Forced Expiratory Volume

Article Author:
Sharoon David

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Christopher Edwards

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Saad Nazir
William Gossman
Hassam Zulfiqar
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
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Mark Pellegrini
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Nazia Sadiq
Hajira Basit
Phillip Hynes

5/13/2019 11:24:33 PM


Forced expiratory volume (FEV) refers to the volume of air that can be exhaled during a forced breath in t seconds.[1] Its usual representation as FEV followed by a subscript that indicates the number of seconds in which the measurement is made. For instance, forced expiratory volume in 1 second (FEV1) is the maximum amount of air that the subject can forcibly expel during the first-second following maximal inhalation.[2] Similarly, forced expiratory volume in 6 seconds (FEV6) is the volume of forcibly exhaled air measured during 6 seconds.[3]

Issues of Concern

Spirometry is a test that is used to measure the ability of a person to inhale and exhale air respective to time. Forced expiratory volume (FEV) is one of the main results of spirometry.[1]

Age and gender are the major factors that affect the average values of FEV in healthy individuals. Height, weight, and ethnicity are some of the other influencing factors.[4][5] FEV values greater than 80% of the predicted average value are considered to be normal.[6] Other factors that can affect the results include decreased patient effort, poor inhalation, inability to follow directions, and some medical conditions prevent successful spirometry. A poor effort correlates with an overestimation of FEV1.[7]

Clinical Significance

Forced expiratory volume in the first second (FEV1) can be used to categorize the severity of obstructive lung diseases, such as asthma, and chronic obstructive pulmonary disease (COPD). This severity can be derived by expressing FEV1 as a percentage of the predicted value in a patient.[8][9][10]

FEV1 can also be helpful in the interpretation of the reversibility test, also known as the bronchodilator test. This test assesses the bronchodilator response in a patient with obstructive lung disease. It involves the administration of a bronchodilator, such as an anticholinergic agent or a short-acting beta-2 agonist. An increase in the FEV1 of greater than or equal to 12%, or greater than or equal to 200 mL, after bronchodilator use, is considered to be a positive bronchodilator response. A positive response typically presents in reversible airway obstruction, such as in asthma; whereas nonreversible obstruction as seen in COPD, may not show a positive response to the administration of a bronchodilator.[8][10][11]

The ratio of FEV1 to FVC (FEV1/FVC, also known as FEV1%) can help distinguish obstructive and restrictive lung diseases. In obstructive diseases, FEV1 reduction is due to the increased airway resistance to expiratory flow. A reduction in the FVC may also present because of premature airway closure in expiration; however, it is not affected as much as FEV1 and thus, is not decreased in the same proportion as FEV1, which can lead to a reduced value of FEV1/FVC, of less than 70%.[9] On the other hand, in restrictive lung diseases, such as chest wall deformities, and idiopathic pulmonary fibrosis, the FVC may be decreased more as compared to FEV1, thus giving an FEV1/FVC ratio of more than 70%.[12]

Forced expiratory volume in 6 seconds (FEV6) has been proposed as a valid alternative for forced vital capacity (FVC) in the diagnosis of airflow obstruction in elderly individuals.[3][13][14]

  • Image 9940 Not availableImage 9940 Not available
    Image courtesy S Bhimji MD
Attributed To: Image courtesy S Bhimji MD

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Forced Expiratory Volume - Questions

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A 60-year-old man who is a chronic smoker presents to the clinic with complaints of chronic productive cough and progressively worsening dyspnea on exertion. The patient does not give any history of fever or chills. Chest x-ray reveals hyperinflation of the lungs with flattening of the diaphragm. Which of the following parameters may be helpful in classifying the severity of this condition?

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A 20-year-old woman with a recent history of upper respiratory tract infection presents with progressively worsening dyspnea and wheezing for the last two days. Chest auscultation reveals evidence of wheezing in both lungs. The patient has had similar episodes in the past as well. Bronchodilator test is performed and the forced expiratory volume in 1 second (FEV1) is measured. Which of the following responses is most likely to be seen in this patient?

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Forced Expiratory Volume - References


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Matarese A,Sardu C,Shu J,Santulli G, Why is chronic obstructive pulmonary disease linked to atrial fibrillation? A systematic overview of the underlying mechanisms. International journal of cardiology. 2019 Feb 1;     [PubMed]
Shapira U,Krubiner M,Ehrenwald M,Shapira I,Zeltser D,Berliner S,Rogowski O,Shenhar-Tsarfaty S,Bar-Shai A, Eosinophil levels predict lung function deterioration in apparently healthy individuals. International journal of chronic obstructive pulmonary disease. 2019;     [PubMed]
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