Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors

Johanna Wennervirta (Corresponding Author), Tapani Salmi, Markku Hynynen, Arvi Yli-Hankala, Anna-Maria Koivusalo, Mark van Gils, Reino Pöyhiä, Anne Vakkuri

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)

Abstract

Objective: To evaluate the usefulness of entropy and the bispectral index (BIS) in braindead subjects. Design and setting: A prospective, open, nonselective, observational study in the university hospital. Patients and participants: 16 brain-dead organ donors. Interventions: Time-domain electroencephalography (EEG), spectral entropy of the EEG, and BIS were recorded during solid organ harvest. Measurements and results: State entropy differed significantly from 0 (isoelectric EEG) 28%, response entropy 29%, and BIS 68% of the total recorded time. The median values during the operation were state entropy 0.0, response entropy 0.0, and BIS 3.0. In four of 16 organ donors studied the EEG was not isoelectric, and nonreactive rhythmic activity was noted in time-domain EEG. After excluding the results from subjects with persistent residual EEG activity state entropy, response entropy, and BIS values differed from zero 17%, 18%, and 62% of the recorded time, respectively. Median values were 0.0, 0.0, and 2.0 for state entropy, response entropy, and BIS, respectively. The highest index values in entropy and BIS monitoring were recorded without neuromuscular blockade. The main sources of artifacts were electrocauterization, 50-Hz artifact, handling of the donor, ballistocardiography, electromyography, and electrocardiography. Conclusion: Both entropy and BIS showed nonzero values due to artifacts after brain death diagnosis. BIS was more liable to artifacts than entropy. Neither of these indices are diagnostic tools, and care should be taken when interpreting EEG and EEG-derived indices in the evaluation of brain death.
Original languageEnglish
Pages (from-to)133-136
JournalIntensive Care Medicine
Volume33
Issue number1
DOIs
Publication statusPublished - 2007
MoE publication typeA1 Journal article-refereed

Fingerprint

Brain Death
Entropy
Artifacts
Tissue Donors
Electroencephalography
Ballistocardiography
Neuromuscular Blockade
Electromyography
Observational Studies
Electrocardiography

Keywords

  • electroencephalography
  • brain death
  • entropy
  • bispectral index

Cite this

Wennervirta, J., Salmi, T., Hynynen, M., Yli-Hankala, A., Koivusalo, A-M., van Gils, M., ... Vakkuri, A. (2007). Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors. Intensive Care Medicine, 33(1), 133-136. https://doi.org/10.1007/s00134-006-0429-6
Wennervirta, Johanna ; Salmi, Tapani ; Hynynen, Markku ; Yli-Hankala, Arvi ; Koivusalo, Anna-Maria ; van Gils, Mark ; Pöyhiä, Reino ; Vakkuri, Anne. / Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors. In: Intensive Care Medicine. 2007 ; Vol. 33, No. 1. pp. 133-136.
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abstract = "Objective: To evaluate the usefulness of entropy and the bispectral index (BIS) in braindead subjects. Design and setting: A prospective, open, nonselective, observational study in the university hospital. Patients and participants: 16 brain-dead organ donors. Interventions: Time-domain electroencephalography (EEG), spectral entropy of the EEG, and BIS were recorded during solid organ harvest. Measurements and results: State entropy differed significantly from 0 (isoelectric EEG) 28{\%}, response entropy 29{\%}, and BIS 68{\%} of the total recorded time. The median values during the operation were state entropy 0.0, response entropy 0.0, and BIS 3.0. In four of 16 organ donors studied the EEG was not isoelectric, and nonreactive rhythmic activity was noted in time-domain EEG. After excluding the results from subjects with persistent residual EEG activity state entropy, response entropy, and BIS values differed from zero 17{\%}, 18{\%}, and 62{\%} of the recorded time, respectively. Median values were 0.0, 0.0, and 2.0 for state entropy, response entropy, and BIS, respectively. The highest index values in entropy and BIS monitoring were recorded without neuromuscular blockade. The main sources of artifacts were electrocauterization, 50-Hz artifact, handling of the donor, ballistocardiography, electromyography, and electrocardiography. Conclusion: Both entropy and BIS showed nonzero values due to artifacts after brain death diagnosis. BIS was more liable to artifacts than entropy. Neither of these indices are diagnostic tools, and care should be taken when interpreting EEG and EEG-derived indices in the evaluation of brain death.",
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Wennervirta, J, Salmi, T, Hynynen, M, Yli-Hankala, A, Koivusalo, A-M, van Gils, M, Pöyhiä, R & Vakkuri, A 2007, 'Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors', Intensive Care Medicine, vol. 33, no. 1, pp. 133-136. https://doi.org/10.1007/s00134-006-0429-6

Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors. / Wennervirta, Johanna (Corresponding Author); Salmi, Tapani; Hynynen, Markku; Yli-Hankala, Arvi; Koivusalo, Anna-Maria; van Gils, Mark; Pöyhiä, Reino; Vakkuri, Anne.

