Bacterial filters in anesthesia: Results of 9 years of surveillance

In 9 years of surveillance of postoperative lower respiratory infections, t he infection rate in patients following regional anesthesia was 0.2% and 0. 1% in patients following general anesthesia. No bacterial filters in the br eathing circuit were used. Infected patients had risk factors such as type of surgery, American Society of Anesthesiologists class greater than or equ al to 2, old age, chronic obstructive pulmonary disease, or smoking habits. Infections were not clustered. This suggests that, in our setting, patient factors are most important in the development of postoperative lower respi ratory infections and that the role of bacterial filters as a preventive me asure is negligible.