Low frequency oscillometry parameters in COPD patients are less variable during inspiration than during expiration

Kubota, Minoru; Shirai, Gakuji; Nakamori, Tomoyuki; Kokubo, Kenichi; Masuda, Noriyuki; Kobayashi, Hirosuke

doi:10.1016/j.resp.2009.01.007

Cited by 28 publications

(36 citation statements)

References 32 publications

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“…Paredi et al reported that the R5 was higher, and the X5 was negative at expiration compared with inspiration in patients with COPD 9. Two other studies also demonstrated the same findings 10 11. Our results showed that the R5 was highest, and X5 was mostly negative at the middle expiratory phase within the eight respiratory phases in most patients with COPD.…”

Section: Discussionsupporting

confidence: 85%

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Application of impulse oscillometry for within-breath analysis in patients with chronic obstructive pulmonary disease: pilot study

et al. 2011

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BackgroundThe impulse oscillometry is increasingly used for assessing the oscillatory mechanics of the respiratory system. The within-breath behaviour of the oscillatory mechanics in chronic obstructive pulmonary disease (COPD) is a well-known physiological feature. The purpose of this study was to develop a new approach for assessing this feature using impulse oscillometry.MethodsThe oscillatory mechanics were assessed by a commercially available impulse oscillometry device. The respiratory system resistance (Rrs) and reactance (Xrs) were measured during tidal breathing in patients with COPD (n=39) and healthy subjects (n=5). Selected data, the Rrs at 5 Hz (R5), Rrs at 20 Hz (R20), Xrs at 5 Hz (X5), and resonant frequency of Xrs (Fres) every 0.2 s, were extracted from the device. These data were divided into eight time fractions during the respiratory cycle to form averaged respiratory phases.ResultsThe time courses of the R5 and X5 were notably dependent on the respiratory cycles in patients with COPD, while there was little such dependency in healthy subjects. Irrespective of respiratory phase, R5 and Fres increased, and X5 fell to a more negative level in patients with COPD in a severity-dependent fashion. The increase in the R5 and negative level in the X5 were more prominent in the middle of the expiratory phase. The severity dependence in the R20 was relatively small compared with that in the R5.ConclusionsThe results of this study suggest that impulse oscillometry can assess the within-breath behaviour of the oscillatory mechanics with high temporal resolution, which may be helpful for evaluating the severity of COPD. Further studies are needed to reveal which biomarkers obtained with this approach would be suitable for evaluating the airway obstruction.

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Section: Discussionsupporting

confidence: 85%

“…Recently, Paredi et al reported that inspiratory–expiratory Xrs analysis (5 Hz) using IO differentiated patients with bronchial asthma from those with COPD 9. Other studies also have focused on the different oscillatory properties between the respiratory phases of patients with COPD and those with bronchial asthma 10 11…”

Section: Introductionmentioning

confidence: 99%

Application of impulse oscillometry for within-breath analysis in patients with chronic obstructive pulmonary disease: pilot study

et al. 2011

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“…Most inspiratory–expiratory FOT studies in patients with COPD have utilised sinusoidal pressure forcing; however, an early investigation used pseudorandom noise,15 and more recently Kubota et al have used IOS16 and found similar results to those in the present study.…”

Section: Discussionsupporting

confidence: 80%

Comparison of inspiratory and expiratory resistance and reactance in patients with asthma and chronic obstructive pulmonary disease

Paredi

Goldman

Alamen

et al. 2010

Thorax

130

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Background The usual analysis of forced oscillometry measures respiratory resistance (Rrs) and reactance (Xrs) averaged over several tidal breaths (whole-breath analysis). Recent within-breath analyses have separated Rrs and Xrs into their mean inspiratory and mean expiratory components (inspiratoryeexpiratory breath analysis) but these have not been used to compare patients with asthma and those with chronic obstructive pulmonary disease (COPD). Large inspiratoryeexpiratory variations in Xrs at 5 Hz (DX5) in an individual have been used as a surrogate marker of expiratory flow limitation. Methods Whole-breath and inspiratoryeexpiratory impulse oscillometry was assessed in 34 patients with asthma (4963 years; 15 male, forced expiratory volume in 1 s (FEV 1 ) 6964% predicted), 48 patients with COPD (6462 years; 32 male, FEV 1 5963% predicted) and 18 normal subjects (3762 years; 8 male). Results Whole-breath analysis failed to discriminate between patients with asthma and patients with COPD either for all patients or for patients with FEV 1 <60% predicted. Inspiratoryeexpiratory analysis in patients with FEV 1 <60% predicted showed that in the COPD group mean expiratory X5 (À0.4460.04 kPa/l/s) was greater than inspiratory X5 (À0.2360.02 kPa/l/s, p<0.001) whereas patients with asthma did not show such changes (À0.3660.07 kPa/l/s vs À0.2660.03 kPa/l/s, p¼0.23). Even though DX5 was larger in patients with COPD (0.2160.03 kPa/l/s) than in patients with asthma (0.1060.07 kPa/l/s), this was not significant (p¼0.15). Conclusions Whole-breath impulse oscillation system analysis failed to discriminate between patients with asthma and those with COPD. Inspiratoryeexpiratory X5 analysis differentiated patients with asthma from those with COPD presumably reflecting enhanced dynamic airway narrowing on expiration in COPD. Further studies are needed to confirm these differences and investigate their cause.

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“…Especially in patients with COPD, it is greater during expiration than inspiration (43). In this context, the evaluation of drug effects, such as tiotropium may be more accurate during inspiration in patients with COPD (46).…”

Section: Copdmentioning

confidence: 99%

Clinical Application of the Forced Oscillation Technique

Shirai

Kurosawa

2016

Intern. Med.

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The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory system resistance and reactance during tidal breathing. Recently, its clinical application has spread worldwide with the expansion of commercially available broadband frequency FOT devices, including MostGraph and Impulse Oscillometry. An increasing number of reports have supported the usefulness of the FOT in the management of asthma and chronic obstructive pulmonary disease (COPD). However, the FOT is not a surrogate test for spirometry, but should be used complementarily. Furthermore, reference values are not necessarily available and the interpretation of some measured data is controversial. There is a need to update the international statement for not only technical aspects but also the clinical use of the FOT. In this review, we summarize the previously published studies and discuss how to use the FOT in a clinical setting.

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Low frequency oscillometry parameters in COPD patients are less variable during inspiration than during expiration

Cited by 28 publications

References 32 publications

Application of impulse oscillometry for within-breath analysis in patients with chronic obstructive pulmonary disease: pilot study

Application of impulse oscillometry for within-breath analysis in patients with chronic obstructive pulmonary disease: pilot study

Comparison of inspiratory and expiratory resistance and reactance in patients with asthma and chronic obstructive pulmonary disease

Clinical Application of the Forced Oscillation Technique

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