Journal article
A comparison of the SNAP II™ and BIS XP™ indices during sevoflurane and nitrous oxide anaesthesia at 1 and 1.5 MAC and at awakening
British journal of anaesthesia : BJA, Vol.97(2), pp.181-186
08/2006
DOI: 10.1093/bja/ael131
PMID: 16720676
Abstract
. Monitoring level of consciousness during anaesthesia, with the ability to predict the intentional or unintentional return to consciousness, is desirable. The purpose of this study was to compare two processed electroencephalographic depth of anaesthesia monitors (SNAP II™ and BIS XP™) during sevoflurane and sevoflurane/nitrous oxide anaesthesia.Methods. In total, 42 subjects received an interscalene block, followed by general anaesthesia with sevoflurane or sevoflurane/nitrous oxide. The indices were recorded at baseline, at 1.5 and 1.0 minimum alveolar concentration (MAC) equivalents, and during emergence.Results. The SNAP and BIS indices decreased from baseline at 1.5 and 1.0 MAC equivalents, but there was no difference within groups between subjects who received nitrous oxide and those who did not. The SNAP index returned to baseline by 1 min before awakening and was higher than baseline at eye opening, but the BIS index remained below baseline at awakening. There was a bias of −1 (95% CI: −3 to 1) between the SNAP and BIS at baseline; this increased to 21 (95% CI: 19–23) during maintenance of anaesthesia and was 6 (95% CI: 4–8) at awakening.Conclusions. The SNAP index tracks loss of consciousness and emergence from sevoflurane and sevoflurane/nitrous oxide anaesthesia. There is significant bias between the SNAP and BIS indices and therefore, the indices are not interchangeable. The SNAP index returns to baseline before awakening, whereas the BIS index remains below baseline at awakening, suggesting that the SNAP index may be more sensitive to unintentional awareness.
Details
- Title: Subtitle
- A comparison of the SNAP II™ and BIS XP™ indices during sevoflurane and nitrous oxide anaesthesia at 1 and 1.5 MAC and at awakening
- Creators
- C. A Wong - Department of Anesthesiology, Feinberg School of Medicine, Northwestern UniversityR. J Fragen - Department of Anesthesiology, Feinberg School of Medicine, Northwestern UniversityP Fitzgerald - Department of Anesthesiology, Feinberg School of Medicine, Northwestern UniversityR. J McCarthy - Department of Anesthesiology, Feinberg School of Medicine, Northwestern University
- Resource Type
- Journal article
- Publication Details
- British journal of anaesthesia : BJA, Vol.97(2), pp.181-186
- Publisher
- Oxford University Press
- DOI
- 10.1093/bja/ael131
- PMID
- 16720676
- ISSN
- 0007-0912
- eISSN
- 1471-6771
- Language
- English
- Date published
- 08/2006
- Academic Unit
- Anesthesia
- Record Identifier
- 9984006466002771
Metrics
34 Record Views