Enhanced analysis of somatosensory evoked potentials at 20–30 milliseconds can predict neurological outcome after cardiac arrest

Abstract

Abstract Objective This study attempted to test the effectiveness of an enhanced analysis of the 20–30 ms complex of somatosensory evoked potentials, in predicting the short-term outcome of comatose survivors of out of hospital cardiac arrest and compare it with the current clinical practice.

Methods Single-centre, prospective, observational study. Median nerve SSEP recording performed at 24–36 h post-return of spontaneous circulation. Recording was analysed using amplitude measurements of P25/30 and Peak-To-Trough of 20–30 ms complex and thresholds to decide P25/30 presence. Neurological outcome was dichotomised into favourable and unfavourable.

Results 89 participants were analysed. 43.8% had favourable and 56.2% unfavourable outcome. The sensitivity, specificity, positive and negative predictive values of the present SSEP and favourable outcome were calculated. P25/30 presence and size of PTT improved positive predictive value and specificity, while maintained similar negative predictive value and sensitivity, compared to the current practice. Inter-interpreter agreement was also improved.

Conclusions Enhanced analysis of the SSEP at 20–30 ms complex could improve the short-term prognostic accuracy for short-term neurological outcome in comatose survivors of cardiac arrest.

Significance Peak-To-Trough analysis of the 20–30 ms SSEP waveform appears to be the best predictor of neurological outcome following out of hospital cardiac arrest. It is also the easiest and most reliable to analyse.