Document Detail

Comparative pharmacodynamic modeling of the electroencephalography-slowing effect of isoflurane, sevoflurane, and desflurane.
MedLine Citation:
PMID:  10443602     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The most common measure to compare potencies of volatile anesthetics is minimum alveolar concentration (MAC), although this value describes only a single point on a quantal concentration-response curve and most likely reflects more the effects on the spinal cord rather than on the brain. To obtain more complete concentration-response curves for the cerebral effects of isoflurane, sevoflurane, and desflurane, the authors used the spectral edge frequency at the 95th percentile of the power spectrum (SEF95) as a measure of cerebral effect. METHODS: Thirty-nine patients were randomized to isoflurane, sevoflurane, or desflurane groups. After induction with propofol, intubation, and a waiting period, end-tidal anesthetic concentrations were randomly varied between 0.6 and 1.3 MAC, and the EEG was recorded continuously. Population pharmacodynamic modeling was performed using the software package NONMEM. RESULTS: The population mean EC50 values of the final model for SEF95 suppression were 0.66+/-0.08 (+/- SE of estimate) vol% for isoflurane, 1.18+/-0.10 vol% for sevoflurane, and 3.48+/-0.66 vol% for desflurane. The slopes of the concentration-response curves were not significantly different; the common value was lambda = 0.86+/-0.06. The Ke0 value was significantly higher for desflurane (0.61+/-0.11 min(-1)), whereas separate values for isoflurane and sevoflurane yielded no better fit than the common value of 0.29+/-0.04 min(-1). When concentration data were converted into fractions of the respective MAC values, no significant difference of the C50 values for the three anesthetic agents was found. CONCLUSIONS: This study demonstrated that (1) the concentration-response curves for spectral edge frequency slowing have the same slope, and (2) the ratio C50(SEF95)/MAC is the same for all three anesthetic agents. The authors conclude that MAC and MAC multiples, for the three volatile anesthetics studied, are valid representations of the concentration-response curve for anesthetic suppression of SEF95.
B Rehberg; T Bouillon; J Zinserling; A Hoeft
Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anesthesiology     Volume:  91     ISSN:  0003-3022     ISO Abbreviation:  Anesthesiology     Publication Date:  1999 Aug 
Date Detail:
Created Date:  1999-08-19     Completed Date:  1999-08-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  397-405     Citation Subset:  AIM; IM    
Klinik und Poliklinik für Anaesthesiologie und spezielle Intensivmedizin, University of Bonn, Germany.
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MeSH Terms
Anesthetics, Inhalation / pharmacology*
Dose-Response Relationship, Drug
Electroencephalography / drug effects*
Isoflurane / analogs & derivatives*,  pharmacology*
Methyl Ethers / pharmacology*
Middle Aged
Prospective Studies
Reg. No./Substance:
0/Anesthetics, Inhalation; 0/Methyl Ethers; 26675-46-7/Isoflurane; 28523-86-6/sevoflurane; 57041-67-5/desflurane

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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