The Anesthesia Gas Machine

Michael P. Dosch PhD CRNA (retired)
University of Detroit Mercy - Nurse Anesthesia
This site is https://healthprofessions.udmercy.edu/academics/na/agm/index.htm.

Revised May 2025

Introduction

• About this site
  • Purpose
  • History of site
  • The author
  • Disclosures
  • Acknowledgments
• Other resources for learning
  • Internet resources
  • Resources in print

Purpose

The purpose of this site is to teach and illustrate the current anesthesia gas machine, and related topics such as vaporization. The site is intended to benefit students, nurse anesthetists (CRNAs), physicians in anesthesiology, or anyone with an interest in anesthesia equipment.

History of site

This site has been in existence since 2000, originating as lecture notes for a graduate course in nurse anesthesia at the University of Detroit Mercy. These documents are copyright Michael P Dosch. You may use them for any non-profit purpose.

The author

Michael Dosch PhD CRNA (retired) is Professor Emeritus of Nurse Anesthesia at the University of Detroit Mercy. His interests include anesthesia equipment, physics as related to monitors and equipment, and statistics. He has taught anesthesia equipment for 30 years, as well as spoken at professional conferences, written book chapters and published research on the topic.

Disclosures

• The author has no ongoing financial relationship with the manufacturers of any devices mentioned here.
• I do not discuss off-label or unapproved uses of drugs or devices.
• The clinical recommendations made here are based on clinical practice, consultation with published materials and colleagues, and published research. Like all such clinical recommendations, they should be subjected to local peer review before adoption in other clinical settings.

Acknowledgments

The author gratefully acknowledges the assistance of sales and technical representatives at Dräger Medical (Telford, PA) and GE Healthcare (Madison WI).

Finally, my sincere gratitude to the nurse anesthesia students, CRNAs and physician colleagues at the University of Detroit Mercy, and Corewell-Dearborn Hospital, who constantly challenge and inspire me.

Other resources for learning

Internet resources:

• Waste Anesthetic Gases 2018 (from AANA) is well-worth reading.
• How the circle breathing system works Don't let the cartoonish appearance fool you. This is an excellent description of why each component is present, & their interaction. Highly recommended.
• Good medicolegal information on equipment is relatively rare. A Patient injuries from anesthesia gas delivery equipment: a closed claims update is a good place to start. See also the current and past issues of the APSF (Anesthesia Patient Safety Foundation) Newsletter, which is a wealth of information.

Resources in print which are helpful

• Tharp D, Dosch MP. Anesthesia equipment. In: Elisha S, Heiner J, Nagelhout J, Eds. Nurse Anesthesia 7th ed, 2022. Many figures and tables, extensively illustrated and referenced.
• Venticinque and Andrews' chapter in Miller Anesthesia 8th ed. Well written and recommended.
• J. Dorsch & S. Dorsch. Understanding Anesthesia Equipment 5th ed 2008: Williams & Wilkins. It's the Brittanica in the field. A must for anyone with a serious interest (or purchasing responsibilities).
• Ehrenwerth & Eisenkraft. Anesthesia Equipment. 2013, 2nd ed. Well written. The chapters on vaporization and electrical safety are the clearest writing on these thorny topics in print. A very worthwhile reference.