Prognostic value of early cortical somatosensory evoked potentials after resuscitation from cardiac arrest.

Short-latency somatosensory evoked potentials (SEPs) were evaluated in patients after cardiorespiratory arrest to study their pattern of recovery in the acute stage of anoxic-ischaemic coma. Fifty consecutive comatose patients were investigated within 8 h after cardiorespiratory resuscitation. In 30 patients no cortical SEPs were recorded and none of the patients recovered cognition. In 20 patients cortical SEPs were recorded and 5 recovered. The different susceptibility of frontal and parietal cortical structures to anoxia was reflected by the dissociated loss of parietal or frontal potentials in 6 patients. Post-mortem pathology in 15 patients confirmed extensive anoxic-ischaemic damage of cerebral and cerebellar cortex and thalamus in patients without cortical SEPs whereas the histological lesions were restricted to Sommer's sector and Purkinje cells in those with preserved SEPs. SEPs thus reflect the extent of brain damage after cardiorespiratory resuscitation.