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Peak flow variability in wheezy children aged 9-11 was studied. Daily peak flow diary recordings showed lower variability than in adult asthmatics, suggesting limited value for diagnosing asthma in children.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Asthma diagnosis in children relies on identifying variable airflow obstruction.
- Peak expiratory flow (PEF) variability is a key indicator of asthma severity and control.
- Previous studies on PEF variability primarily focused on adult asthmatic populations.
Purpose of the Study:
- To assess peak flow variability in a population sample of wheezy children.
- To compare PEF variability in children with previously reported data in adults.
- To evaluate the utility of peak flow diaries in demonstrating airflow obstruction in pediatric asthma.
Main Methods:
- A 12-day peak flow diary study was conducted in 63 wheezy children (aged 9-11 years).
- PEF recordings were taken three times daily: morning, after school, and bedtime.
- Cosinor analysis was used to determine daily rhythm and amplitude of PEF variability.
Main Results:
- 89% of children experienced symptoms during the study period.
- Mean daily PEF amplitude was 17% of the mean daily value (range 4-48%), with cosinor analysis showing 12% (range 1-53%).
- The lowest point of the daily rhythm occurred between midnight and 8 am in 65% of children, but was statistically significant in only 22%.
Conclusions:
- PEF variability in these wheezy children was lower than previously reported in adult asthmatics.
- A peak flow diary alone may have limited value in demonstrating the variable airflow obstruction characteristic of childhood asthma.
- Further research may be needed to establish optimal methods for assessing airflow obstruction in pediatric asthma.
Abstract:
A study of peak flow variability was carried out among a population sample of 63 wheezy children aged 9-11 years. Recordings were made over 12 days at three times during the day--first thing in the morning, on returning home from school and at bedtime. Eighty nine per cent of the children had symptoms during the diary period. The mean amplitude (difference between the highest and lowest daily peak flow values) was 17% of the mean daily value (range 4-48%). By cosinor analysis the amplitude was 12% of the mean value (range 1-53%). In 65% of the children the lowest point of the daily rhythm as determined by cosinor analysis lay between midnight and 8am; the rhythm was, however, statistically significant in only fourteen individuals (22%). These levels of variability are considerably lower than those previously reported in hospital based studies of adult asthmatics. As a method of demonstrating variable airflow obstruction, which is the defining physiological characteristic of asthma, the use of a peak flow diary alone appears to be of limited value in children.