Short-Latency Positive Peak Following N20 Somatosensory Evoked Potential Is Superior to N20 in Predicting Neurologic Outcome After Out-of-Hospital Cardiac Arrest

Objectives: The absence of N20 somatosensory evoked potential after cardiac arrest is related to poor outcome. However, discrimination between the low-amplitude and the absence of N20 is challenging. P25 and P30 are short-latency positive peaks with latencies between 25 and 30 ms following N20 (P25/30). P25/30 is evident even with an ambiguous N20 in patients with good outcome. Therefore, we evaluated the predictive value of P25/30 after cardiac arrest. Design: A retrospective observational study. Setting: University-affiliated hospital. Subjects: Comatose survivors after out-of-hospital cardiac arrest treated by hypothermic targeted temperature management. Intervention: None. Measurements and Main Results: The specificity and the positive predictive value of P25/30 and N20 in predicting poor outcome were the same, showing a rate of 100%. The sensitivity of P25/30 in predicting poor outcome (90.12% [95% CI, 81.5–95.6%]) was higher than that of N20 (70.37% [95% CI, 59.2–80%]). Also, the negative predictive value of P25/30 in predicting poor outcome (81.4% [95% CI, 69.4–89.4%]) was higher than that of N20 (59.3% [95% CI, 51–67.1%]). The P25/30-based adjusted model showed a larger area under the curve (0.98 [95% CI, 0.95–1]) compared with the N20-based adjusted model (0.95 [95% CI, 0.91–0.98]) (p = 0.02). Conclusions: The absence of P25/30 is related to poor outcome with a higher sensitivity, negative predictive value than the absence of N20. This work was performed at Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Uijeongbu-si, Republic of Korea. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://ift.tt/29S62lw). A full list of the Cerebral Resuscitation and Outcome evaluation Within catholic Network (CROWN) Investigators can be found in Appendix 1. The statistical analysis was supported by a grant of the Korea Health Technology Research and Development Project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare, Republic of Korea (grant number: HI14C1062). The authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: erkeeper@catholic.ac.kr Copyright © by 2018 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.

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