Abstract
The effectiveness of monitoring somatosensory evoked potentials (SEPs) intraoperatively to detect brain damage early remains controversial. To assess the diagnostic accuracy of this modality, a study was conducted between 1991 and 1994, recording SEPs in 287 consecutive patients undergoing cardiac and aortic surgery using cardiopulmonary bypass (CPB) with moderate hypothermia or deep hypothermic circulatory arrest. From P1 to N2 of the SEPs occurring within 50 ms latency in response to electrical stimulation of the median nerve were recorded over the contralateral postcentral cortex at 5-min intervals using a Neuropack-2 (Nihon Koden, Tokyo, Japan). Normal SEPs were recovered in 247 patients postoperatively; however, 2 of these patients had suffered a cerebral infarction and 1, a transient stroke intraoperatively, demonstrating a false-negative incidence of 1.2%. On the other hand, three different types of abnormal SEPs were recorded postoperatively. P1 and N1 absence, probably caused by a subcortical lesion, was observed in 4 patients; P2 and N2 absence, probably caused by a cortical lesion, was observed in 8 patients; and a flat SEP, representing diffuse damage, was observed in 2 patients. Among these 14 patients with abnormal SEPs, 7 showed no neurologic disturbance at all, demonstrating a false-positive incidence of 50%. Thus, we concluded that when normal SEPs are recovered during weaning from CPB, the incidence of brain damage could be predicted at below 5%. Conversely, when abnormal SEPs are demonstrated, the incidence of brain dysfunction impeding a return to active life is estimated to be about 70%.
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Govier AV, Reves JG, McKay RD, Karp RB, Zorn GL, Morawetz RB, Smith LR, Adams M, Freeman AM (1984) Factors and their influence on regional cerebral blood flow during nonpulsatile cardiopulmonary bypass. Ann Thorac Surg 38:592–600
Henriksen L (1984) Evidence suggestive of diffuse brain damage following cardiac operations. Lancet 14:816–820
Kawada T, Ando N, Hinata S, Mieda T, Masaki H, Hoson M, Hunaki S, Okada T, Hiekata T, Noguchi T (1988) Auditory brainstem response (ABR) during open heart surgery under hypothermia in infants and small children (in Japanese with English abstract). Nippon Kyoubu Geka Gakkai Zasshi (Jpn J Assoc Thorac Surg) 36:935–941
Yamagata S, Carter LP, Erspamer R (1982) Cortical ischemia: Effect upon direct cortical response. Stroke 13:680–686
Coles JG, Taylor MJ, Pearce JM, Lowry NJ, Stewart DJ, Trusler GA, Williams WG (1984) Cerebral monitoring of somatosensory evoked potentials during profoundly hypothermic circulatory arrest. Circulation 70 [Suppl I]:I-96–I-102
Wilson GJ, Rebeyka IM, Coles JG, Desrosiers AJ, Dasmahapatra HK, Adler S, Feitler DA, Sherret H, Kielmanowicz S, Ikonomidis J, Gatley RAA, Taylor M (1988) Loss of the somatosensory evoked response as an indicator of reversible cerebral ischemia during hypothermic, low-flow cardiopulmonary bypass. Ann Thorac Surg 45:206–209
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Kawada, T., Nakamura, S., Nishimura, K. et al. Continuous monitoring of short-latency somatosensory evoked potentials during cardiac and aortic surgery. Surg Today 26, 328–332 (1996). https://doi.org/10.1007/BF00311601
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DOI: https://doi.org/10.1007/BF00311601