| Effects of Intravenous Anesthetics on EEG Spectral Analysis during Cesarean Section. |
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Woon Yi Beak, Si Oh Kim, Chul Won Moon |
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Department of Anesthesiology, School of Medicine, Kyungpook National University, Taegu, Korea. |
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| Abstract |
BACKGROUND
Anesthesia induces the spectral changes in EEG.
Attempts to relate these spectral changes to adequacy of anesthesia have been hindered due to the complex waveforms of EEG. The objective of this investigation is to monitor the awareness of patients during cesarean section by means of EEG spectral analysis.
METHODS
20 patients for cesarean section aged from 24 to 39 and ASA class I or II, were maintained with O2(50%)-N2O(50%)-enflurane(0.8%). And they were administered with midazolam(0.07 mg/kg) in group I(n=6), fentanyl(1 microgram/kg) in group II(n=7), and fentanyl(2 microgram/kg) in group III(n=7) after birth. The density of each spectral band in EEG (delta 1-3.25 Hz, theta 3.5-7.75 Hz, alpha 8-12.15 Hz and beta 13-31.75Hz) was analyzed to derive total density, delta ratio and median power frequency.
RESULTS
The spectral data demonstrated that the alpha rhythm was dominant in pre-induction period and beta rhythm was abundant both in the immediate post-induction period and after birth for all three groups. Delta ratio and median power frequency decreased after injection of midazolam and fentanyl in all three groups. None of patients could recall the memory about experience during cesarean section.
CONCLUSIONS
These findings indicate that EEG spectral analysis is potentially useful to determine the changes of cerebroelectrical activity but difficult to monitor the awareness of patients during cesarean section. |
| Key Words:
Surgery obstetrics; cesarean section; Monitoring electroencephalography; Memory awareness; Anesthetics; volatile halothane; enflurane; isoflurane |
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