Abstract 17382: Somatosensory Evoked Potentials, but Not Neuron-Specific Enolase, are Suitable for the Prediction of Neurologic Outcome in Patients with Out-of-Hospital Cardiac Arrest Treated With Mild-Hypothermia
BACKGROUND: We aimed to investigate the prognostic value of an algorithm involving neuron-specific enolase (NSE) and evoked potentials (EP) to predict neurological outcome in patients with out-of-hospital cardiac arrest (OHCA) treated with mild-therapeutic hypothermia (MTH), a common scenario where reliable prognostic data are confounding or lacking.
METHODS: 64 consecutive OHCA-patients subjected to MTH were retrospectively evaluated. NSE was measured 24, 48 and 72 hours after admission. Patients with inadequate arousal or no spontaneous motor response 48 hours after termination of analgosedation (n=34) were subjected to clinical neurological examination and assessment of EPs, including somatosensory evoked potentials (SSEP) and auditory evoked potentials (AEP). Neurological outcome was assessed after two months based on the cerebral performance categories (CPC). Prognosis was categorized as good (CPC 1-3) or poor (CPC 4 and 5).
RESULTS: 39 patients had a CPC-score of 1-3, 25 patients had a CPC 4-5. Baseline characteristics did not differ between groups. In comatose patients, SSEPs showed a specificity of 100%, sensitivity of 24%, positive-predictive value (PPV) of 100%, and negative predictive value (NPV) of 50% to predict poor outcome. Conversely, AEPs, clinical examination and the absence of motor response were not reliable to predict poor outcome. An increase of NSE >33 µg/l within 24 to 48 hours predicted poor outcome (odds ratio of 2.1; 95%-CI 0.5-8.7 vs. 3.0; 95% CI 0.9-19.1) with a specificity of 65%, sensitivity of 84%, PPV of 64%, and NPV of 85%. A change of NSE (increase or decline) did not correlate with prognosis at any time-point. Intriguingly, two patients with excessive NSE-values (24-hour NSE of 101 µg/L and 256 µg/L, and 48-hour NSE-values of 93 µg/L and 110 µg/L, respectively) regained adequate conscious (CPC-score of 1 and physiological SSEPs). Interestingly, NSE levels correlated with a change of creatinine at 48 hours after cardiac arrest, but not at 24 hours (48 hours r=0.11, p=0.030; 24 hours r=0.04 p=0.252).
CONCLUSIONS: SSEPs, but not NSE, are suitable to predict neurological outcome in OHCA-patients after MTH. This suggests favoring the assessment of SSEPs in clinical decision making, whereas NSE should be excluded.
- © 2012 by American Heart Association, Inc.