[Efficacy of an antibacterial filter for preventing contamination of respiratory function diagnostic equipment]

Devices to assess lung function are a potential source of nosocomial infection. Our aims in this study were: 1) to determine the efficacy of an antimicrobial filter to prevent contamination of a multifunctional device; 2) to assess the ability of the filter to prevent cross contamination of individuals being tested; and 3) to evaluate the efficacy of the recommendations of the Spanish Society of Respiratory Diseases and Thoracic Surgery for disinfecting lung function equipment.

In this prospective, randomized study in two phases we used filters in phase 1 but not in phase 2. A pharyngeal swab culture was started within 7 days of a patient's lung function test. Swab samples for culturing were taken from three different places in the equipment at the beginning and end of each working day.

Sixty-five patients (31 in phase 1 and 34 in phase 2) were studied. Thirty-two (49.2%) were men and the mean age was 49.4 15.7 years.

Significantly less equipment contamination was found in phase 1 (4.2%) than in phase 2 (21%). We detected no cases of cross contamination using the criteria in this study. No cultures from any of the samples taken before exploration were positive.

a) The antimicrobial filter used is effective for preventing the contamination of lung function testing equipment, b) throughout both phases of the study, we observed no cross contamination of patients tested, such that we cannot conclude that the antimicrobial filter is effective for preventing possible nosocomial infections, c) the recommendations of SEPAR for disinfecting lung function equipment are effective.