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Recovery of FEV1 after histamine challenge in asthmatic children
Insights
The time for children with asthma to recover their FEV1 after a histamine challenge primarily depends on the provocation dose (PD20). A second histamine challenge confirms reproducible PD20 values, crucial for accurate asthma testing.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Allergy and Immunology
Background:
- Asthma management requires accurate assessment of bronchial hyperresponsiveness.
- Histamine challenge tests are used to evaluate airway reactivity in asthmatic children.
- Understanding recovery time after histamine challenge is critical for test interpretation.
Purpose of the Study:
- To identify factors influencing FEV1 recovery time after histamine inhalation in children with asthma.
- To assess the reproducibility of PD20-histamine values after a second challenge.
- To establish guidelines for performing subsequent tests post-challenge.
Main Methods:
- Analysis of 45 children with asthma undergoing histamine challenge.
- Measurement of baseline FEV1, histamine provocation dose (PD20), and FEV1 fall.
- Evaluation of recovery time and reproducibility of PD20 after a second challenge.
Main Results:
- Recovery time varied widely (15-75+ minutes) and was mainly determined by the PD20 value.
- Initial bronchial obstruction and FEV1 fall did not significantly correlate with recovery time.
- A second histamine challenge yielded highly reproducible PD20 values.
Conclusions:
- PD20 is the primary determinant of FEV1 recovery time post-histamine challenge in asthmatic children.
- Histamine challenge reproducibility supports its use in clinical practice.
- Subsequent pulmonary function tests should only be conducted when FEV1 returns to 95% of baseline.
Abstract:
Factors that influence the time necessary for complete recovery of FEV1 after inhaling histamine were analysed in forty-five children with asthma. These included the initial bronchial obstruction (baseline FEV1), the provocation dose of histamine producing a 20% fall in FEV1 (PD20) and the fall in FEV1 after the histamine challenge. In addition it was also investigated whether a second challenge carried out after complete recovery of FEV1 would produce a reproducible PD20-histamine value. The time for complete recovery varied widely from 15 to more than 75 min. The time needed for complete recovery of FEV1 after the histamine challenge seems to be mainly determined by the PD20 value. The other factors such as initial bronchial obstruction and the fall in FEV1 after the challenge showed no significant relationship with the recovery time. A second challenge with histamine resulted in a highly reproducible PD20 value. The clinical implication of this study is that other tests can only be performed when FEV1 has returned to 95% of baseline.