Contamination of Anaesthetic Tubing – a Real Hazard?

Abstract

This study aimed to find whether a patient placed on an anaesthetic machine could contaminate the tubing resulting in possible cross-infection to subsequent patients. Twenty randomly chosen anaesthetic circuits were collected after use during operations and cultured for bacteria and fungi. These were compared with ten circuits which had been washed and dried. Another ten washed circuits were attached to an anaesthetic machine and each circulated with air for four hours before similar cultures were performed. No accepted respiratory pathogens were found contaminating the tubing in any of the above situations. Cleaned circuits purposely seeded with either ‘viridans streptococci’ or staphylococcal bacteriophage were attached to an anaesthetic machine, the other end being held over an air sampler to collect organisms which might be blown out. Seeded tubing did not contaminate the air passing through it, demonstrating that dry anaesthetic gases do not facilitate pick-up and carriage of microorganisms.

The bacterial and viral filtration performance of breathing system filters*

“…Microbes expelled by a patient which do pass through a breathing system filter will attach to the walls of the breathing system. Ibrahim and Perceval [26] demonstrated that air passing through breathing system tubing ‘seeded’ with microbes did not become contaminated. Nielsen and colleagues measured a mean bacterial count of 0.385 l −1 (range 0.033–1.298 l −1 ) in a 50% oxygen in nitrous oxide mixture delivered through a ‘seeded’ breathing system [27].…”

Infektionsprävention bei der Narkosebeatmung durch Einsatz von Atemsystemfiltern

“…[3,4,5,6]. Nach Inhalationsnarkosen ohne ASF betrug die Kontaminationsrate von Narkoseschlauch-und Atemsystem 8-13% [7,8,9,10], darunter jedoch nur selten lungenpathogene Erreger [9]. Das virale Übertragungsrisiko wird als vergleichsweise gering eingeschätzt [1,2].…”

Infection prevention during anaesthesia ventilation by the use of breathing system filters (BSF): Joint recommendation by German Society of Hospital Hygiene (DGKH) and German Society for Anaesthesiology and Intensive Care (DGAI)

“…After use on the patient, all breathing gas conducting parts of the anaesthetic system can therefore be contaminated with pathogens, with the greatest levels of contamination being detectable close to the patient [10], [11], [12], [13]. After inhalation anaesthesia without BSF, the contamination rate of the anaesthesia breathing system and circle system amounted to 8–13% [14], [15], [16], [17], however, showing pulmonary pathogens only rarely enter the breathing system [16]. The risk of viral transmission is considered to be comparatively low [1], [2].…”