Somatosensory Evoked Potentials Correlate With Neurological Outcome In Rabbits Undergoing Cerebral Air Embolism

Background and Purpose Somatosensory evoked potentials (SSEPs) have been used as an outcome measure in models of cerebral air embolism despite the lack of studies correlating SSEPs with other measures of neurological injury. We examined the relationship between SSEPs and neurological impairment in the setting of cerebral air embolism.Methods Anesthetized New Zealand White rabbits received either 0, 50, 100, or 150 mu L/kg of air into the internal carotid artery. SSEPs were recorded at intervals for the subsequent 2 hours. After the final recording the anesthetic was discontinued, and the animals recovered. Animals were neurologically evaluated at 3 and 24 hours after cerebral air embolism on a scale of zero (normal) to 97 (coma) points.Results There was a clear relationship between the dose of air and 2-hour SSEP amplitude (P=.00003). SSEP amplitudes at 2 hours were inversely correlated with neurological impairment scores at 3 hours (tau=-0.71, P<.0001). SSEP amplitudes at 2 hours were less in animals that died (11+/-16%; n=9) than in those that survived to 24 hours (53+/-20%; n=9) (P=.0008).Conclusions These results support SSEPs as an index of neurological impairment in this model of cerebral air embolism.