Interrelationship between postocclusional oscillatory pressure transients and standard lung function in healthy and asthmatic children

Frey, Urs; Kraemer, Richard

doi:10.1002/ppul.1950190612

Cited by 16 publications

(25 citation statements)

References 24 publications

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“…In our previous work, we also found only a single antiresonance in the power spectrum of Pao(t ') [13,14]. We have speculated that this single antiresonance is caused by an acoustic phenomenon of the air in the airways.…”

mentioning

confidence: 73%

“…We have speculated that this single antiresonance is caused by an acoustic phenomenon of the air in the airways. We demonstrated that the damping properties of these oscillations are sensitive to airway mechanics, and change during bronchial challenge test in children [13,14]. This is especially interesting, since these oscillatory pressure transients are highly damped and independent of complete equilibration between alveolar and airway opening pressure.…”

mentioning

confidence: 86%

“…1) were analysed in time domain (1st derivative dPao(t ')/dt of Pao(t ')) and frequency domain (Fourier analysis). The theory of mathematical analysis has been described previously [13,14]. The damping characteristics of the pressure oscillations seen were characterized by an exponential damping factor, d. Values between 0 (undamped) and 1 (critically damped) describe the degree of damping.…”

Section: The Interrupter Techniquementioning

confidence: 99%

“…In general, the intrasubject variability of the 10 baseline measurements was higher in the healthy than in the asthmatic subjects. Relationships between Rint,EI(bl), d and f 'FS and plethysmographic data have been described previously [13].…”

Section: Biometric Data and Baseline Measurementsmentioning

confidence: 99%

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Oscillatory pressure transients after flow interruption during bronchial challenge test in children

Frey¹,

Kraemer²

1997

Eur Respir J

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The measurement of the conventional interrupter resistance (Rint) is dependent on pressure equilibration between alveolar and airway opening pressure, which is often not achieved in the presence of severe airways obstruction or in small children. The damping properties (d) of postocclusional oscillatory pressure transients after rapid flow interruption can be assessed independent of complete pressure equilibration, and we have previously shown them to be correlated to resistive properties of the respiratory system. We wanted to determine whether these transients were an expression of acoustic properties of the air in the airways, or whether they were caused by an interaction of gas and lung tissue, and whether d was more sensitive than Rint to changes in airway mechanics.Bronchial challenge tests were carried out with cumulative doses of inhaled carbachol in 10 healthy children (aged 7-14 yrs) and 50 asthmatic children (aged 5-15 yrs). The airflow interruptions were performed with a combined nebulizer-shutter head, allowing resistance measurements with each breath.The frequency, and the damping factor of the postocclusional pressure transients changed significantly during carbachol challenge in both groups of children. The provocation dose (PD) at which the damping factor (d) of the oscillatory pressure transients increased more than 2 SD above the baseline mean ("variancebased", PDvb) was lower than the PDvb of the end-interruption resistance (Rint,EI). These changes in frequency and damping factor were reversible after inhaling salbutamol.These findings suggest that the damping properties of the postocclusional pressure transients after flow interruption can be used as a sensitive parameter to assess changes in airway mechanics during bronchial challenge test in children in whom pressure equilibration is frequently not achieved during airflow interruption due to airways obstruction. Eur Respir J., 1997; 10: 75- The interrupter technique [1-6] has been shown to be a simple noninvasive method of measuring changes in airway mechanics in children [7] or patients with limited co-operation. However, the reliability of the measurements of the interrupter resistance (Rint) has been questioned in severe airway obstruction or in small children with a generally higher airway resistance, since the measurement of Rint depends on complete pressure equilibration between alveoli and airway opening. Different techniques to analyse the airway opening pressure curve after flow interrupter have been proposed. A comparison of these analytical techniques by PHAGOO et al. [8] showed that the end-interrupter resistance (Rint,EI) reflects changes in lung mechanics most sensitively.This Rint,EI is calculated from the airway opening pressure (time function) signal Pao(t ') as follows: based on the assumption that, during a brief period (100 ms) of airflow interruption, rapid equilibration between alveolar pressure (PA) and airway opening pressure (Pao) occurs, the Rint,EI is obtained by dividing the change in pressure 100 ms...

