Usefulness of permutation entropy as an anesthetic depth indicator in children

  • Pil-Jong Kim
  • Hong-Gee Kim
  • Gyu-Jeong Noh
  • Yong-Seo Koo
  • Teo Jeon Shin
Original Paper


Permutation entropy (PE) as a complexity measure has been introduced to monitor anesthetic depth for adult. However, PE has not yet been evaluated for its clinical applicability as an indicator of anesthetic depth in children. Therefore, in order to investigate the validity of PE, we compared PE with BIS using pharmacodynamic (PD) modeling in children. Electroencephalogram (EEG) was obtained from BIS monitor during sevoflurane deepening and lightening protocol. End-tidal sevoflurane concentration (Etsevo) and BIS were measured simultaneously. PE was calculated from the processed EEG with the scale ranging from 0 to 100. NONMEM software was used to investigate the PD relationship between Etsevo with BIS and PE. Adjusted PE (APE) values were decreased as anesthesia deepened. APE and BIS showed significant linear correlation (P < 0.001), indicating that PE also reflects anesthesia depth. PD parameters for APE and BIS were estimated with a sigmoid Emax model which describes the relationship between Etsevo and APE/BIS (E o : 78, E max : 17.6, C e50 : 2.5 vol%; γ: 13.1, k eo : 0.47 min−1 for APE; E o : 89.4; E max : 15.7; C e50 : 2.2 vol%; γ: 6.6, keo: 0.52 min−1 for BIS). PE seems to be a useful indicator of anesthetic depth, which is comparable to BIS in children.


Anesthesia Entropy NONMEM Sevoflurane 



We are grateful to all members in Biomedical Knowledge Engineering Lab, Seoul National University, College of Dentistry for their assistance. And we are also grateful to Professor Satoshi Hagihria for providing Bispectrum Analyzer software.

Conflict of interest

The authors declared no conflict of interest.

Supplementary material

10928_2015_9405_MOESM1_ESM.pptx (191 kb)
Supplementary material 1 (PPTX 190 kb)


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Biomedical Knowledge Engineering Laboratory, School of DentistrySeoul National UniversitySeoulRepublic of Korea
  2. 2.Department of Clinical Pharmacology and Therapeutics/Anesthesiology and Pain Medicine, Asan Medical CentreUniversity of Ulsan College of MedicineSeoulRepublic of Korea
  3. 3.Department of NeurologyKorea University College of MedicineSeoulRepublic of Korea
  4. 4.Department of Pediatric Dentistry and Dental Research Institute, School of DentistrySeoul National UniversitySeoulRepublic of Korea

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