Middle latency auditory-evoked potential index for predicting the degree of consciousness of comatose patients in EDs

IntroductionDigitized assessment of the degree of consciousness is a universal challenge in emergency departments (EDs) and intensive care units (ICUs). The middle latency auditory-evoked potential index (MLAEPi) monitor aepEX plus (Audiomex, Glasgow, Scotland, UK) is the first mobile middle latency auditory-evoked potential monitor. We speculated that the initial MLAEPi determined on arrival at EDs could indicate cerebral function and predict the degree of consciousness of comatose patients.MethodsWe used MLAEPi-related data from 50 comatose patients with disturbance of consciousness (DOC), 50 patients with cardiopulmonary arrest (CPA), and 50 healthy volunteers (control). Comatose patients were defined as those with an initial Glasgow Coma Scale score of 8 or less. The CPA group consisted of patients who arrived at EDs without restoration of spontaneous circulation. Among the patients with DOC who underwent sedation at EDs, the change in the MLAEPi was evaluated between arrival at the ED and ICU admission.ResultsThe initial MLAEPi was significantly lower in the DOC group than in the control group but significantly higher in the DOC group than in the CPA group. Among the comatose patients, the receiver operating characteristic curve for the initial MLAEPi showed an area under the curve of 0.93 (P < .01) for the DOC group. Thirty patients with DOC underwent sedation at EDs, and the initial MLAEPi was significantly higher than those at other periods during emergency care.ConclusionThe MLAEPi (simple numerical value) may be used to evaluate the degree of consciousness in comatose patients while performing emergency care in EDs.