• J Clin Neurophysiol · Mar 2001

    Clinical Trial

    The development of spectral EEG changes during short periods of circulatory arrest.

    • G H Visser, G H Wieneke, A C Van Huffelen, J W De Vries, and P F Bakker.
    • Department of Clinical Neurophysiology, University Hospital Utrecht and Rudolf Magnus Institute for Neurosciences, Utrecht, The Netherlands.
    • J Clin Neurophysiol. 2001 Mar 1;18(2):169-77.

    AbstractThe EEG was monitored in 56 patients during implantation of an internal cardioverter defibrillator. The purpose of this study was to determine the main EEG frequency ranges that represent ischemic changes during short periods of circulatory arrest. The EEG was recorded with a 16-channel common reference montage (Cz). After onset of circulatory arrest, the log spectral changes of three-epoch moving averages were calculated relative to the baseline spectrum. For factor analysis, 17 EEG periods were selected that showed changes progressing to an isoelectrical period. Topographic differences and the time course of quantitative EEG (qEEG) changes were studied in all 56 patients. For each patient the EEG period with the longest duration of circulatory arrest was chosen. Factor analysis revealed four factors that represented the spectral EEG changes occurring during circulatory arrest and recovery. The frequency intervals of these factors were 0 to 0.5 Hz, 1.5 to 3 Hz, 7.5 to 9.5 Hz, and 15 to 20 Hz for all channels. Only minor topographic differences were found in the power of the spectral changes; the sequence of events was similar for all electrode positions. The first EEG change after circulatory arrest was an initial increase in alpha power and a decrease in beta power. On average, after approximately 15 seconds alpha power started to decrease, beta power decreased further, delta-1 power started to increase, and delta-2 power started to decrease. After approximately 25 seconds, the delta-1 power increase appeared to plateau or to decrease. A circulatory arrest longer than approximately 30 seconds resulted in an isoelectrical EEG. After restoration of the circulation, there was a fast transient increase in delta-1 and delta-2 power, followed by a decrease to baseline. alpha and beta power showed a more gradual increase in power toward baseline and were the last to restore after 60 to 90 seconds. In general, the spectral changes in the alpha and beta frequency ranges were most pronounced and consistent. In conclusion, to detect intraoperative cerebral ischemia, monitoring of changes in the four frequency ranges found is preferable to monitoring changes in the classically defined frequency bands. Furthermore, these results stress the importance of the alpha and beta ranges in detecting cerebral ischemia.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…