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Assessment and validation of bronchodilation using the interrupter technique in preschool children
Laura Mele1, Peter D Sly, Claudia Calogero
1Department of Pediatrics, University of Florence, Florence, Italy.
Insights
Bronchodilation can be assessed in preschool children using interrupter resistance (Rint) changes. A decrease in Rint or Z-score effectively identifies bronchodilation in children with recurrent wheezing.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Assessing bronchodilation in preschool children is challenging.
- Interrupter resistance (Rint) is a potential tool for measuring lung function.
Purpose of the Study:
- To establish and validate a cut-off value for bronchodilation using Rint in preschool children.
- To compare different methods for assessing bronchodilation.
Main Methods:
- Rint was measured in healthy children before and after salbutamol inhalation.
- Four methods for assessing bronchodilation were evaluated: percent change from baseline, percent change of predicted values, absolute change in Rint, and change in Z-score.
- Cut-off values were determined from healthy children and applied to symptomatic and asymptomatic children with recurrent wheezing.
Main Results:
- Established cut-off values for bronchodilation in healthy children: -32% baseline, -33% predicted, -0.26 kPa L(-1) sec, and -1.25 Z-scores.
- Assessing bronchodilation by absolute Rint decrease or Z-score decrease showed >80% sensitivity and specificity in detecting current respiratory symptoms in wheezing children.
Conclusions:
- A decrease in Rint ≥0.26 kPa L(-1) sec or a Z-score decrease ≥1.25 are appropriate for assessing bronchodilation in preschool children with recurrent wheezing history.
- Recommends using Z-score change for bronchodilation assessment in this age group due to its general applicability.
- Further research is needed to determine the clinical utility of measuring bronchodilation in managing pediatric lung diseases.
Objective:
To determine and validate a cut-off value for bronchodilation using the interrupter resistance (Rint) in preschool children.
Patients And Methods:
Rint was measured in 60 healthy children (age range 2.7-6.4 years) before and after salbutamol inhalation (200 microg). Four potential methods for assessing BDR were evaluated: percent change from baseline, percent change of predicted values, absolute change in Rint, and change in Z-score. These cut-off values, determined as the fifth percentile of the healthy group, were applied to children referred for the assessment of recurrent wheezing, classified on the basis of acute symptoms and/or abnormal chest examination into symptomatic (n = 60, age range 2.9-6.1 years) and asymptomatic (n = 60, age range 2.5-5.7 years) groups.
Results:
The cut-off values for bronchodilation calculated in healthy children were: -32% baseline; -33% predicted; -0.26 kPa L(-1) sec; and -1.25 Z-scores. Assessing BDR in children with a history of wheezing by either a decrease in absolute Rint or a decrease in Z-score gave sensitivity, specificity, negative predictive value, and positive predictive value all >80% for detecting children with current respiratory symptoms.
Conclusions:
Both a decrease in Rint > or =0.26 kPa L(-1) sec and a decrease in Z-score of > or =1.25 are appropriate for assessing BDR in preschool children with a history of recurrent wheezing. As Z-score is a more general solution, we recommend using a change in Z-score to determine BDR in preschool children. Further longitudinal studies will be required to determine the clinical utility of measuring BDR in managing lung disease in such children.
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