Anaesthetic breathing circuits

doi:10.1017/CBO9780511544644.007

5 - Anaesthetic breathing circuits

Published online by Cambridge University Press: 13 August 2009

Edited by

Paul Wicker and

Brian Smith: Affiliation:
Edge Hill College of Higher Education, Liverpool
Paul Rawling: Affiliation:
Edge Hill College of Higher Education, Liverpool
Paul Wicker: Affiliation:
Edge Hill College of Higher Education, Liverpool
Chris Jones: Affiliation:
Edge Hill College of Higher Education, Liverpool

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Summary

Key learning points

Discuss the basic design of breathing circuits
Describe the evolution of breathing circuits
Identify the benefits and disadvantages of each circuit

An anaesthetic breathing circuit is an assembly of parts, which connects the patient's airway to the anaesthetic machine creating an artificial atmosphere, from and into which a patient breathes (Ravi Shankar, 2004).

Shankar also states that a breathing circuit mostly consists of:

a tube through which fresh anaesthetic gases are delivered from the anaesthetic machine to the patient
a method of connecting the circuit to the patient's airway
a rebreathing bag or corrugated rubber tubing (used in the early circuits) which acts as a gas reservoir, which would meet the peak inspiratory flow requirements
an expiratory valve which allows the expired gases to pass into the scavenging circuit
a carbon dioxide absorber for total rebreathing, and tubing to connect all the parts; as stated earlier in the early stages the tubing was composed of corrugated rubber. (Ravi Shankar, 2004).

Even though the design and materials used for breathing circuits have developed over the years, the individual component's roles have remained almost unchanged.

Since introducing ether as an anaesthetic in 1846, many improvements in the design of breathing circuits have occurred. Initially, inventors developed apparatus to deliver a single anaesthetic agent, such as nitrous oxide. Nitrous oxide fell from favour as a single-agent anaesthetic but was reintroduced in 1868, stored in cylinders, as part of a combination of anaesthetic agents.

Type: Chapter
Information: Core Topics in Operating Department Practice
Anaesthesia and Critical Care
, pp. 35 - 44

DOI: https://doi.org/10.1017/CBO9780511544644.007 [Opens in a new window]

Publisher: Cambridge University Press

Print publication year: 2007

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References

Anaesthesia UK (2005) is available at www.frca.co.uk.

Gwinnutt, C. (1996). Clinical Anaesthesia. Oxford: Blackwell Science Ltd.

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Online Medical Dictionary. (1997). Available at: http://cancerweb.ncl.ac.uk/omd/index.html (Accessed March 2006).

Ravi Shankar, M. (2004). Anaesthetic Breathing Systems. Available at: www.capnography.com/Circuits/Breathingsys/ravi.htm (Accessed January 2005).

Aitkenhead, A. R., Rowbotham, D. J. & Smith, G. (2001). Textbook of Anaesthesia, 4th edn. London: Elsevier Science Ltd.

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Davey, A. & Ince, C. (2000). Fundamentals of Operating Department Practice. London: Greenwich Medical Media Ltd.

Kumar, B. (1998). Working in the Operating Department. New York: Churchill Livingstone.

Robson, N. (2004). Anaesthesia Breathing Systems. Available at: www.usyd.edu.au/su/anaes/lectures/breathing-sys-nr.html (Accessed February 2005).