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Assessing the measurement of airway resistance by the interrupter technique
Insights
The interrupter technique (Rint) is a reproducible method for measuring airway resistance in children, correlating well with other methods. However, it may underestimate obstruction in severe cases.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Diagnostic Techniques
Background:
- Pulmonary function tests objectively assess bronchial obstruction in cooperative individuals.
- Passive methods for measuring airway resistance are valuable for non-collaborative subjects.
- The interrupter technique (Rint) offers a potential method for assessing airway resistance in children.
Purpose of the Study:
- To evaluate the applicability, reproducibility, reliability, and accuracy of the interrupter technique (Rint) for measuring airway resistance in pediatric subjects.
- To compare Rint measurements with established airway resistance techniques.
- To determine the influence of various measurement parameters on Rint reproducibility.
Main Methods:
- A cross-sectional study involving 460 healthy children and those with obstructive airway disease (ages 2-18).
- Airway resistance measured using a portable interrupter technique device.
- Rint results compared against airway resistance measured by oscillometry and plethysmography.
- Reproducibility assessed, including the impact of mask/mouthpiece, cheek support, and nose clip usage.
Main Results:
- Valid Rint measurements were obtained in 82.6% of participants.
- The technique demonstrated very good reproducibility (ICC=0.9412, p <0.00001) with no significant differences between measurements at different intervals.
- Measurement parameters did not affect reproducibility.
- Rint values correlated positively with oscillometry and plethysmography, though plethysmography correlation decreased with higher obstruction.
- Plethysmography and oscillometry yielded higher resistance values than Rint.
Conclusions:
- The interrupter technique (Rint) is a plausible and reproducible method for assessing airway resistance, particularly in non-collaborative pediatric patients.
- Rint shows adequate correlation with oscillometry and plethysmography.
- Rint may underestimate airway resistance in cases of moderate to severe obstruction, potentially limiting its use in follow-up or bronchial challenge tests.
Introduction:
Pulmonary function tests allow an objective assessment of the degree of bronchial obstruction in collaborative subjects. The measurement of airway resistance using passive methods is very helpful in non-collaborative subjects. The objective of this study was to assess the applicability of measuring airway resistance by the interrupter technique (Rint) in pediatric subjects, determining its reproducibility, reliability and accuracy versus other techniques to measure airway resistance.
Material And Methods:
Cross-sectional study in healthy children and in children with an obstructive airway disease, all aged 2-18 years old. The Rint was measured using a portable device and results were compared to airway resistance measured by oscillometry and plethysmography. The reproducibility of measurements and the infuence of the different outcome measures (use of mask or mouthpiece, cheek support, or nose clip) were assessed.
Results:
Valid measurements were obtained in 82.6% of 460 children (47.6% younger than 7 years old). Reproducibility was very good (ICC= 0.9412; p <0.00001), and no differences were found among the measurements obtained at separate time intervals (0.75 ± 0.3 versus 0.74 ± 0.28; p= 0.435). None of the factors indicated before had an effect on the reproducibility of measurements. Resistance values obtained by plethysmography and oscillometry were higher than those obtained using the Rint, with a positive correlation between them. The higher the degree of airway obstruction, the worse the correlation with plethysmography.
Conclusions:
The Rint measurement is a plausible and reproducible technique, and has an adequate correlation with the resistance measurements obtained using oscillometry or plethysmography, thus making it useful for non-collaborative patients. In patients with airway obstruction, this technique could underestimate resistance, so it would be a hurdle to use it to follow-up subjects with a moderate to severe obstructive disease or in bronchial challenge tests.
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