AUTHOR=Glimmerveen Astrid B. , Keijzer Hanneke M. , Ruijter Barry J. , Tjepkema-Cloostermans Marleen C. , van Putten Michel J. A. M. , Hofmeijer Jeannette 

TITLE=Relevance of Somatosensory Evoked Potential Amplitude After Cardiac Arrest

JOURNAL=Frontiers in Neurology

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2020.00335

DOI=10.3389/fneur.2020.00335

ISSN=1664-2295

ABSTRACT=Abstract 
Objective
We present relations of SSEP amplitude with neurological outcome and of SSEP amplitude with EEG amplitude in comatose patients after cardiac arrest.
Methods 
This is a post hoc analysis of a prospective cohort study in comatose patients after cardiac arrest. Amplitude of SSEP recordings obtained within 48-72h, and EEG patterns obtained at 12 and 24h after cardiac arrest were related to good (CPC 1-2) or poor (CPC 3-5) outcome at six months. In 39% of the study population multiple SSEP measurements were performed.  Additionally, SSEP amplitude was related to mean EEG amplitude. 
Results
We included 138 patients (77% poor outcome). Absent SSEP responses,  a N20 amplitude <0.4 μV within 48-72h, and suppressed or synchronous EEG with suppressed background at 12 or 24h after cardiac arrest were invariably associated with a poor outcome. Combined, these tests reached a sensitivity for prediction of poor outcome up to 58% at 100% specificity. N20 amplitude increased with a mean of 0.55µV per day in patients with a poor outcome, and remained stable with a good outcome. There was no statistically significant correlation between SSEP and EEG amplitudes in 182 combined SSEP and EEG measurements (R2<0.01).
Conclusions 
N20 amplitude <0.4μV is invariably associated with poor outcome. There is no correlation between SSEP and EEG amplitude.
Significance
SSEP amplitude analysis may contribute to outcome prediction after cardiac arrest.