Related Experiment Videos
Infant respiratory function after RSV-proven bronchiolitis
C Dezateux1, M E Fletcher, I Dundas
1Department of Epidemiology and Biostatistics, Institute of Child Health, London, United Kingdom. C.Dezateux@ich.ucl.ac.uk
Insights
Infant bronchiolitis recovery shows normal lung function, unlike previous findings. Respiratory rate and expiratory time were slightly altered, suggesting a better prognosis for infant lung health post-illness.
Area of Science:
- Pediatric Respiratory Medicine
- Infant Health
- Pulmonology
Background:
- Acute bronchiolitis in infancy is linked to increased wheezing risk in early childhood.
- Previous studies on infant respiratory function post-bronchiolitis lack concurrent comparison groups, limiting interpretation.
- Mechanisms behind post-bronchiolitis wheezing risk remain unclear.
Purpose of the Study:
- To compare respiratory function in infants after acute bronchiolitis with healthy controls.
- To investigate potential subclinical alterations in airway function following bronchiolitis.
- To assess the long-term lung function prognosis after infant bronchiolitis.
Main Methods:
- Comparison of respiratory function (FRC, Raw, compliance, respiratory rate, tPTEF:tE) between 29 infants post-bronchiolitis and 29 matched controls.
- Measurements taken at a median of 36 weeks post-hospitalization for index infants.
- Recruitment of infants from an inner London hospital and local general practices.
Main Results:
- No significant differences in functional residual capacity (FRC), airway resistance (Raw), or respiratory system compliance.
- Significantly diminished respiratory rate and prolonged time to peak tidal flow relative to expiratory time (tPTEF:tE) in index infants.
- 55% of index infants experienced subsequent wheezing by the follow-up interval.
Conclusions:
- Infant lung function prognosis after acute bronchiolitis may be better than previously suggested.
- Subtle alterations in respiratory rate and expiratory timing observed post-bronchiolitis.
- Longitudinal studies are recommended to determine if subclinical airway changes precede acute bronchiolitis.
Abstract:
The mechanisms underlying the increased risk of wheezing in early childhood following acute bronchiolitis in infancy remain unclear. Previous studies have reported significant abnormalities in infant respiratory function after clinical recovery from bronchiolitis, but are difficult to interpret because of the frequent omission of a concurrent comparison group. Respiratory function was compared within pairs of previously healthy full-term caucasian infants admitted with a first episode of acute bronchiolitis to an inner London hospital, and age- and sex-matched control infants without prior wheezing, asthma, or lower respiratory illness who were recruited from local general practices. Respiratory function was measured in 29 control and 29 asymptomatic index infants, with measurements in the latter done at a median interval of 36 wk (range: 16 to 49 wk) after admission, when 16 (55%) had experienced subsequent wheezing. Index infants tended to be autumn-born and of shorter gestation than control infants, to have younger mothers, and to have been exposed to tobacco smoke. There were no statistically significant differences in plethysmographic FRC, initial inspiratory airway resistance (Raw), or respiratory system compliance (mean [index minus control] within-pair difference [95% confidence interval]: -11 ml [-29, 7 ml]; -0.2 kPa/L/s [-0.7, 0.4 kPa/L/s]; -8 ml/kPa [-21, 4 ml/kPa], respectively), but respiratory rate and time to peak tidal flow as a proportion of total expiratory time (tPTEF:tE) were significantly diminished in index as compared with control infants (-4.0 breaths/min [-7.6, -0.4 breaths/min], versus -0.035 [-0.066, -0.005], respectively). These findings suggest a better prognosis for infant lung function after acute bronchiolitis than reported previously. Longitudinal studies are needed to clarify whether subclinical alterations in airway function precede acute bronchiolitis.