OBJECTIVE: To evaluate the usefulness of entropy and the bispectral index (BIS) in brain-dead 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.
OBJECTIVE: To evaluate the usefulness of entropy and the bispectral index (BIS) in brain-dead 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.
Authors: D R Feikin; A Schuchat; M Kolczak; N L Barrett; L H Harrison; L Lefkowitz; A McGeer; M M Farley; D J Vugia; C Lexau; K R Stefonek; J E Patterson; J H Jorgensen Journal: Am J Public Health Date: 2000-02 Impact factor: 9.308
Authors: John R Lonks; Javier Garau; Lucía Gomez; Mariona Xercavins; Anna Ochoa de Echagüen; Ilana F Gareen; Philip T Reiss; Antone A Medeiros Journal: Clin Infect Dis Date: 2002-08-09 Impact factor: 9.079
Authors: Victor L Yu; Christine C C Chiou; Charles Feldman; Ake Ortqvist; Jordi Rello; Arthur J Morris; Larry M Baddour; Carlos M Luna; David R Snydman; Margaret Ip; Wen Chien Ko; M Bernadete F Chedid; Antoine Andremont; Keith P Klugman Journal: Clin Infect Dis Date: 2003-07-07 Impact factor: 9.079
Authors: Larry M Baddour; Victor L Yu; Keith P Klugman; Charles Feldman; Ake Ortqvist; Jordi Rello; Arthur J Morris; Carlos M Luna; David R Snydman; Wen Chien Ko; M Bernadete F Chedid; David S Hui; Antoine Andremont; Christine C C Chiou Journal: Am J Respir Crit Care Med Date: 2004-06-07 Impact factor: 21.405
Authors: Massimo Antonelli; Elie Azoulay; Marc Bonten; Jean Chastre; Giuseppe Citerio; Giorgio Conti; Daniel De Backer; François Lemaire; Herwig Gerlach; Johan Groeneveld; Goran Hedenstierna; Duncan Macrae; Jordi Mancebo; Salvatore M Maggiore; Alexandre Mebazaa; Philipp Metnitz; Jerôme Pugin; Jan Wernerman; Haibo Zhang Journal: Intensive Care Med Date: 2008-01-04 Impact factor: 17.440