@article {RaymentPA2638, author = {Jonathan Rayment and Rodrigo Sandoval and Juliana Roden and Mark Chilvers and Kirk Schultz}, title = {Multiple breath washout testing after paediatric blood and marrow transplantation}, volume = {54}, number = {suppl 63}, elocation-id = {PA2638}, year = {2019}, doi = {10.1183/13993003.congress-2019.PA2638}, publisher = {European Respiratory Society}, abstract = {Background: Pulmonary chronic graft versus host disease (cGvHD) occurs in 5-10\% of children after blood and marrow transplantation (BMT). Early disease is likely more responsive to treatment1. In older children and adults, multiple breath washout (MBW) testing is often abnormal after BMT2,3, suggesting a potential role in early disease detection.Objective: To assess lung function after BMT using MBW and spirometry in children as young as 3 years.Methods: Cross sectional analysis of children age 3 to 18 years, between 100 days and 5 years after allogenic BMT. All children attempted nitrogen MBW on the Exhalyzer D (EcoMedics). Children age 6 and over attempted spirometry.Preliminary Results: 44 children were eligible; 15 were tested to date. Median age was 11.9 years. 11/15 performed MBW and spirometry (Fig 1A); 4/15 performed MBW alone (Fig 1B). Median lung clearance index (LCI) was 7.5 (IQR 7.1, 8.0; 8/15 [53\%] greater than 7.5). Median FEV1/FVC was 86\% (IQR 82, 90); 1/11 [9\%] less than 70\%).Discussion: MBW is feasible in young children after BMT. LCI is abnormal in a significant proportion of children studied, despite normal spirometry, suggesting occult pulmonary dysfunction in this population. These data support the need for a longitudinal study to investigate the utility of this technique to monitor pulmonary function following BMT.References:1. A Holbro Biol BMT. 2013;192. S Nyilas Chest. 2018;1543. HH Uhlving Ped Pulm. 2015;50FootnotesCite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA2638.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/54/suppl_63/PA2638}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }