Post-infectious bronchiolitis obliterans (PIBO) is a respiratory disease characterised by obstruction of the small airways. This obstruction limits the exercise capacity and reduces the quality of life of affected children. Two children with PIBO who were 10 and 14 years of age and both oxygen-dependent are presented. Both children underwent heart rate variability (HRV) measurements, revealing an increase in the LFnu and the LF/HF ratio and demonstrating a predominant effect on the sympathetic system. The functional capacity was assessed by a six-minute walking test (6MWT), and the distance travelled was lower than the reference values. Spirometry revealed advanced obstructive ventilatory limitation in both cases. The HRV measurements are consistent with the decrease in physical fitness in these children and indicate the need for further studies on HRV in this pathology.
Evaluation of the heart rate variability (HRV) was performed with a portable Polar RS800 heart rate monitor (Polar Electro OY, Kempele, Finland) with the patient in a supine position for 15 minutes. During the recording, both patients were resting in a quiet environment. The first 5 minutes were used to normalise the parameters, and the next 10 minutes were considered for the analysis. The data were analysed using the HRV Analysis software 1.1 (Biomedical Signal Analysis Group, Department of Applied Physics, University of Kuopio, Finland).