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Applicability of interrupter resistance measurements using the MicroRint in daily practice
H G M Arets1, H J L Brackel, C K van der Ent
1Department of Pediatric Pulmonology, University Medical Centre Utrecht, Utrecht, The Netherlands. h.arets@wkz.azu.nl
Abstract:
This study was performed to evaluate the applicability of a simple device (MicroRint) for measuring airway resistance, to derive normal values and to compare values with maximal expiratory flow volume (MEFV) parameters in asthmatic and healthy children. Repetitive R(int) measurements were performed in 125 healthy children and 107 asthmatic children (age range 0.8-16.8 years). In 42 asthmatic patients R(int) and MEFV values were compared and in 29 asthmatic children bronchodilation testing was performed. Successful R(int) measurements were possible in 91% of the children. The mean coefficient of variation of repeated measurements was 7.1 (+/-6.1)%. R(int) values of healthy children showed a significant curvilinear correlation with age (r=-0.80, P < 0.001) and height (r=-0.81, P < 0.001). In asthmatic and healthy children R(int) values were comparable. A significant inverse correlation was found between R(int) and MEFV values (for FEV1 and R(int) r=-0.80, P < 0.001). After bronchodilation there was a significant increase in FEV1 and decrease in R(int), but changes between the two parameters did not correlate. In conclusion, the interrupter technique is feasible and repeatable in children and has a significant correlation with other parameters of airway caliber. Baseline values do not discriminate healthy from asthmatic children.
Insights
The MicroRint device effectively measures airway resistance in children, showing good repeatability. While baseline airway resistance doesn't distinguish between healthy and asthmatic children, it correlates with lung function tests.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Assessing airway resistance in children is crucial for diagnosing respiratory conditions.
- Maximal expiratory flow volume (MEFV) parameters are commonly used, but simpler methods are desirable.
Purpose of the Study:
- Evaluate the MicroRint device for measuring airway resistance in children.
- Establish normal R(int) values and compare them with MEFV parameters.
- Assess the utility of R(int) in asthmatic children, including response to bronchodilation.
Main Methods:
- The interrupter technique (Rint) was used with the MicroRint device in 125 healthy and 107 asthmatic children (0.8-16.8 years).
- Rint and MEFV values were compared in 42 asthmatic patients.
- Bronchodilation testing was performed in 29 asthmatic children.
Main Results:
- Successful Rint measurements were achieved in 91% of children with good repeatability (CV 7.1%).
- Rint values correlated inversely with age and height in healthy children.
- Baseline Rint values were comparable between healthy and asthmatic children and showed a significant inverse correlation with FEV1.
- Bronchodilation led to decreased Rint and increased FEV1, though changes didn't correlate.
Conclusions:
- The interrupter technique is a feasible and repeatable method for measuring airway resistance in children.
- Rint correlates significantly with other measures of airway caliber.
- Baseline Rint values alone cannot differentiate between healthy and asthmatic children.