Impulse oscillometry: A measure for airway obstruction

Abstract

The impulse oscillometry system (IOS) was introduced as a new technique to assess airflow obstruction in patients who are not able to perform forced breathing maneuvers, e.g., subjects with cerebral palsy or severe mental retardation, and young children. This study evaluates the sensitivity and specificity of IOS parameters to quantify changes in airflow obstruction in comparison with forced expiratory volume in the first second (FEV(1)) and peak expiratory flow (PEF) measurements. Measurements of FEV(1), PEF, and resistance (R) and reactance (X) at frequencies of 5-35 Hz were performed in 19 children with asthma before, during, and after methacholine challenge and subsequent bronchodilatation. All parameters changed significantly during tests. Values of R5 and R10 correlated with FEV(1) (r = -0.71 and -0.73, respectively, P < 0.001), as did values of X5 and X10 (r = 0.52 and 0.57, respectively, P < 0.01). Changes in R preceded changes in PEF and FEV(1) during methacholine challenge. The area under the receiver operating characteristic (ROC) curve to predict a 15% fall in FEV(1) showed better sensitivity and specificity for R5 (area under the curve, 0.85) compared to PEF (0.79) or R10 (0.73). We conclude that IOS parameters can be easily used as an indirect measure of airflow obstruction. This might be helpful in patients who are not able to perform forced breathing maneuvers. In individual subjects, R values measured at 5 Hz showed to be superior to PEF measurements in the detection of a 15% fall in FEV(1).

Sistema de oscilometria de impulso em pediatria: revisão de literatura

“…32,34,35,36 Alguns estudos recentes aceitam o período de 30s 37,12,16 , entre 30 a 45s 37 e 45s 38 . Os autores Vink et al 39 e Song et al 40,41 publicaram dados de até 60s de gravação. Durante esse período de registro, a criança necessita permanecer na postura adequada, sem falar, deglutir, chorar ou tossir durante as medições.…”

“…39,12,14,38,41,62 Vem sendo constatada uma forte correlação entre algumas medidas do IOS e o VEF 1 , como nos estudos de Nowowiejska et al 38 e de Kalahoff et al 62 Vink et al 39 no qual, observaram que mudanças significativas na obstrução do fluxo aéreo foram identificadas por meio de correlações entre os valores de R e X com o VEF 1. Nos resultados obtidos por Song et al 41 as medidas de VEF 1 e PFE apresentaram correlação significativa com Z e R a 5, 10, 20 e 35 Hz, em asmáticos atópicos e em crianças saudáveis, sendo que as medidas de CVF também mostraram correlação com Z e com R em 10 Hz. A medida de FEF 25%-75% também teve correlação com parâmetro oscilométrico de X 18 , parecendo complementar informações fornecidas pelo VEF 1 .…”

Impulse Oscillometry vs. Body Plethysmography in Assessing Respiratory Resistance in Children

“…This makes FOT or IOS measurements especially interesting in pediatric population. Several works have been published showing the usefulness of IOS in different pathological conditions and in different groups of patients, including preschool children, 4,5 cystic fibrosis patients, 6 and asthmatic children.…”

Values of Impulse Oscillometry in Healthy Mexican Children and Adolescents

“…2 Several studies have shown that IOS correlates well with spirometric indexes, and that it is comparable to, or even more sensitive than, spirometry for detecting airway responses during bronchodilation or bronchoconstriction. [3][4][5] Moreover, in patients with asthma, IOS is useful to assess therapeutic responses to corticosteroids 6 and to predict ongoing loss of disease control. 7 Thus, IOS appears to be a valuable tool for managing lung diseases.…”