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Forced oscillation technique and maximum expiratory flows in bronchial provocation tests in children
European Journal of Respiratory Diseases
|October 1, 1984
Summary
The forced oscillation technique accurately assessed bronchial allergen challenge tests in children with asthma, showing higher agreement with clinical evaluation than the forced vital capacity maneuver. This technique detected early bronchial reactions at lower allergen concentrations.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Respiratory Physiology
Background:
- Asthma diagnosis and monitoring in children require sensitive methods to assess bronchial hyperresponsiveness.
- The bronchial allergen challenge test is a key diagnostic tool, but its sensitivity can vary.
- Evaluating different respiratory measurement techniques is crucial for optimizing diagnostic accuracy.
Purpose of the Study:
- To compare the efficacy of the forced oscillation technique (FOT) and forced vital capacity (FVC) maneuver in evaluating bronchial allergen challenge tests in asthmatic children.
- To assess the agreement between FOT and FVC measurements and clinical assessments.
- To identify the most sensitive respiratory variables for detecting early bronchial reactions.
Main Methods:
- Two groups of asthmatic children underwent bronchial allergen challenge tests.
- Respiratory variables were measured using the forced oscillation technique (total respiratory resistance and impedance at 2, 4, and 12 Hz) and forced vital capacity maneuver (FVC, FEV1, MMEF, MEF75, MEF50, MEF25).
- Measurements were taken during 15 provocation tests, and changes were compared with clinical assessments.
Main Results:
- The forced oscillation technique showed 100% agreement (15/15) with clinical evaluation, while the forced vital capacity maneuver showed 80% agreement (12/15).
- FOT detected bronchial reactions in 6/10 patients at 1/10th of the allergen concentration causing clinical signs, with resistance at 4 Hz being the most sensitive variable (5/10 significant changes).
- FVC maneuver detected reactions preceding clinical signs in 2/9 cases at a tenfold lower allergen concentration, with FEV1 and MEF25 being the most sensitive variables.
Conclusions:
- The forced oscillation technique is a highly reliable method for evaluating bronchial allergen challenge tests in pediatric asthma, demonstrating superior agreement with clinical assessment.
- FOT is more sensitive in detecting early, subclinical bronchial reactions at lower allergen doses compared to the FVC maneuver.
- Resistance at 4 Hz is identified as a particularly sensitive indicator of bronchial reactivity in asthmatic children during allergen challenge.