Even in a comatose state, electrically induced nerve responses can be interpreted because the nerve responses are not affected by therapeutic muscular paralysis that occurs when sedatives are given at high dosage. In a recent study, evoked nerve responses were studied to correlate the nerve activity with the likelihood of survival.
Researchers studied 47 nontraumatic comatose adults. 188 somatosensory evoked potential (SEP) measurements were taken from comatose patients within five days after they became comatose. Eight patients (17 percent) had bilateral loss of cortical SEPs from the scalp. Despite long term intensive care unit (ICU) treatment, all eight of these patients died.
Nerve activity in the scalp was present in a group of 39 patients. Of those 39, 14 patients (35.8 percent) survived and 25 patients died (64.1 percent). The study suggests that bilateral nerve response loss can predict the death of the patient. However, having some nerve response cannot predict whether the patient will live or die.
According to the researchers, there is sufficient evidence for clinicians to use SEPs in the prediction of outcome after brain injury; however, in nontraumatic coma due to various systemic diseases, mainly in children, they say a larger group of patients must be analysed to be sure of the accuracy of the study. They suggest that a systematically multimodal neuromonitoring helps not only to assess the patient’s prognosis, but also to prevent cerebral deterioration, and to evaluate and determine the therapeutic improvement of the ICU patient.
MEDICA.de; Source: American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM)