The Diagnostic Value of Forced Expiratory Time

Objective: Airway obstruction can be clinically quantified at the bedside by measuring the time taken for forced expiration. The aim of this study was to examine the accuracy of the forced expiratory time in detecting airflow limitation, and small airway disease when compared with simple spirometry as a gold standard test. Method: Simple spirometry and forced expiratory time were performed on 201 subjects (age range; 12-81 years), referred to a pulmonary function laboratory at a tertiary care hospital. The diagnostic accuracy of forced expiratory time and its correlation with spirometric parameters were tested. Forced expiratory time > 6 seconds was regarded as abnormal, and the ratio of forced expiratory volume in the first second to forced vital capacity of < 70% was considered indicative of an airflow limitation. Results: Forced expiratory time was found to correlate weakly with spirometric parameters. Forced expiratory time at a cut-off value of => 6 seconds had a sensitivity of 61% and a specificity of 79% in predicting obstructive airway disease when compared with simple spirometry. On the other hand, the sensitivity and the specificity of forced expiratory time in predicting small airway disease were 47% and 86%, respectively. Conclusion: Forced expiratory time does not correlate well with all parameters of a simple spirometry. Its sensitivity and specificity for detecting airflow limitation and small airway disease were not high enough to be used as a diagnostic test. However, it may be effective enough to be utilized to confirm the diagnosis of small airway disease.

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Validation of Forced Expiratory Volume at 6 Seconds of Exhalation (FEV 6 ) in the Detection of Small Airway Disease

CHEST Journal ◽

10.1378/chest.2277470 ◽

2015 ◽

Vol 148 (4) ◽

pp. 894A

Author(s):

Edgardo Tiglao ◽

Teresita DeGuia ◽

Maria Encarnita Limpin ◽

Aileen Guzman-Banzon

Keyword(s):

Airway Disease ◽

Forced Expiratory Volume ◽

Small Airway ◽

Small Airway Disease

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EVALUATION OF SMALL AIRWAY REVERSIBILITY AMONG ASTHMATIC PATIENTS WITH NON-OBSTRUCTIVE PATTERNS OF SPIROMETRY

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v5i3.1809 ◽

2021 ◽

Vol 5 (3) ◽

Author(s):

Tarig Merghani ◽

Azza Alawad

Keyword(s):

Airway Disease ◽

Forced Expiratory Volume ◽

Small Airway ◽

Small Airways ◽

Asthmatic Patients ◽

Peripheral Airways ◽

Flow Parameters ◽

Small Airway Disease ◽

Forced Expiratory Flow ◽

Airway Reversibility

Background: Although the forced expiratory flow parameters are increasingly used in the diagnosis of small airway disease (SAD), the reversibility of these indicators is rarely described. The aim of this study is to evaluate the association of small airways reversibility with the presence of SAD and bronchodilator reversibility (BDR) of the proximal airways. Methods: The forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and the indicators of SAD (FEF25%, FEF50%, FEF75%, FEF25-75%, and FEF75-85%) were measured before and 20 minutes after salbutamol administration (200 mcg by using inhaler/Spacer). Positive BDR was accepted when FEV1 or FVC was increased ? 12% and > 200 ml, indicating responsive proximal airways. Positive small airway reversibility was diagnosed when any of the small airway indicators is increased ? 30% above the baseline results. All measurements were performed with the All-flow spirometer (Clement Clarke International, Harlow, UK). Results: Evidence of SAD was found in 62.1% of all participants and in 75.2% of those who showed responsive proximal airways. The positive predictive value of the SAD in diagnosing responsive proximal airways was 67.8%. The reversibility of the small airway indicators showed insignificant association with the FEV1 or FVC BDR. The reversibility of FEF50%, FEF75% and FEF25-75% showed significant association with the diagnosis of SAD, with specificities ranging from 75.5%-81.1%. Conclusion: SAD has a significant association with positive reversibility of both the proximal and the peripheral airways. Further studies are needed to evaluate the clinical significance of positive small airway reversibility in the diagnosis and management of obstructive lung diseases. Keywords: Asthma; Small airway disease; Bronchodilator Reversibility, FEV1, FVC; FEF25-75%

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Bullous Parametric Response Map for Functional Localization of COPD

Journal of Digital Imaging ◽

10.1007/s10278-021-00561-z ◽

2022 ◽

Author(s):

Kuo-Lung Lor ◽

Yeun-Chung Chang ◽

Chong-Jen Yu ◽

Cheng-Yi Wang ◽

Chung-Ming Chen ◽

...