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mentioning

confidence: 73%

mentioning

confidence: 86%

Section: The Interrupter Techniquementioning

confidence: 99%

Section: Biometric Data and Baseline Measurementsmentioning

confidence: 99%

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Oscillatory pressure transients after flow interruption during bronchial challenge test in children

Frey¹,

Kraemer²

1997

Eur Respir J

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“…Medidas como complacência (C), resistência (R), monitorização contínua de gases arteriais e volume de oclusão das vias aéreas podem ser avaliadas e complementam o estudo da função pulmonar 2,8,[17][18][19][20][21][22][23] .…”

Section: Introductionunclassified

Pulmonary function tests in children and adolescents

Kantor

1997

J Pediatr (Rio J)

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ResumoObjetivo: Avaliação da função pulmonar em pacientes pediátricos.Métodos: Revisão bibliográfica das principais técnicas de testagem da função pulmonar.Conclusões: Os testes de função pulmonar são importante complemento para avaliação diagnóstica das doenças respiratórias em crianças. São utilizados também para auxiliar o seguimento e a terapêutica, além de reproduzir em laboratório, fenômenos fisiopatológicos que facilitam o estudo de várias doenças. Os testes espirométricos básicos utilizados são a curva volume-tempo (curva V-T) e a curva fluxo-volume (curva F-V). A medida da hiperreatividade brônquica (HRB) por meio de testes de provocação e de esforço pode ser empregada.J. pediatr. (Rio J.). 1997; 73(3):145-150: testes de função pulmonar, testes de provocação brônquica, curvas de fluxo-volume expiratório máximo, pico de fluxo expiratório. AbstractObjective: Evaluation of pulmonary function in pediatric patients.Methods: Bibliographic review of the main techniques of pulmonary function testing.Conclusions: Pulmonary function tests are an important complement to the diagnosis of respiratory illnesses in children. They can also be of help in the follow-up and treatment of these illnesses, and since they can reproduce physiopathological phenomena under laboratory conditions they can also be of help in the study of several diseases. The basic spirometric tests most often used are the volume-time curve (V-T curve) and the flow-volume curve (F-V curve). Bronchial hyperreactivity can be assessed through provocation and effort tests.J. pediatr. (Rio J.). 1997; 73(3):145-150: respiratory function tests, spirometry, bronchial provocation tests, maximal expiratory flow-volume curves, peak expiratory flow rate. IntroduçãoA formação de grandes aglomerados humanos, a industrialização e a poluição ambiental são fatores que contribuíram para o aumento das doenças respiratórias pediátricas em nosso meio. A melhoria dos serviços médico-pediátricos tem proporcionado a esses pacientes diagnósticos mais precoces, diminuindo a morbidade e mortalidade infantil.Com o desenvolvimento da Pneumologia infantil, doenças respiratórias crônicas como asma, fibrose cística, pneumonites, etc. passaram a receber cuidados especiais em seu diagnóstico, seguimento e tratamento. Associada à avaliação clínica, a introdução dos testes de função pulmonar trouxe maior segurança no manejo desses pacientes 1-5 .Martin descreveu que a maioria dos pacientes asmáti-cos têm avaliação subjetiva tanto pela família quanto pelo médico. Segundo ele, a melhor avaliação clínica e a aplicação dos testes de função pulmonar em seus pacientes reduziram os custos de tratamento, diminuiram o número de consultas e internamentos, as faltas escolares ou ao trabalho e o uso excessivo de medicamentos 1 .Dois testes básicos, a curva volume-tempo (curva V-T) e a curva fluxo-volume (curva F-V), são utilizados para avaliação de volumes e fluxos no estudo da função pulmonar por meio de espirômetros [6][7][8][9][10] . Na curva V-T obtemos os valores da capacidade vital forçada...

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Measurements of respiratory system resistance by the interrupter technique in healthy and asthmatic children

et al. 1997

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Interrelationship between postocclusional oscillatory pressure transients and standard lung function in healthy and asthmatic children

Cited by 16 publications

References 24 publications

Oscillatory pressure transients after flow interruption during bronchial challenge test in children

Oscillatory pressure transients after flow interruption during bronchial challenge test in children

Pulmonary function tests in children and adolescents

Measurements of respiratory system resistance by the interrupter technique in healthy and asthmatic children

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