CJA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Résumé de cet Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit a scholarly reply
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Weiss, M.
Right arrow Articles by Dullenkopf, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Weiss, M.
Right arrow Articles by Dullenkopf, A.
Canadian Journal of Anesthesia 50:930-932 (2003)
© Canadian Anesthesiologists' Society, 2003
Obstetrical and Pediatric Anesthesia

Nitrous oxide does not affect automated air tonometry in children

[Le protoxyde d’azote n’agit pas sur la tonométrie à l’air, automatisée, chez les enfants]

Markus Weiss, MD, Andreas Gerber, MD and Alexander Dullenkopf, MD

1 From the Department of Anaesthesia, University Children’s Hospital, Zurich, Switzerland.

Address correspondence to: Dr. Markus Weiss, Department of Anaesthesia, University Children’s Hospital, Steinwiesstrasse 75, 8032 Zurich, Switzerland. Phone: +41-1-266-71-11; Fax: +41-1-266-79-94; E-mail: markus.weiss{at}kispi.unizh.ch

Purpose: To evaluate the effects of nitrous oxide on automated air tonometry in the clinical setting.

Material and methods: With approval of the Hospital Ethical Committee and after obtaining informed parental consent, an 8-F tonometry catheter was inserted orogastrically in ten children aged one to three years scheduled for elective surgery with combined regional and general anesthesia. A standardized general anesthesia technique with tracheal intubation was used in all patients and consisted of sevoflurane in oxygen/nitrous oxide (30%/70%; n = 5 patients) or in oxygen/air (FIO2 0.3; n = 5 patients). After obtaining steady state gastric CO2 values (PrCO2), fresh gas mixtures were rapidly changed from oxygen/nitrous oxide to oxygen/air (A) or vice versa (B). In addition, balloon pressures were recorded using a pressure transducer. Measurements were performed at intervals of ten minutes with recording of balloon pressures, end-tidal CO2 (PETCO2) and PrCO2 values. Pr-ETCO2-gap were calculated to eliminate influences of changes in PaCO2.

Results: Changing the fresh gas mixture from N2O/O2 to O2/air resulted in a decrease of balloon pressure of -10.4% (113.4 ± 14.7 mmHg to 101.6 ± 25.0 mmHg). Changing the fresh gas mixture from O2/air to N2O/O2 resulted in an increase of balloon pressures of 6.4% (107.6 ± 19.3 mmHg to 114.0 ± 20.3 mmHg). During both fresh gas exchange experiments no significant changes (> 0.2 kPa) in calculated Pr-ETCO2-gaps were observed.

Conclusions: Based on our in vivo data, nitrous oxide during general anesthesia can be used with automated air tonometry and does not affect air tonometric PrCO2 reading in clinical practice.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2003 by the Canadian Anesthesiologists' Society.