Combined short- and mid-latency SSEP amplitudes for early prediction of favorable neurological recovery after cardiac arrest.

AIM: Early identification of patients with preserved neurological recovery after cardiac arrest remains challenging. We evaluated whether mid-latency somatosensory evoked potentials (SSEPs) provide additional prognostic information during the acute post-cardiac arrest period.

METHODS: In this retrospective cohort study, we included comatose adult cardiac arrest patients treated with targeted temperature management between 2009 and 2023 who underwent SSEP recording within 24 h after return of spontaneous circulation (ROSC). Short- and mid-latency SSEP amplitudes (N20, N20-P25, P25, P25-N30, and N30-P45) and latencies were quantified. Favorable neurological outcome was defined as a 6-month Cerebral Performance Category (CPC) score of 1-2. Discriminative performance was compared with other early prognostic variables obtained within the same time window, including neurological examination, brain computed tomography, electroencephalography, and neuron-specific enolase.

RESULTS: Among 73 patients, 29 (40%) achieved favorable neurological outcome. Cortical SSEP amplitudes were consistently higher in patients with favorable outcomes. P25-N30 amplitude demonstrated strong discrimination (AUC 0.943, 95% CI 0.862-0.984), achieving 100% sensitivity (95% CI 88.1-100%) and 84.1% specificity (95% CI 69.9-93.4%). Its performance was comparable to that of the conventional N20-P25 amplitude (AUC 0.922, 95% CI 0.836-0.972; p = 0.417). The addition of non-SSEP predictors did not significantly improve overall discrimination.

CONCLUSIONS: Quantitative assessment of the P25-N30 amplitude within 24 h after cardiac arrest was associated with favorable neurological outcome and may contribute to early multimodal prognostication.