MULTIPLE BREATH WASHOUT FEASIBILITY IN PRESCHOOL CHILDREN WITHIN A BUSY CYSTIC FIBROSIS CLINIC

Abstract

Introduction/Aim: Multiple breath washout (MBW) detects early lung disease in patients with cystic fibrosis. Success of implementation within CF clinics remains unclear with reports of low feasibility. In our tertiary CF clinic (n ≈ 480 children), we introduced MBW aiming to achieve technically acceptable Lung Clearance Index (LCI) values at least annually in preschool children (3-6 years). This study aimed to assess the feasibility of performing MBW during CF clinic visits over a 12-month period. Method: Retrospective analysis of MBW performed in CF children aged 3-6 years between September 2023-24 was conducted. Eligible patients were pre-identified as standard practice. MBW was performed using the Exhalyzer D (EcoMedics AG, Spiroware v3.3.2) with two operators for facemask interface, and one for mouthpiece testing. Acceptability was defined by preschool standards1, and LCI reported as the mean of ≥2 technically acceptable trials. Testing duration was recorded from start to end of data collection. LCI abnormality was defined using preschool and equipment-specific healthy control data (unpublished). Results: Tests (n = 95) were completed in 67 CF patients: mean (SD) age 4.9 (1.2) years (48% female). 33% (22/67) were MBW-naïve, and 36% (24/67) were tested on >1 occasion (range 2-3). The mean (range) number of patients tested per clinic was 0.7 (0-4) (140 clinic days). Acceptable tests were achieved on 94% (89/95) of occasions, 75% using facemask interface. Mean (SD) LCI was 7.4 (1.1), 55% (49/89) showing abnormal results. Mean (range) number of trials attempted and deemed acceptable per test was 5.7 (2-15) and 2.8 (0-5), respectively. Mean (SD) test duration was 21.5 (10.5) minutes. MBW was performed on 67 of 93 (72%) eligible children. Conclusion: Annual MBW testing in preschool children during routine CF clinics was feasible. When LCI abnormalities were present, they were generally mild. Future efforts will focus on identifying barriers to testing eligible patients and improving screening success.