Even when patients are unable to respond, physicians can get valuable information from nerves that can assist in determining whether the patient will live or die in nontraumatic comatose patients. 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 liklihood of survival. Researchers studied forty-seven nontraumatic comatose adults. One hundred eighty-eight somatosensory evoked potential (SEP) measurements were taken from comatose patients within 5 days after they became comatose. Eight patients (17%) 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%) survived and 25 patients died (64.1%). 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 researcher, Dr. Margareth Kai of Sao Paulo, Brazil, "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, we must study a larger group of patients to be sure of the accuracy of the study. A systematically multimodal neuromonitoring, will help not only to assess the patient's prognosis, but help us to prevent cerebral deterioration, and to evaluate and determine the therapeutic improvement of the ICU patient."
The complete findings and results of this study are being presented at the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) 55th Annual Meeting in Providence, Rhode Island, September 17-20, 2008. The AANEM is the largest organization worldwide, with over 5000 members dedicated to advancing neuromuscular, musculoskeletal, and electrodiagnostic medicine.