Airway resistance measured by the interrupter technique: normative data for 2-10 year olds of three ethnicities

McKenzie, S A; Chan, E. Y.; Dundas, Isobel; Bridge, P D; Pao, C.; Mylonopoulou, M.; Healy, M. J. R.

doi:10.1136/adc.87.3.248

Cited by 62 publications

(56 citation statements)

References 23 publications

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“…17 Interestingly, Rint values expressed as absolute and z-scores were significantly higher in preterm children in this study (1.16 and 1.00 kPa l À1 s) compared to healthy controls in a recent study (0.70 and 0.0 kPa l À1 s). 26 Thus, Rint is also able to discriminate between prematurely born children without CLD and healthy controls as shown previously.…”

Section: Discussioncontrasting

confidence: 43%

“…The baseline differences found between the study groups were in accordance with a previous study. 26 Although Rint is related to both age and height 17 its correlation with birthweight and gestation is not known. It is plausible that the baseline difference in neonatal gestation and birth weight in CLD group may be responsible for the increased Rint in this study, though this baseline difference did not influence Rint in the study by Vrijlandt et al 26 Furthermore; anthropometric data including weight, height and corrected age were comparable between the groups at the time of this study.…”

Section: Discussionmentioning

confidence: 99%

“…16 Additionally, the reference data we used to derive the z-scores were collected using this method. 17 All measurements were carried out using the manufacturer's disposable mouthpiece filter unit, the resistance of which equalled the value incorporated in the software of the device.…”

Section: Interrupter Techniquementioning

confidence: 99%

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Lung function measurement in prematurely born preschool children with and without chronic lung disease

et al. 2008

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Objective: Prematurely born infants often have recurrent wheeze and long-term respiratory morbidity at follow-up. Assessment of airways obstruction in preschool children is feasible using the interrupter resistance (Rint) but has rarely been examined in preterm children with and without chronic lung disease (CLD). The objective of this study was to determine lung function measured by the interrupter technique, its feasibility in the ambulatory setting and respiratory health in prematurely born preschool children with and without CLD.Study Design: Preterm children of 2 to 4 years with severe CLD (>30% oxygen at 36 weeks and discharged home receiving supplemental oxygen) (n ¼ 43, median gestational age 27 weeks and median birth weight 995 g) and without CLD (n ¼ 33, median gestational age 29 weeks and median birth weight 1366 g) attempting lung function test for the first time were enrolled. Respiratory symptoms score was calculated using a questionnaire. A single set of 10 consecutive Rint measurements was obtained using a portable device (MicroRint). Median of at least five occlusions with consistent shape of mouth pressure-time curves was taken to be a Rint measurement. To assess feasibility the children were categorized as 'satisfactory', 'failure' and 'rejected' depending on the outcome of the test. Outcome variables were respiratory symptoms score and Rint.Result: Satisfactory Rint measurement was obtained in 46 (61%) children, 9 (36%) 2-year olds, 17 (65%) 3-year olds and 20 (80%) 4-year olds. As compared with the preterm control children (n ¼ 18), CLD children (n ¼ 28) had significantly higher respiratory symptoms score (18.5 vs 6, P<0.01) and Rint expressed as absolute values (kPa l À1 ) and z-scores (1.33 vs 1.16 and 1.42 vs 1.0, P<0.01), respectively. Conclusion:Rint measurement is feasible in prematurely born children of preschool age in the ambulatory setup. Preschool children with severe CLD may be identified from preterm children without CLD by increased Rint that may be used as a screening tool and as an outcome measure for interventions.

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Section: Discussioncontrasting

confidence: 43%

Section: Discussionmentioning

confidence: 99%

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Lung function measurement in prematurely born preschool children with and without chronic lung disease

et al. 2008

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“…The user-friendliness of the technique and the portability of the equipment, as well as the possibility of a correlation between Rint and spirometric values, have increased the interest in the method and its use in children and adolescents with pulmonary disease. (3,(7)(8)(9)(10)(11)(12)(13)(14) Many patients with CF use bronchodilators to relieve their symptoms or prior to physical therapy, and the measurement of bronchodilator response is an important part of the follow-up of such patients. In studies involving asthma patients, the Rint technique was shown to be accurate in measuring such a response.…”

Section: Introductionmentioning

confidence: 99%

Utilização da técnica de resistência do interruptor na avaliação da resistência das vias aéreas em pacientes com fibrose cística

