Normal Values of Total Respiratory Resistance and Reactance Determined by Forced Oscillations

Lándsér, F. J.; Clément, Jan; Woestijne, K. P. Van de

doi:10.1378/chest.81.5.586

Cited by 95 publications

(90 citation statements)

References 7 publications

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“…It is of note that, in such studies, subject height should be homogeneous, since it is the parameter that has the most influence on impedance values. (2,3,20) In the control group, bronchodilator use resulted in a small and homogeneous reduction in the Rrs values between 4 and 32 Hz (0.40 ± 0.04 cmH 2 O•L −1 •s; Figure 1a and Table 2), which corroborates the findings of another study. (21) However, in the severe obstruction with BR+ subgroup, bronchodilator use resulted in a greater reduction in total resistance (MDRrs = 0.87 ± 0.65 cmH 2 O •L −1 •s).…”

Section: Discussionsupporting

confidence: 88%

Efeito da obstrução de vias aéreas nas variações das propriedades resistivas e elásticas do sistema respiratório de asmáticos, mediadas pelo uso de salbutamol

et al. 2009

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Objective: To investigate the effects of airway obstruction on albuterol-mediated variations in the resistive and elastic properties of the respiratory system of adult patients with asthma. Methods: This study comprised 24 healthy controls and 69 patients with asthma, all of whom were nonsmokers. The patients were divided into three groups according to the severity of airway obstruction (mild, moderate or severe). Each of the three groups was divided into two subgroups according to the bronchodilator response (BR): positive (BR+) or negative (BR−). These measurements were conducted before and after albuterol use (300 µg). Airway obstruction was determined by means of spirometry, and the resistive and elastic properties were determined by means of the forced oscillation technique. Results: The resistance at the intercept (R 0 ) presented greater reductions in the groups with higher obstruction. This reduction was more evident in the BR+ subgroups than in the BR− subgroups (p < 0.02 and p < 0.03, respectively). There was a significant difference between the control group and the BR+ subgroup with severe obstruction (p < 0.002). The reductions in dynamic elastance (Edyn) were significantly greater in proportion to the degree of obstruction, in the BR− subgroups (p < 0.03), and in the BR+ subgroups (p < 0.003). The reductions in Edyn were significantly greater in the BR− subgroup with moderate obstruction (p < 0.008) and in the BR+ subgroup with severe obstruction (p < 0.0005) than in the control group. Conclusions: In patients with asthma, increased airway obstruction results in greater reductions in R 0 and Edyn after albuterol use. These reductions are greater among BR+ patients than among BR− patients.Keywords: Asthma; Bronchodilator agents; Respiratory mechanics; Spirometry; Albuterol. ResumoObjetivo: Investigar os efeitos da obstrução de vias aéreas nas variações das propriedades resistivas e elásticas do sistema respiratório de asmáticos adultos mediadas pelo uso de salbutamol. Métodos: Foram analisados 24 indivíduos controles e 69 asmáticos, todos não tabagistas, divididos em três grupos segundo o nível de obstrução de vias aéreas (leve, moderada e acentuada). Cada grupo foi dividido em dois subgrupos de acordo com a resposta broncodilatadora: resposta broncodilatadora positiva (RB+) ou negativa (RB−). A espirometria foi utilizada para a avaliação da obstrução, e a técnica de oscilações forçadas, para a análise das propriedades resistivas e elásticas, sendo realizadas antes e após a utilização de 300 µg de salbutamol. Resultados: A resistência no intercepto (R 0 ) apresentou maior redução nos grupos com maior obstrução. Essa redução foi mais evidente nos subgrupos RB+ do que nos RB− (p < 0,02 e p < 0,03, respectivamente). Houve diferença significativa entre o grupo controle e a o subgrupo com obstrução acentuada RB+ (p < 0,002). As reduções na elastância dinâmica (Edyn) se acentuaram significativamente com a obstrução, tanto para os subgrupos RB− (p < 0,03), quanto para os RB+ (p < 0,003). As reduçõe...