In: Intensive Care Medicine, Vol. 33, No. 1, 2007, p. 133-136.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors

AU - Wennervirta, Johanna

AU - Salmi, Tapani

AU - Hynynen, Markku

AU - Yli-Hankala, Arvi

AU - Koivusalo, Anna-Maria

AU - van Gils, Mark

AU - Pöyhiä, Reino

AU - Vakkuri, Anne

N1 - Project code: 1305

PY - 2007

Y1 - 2007

N2 - Objective: To evaluate the usefulness of entropy and the bispectral index (BIS) in braindead subjects. Design and setting: A prospective, open, nonselective, observational study in the university hospital. Patients and participants: 16 brain-dead organ donors. Interventions: Time-domain electroencephalography (EEG), spectral entropy of the EEG, and BIS were recorded during solid organ harvest. Measurements and results: State entropy differed significantly from 0 (isoelectric EEG) 28%, response entropy 29%, and BIS 68% of the total recorded time. The median values during the operation were state entropy 0.0, response entropy 0.0, and BIS 3.0. In four of 16 organ donors studied the EEG was not isoelectric, and nonreactive rhythmic activity was noted in time-domain EEG. After excluding the results from subjects with persistent residual EEG activity state entropy, response entropy, and BIS values differed from zero 17%, 18%, and 62% of the recorded time, respectively. Median values were 0.0, 0.0, and 2.0 for state entropy, response entropy, and BIS, respectively. The highest index values in entropy and BIS monitoring were recorded without neuromuscular blockade. The main sources of artifacts were electrocauterization, 50-Hz artifact, handling of the donor, ballistocardiography, electromyography, and electrocardiography. Conclusion: Both entropy and BIS showed nonzero values due to artifacts after brain death diagnosis. BIS was more liable to artifacts than entropy. Neither of these indices are diagnostic tools, and care should be taken when interpreting EEG and EEG-derived indices in the evaluation of brain death.

AB - Objective: To evaluate the usefulness of entropy and the bispectral index (BIS) in braindead subjects. Design and setting: A prospective, open, nonselective, observational study in the university hospital. Patients and participants: 16 brain-dead organ donors. Interventions: Time-domain electroencephalography (EEG), spectral entropy of the EEG, and BIS were recorded during solid organ harvest. Measurements and results: State entropy differed significantly from 0 (isoelectric EEG) 28%, response entropy 29%, and BIS 68% of the total recorded time. The median values during the operation were state entropy 0.0, response entropy 0.0, and BIS 3.0. In four of 16 organ donors studied the EEG was not isoelectric, and nonreactive rhythmic activity was noted in time-domain EEG. After excluding the results from subjects with persistent residual EEG activity state entropy, response entropy, and BIS values differed from zero 17%, 18%, and 62% of the recorded time, respectively. Median values were 0.0, 0.0, and 2.0 for state entropy, response entropy, and BIS, respectively. The highest index values in entropy and BIS monitoring were recorded without neuromuscular blockade. The main sources of artifacts were electrocauterization, 50-Hz artifact, handling of the donor, ballistocardiography, electromyography, and electrocardiography. Conclusion: Both entropy and BIS showed nonzero values due to artifacts after brain death diagnosis. BIS was more liable to artifacts than entropy. Neither of these indices are diagnostic tools, and care should be taken when interpreting EEG and EEG-derived indices in the evaluation of brain death.

KW - electroencephalography

KW - brain death

KW - entropy

KW - bispectral index

U2 - 10.1007/s00134-006-0429-6

DO - 10.1007/s00134-006-0429-6

M3 - Article

VL - 33

SP - 133

EP - 136

JO - Intensive Care Medicine

JF - Intensive Care Medicine

SN - 0342-4642

IS - 1

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