et al. 2012

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Objective: To measure airway resistance with the interrupter resistance (Rint) technique in patients with cystic fibrosis (CF) and to determine whether Rint values correlate with spirometric parameters, as well as to evaluate the accuracy of the Rint technique in determining the airway response to a bronchodilator. Methods: This was a cross-sectional study involving 38 children and adolescents with CF followed at the Cystic Fibrosis Outpatient Clinic of the São Lucas Hospital, located in the city of Porto Alegre, Brazil. After Rint had been measured, the subjects underwent spirometry. To evaluate bronchodilator response, we repeated the measurements after the use of inhaled albuterol. Results: There was a strong correlation between inverse Rint and FEV 1 (r = 0.8; p < 0.001), and there was a moderate correlation between inverse Rint and FEF 25-75% (r = 0.74; p < 0.001), as well as between inverse Rint and body mass index (r = 0.62; p < 0.001). We used a ROC curve to compare the bronchodilator response, as determined by Rint, with spirometric values. For a Rint cut-off point of −28%, the area under the curve was 0.75, with a sensitivity of 66% and a specificity of 82%. Conclusions: Our findings suggest that Rint correlates well with spirometric parameters, although the Rint technique was not sufficiently accurate to replace spirometry in the evaluation of bronchodilator responses. Keywords:Respiratory function tests; Cystic fibrosis; Spirometry; Airway resistance. ResumoObjetivo: Medir a resistência de vias aéreas utilizando a técnica de resistência do interruptor (Rint) em pacientes com fibrose cística (FC) e correlacioná-la com parâmetros espirométricos, assim como avaliar a acurácia de Rint para determinar a resposta das vias aéreas a um broncodilatador. Métodos: Estudo transversal com 38 crianças e adolescentes com FC acompanhados no Ambulatório de FC do Hospital São Lucas, em Porto Alegre (RS). Após a determinação de Rint, os pacientes foram submetidos à espirometria. Para a avaliação da resposta ao broncodilatador, as medições foram repetidas após o uso de salbutamol inalatório. Resultados: Houve uma forte correlação entre o inverso de Rint e VEF 1 (r = 0,8; p < 0,001) e moderadas correlações entre o inverso de Rint e FEF 25-75% (r = 0,74; p < 0,001) e entre o inverso de Rint e índice de massa corpórea (r = 0,62; p < 0,001). A curva ROC foi utilizada na comparação da resposta ao broncodilatador determinada por Rint com aquela determinada por valores espirométricos. Para um ponto de corte de −28% para Rint, a área sob a curva foi de 0,75, com uma sensibilidade de 66% e uma especificidade de 82%. Conclusões: Nossos achados indicam que Rint apresenta uma boa correlação com parâmetros espirométricos, embora a técnica Rint não tenha sido suficientemente acurada para substituir a espirometria na avaliação da resposta ao broncodilatador.Descritores: Testes de função respiratória; Fibrose cística; Espirometria; Resistência das vias respiratórias.

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“…The pressure is measured using two points by linear back-extrapolation. (5,14,15) Flow and pressure calibration of the MicroRint ® , accurate to within 1%, was carried out every 50 measurements, using a manometer and a 3-L syringe.…”

Section: Introductionmentioning

confidence: 99%

Resistência de vias aéreas em crianças medida pela técnica do interruptor: valores de referência

et al. 2008

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Objective: The interrupter technique is used for determining interrupter resistance (Rint) during quiet breathing. This noninvasive method requires minimal cooperation and can therefore be useful in evaluating airway obstruction in uncooperative children. To date, no reference values have been determined for Rint in a Brazilian population. The objective of this study was to define a prediction equation for airway resistance using the interrupter technique for healthy children aged 3-13 years. Methods: This was a prospective, cross-sectional study involving preschool and school children in Porto Alegre, Brazil, in whom Rint was measured during peak expiratory flow. Results: One-hundred and ninety-three children were evaluated. Univariate analysis using linear regression showed that height, weight and age correlated significantly and independently with Rint. Multiple regression with height, weight, age and gender as variables resulted in a model in which only height and weight were significant, independent predictors of Rint. Collinearity was identified among height, weight and age. Conclusions: Reference values and an equation for calculating Rint in healthy children were obtained and are adjusted for height.Keywords: Respiratory function tests; Airway resistance; Diagnostic techniques, respiratory system; Airway obstruction/diagnosis; Reference values. ResumoObjetivo: A técnica do interruptor é usada para determinar interrupter resistance (Rint, medida de resistência das vias aéreas através da técnica do interruptor) durante respiração tranqüila. Este método não-invasivo requer mínima cooperação e, por isso, pode ser útil para avaliar obstrução de vias aéreas em crianças não-colaborativas. Não existem dados publicados de valores de referência para Rint na população brasileira até o momento. O objetivo deste estudo foi definir uma equação para prever a resistência das vias aéreas pela técnica do interruptor em crianças saudáveis de 3 a 13 anos de idade. Métodos: Este estudo transversal prospectivo com crianças pré-escolares e escolares em Porto Alegre, Brasil, mensurou Rint durante pico de fluxo expiratório no volume corrente. Resultados: Cento e noventa e três crianças completaram as medidas. Estatura, peso corporal e idade mostraram correlação significante e independente com Rint na análise univariada usando regressão linear. A regressão múltipla com estatura, peso corporal, idade e gênero como variáveis resultou em um modelo no qual somente estatura e peso corporal foram significativos e independentes para predizer Rint. Colinearidade foi identificada entre estatura, peso corporal e idade. Conclusões: Valores e equação de referência para Rint em crianças saudáveis foram obtidos e são relacionados a estatura. Descritores: Testes de função respiratória; Resistência das vias respiratórias; Técnicas de diagnóstico do sistema respiratório; Obstrução das vias respiratórias/diagnóstico; Valores de referência.

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Airway resistance measured by the interrupter technique: normative data for 2-10 year olds of three ethnicities

Cited by 62 publications

References 23 publications

Lung function measurement in prematurely born preschool children with and without chronic lung disease

Lung function measurement in prematurely born preschool children with and without chronic lung disease

Utilização da técnica de resistência do interruptor na avaliação da resistência das vias aéreas em pacientes com fibrose cística

Resistência de vias aéreas em crianças medida pela técnica do interruptor: valores de referência

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