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Section: Discussionsupporting

confidence: 88%

Efeito da obstrução de vias aéreas nas variações das propriedades resistivas e elásticas do sistema respiratório de asmáticos, mediadas pelo uso de salbutamol

et al. 2009

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“…The age distribution is shown in figure 1. [13,17,[22][23][24][25]. In females, Rrs values were slightly higher than in males, as reported in younger healthy adults [23][24][25].…”

Section: Resultsmentioning

confidence: 91%

“…The range of values reported, similar or even lower to that of younger nonsmoking or never-smoking adults, shows that previous smoking apparently does not significantly affect Zrs parameters in older subjects with normal spirometric values. In fact, previous studies show that Zrs values in smokers do not differ significantly from those of nonsmokers [17,22,41].…”

Section: Respiratory Resistance In the Elderly Yf Guo Et Almentioning

confidence: 92%

Normal values for respiratory resistance using forced oscillation in subjects >65 years old

Guo

Herrmann²,

Michel³

et al. 2005

Eur Respir J

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The aim of the present study was to determine reference values and predictive variables for respiratory impedance (Zrs) by the forced oscillation technique (FOT) in subjects aged .65 yrs.The investigation involved a prospective study of nonsmoking subjects, with normal forced expiratory volumes. The Zrs parameters, which included average resistance between 4-16 Hz (R4-16), average resistance between 4-30 Hz (RM), resonant frequency (FN), capacitance (C) and inertance (I), were measured along with forced expiratory manoeuvres. Every subject had each parameter measured in the same sequence using FOT and spirometry.A total of 223 subjects aged 83¡8 yrs were included in the study. The mean values for forced expiratory volume in one second (FEV1) % predicted were 110¡23. The forced vital capacity (FVC) % pred was 114¡21 and the FEV1/FVC % pred was 112¡11. . In multiple regression models adjusted for age, sex, height and weight, height was the most influential predictor for Zrs parameters based on the magnitude of the regression coefficient.In conclusion, it was found that height was the best predictor for respiratory impedance parameters. Contribution of age and weight was negligible. However, the level of predictability for respiratory impedance parameters by regression equations was low.

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“…In an early study, use of FOT alone failed to clearly separate smokers from nonsmokers [28]. COE et al [75] analysed Rrs and its frequency dependence in healthy neversmokers and in smokers.…”

Section: Follow-up and Field Studiesmentioning

confidence: 99%

The forced oscillation technique in clinical practice: methodology, recommendations and future developments

Oostveen¹,

MacLeod²,

Lorino³

et al. 2003

Eur Respir J

1,105

1,120

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The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory mechanics. FOT employs small-amplitude pressure oscillations superimposed on the normal breathing and therefore has the advantage over conventional lung function techniques that it does not require the performance of respiratory manoeuvres.The present European Respiratory Society Task Force Report describes the basic principle of the technique and gives guidelines for the application and interpretation of FOT as a routine lung function test in the clinical setting, for both adult and paediatric populations.FOT data, especially those measured at the lower frequencies, are sensitive to airway obstruction, but do not discriminate between obstructive and restrictive lung disorders. There is no consensus regarding the sensitivity of FOT for bronchodilation testing in adults. Values of respiratory resistance have proved sensitive to bronchodilation in children, although the reported cutoff levels remain to be confirmed in future studies.Forced oscillation technique is a reliable method in the assessment of bronchial hyperresponsiveness in adults and children. Moreover, in contrast with spirometry where a deep inspiration is needed, forced oscillation technique does not modify the airway smooth muscle tone. Forced oscillation technique has been shown to be as sensitive as spirometry in detecting impairments of lung function due to smoking or exposure to occupational hazards. Together with the minimal requirement for the subject9s cooperation, this makes forced oscillation technique an ideal lung function test for epidemiological and field studies. Novel applications of forced oscillation technique in the clinical setting include the monitoring of respiratory mechanics during mechanical ventilation and sleep.

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Normal Values of Total Respiratory Resistance and Reactance Determined by Forced Oscillations

Cited by 95 publications

References 7 publications

Efeito da obstrução de vias aéreas nas variações das propriedades resistivas e elásticas do sistema respiratório de asmáticos, mediadas pelo uso de salbutamol

Efeito da obstrução de vias aéreas nas variações das propriedades resistivas e elásticas do sistema respiratório de asmáticos, mediadas pelo uso de salbutamol

Normal values for respiratory resistance using forced oscillation in subjects >65 years old

The forced oscillation technique in clinical practice: methodology, recommendations and future developments

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