New Haven, Connecticut, U.S.A.; †Department of Neurology, Emory University Hospital, Emory University, Atlanta, Georgia, U.S.A.; ‡Department of Neurology, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New York, U.S.A.; and §Department of Neurology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medical College, New York, New York, U.S.A.
J Clin Neurophysiol. 2017 Sep;34(5):469-475. doi: 10.1097/WNP.0000000000000392.
The reliability of somatosensory evoked potentials (SSEPs) in predicting outcome in comatose survivors of cardiac arrest treated with therapeutic hypothermia (TH) has been questioned. We investigated whether the absence of cortical (N20) responses was a reliable predictor of a nonawakening in the setting of TH.
A retrospective review was conducted in cardiac arrest survivors treated with TH admitted to a single tertiary care hospital from April, 2010 to March, 2013 who underwent SSEP testing at various time points after cardiac arrest. N20 responses were categorized as normal, present but abnormal, bilaterally absent, or inadequate for interpretation. Neurologic outcome was assessed at discharge by the Cerebral Performance Category Scale (CPC).
Ninety-three SSEP studies were performed in 73 patients. Fourteen patients had absent N20 responses; all had poor outcome (CPC 4-5). Eleven patients had absent N20 s during hypothermia, three of whom had follow-up SSEPs after rewarming and cortical responses remained absent. Fifty-seven patients had N20 peaks identified and had variable outcomes. Evaluation of 1 or more N20 peaks was limited or inadequate in 11.4% of SSEPs performed during the cooling because of artifact.
Somatosensory evoked potentials remain a reliable prognostic indicator in patients undergoing TH. The limited sample size of patients who had SSEP performed during TH and repeated after normothermia added to the effect of self-fulfilling prophecy limit the interpretation of the reliability of this testing when performed during cooling. Further prospective, multicenter, large scale studies correlating cortical responses in SSEPs during and after TH are warranted. Technical challenges are commonplace during TH and caution is advised in the interpretation of suboptimal recordings.
体感诱发电位（SSEPs）在预测接受治疗性低温（TH）的心脏骤停昏迷幸存者预后方面的可靠性受到质疑。我们研究了在TH情况下，皮层（N20）反应缺失是否是无法苏醒的可靠预测指标。
对2010年4月至2013年3月入住一家三级医疗中心医院并接受TH治疗的心脏骤停幸存者进行回顾性研究，这些患者在心脏骤停后的不同时间点接受了SSEP测试。N20反应分为正常、存在但异常、双侧缺失或无法解读。出院时通过脑功能表现分类量表（CPC）评估神经功能预后。
对73例患者进行了93次SSEP研究。14例患者N20反应缺失；所有患者预后均较差（CPC 4 - 5）。11例患者在低温期间N20缺失，其中3例复温后进行了随访SSEP，皮层反应仍缺失。57例患者检测到N20波峰，预后各不相同。在降温期间进行的SSEP中，11.4%因伪迹导致对1个或更多N20波峰的评估受限或不充分。
体感诱发电位在接受TH的患者中仍然是可靠的预后指标。在TH期间进行SSEP且复温后重复检测的患者样本量有限，加上自我实现预言的影响，限制了在降温期间进行此项检测时对其可靠性的解读。有必要进一步开展前瞻性、多中心、大规模研究，以关联TH期间及之后SSEP中的皮层反应。在TH期间技术挑战很常见，对记录欠佳的结果进行解读时应谨慎。
