2017 年 3 巻 2 号 p. 40-43
Objectives: Demonstration of flat electroencephalogram (EEG) both at low- and high-sensitivity is required to legally determine brain death. Critically brain-injured patients frequently undergo decompressive craniectomy (DC) to relieve the raised intracranial pressure before being considered as candidates for legal brain death determination. The main objective of this study was to evaluate influence of DC on the interpretation of EEG at high-sensitivity.
Methods: A retrospective study was conducted in 23 critically brain-injured patients with flat EEGs at low-sensitivity. An experienced EEG technician determined whether each high-sensitivity EEG was interpretable as flat in a blinded manner. DC had been performed in 13 patients (57%).
Results: There was no significant difference in the demographics between the DC and non-DC group. The frequency of flat EEG at high-sensitivity was 62% in DC and 100% in the non-DC group, and the difference was statistically significant (p = 0.045). Determination of flat EEG at high-sensitivity was unable to be made in five DC patients (38%). All five patients died within 4 days of the initial EEG.
Conclusions: In DC patients, EEG amplitudes at high-sensitivity may be exaggerated on the side of DC due to the absence of the skull. The findings of this study are: (1) 38% of DC patients showed some electrical activity at high-sensitivity on the side of DC; and (2) the electrical activity disappeared within several days and did not predict resuscitability. These findings may be useful to physicians who treat critically brain injured patients.