Keyword(s):

Target Selection ◽

Airway Disease ◽

Routine Care ◽

Small Airway ◽

Airflow Limitation ◽

Normal Lung ◽

Severe Emphysema ◽

Small Airway Disease ◽

Functional Localization ◽

Parametric Response

AbstractAdvanced bronchoscopic lung volume reduction treatment (BLVR) is now a routine care option for treating patients with severe emphysema. Patterns of low attenuation clusters indicating emphysema and functional small airway disease (fSAD) on paired CT, which may provide additional insights to the target selection of the segmental or subsegmental lobe of the treatments, require further investigation. The low attenuation clusters (LACS) were segmented to identify the scalar and spatial distribution of the lung destructions, in terms of 10 fractions scales of low attenuation density (LAD) located in upper lobes and lower lobes. The LACs of functional small airway disease (fSAD) were delineated by applying the technique of parametric response map (PRM) on the co-registered CT image data. Both emphysematous LACs of inspiratory CT and fSAD LACs on expiratory CT were used to derive the coefficients of the predictive model for estimating the airflow limitation. The voxel-wise severity is then predicted using the regional LACs on the co-registered CT to indicate the functional localization, namely, the bullous parametric response map (BPRM). A total of 100 subjects, 88 patients with mild to very severe COPD and 12 control participants with normal lung functions (FEV1/FVC % > 70%), were evaluated. Pearson’s correlations between FEV1/FVC% and LAV%HU-950 of severe emphysema are − 0.55 comparing to − 0.67 and − 0.62 of LAV%HU-856 of air-trapping and LAV%fSAD respectively. Pearson’s correlation between FEV1/FVC% and FEV1/FVC% predicted by the proposed model using LAD% of HU-950 and fSAD on BPRM is 0.82 (p < 0.01). The result of the Bullous Parametric Response Map (BPRM) is capable of identifying the less functional area of the lung, where the BLVR treatment is aimed at removing from a hyperinflated area of emphysematous regions.

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Central airway and peripheral lung structures in airway disease dominant COPD

ERJ Open Research ◽

10.1183/23120541.00672-2020 ◽

2021 ◽

pp. 00672-2020

Author(s):

Naoya Tanabe ◽

Kaoruko Shimizu ◽

Kunihiko Terada ◽

Susumu Sato ◽

Masaru Suzuki ◽

...

Keyword(s):

Airway Disease ◽

Small Airway ◽

Airflow Limitation ◽

Volume Percent ◽

Wall Area ◽

Small Airway Disease ◽

Peripheral Lung ◽

Airway Tree ◽

N 93 ◽

Central Airway

The concept that the small airway is a primary pathological site for all COPD phenotypes has been challenged by recent findings that the disease starts from the central airways in COPD subgroups and that a smaller central airway tree increases COPD risk. This study aimed to examine whether the computed tomography (CT)-based airway disease-dominant (AD) subtype, defined using the central airway dimension, was less associated with small airway dysfunction (SAD) on CT, compared to the emphysema-dominant (ED) subtype.COPD patients were categorised into mild, AD, ED, and mixed groups based on wall area percent (WA%) of the segmental airways and low attenuation volume percent in the Kyoto-Himeji (n=189) and Hokkaido COPD cohorts (n=93). The volume percent of SAD regions (SAD%) was obtained by nonrigidly registering inspiratory and expiratory CT.The AD group had a lower SAD% than the ED group and similar SAD% to the mild group. The AD group had a smaller lumen size of airways proximal to the segmental airways and more frequent asthma history before age 40 years than the ED group. In multivariable analyses, while the AD and ED groups were similarly associated with greater airflow limitation, the ED, but not the AD group, was associated with greater SAD%, whereas the AD, but not the ED group, was associated with a smaller central airway size.The CT-based AD COPD subtype might be associated with a smaller central airway tree and asthma history, but not with peripheral lung pathologies including small airway disease, unlike the ED subtype.

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