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

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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The Diagnostic Value of Forced Expiratory Time

Saudi Journal of Internal Medicine ◽

10.32790/sjim.1.1.7 ◽

2011 ◽

Vol 1 (1) ◽

pp. 39-42

Author(s):

Siraj O. Wali

Keyword(s):

Tertiary Care ◽

Airway Disease ◽

Diagnostic Value ◽

Forced Expiratory Volume ◽

Small Airway ◽

Airflow Limitation ◽

Forced Expiration ◽

Care Hospital ◽

Expiratory Time ◽

Small Airway Disease

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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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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