[Evaluation of electrophysiological neuromonitoring in the diagnosis of brain death: Part III. Compressed spectral arrays].
Electrophysiological neuromonitoring of compressed spectral array (CSA) EEG, brainstem auditory evoked potentials (BAEP) and short-latency somatosensory evoked potentials (SEP) can provide precise and immediate information concerning functional integrity of severe brain damage. We applied this neuromonitoring system in 185 cases of severe brain damage in order to evaluate its reliability in the diagnosis of brain death. This report considers the relationships between CSA and neurological, conventional EEG (CEEG), BAEP and SEP findings, and the significance of CSA in the assessment of brain death. CSA monitoring of 59 patients (37 brain-dead in group A and 22 non brain-dead in group B) was performed and analysed. Brain damage was caused by cerebrovascular insult in 31 cases, head injury in 25, meningitis in 2, dan anoxia in 1. Mean patient age was 49 (ages 5-84). There were no significant differences in causes and age distribution between the two groups. CSA monitoring, using 5 or 7 microV/mm, of two channels (Cz-A1 and Cz-A2) of EEG activity was performed. Power spectral analysis (0-16 Hz) was carried out at 10 to 120 second epochs. Automatic BAEP (54 patients) and/or SEP (33 patients) monitoring was performed simultaneously 10 to 30 minutes. CSA was classified into three patterns: 1) "Electrocerebral silence; ECS" revealed bilateral absence of the CSA power spectra for periods longer than 40 seconds. 2) "Biological activity; BA" showed continuous peaks of activity. 3) "Equivocal; EQ" pattern showed intermittent peaks of activity, and unilateral loss of power spectra or bilateral loss within 30 seconds. CSA findings indicated the loss of CSA "BA" pattern (LCBP) in 36 group A patients (17 "ECS" and 19 "EQ"). All but two revealing LCBP had satisfied the neurological criteria of brain death (deep coma, absent brainstem reflexes and apnea) during CSA monitoring. "BA" was always present in 22 group B and one group A patients had not fulfilled neurological criteria of brain death. The CEEG results of all group A patients demonstrating "ECS" of CSA were of the classification Hockaday grade Va or Vb. Four patients classified as grade IV b demonstrated "EQ" An examination of CSA and neurological brainstem function of 28 group A patients revealed LCBP preceded the loss of brainstem reflexes and apnea in 15 patients or was coincided with them in 13.(ABSTRACT TRUNCATED AT 400 WORDS)
Department of Neurosurgery, Kyorin University School of Medicine, Tokyo, Japan.
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Shiogai
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001925:Brain Damage, Chronic / Q000503:physiopathology; D001926:Brain Death / Q000175:diagnosis*; D001933:Brain Stem / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000379:methods; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009420:Nervous System / Q000503:physiopathology*; D011237:Predictive Value of Tests