JOURNAL HOME CME HOME THIS MONTH PAST ISSUES ETOC COLLECTIONS
AUTHORS REVIEWERS EDITORIAL BOARD FEEDBACK RSS HELP
A&A International Anesthesia Research Society
QUICK SEARCH:   [advanced]


     

Anesth Analg 2008; 106:823-829
© 2008 International Anesthesia Research Society
doi: 10.1213/ane.0b013e318161534b
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a colleague
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Barakat, A. R.
Right arrow Articles by Schraag, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barakat, A. R.
Right arrow Articles by Schraag, S.
Related Collections
Right arrow Clinical Pharmacology
Right arrow Pharmacology

ANESTHETIC PHARMACOLOGY

The Effective Concentration 50 (EC50) for Propofol with 70% Xenon Versus 70% Nitrous Oxide

Ahmed R. Barakat, MD, FRCA*, Markus N. Schreiber, MD{dagger}, Joachim Flaschar, Dipl.-Ing. (FH){dagger}, Michael Georgieff, MD{dagger}, and Stefan Schraag, MD*

From the *Department of Perioperative Medicine, Golden Jubilee National Hospital, Clydebank, UK; and {dagger}Department of Anesthesiology, University of Ulm, Germany.

Address correspondence and reprint requests to Stefan Schraag, MD, PhD, Department of Perioperative Medicine, Golden Jubilee National Hospital, Clydebank G81 4HX, Scotland, UK. Address e-mail to stefanschraag{at}btinternet.com.

BACKGROUND: Xenon anesthesia has many favorable properties, such as pain modulation and organ protection. However, due to its MAC of 70%, it cannot be used as a sole anesthetic. We estimated the amount of propofol required to supplement xenon to produce adequate anesthesia in 50% and 95% of patients in comparison with nitrous oxide.

METHODS: We randomized 75 premedicated female patients to receive either 70% xenon or 70% nitrous oxide in oxygen supplemented by propofol target-controlled infusion anesthesia starting with 4.5 µg/mL for the first patient in each group. Dixon's up and down method was used to determine the propofol concentration for subsequent patients. After induction of anesthesia with propofol, patients breathed 70% xenon or 70% nitrous oxide in oxygen via a facemask for 15 min. They were then observed for movement in response to skin incision for 60 s after the incision and assigned as movers or nonmovers. Probit analysis was used to estimate the effective concentration 50% and 95% (EC50 and EC95) for propofol in both groups.

RESULTS: The EC50 for propofol with 70% xenon was1.5µg/mL and the EC95 was 2.3 µg/mL. The EC50 and EC95 values for propofol with nitrous oxide were 2.2 and 8.2 µg/mL, respectively. This implies a reduction of propofol requirements between 32% (EC50) and 72% (EC95) by xenon compared with nitrous oxide. The suppression of auditory evoked potentials was more pronounced with xenon than with nitrous oxide.

CONCLUSION: Xenon seems to be clinically more potent than nitrous oxide, but still requires minimal supplement of a hypnotic anesthetic to suppress noxious stimulation during and after skin incision.






Lippincott, Williams & Wilkins Anesthesia & Analgesia® is published for the International Anesthesia Research Society® by Lippincott Williams & Wilkins with the assistance of Stanford University Libraries' HighWire Press®. Copyright 2006 by the International Anesthesia Research Society. Online ISSN: 1526-7598   Print ISSN: 0003-2999 HighWire Press
Copyright © 2008 by the International Anesthesia Research Society.