Exhaled air temperature in children with bronchopulmonary dysplasia

Background Because they have similar functional and clinical profiles, bronchopulmonary dysplasia (BPD) survivors are often treated as asthmatic patients. In truth, very little is known about the possible biochemical and inflammatory mechanisms playing a part in BPD survivors' lungs. The aim of this study was to measure exhaled breath temperature in BPD survivors by comparison with asthmatic cases and healthy controls. Methods Three groups of age-matched adolescents (n = 17 each), that is, BPD survivors (gestational ages <31 weeks, birth weights <1,500 g), asthmatic subjects and healthy controls, underwent exhaled breath temperature and exhaled nitric oxide measurements, and spirometry. Results Exhaled breath temperature was significantly lower in the BPD survivors (26.72°C [25.11–27.57]) than in the asthmatic patients (29.60°C [29.20–30.02], P < 0.001), while no significant difference emerged by comparison with healthy controls (26.97°C [26.58–27.38]). Considering the whole study population, a significant correlation was found between exhaled breath temperatures and exhaled nitric oxide concentrations (R = 0.42, P = 0.004). Spirometry revealed an obstructive lung function pattern in both the asthmatic cases and the BPD survivors, with lower parameters in the latter. Conclusions Exhaled breath temperatures and exhaled nitric oxide concentrations are significantly lower in BPD survivors than in asthmatic cases, suggesting that different pathogenetic mechanisms characterize these two chronic obstructive lung diseases. Pediatr Pulmonol. 2010;45:1240–1245. © 2010 Wiley-Liss, Inc.