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Diurnal rhythms in airway obstruction
British Journal of Diseases of the Chest
|October 1, 1979
Summary
Diurnal variation in peak expiratory flow rate shows distinct patterns in airway obstruction. Bronchodilators can reduce these patterns, but do not eliminate them, impacting asthma and bronchitis management.
Area of Science:
- Pulmonary Medicine
- Respiratory Physiology
Background:
- Diurnal variation in respiratory function is significant in airway obstruction.
- Understanding these patterns aids in disease management and treatment efficacy assessment.
Purpose of the Study:
- To investigate diurnal patterns of peak expiratory flow rate (PEFR) in patients with various airway obstructions.
- To differentiate PEFR patterns between asthma and bronchitis.
- To assess the impact of bronchodilators and corticosteroids on these patterns.
Main Methods:
- Patients with airway obstruction were monitored for diurnal PEFR variations.
- Patterns were classified as morning dip (M) or double dip (P).
- Effects of bronchodilators and corticosteroids on PEFR patterns and amplitude were analyzed.
Main Results:
- Regular diurnal PEFR patterns (M and P) were observed, most frequently in asthma and bronchitis with wheeze.
- Bronchodilators reduced the prevalence of regular patterns but did not abolish them.
- The M pattern is characteristic of asthma, while the P pattern is more common in bronchitis.
- Asthmatics exhibit greater PEFR variation amplitude than those with simple bronchitis, reduced by ~20% with bronchodilators.
- Corticosteroids showed no significant influence on PEFR patterns or amplitude.
Conclusions:
- Diurnal PEFR patterns are prevalent in airway obstruction and differ between asthma and bronchitis.
- Bronchodilators can modulate but not eliminate these variations.
- Assessing PEFR variation requires consideration of diurnal patterns, as random measurements may underestimate the true amplitude.