Abstract
Introduction
Objective physiological data are technically difficult to obtain in acute bronchiolitis (AB). Hence, severity assessment relies on subjective parameters. We aimed to 1. Test feasibility of tidal breathing (TB), exhaled nitric oxide (eNO) and multiple breath washout (MBW) measurements during natural sleep in infants with AB; 2. Compare these measures to healthy controls (HC); and 3. Assess effect of convalescence on lung function.
Methods
Infants aged 1-12 months with AB and HC underwent LFT via facemask and ultrasonic flow meter (Ecomedics, Switzerland). MBW with sulfur hexafluoride (SF6) served to obtain lung clearance index (LCI). AB babies were invited to repeat LFT following convalescence.
Results
29 AB infants and 23 HC were recruited. Mean age (SD): 2.9 months (2.1) for AB and 4.2 (2.5) for HC (p=0.07).
AB: Valid TB measurements were obtained in 19/29 (66%). 15 out of 19 (79%) achieved ≥2 valid MBW measurements with CV≤10%. The high failure rate was due to waking up during facemask application or irregular respiratory pattern. HC: 22/23 (97%) achieved valid TB measurements, 19 out of 22 (86%) achieved ≥2 valid MBW measurements with CV≤10%.
Mean tidal volume (SD) was 7.4 (2.1) ml/kg for AB and 9.1 (1.3) for HC (p=0.003). ENO was 2.26 (2.7) ppb in AB and 7.9 (6.9) ppb in HC (p=0.004); LCI was 8.4 (0.8) and 7.3 (0.7) (p<0.001) respectively.
In 5 AB infants, who returned after mean 4 months, eNO rose from 3.6 (4.6) ppb to 8.4 (8.3) (p=0.26) and LCI fell from 8.3 (0.9) to 7.4 (0.7) (p=0.08).
Conclusion
LCI measurements in AB are feasible although technically challenging. LCI was significantly raised in AB compared to HC and can potentially serve as objective severity measure.
- © 2014 ERS