Sterilisation of anaesthetic equipment*

Abstract

During the last few years there have been many publications devoted to almost all aspects of cross-infection. Only a small proportion of these deal with anasthetic equipment and, in particular, little attention has been paid to masks, connecting pieces, corrugated tubing and the other parts of anzesthetic machines. In many hospitals little or no attempt is made to sterilise such equipment. We therefore decided to investigate the question of whether infection is likely to be spread by equipment of this type and if so, what steps should be taken to prevent this occurring. In this paper we describe our investigations and findings and also consider briefly the sterilisation of other apparatus used in inhalational anaesthesia. METHODS OF STERILISATION AND DISINFECTIONWhenever possible physical methods of sterilisation should be used rather than chemical methods because chemical methods are much less reliable and often fail to achieve sterility1.2. This does not mean that there is no place for the use of chemical disinfectants and antiseptics; for many purposes other than the sterilisation of instruments and equipment they are invaluable and indeed essential394. There are several reasons for preferring physical methods. Tubercle bacilli and bacterial spores are highly resistant to most chemical agents and Pseudornonas pyocyanea is relatively resistant to the quaternary am-* This article contains the substance of two separate papers read before the

A Critical Look at Chemical Disinfection of Anaesthetic Apparatus

“…Its use for disinfection of anaesthetic equipment has been described by Haselhuhn, Wells Brason and Borick (1967) and Meeks, Pembleton and Hench (1967). In both of these studies, contamination was Many of the studies on anaesthetic apparatus reported in the literature have relied on bacteriological swabbing to detect contamination, although a broth sampling method similar to that reported here was used by Jenkins andEdgar (1964), Stratford, Clark andDixson (1964), and Barrow and Meynell (1966). In the present study, swabbing alone would appear to have been ineffective in detecting contamination in a large number of cases.…”

“…DISCUSSION Joseph and Shay (1952) demonstrated high levels of contamination of breathing circuits with streptococci, and Gross (1955) and Rittenbury and Hench (1965) have shown contamination with a variety of pathogenic bacteria. Jenkins and Edgar (1964) showed that pathogens within a patient's respiratory tract readily contaminate anaesthetic equipment, and Henschel, Hollman and Just (1959) showed experimentally that bacteria in anaesthetic tubing could be transmitted to patients during anaesthesia. Shay and Joseph (1952) and Joseph and Shay (1952) have produced evidence which shows that infection may spread from one patient to another as a result of inadequately sterilized anaesthetic tubing.…”

“…This may be the result of the frequency with which residual pockets of air occur near the middle of lengths of corrugated tubing. Jenkins and Edgar (1964) suggested that it may be necessary to determine if disinfectant reaches all parts of equipment, and swabbing is unsuitable for this. It cannot be recommended as a method of sampling unless used in conjunction with a method such as broth extraction.…”

“…Both physical and chemical methods are available for the disinfection of anaesthetic tubing and reservoir bags, and there have been reports of disinfection of these items by immersion in a variety of disinfectants, including glutaraldehyde (Rittenbury and Hench, 1965;Ross, 1966;Meeks, Pembleton and Hench, 1967). Barrow and Meynell (1966) noted the difficulty in removing pockets of air from corrugated tubing, and Jenkins and Edgar (1964) and Williams and his colleagues (1966) were of the opinion that chemicals might fail to reach inaccessible areas of some types of equipment.…”

Postanaesthetic tracheal strictures in three rabbits

“…One text advises that PVC tubes may safely be re-used after cleaning and sterilizing (Clutton 1994). Residues such as formaldehyde (Keenleyside 1957), phenolic compounds, (Jenkins & Edgar 1964) and ethylene oxide (Scherer & Holtmann 1986) persisting on ETT have caused tracheitis in people. MedDis (Medichem International, Sevenoaks, Kent, UK) is used in veterinary and human medicine for disinfection of endoscopes and other instruments.…”