Dataset Information

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

ABSTRACT:

Background

The 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.

Methods

The 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.

Results

The 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.

Conclusions

The 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.

SUBMITTER: Ohishi J

PROVIDER: S-EPMC3191594 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature

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Publications

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

Ohishi Junichi J Kurosawa Hajime H Ogawa Hiromasa H Irokawa Toshiya T Hida Wataru W Kohzuki Masahiro M

BMJ open 20110101 2

<h4>Background</h4>The 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.<h4>Methods</h4>The oscillatory mechanics were assessed by a commercially available impulse oscillometry device. T ...[more]

PMID: 22021880

Similar Datasets

Project description:OBJECTIVE:Recent work has suggested that within-breath respiratory impedance measurements performed using the forced oscillation technique may help to noninvasively evaluate respiratory mechanics. We investigated the influence of airway obstruction on the within-breath forced oscillation technique in smokers and chronic obstructive pulmonary disease patients and evaluated the contribution of this analysis to the diagnosis of chronic obstructive pulmonary disease. METHODS:Twenty healthy individuals and 20 smokers were assessed. The study also included 74 patients with stable chronic obstructive pulmonary disease. We evaluated the mean respiratory impedance (Zm) as well as values for the inspiration (Zi) and expiration cycles (Ze) at the beginning of inspiration (Zbi) and expiration (Zbe), respectively. The peak-to-peak impedance (Zpp=Zbe-Zbi) and the respiratory cycle dependence (?Zrs=Ze-Zi) were also analyzed. The diagnostic utility was evaluated by investigating the sensitivity, the specificity and the area under the receiver operating characteristic curve. ClinicalTrials.gov: NCT01888705. RESULTS:Airway obstruction increased the within-breath respiratory impedance parameters that were significantly correlated with the spirometric indices of airway obstruction (R=-0.65, p<0.0001). In contrast to the control subjects and the smokers, the chronic obstructive pulmonary disease patients presented significant expiratory-inspiratory differences (p<0.002). The adverse effects of moderate airway obstruction were detected based on the Zpp with an accuracy of 83%. Additionally, abnormal effects in severe and very severe patients were detected based on the Zm, Zi, Ze, Zbe, Zpp and ?Zrs with a high degree of accuracy (>90%). CONCLUSIONS:We conclude the following: (1) chronic obstructive pulmonary disease introduces higher respiratory cycle dependence, (2) this increase is proportional to airway obstruction, and (3) the within-breath forced oscillation technique may provide novel parameters that facilitate the diagnosis of respiratory abnormalities in chronic obstructive pulmonary disease.

Dataset Information

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

Background

Methods

Results

Conclusions

Publications

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

Similar Datasets

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