Therapeutic hypothermia does not diminish the vital and necessary role of SSEP in predicting unfavorable outcome in anoxic-ischemic coma

Abstract

Rational medical management of patients who remain comatose following cardio-pulmonary resuscitation (CPR) due to anoxic-ischemic encephalopathy depends upon the early identification of those with a hopeless prognosis - regardless of how aggressively they are managed. Conversely, it is mandatory that we recognize those patients with the potential to recover in order to institute aggressive therapeutic measures. The bilateral absence of the N20 Cortical Somatosensory Evoked Potential has been identified as the most reliable predictor of an unfavorable prognosis in normothermic patients. Two randomized trials have determined that mild therapeutic hypothermia (TH) delivered immediately after CPR improves neurologic outcomes. TH has now become the standard of care in the management of patients with cardio-pulmonary arrest. Eight studies targeting patients who were comatose following CPR, treated with TH, and using SSEP as an outcome predictor are reviewed. There is only one patient treated with TH who appears to have fully recovered following cardiac arrest who was initially found to have bilateral absent cortical potentials. This opinion paper will address whether the criteria that placed reliance upon SSEP to predict unfavorable outcome in post cardio-pulmonary arrest patients after receiving TH, still apply.

Keywords: Anoxic-ischemic coma; Cardio-pulmonary arrest; Outcome prediction; Somatosensory evoked potentials; Therapeutic hypothermia.