Bacterial contamination of the anesthesia breathing machine: effectiveness of current infection control measures

Background Bacterial contamination of anesthesia breathing machines and its potential hazard for anesthetized patients have been a concern for many decades. Bacterial filters are effective in preventing breathing circuit contamination but clear recommendations about their use are lacking. The objective of this study is to verify whether the current infection control standards for the operating theater at our institution are effective in preventing contamination of the anesthesia breathing machine. Materials and methods For 5 consecutive days, samples were collected from both the inspiratory and expiratory ports of two anesthesia breathing machines. Samples were incubated and followed up for identification of any microorganism. Results A total of 20 samples were collected, and no bacterial growth was observed. Conclusion In this study both the inspiratory and expiratory ports of the anesthesia machine remained sterile when using the Air-Guard Clear (Intersurgical®) in the expiratory port of the breathing circuit, together with a disposable HME filter for each patient. We conclude that the current infection control protocol is effective in preventing bacterial contamination of the anesthesia breathing machine. Despite Intersurgical® only warrantees filter efficacy over 24h, the filter appears to be effective for 5 days. This increased interval in filter change allows the hospital an estimated annual saving of 4.442€. Clear national and international guidelines about breathing circuit management are lacking and regulatory policies would be most welcome. Introdução A contaminação bacteriana dos ventiladores de anestesia e o potencial risco para doentes anestesiados tem sido uma preocupação há muitas décadas. Os filtros bacterianos são eficazes na prevenção da contaminação do circuito respiratório, mas faltam claras recomendações sobre a sua utilização. O objetivo deste estudo é verificar se as normas de controlo de infeção para o bloco operatório da nossa instituição são eficazes na prevenção da contaminação do ventilador anestésico. Material e métodos Durante 5 dias consecutivos, foram colhidas amostras das portas inspiratória e expiratória de dois ventiladores de anestesia. As amostras foram incubadas e observadas para identificação de microrganismos. Resultados Um total de 20 amostras foram colhidas e não foi observado crescimento bacteriano. Conclusão Neste estudo, tanto a porta inspiratória como a porta expiratória do ventilador de anestesia p