WS19.6 N 2 -MBW in CF patients with chronic lung bacterial colonizations

Background: Over the last decade multiple breath washout technique (MBW) has been widely used in cystic fibrosis (CF) to study early pulmonary changes due to pulmonary inflammation and infection. Objectives: We want to find out whether MBW was able to detect earlier than spirometry the progressive lung injury due to bacterial colonization. Moreover we want to assess the effects of A. Xilosoxidans or S. Maltophilia colonizations on CF patients’ lung function Methods: Forced expiratory volume in 1 second (FEV1) and lung clearance index (LCI) derived from N2-Multiple Breath Wash Out (N2-MBW, Exhalyzer D, Ecomedix) were recorded in 85 children with CF. Patients were divided in 3 groups: P. Aeruginosa (PA) colonized patients (32 children), A. Xilosoxidans or S. Maltophilia colonized patients (13 children), negative or intermittent MS S. Aureus or H. Parainfluenzae positive sputum (40 patients). Results: 85 CF patients (mean age 10.4 yrs, range 4.9–18.6) were tested. Mean LCI of PA colonized patients was 10.86 and was significantly higher (P < 0.0001) than mean LCI of non-colonized group (8.52). Basal FEV1 was no statistically different between the 2 groups. Mean LCI of A. Xilosoxidans or S. Maltophilia colonized patients was 12.91 and was significantly higher (P < 0.001) than mean LCI of non-colonized group. In this group mean FEV1 was significantly lower (P = 0.003) than mean FEV1 of non-colonized group. Conclusions: Our data showed that LCI could be more sensitive than FEV1 in detecting pulmonary changes due to chronic PA colonization. Studieswith a larger number of patients are needed, but from our preliminary data we can suggest that A. Xilosoxidans and S. Maltophilia seem to cause more severe lung damage than other infections. Given these facts it might be appropriate to start treatment even in asymptomatic patients in the attempt to prevent pulmonary damage.