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Relationship between baseline and post-bronchodilator interrupter resistance and specific airway resistance in
Pauline Mauger-Hamel1, Cécile Du Boisbaudry2, Karelle Léon3
1Service de Pédiatrie Générale, CHRU de Brest, Brest, France; Service des Explorations Fonctionnelles Respiratoires, Brest, France.
Insights
Assessing preschool children's airway function using interrupter resistance (Rint) and specific airway resistance (sRaw) showed poor agreement, indicating neither technique alone is reliable for diagnosing obstruction. Both methods are needed alongside bronchodilator response (BDR) testing.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Preschool children's airway function assessment utilizes techniques like interrupter resistance (Rint) and specific airway resistance (sRaw).
- Accurate assessment is crucial for diagnosing and managing pediatric respiratory conditions.
Purpose of the Study:
- To evaluate the relationship and agreement between Rint and sRaw measurements in preschool children.
- To compare baseline and bronchodilator response (BDR) assessments using current reference equations.
Main Methods:
- Included 130 children aged 3-6 years undergoing airway function testing.
- Performed concurrent baseline and post-bronchodilator measurements of Rint and sRaw.
- Analyzed data using z-scores and Cohen Kappa for agreement.
Main Results:
- Strong correlation found between baseline Rint and sRaw z-scores (r=0.5), but poor agreement (Kappa=0.09).
- Fair agreement observed for bronchodilator response (BDR) (Kappa=0.33).
- Children with poorly controlled asthma exhibited higher baseline Rint/sRaw and post-bronchodilator changes.
Conclusions:
- Poor agreement between Rint and sRaw suggests neither is solely reliable for diagnosing airway obstruction.
- Concomitant use of Rint, sRaw, and BDR testing is recommended for accurate assessment.
- Further research with larger cohorts is needed to establish BDR thresholds, particularly for sRaw.
Background:
The assessment of airway function in preschool children can be done using simple measurement techniques such as interrupter resistance (Rint) or specific airway resistance (sRaw).
Objective:
The aim of the study was to assess the relationship and the agreement between Rint and sRaw baseline measurements expressed in z-score and bronchodilator response (BDR) in accordance with the latest reference equations and recommended procedures.
Methods:
One hundred thirty children aged 3 to 6 years old, referred to our pediatric pulmonary function test unit for assessment of airway function were consecutively included. Children performed baseline and post-bronchodilator measurements of Rint and sRaw.
Results:
One hundred twenty baseline measurements were obtained (98.7%) with both techniques. At baseline there was a strong correlation between Rint and sRaw z-score (r = 0.5, P < .01) despite the poor agreement (Cohen Kappa coefficient 0.09 [-0.08; 0.26]). The agreement for BDR was fair, with Cohen Kappa coefficient (95% IC) = 0.33 (0.13; 0.54). Children with poorly or partially controlled asthma had both higher baseline Rint and sRaw (P < .01), and higher post-bronchodilator mean change (P < .01), than children with well-controlled asthma.
Conclusion:
The poor agreement between the Rint and sRaw reference measurements demonstrates the lack of reliability of sole Rint or sRaw technique for airway obstruction diagnosis and the need to perform each technique concomitantly with BDR test. Other longitudinal and larger sample studies are needed to confirm the threshold value for a positive BDR, especially for sRaw.
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