Peripheral airway abnormalities are common in children post bone marrow transplantation

Abstract

Aim: Pulmonary complications are common following Bone Marrow Transplantation (BMT) but peripheral airway involvement may be underestimated by conventional lung function measures, such as spirometry. This study aimed to characterize peripheral airway function in children post BMT using Multiple Breath Washout (MBW) in comparison to standard lung function.

Methods: Cross sectional study of children following BMT at a single tertiary centre. Inclusion criteria included age ≥3 years, allogenoeic BMT, similar conditioning regimens and stability at the time of testing. Assessment included MBW (performed using simultaneous inert gas washout with SF₆ and Helium) and conventional lung function. Non-parametric data displayed as median (range).

Results: 24 subjects have been recruited to date: 16 (67%) male, age 14.3 (4.3-18.6) years, tested at 4.8 (0.7-12.1) years post BMT. Spirometry was feasible in 15/24 (63%) of the cohort, with abnormal values present in 5/24 (21%) for FEV₁ and 4/15 (17%) for FEF_25-75. MBW was feasible in all subjects. Abnormal MBW parameters were observed in a greater proportion (18/24, 75%) vs. either FEV₁ or FEF_25-75 (p<0.05). The proportion with abnormality in SF₆ MBW indices was greatest with S_cond (0.034 (0.004-0.089), Upper limit of normal (ULN) 0.023, abnormal in 18/24, (75%) followed by LCI (7.52 (5.03-23.59), ULN 7.35, abnormal in 14/24, 58%) and S_acin (0.105 (0.056-0.463), ULN 0.121, abnormal in 8/24, 33%).

Conclusion: MBW offered improved feasibility, compared to spirometry, for lung function assessment. Peripheral airway involvement was present in the majority of the cohort, and was underappreciated by spirometry.