PubMed HealthSearch

PubMed · 8179170

[Low flow anesthesia].

Abstract

It is a strange contradiction that increasingly sophisticated anaesthesia machines are developed meeting all requirements for rebreathing techniques and the highest safety standards, but the usual anaesthetic management is still based on the use of fresh gas flows that preclude substantial rebreathing. The advantages of rebreathing can only be realised if low-flow anesthesia techniques are adopted. Increasing acceptance of these methods is due to the availability of comprehensive anaesthetic gas monitoring. Different techniques of low-flow anaesthesia, the characteristic features, technical requirements, and considerations concerning their performance and contraindications are discussed. This paper presents a topic that is left unmentioned by most anaesthesia textbooks. The use of new inhalational anaesthetics such as desflurane that require comparatively high concentrations, or even xenon, will motivate to sparing use. Increasingly stringent health and safety regulations as well as sharpened ecological awareness will prompt anaesthetists to minimise all anaesthetic gas emission according to the possibilities of available equipment. Last but not least, the demand for economical working methods will be an argument for applying low-flow anaesthesia techniques.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J Baum. 1994. [Low flow anesthesia].. https://doi.org/10.1007/s001010050049

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The anesthesia machine valve tester: a new device and method for evaluating the competence of unidirectional anesthetic valves.

OBJECTIVE: Current methods of determining anesthesia machine unidirectional valve (UDV) competence are time-consuming, ineffective, or carry the risk of transmitting infectious disease to the anesthetist or patient. New methods of testing these valves are needed. The purpose of this study was to determine the prevalence of incompetent UDVs at one institution by employing the Anesthesia Machine Valve Tester (AMVT), a new way to test anesthesia machine UDVs. METHODS: We tested each expiratory and inspiratory UDV on all anesthesia machines in functioning operating rooms at the Brigham and Women's Hospital. If a UDV was found to be incompetent, we cleaned and reseated it, and then tested it again with the AMVT. RESULTS: We found a 13% prevalence of UDV malfunction in our machines. Three of the 10 incompetent valves were repaired quickly by us and were made competent by either reseating the valve or by first cleaning and then reseating it. CONCLUSIONS: We found that the AMVT was able to detect UDV failure quickly with no risk to the tester or to the patient. We conclude that the AMVT can be used to check the UDV as recommended by the FDA anesthesia machine check-out protocol.

Anesthesia, Closed-Circuit

Oxygen flow through nasal cannulae.

PURPOSE: Since many operating theatres do not have distinct oxygen flowmeters, flow rates of oxygen were measured via nasal prongs at several settings and attachments to three anaesthetic machines. METHODS: Oxygen-flow rates were measured using a Timeter RT-200 Calibration Analyzer at three, five and eight L.min-1 via nasal prongs attached to a distinct flowmeter, the common gas outlet (CGO) and the Y-piece of a circle system with the adjustable pressure release (APL) valve closed, open and partially open at circuit pressures of 10 and 20 cm H2O. RESULTS: The most accurate delivery of oxygen from a distinct flowmeter and the CGO (mean difference 0.2 +/- 0.2 and 0.4 +/- 0.4 respectively). Differences between the flowmeter and CGO were not significant (P = 0.1). Accuracy of flows via the Y-piece were worse than via the flowmeter and CGO (P < 0.0001). Flows via the Y-piece were less than those dialed, especially at high rates. With a partially open APL valve, flow depended upon pressure in the anaesthetic circuit, not upon the flow set. With the APL valve completely open, no flow occurred. CONCLUSIONS: To deliver supplemental oxygen in the operating theatre when there are no distinct flowmeters, nasal prongs should be attached to the CGO of the anaesthetic machine or a flowmeter on a portable E-tank oxygen cylinder. Connecting nasal prongs to the Y-piece of a circle system should be avoided since oxygen delivery is less than dialed, especially when the APL valve is open.

Anesthesia, Closed-Circuit