Functional capacity assessment in children and adolescents with post-infectious bronchiolitis obliterans

To assess functional capacity during exercise in children and adolescents with post-infectious bronchiolitis obliterans (PIBO).

20 children with PIBO, aged 8-16 years old, and in follow-up at an outpatient clinic carried out cardiopulmonary exercise testing (CPET), a 6-minute walk test (6MWT) and pulmonary function tests (PFT), according to American Thoracic Society (ATS), European Respiratory Society (ERS) and American College of Chest Physicians (ACCP) guidelines. Results were expressed as percentages of predicted reference values: Armstrong's for CPET, Geiger's for 6MWT, Knudson's for spirometry, and Zapletal's for plethysmography.

Mean age (+/- SD) was 11.4+/-2.2 years; 70% were boys; mean weight: 36.8+/-12.3 kg; mean height: 143.8+/-15.2 cm. When compared to reference values, PFT detected lower airflows (spirometry) and higher volumes (plethysmography). Eleven patients had reduced peak VO2 values in CPET (< 84% predicted). The mean distance walked (6MWT) was 77.0+/-15.7% of predicted (512+/-102 m). Peak VO2 was not correlated with 6MWT, but it was correlated with FVC (L) (r = 0.90/p = 0.00), with FEV1 (L) (r = 0.86/p = 0.00) and with RV/TLC, both in absolute values (r = -0.71/p = 0.02) and as percentages of predicted values (r = -0.63/p = 0.00).

The majority of these post-infectious bronchiolitis obliterans patients exhibited reduced functional capacity, exhibited during both CPET and the 6MWT. Due to its greater feasibility, 6MWT could be an alternative where CPET is not available.