Differences in Airway Resistances in Children Measured by Plethysmography With and Without Closure of the Occluder

BackgroundThere have been several studies that have measured airway resistances using plethysmography without closing the occluderObjectiveTo investigate the differences between the total resistances (sRawTOT) and the specific resistances (sRaw) with the same technique (plethysmography) but different methodology (with and without closure of the occluder) in child subjects.Material and methodsAn observational and cross-sectional study of a consecutive sample of children between 6 and 14 years old who were seen at the Childhood Pneumology clinics from 15th January to 15th February 2009. Determination of sRawTOT, sRaw and specific conductance (sGaw) using plethysmography (MasterLab V5.1, Viasys®, Wuerzburg, Germany) without closing the occluder. The same determinations were then performed with the occluder closed. The qualitative variables were: sex, diagnosis and treatment, and the quantitative variables: age, weight, height, sRawTOT, sRaw, sGaw and respiratory rate with and without closing the occluder. The results were analysed for association and concordance between sRawTOT, sRaw and sGaw with and without closure of the occluder using paired Student t test, Bland-Altman method and a scatter plot.ResultsThirty-six cases were included and all (100%) the tests were performed successfully. The mean age was 9.91±2.37 years. There were no differences between sRawTOT, sRaw or sGaw with and without closure of the occluder. Neither were there any differences between the regression of the means obtained for sRawTOT, sRaw and sGaw with and without closure of the occluder.ConclusionsThere is good agreement between the sRawTOT y sRaw obtained by plethysmography with and without closure of the occluder.

ResumenAntecedentesDiversos investigadores han estudiado las resistencias de la vía aérea mediante pletismografía sin cierre del oclusor.ObjetivoComprobar la concordancia entre las resistencias totales (sRawTOT) y las resistencias específicas (sRaw) con la misma técnica (pletismografía) y diferente metodología (con y sin cierre del oclusor) en niños colaboradores.Material y métodosEstudio observacional y transversal de una muestra consecutiva de niños entre 6 y 14 años que acudieron a consultas de Neumología Infantil, desde el 15 de enero hasta el 15 de febrero de 2009. Determinación de sRawTOT, sRaw y conductancia específica (sGaw) mediante pletismografía (MasterLab V5.1, Viasys®, Wuerzburg, Alemania) sin cierre del oclusor. En todos se realizaron a continuación las mismas determinaciones con cierre del oclusor. Variables cualitativas: sexo, diagnóstico y tratamiento, y variables cuantitativas: edad, peso, talla, sRawTOT, sRaw, sGaw y FR con y sin cierre del oclusor. Análisis de la asociación y concordancia entre sRawTOT, sRaw y sGaw con y sin cierre del oclusor mediante t de Student pareada, método Bland-Altman y diagrama de puntos (Scatter plot).ResultadosSe incluyeron 36 casos. El 100% realizó las pruebas con éxito. Edad media: 9,91 ± 2,37 años. No hubo diferencias entre sRawTOT, sRaw ni sGaw con y sin cierre del oclusor. Tampoco hubo diferencias entre la regresión de las medias obtenidas de sRawTOT, sRaw y sGaw con y sin cierre del oclusor, respecto a la diferencia de las mismas.ConclusionesExiste una buena concordancia entre sRawTOT y sRaw obtenidas por pletismografía con y sin cierre del oclusor.