Comparison of Anesthetic Depth Indexes Based on Thalamocortical Local Field Potentials in Rats

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Silva A (Author) Other; Cardoso-Cruz H (Author) Other; Silva F (Author) Other; Galhardo V (Author) FMUP; Antunes L (Author) Other

Journal

Title: Anesthesiology

Vol. 112

Pages: 355-363

ISSN: 0003-3022

Publisher: Wolters Kluwer Health

Indexing

ISI Web of Knowledge - 51 Citations

ISI Web of Science

Scopus - 57 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

CORDIS: Health sciences ; Health sciences > Neuroscience

Other information

Authenticus ID: P-003-96Y

DOI: 10.1097/ALN.0b013e3181ca3196

Abstract (EN): Background: Local field potentials may allow a more precise analysis of the brain electrical activity than the electroencephalogram. In this study, local field potentials were recorded in the thalamocortical axis of rats to (i) compare the performance of several indexes of anesthetic depth and (ii) investigate the existence of thalamocortical correlated or disrupted activity during isoflurane steady-state anesthesia. Methods: Five rats chronically implanted with microelectrodes were used to record local field potentials in the primary somatosensory cortex and ventroposterolateral thalamic nuclei at six periods: before induction of anesthesia; in the last 5 min of randomized 20-min steady-state end-tidal 0.8, 1.1, 1.4, and 1.7% isoflurane concentrations; and after recovery. The approximate entropy, the index of consciousness, the spectral edge frequency, and the permutation entropy were estimated using epochs of 8 s. A correction factor for burst suppression was applied to the spectral edge frequency and to the permutation entropy. The correlation between the derived indexes and the end-tidal isoflurane was calculated and compared for the two studied brain regions indexes. Coherence analysis was also performed. Results: The burst suppression-corrected permutation entropy showed the highest correlation with the end-tidal isoflurane concentration, and a high coherence was obtained between the two studied areas. Conclusions: The permutation entropy corrected with the classic burst suppression ratio is a promising alternative to other indexes of anesthetic depth. Furthermore, high coherence level of activity exists between the somatosensory cortical and thalamic regions, even at deep isoflurane stages.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9