Variance of interburst intervals in burst suppression

Abstract

Each EEG performed over a 3 year period at the University of Michigan with a diagnosis of generalized burst-suppression (BS) was reviewed. Ten EEGs from 10 patients with hypoxic-ischemic encephalopathy (HIE-BS) and 21 records from 8 patients with pentobarbital induced burst-suppression for treatment of status epilepticus (SE-BS) were reviewed. For each EEG, the mean duration of 40 interburst intervals (IBIs) as well as their coefficient of variability were calculated. We found that in the SE-BS group the coefficient of variability of IBI duration was highly correlated with the logarithm of mean IBI duration while in the HIE-BS group, there was no significant correlation between these 2 variables. This suggests that the underlying mechanism causing BS is different in the 2 groups and might be related to a uniform and progressive affection of similar brain structures in the SE-BS group and a more patchy and variable pathology in the HIE-BS group.

Observations on comatose survivors of cardiopulmonary resuscitation with generalized myoclonus

“…Each of these EEG-patterns is recognized as an unfavourable sign [1-7,13,15,28-35]. Our data indicate that each of these EEG-pattern is a transient phenomenon in comatose survivors of CPR with generalized myoclonus.…”

“…In accordance with others [13-15], we fixed the duration of isoelectric or low amplitude interburst intervals to at least 1 second to exclude patients with generalized continuous epileptiform discharges. Flat recordings were those with amplitudes below 20 μV, and isoelectric recordings those without any detectable activity (sensitivity of the recording system: 2 μV/mm).…”

Hypersensitivity of the Anesthesia-Induced Comatose Brain

“…Some of them have dealt with the pseudorhythmicity of the bursts (Beydoun et al, 1991), others with their occurrence in deafferented preparations (Henry and Scoville, 1952). In view of our data, it might be that many, if not all, bursts could be the result of subliminal, undetected stimuli.…”

Adaptive segmentation of burst-suppression pattern in isoflurane and enflurane anesthesia

“…On the other hand, in several recent studies BS patterns are characterized by their timing properties i.e. the durations of bursts and suppression segments and the dynamics of these durations [8,9]. We include measures of the timing properties to our analysis as monitoring these measures might give additional information about the changes in the state of the patient.…”