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Within-breath analysis of respiratory mechanics in asthmatic patients by forced oscillation.

Veiga J, Lopes AJ, Jansen JM, Melo PL - Clinics (Sao Paulo) (2009)

Bottom Line: The within-breath analysis of respiratory mechanics by the monofrequency Forced Oscillation Technique (mFOT) is of great interest in both physiopathology studies and the diagnosis of respiratory diseases.Forced Oscillation Technique data were interpreted using the mean respiratory impedance (Zt), the impedance during inspiration (Zi), expiration (Ze), at the beginning of inspiration (Zii), and at expiration (Zie).The peak-to-peak impedance (Zpp) was also calculated by the subtraction of Zii from Zie.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Instrumentation Laboratory, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro/RJ, Brazil.

ABSTRACT

Introduction: The within-breath analysis of respiratory mechanics by the monofrequency Forced Oscillation Technique (mFOT) is of great interest in both physiopathology studies and the diagnosis of respiratory diseases. However, there are limited data on the use of this technique in the analysis of asthma. This study evaluates within-breath mechanics of asthmatic individuals and the contribution of the mFOT in the asthma diagnosis.

Methods: Twenty-two healthy and twenty-two asthmatic subjects, including patients with mild (n=8), moderate (n=8), and severe (n=6) obstruction, were studied. Forced Oscillation Technique data were interpreted using the mean respiratory impedance (Zt), the impedance during inspiration (Zi), expiration (Ze), at the beginning of inspiration (Zii), and at expiration (Zie). The peak-to-peak impedance (Zpp) was also calculated by the subtraction of Zii from Zie. Receiver operating characteristic curves were used to determine the sensitivity (Se) and specificity (Sp) of m Forced Oscillation Technique parameters in identifying asthma.

Results: Respiratory impedance values were significantly higher in asthmatics: Zt (p<0.001), Zi (p<0.001), Ze (p<0.001), Zii (p<0.001), Zie (p<0.001), and Zpp (p<0.003). The best parameters for detecting asthma were Zi, Zii, and Zie (Se=90.9%, Sp=90.9%), followed by Zt and Ze. These results are in close agreement with recently published theories and pathophysiological fundamentals.

Conclusions: mFOT permits a non-invasive and detailed analysis in different phases of the respiratory cycle, providing parameters that are adequate for the diagnosis of asthma with high accuracy. These results confirm the high clinical and scientific potential of this methodology in the evaluation of asthmatic patients.

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Related in: MedlinePlus

Typical airflow and respiratory impedance analyzed in the control group (A) and asthmatic (B) individuals. Notice the difference in the impedance scales.
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f1-cln64_7p649: Typical airflow and respiratory impedance analyzed in the control group (A) and asthmatic (B) individuals. Notice the difference in the impedance scales.

Mentions: A representative example of the typical morphology of the airflow and impedance signals obtained in a control (A) and asthmatic (B) individual is presented in Figure 1. Notice the difference in the impedance scales.


Within-breath analysis of respiratory mechanics in asthmatic patients by forced oscillation.

Veiga J, Lopes AJ, Jansen JM, Melo PL - Clinics (Sao Paulo) (2009)

Typical airflow and respiratory impedance analyzed in the control group (A) and asthmatic (B) individuals. Notice the difference in the impedance scales.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2710438&req=5

f1-cln64_7p649: Typical airflow and respiratory impedance analyzed in the control group (A) and asthmatic (B) individuals. Notice the difference in the impedance scales.
Mentions: A representative example of the typical morphology of the airflow and impedance signals obtained in a control (A) and asthmatic (B) individual is presented in Figure 1. Notice the difference in the impedance scales.

Bottom Line: The within-breath analysis of respiratory mechanics by the monofrequency Forced Oscillation Technique (mFOT) is of great interest in both physiopathology studies and the diagnosis of respiratory diseases.Forced Oscillation Technique data were interpreted using the mean respiratory impedance (Zt), the impedance during inspiration (Zi), expiration (Ze), at the beginning of inspiration (Zii), and at expiration (Zie).The peak-to-peak impedance (Zpp) was also calculated by the subtraction of Zii from Zie.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Instrumentation Laboratory, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro/RJ, Brazil.

ABSTRACT

Introduction: The within-breath analysis of respiratory mechanics by the monofrequency Forced Oscillation Technique (mFOT) is of great interest in both physiopathology studies and the diagnosis of respiratory diseases. However, there are limited data on the use of this technique in the analysis of asthma. This study evaluates within-breath mechanics of asthmatic individuals and the contribution of the mFOT in the asthma diagnosis.

Methods: Twenty-two healthy and twenty-two asthmatic subjects, including patients with mild (n=8), moderate (n=8), and severe (n=6) obstruction, were studied. Forced Oscillation Technique data were interpreted using the mean respiratory impedance (Zt), the impedance during inspiration (Zi), expiration (Ze), at the beginning of inspiration (Zii), and at expiration (Zie). The peak-to-peak impedance (Zpp) was also calculated by the subtraction of Zii from Zie. Receiver operating characteristic curves were used to determine the sensitivity (Se) and specificity (Sp) of m Forced Oscillation Technique parameters in identifying asthma.

Results: Respiratory impedance values were significantly higher in asthmatics: Zt (p<0.001), Zi (p<0.001), Ze (p<0.001), Zii (p<0.001), Zie (p<0.001), and Zpp (p<0.003). The best parameters for detecting asthma were Zi, Zii, and Zie (Se=90.9%, Sp=90.9%), followed by Zt and Ze. These results are in close agreement with recently published theories and pathophysiological fundamentals.

Conclusions: mFOT permits a non-invasive and detailed analysis in different phases of the respiratory cycle, providing parameters that are adequate for the diagnosis of asthma with high accuracy. These results confirm the high clinical and scientific potential of this methodology in the evaluation of asthmatic patients.

Show MeSH
Related in: MedlinePlus