Chronic obstructive pulmonary disease study of choice

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Roukoz A. Karam, M.D.[2]

Overview[edit | edit source]

The diagnosis of COPD is confirmed by spirometry, a test that measures the forced expiratory volume in one second (FEV₁), which is the greatest volume of air that can be breathed out in the first second of a large breath. Spirometry also measures the forced vital capacity (FVC), which is the greatest volume of air that can be breathed out in a whole large breath. Normally, at least 70% of the FVC comes out in the first second (i.e. the FEV₁/FVC ratio is >70%). A ratio less than normal defines the patient as having COPD.

Diagnostic Study of Choice[edit | edit source]

Pulmonary Function Test / Spirometry[edit | edit source]

• Many patients labeled as having airway obstruction do not have obstruction when tested^[1].
• COPD is particularly characterized if a ratio of forced expiratory volume over 1 second (FEV₁) to forced vital capacity (FVC) being < 0.7 and the FEV₁ < 70% of the predicted value when compared with a matched control. ^[2], ^[3] (see Spirometry).^[4]

• Normally, at least 70% of the FVC comes out in the first second (i.e. the FEV₁/FVC ratio is >70%). A ratio less than normal defines the patient as having COPD.
• More specifically, the diagnosis of COPD is made when the FEV₁/FVC ratio is <70%.
• The GOLD criteria also require that values are after bronchodilator medication has been given to make the diagnosis,
• The NICE criteria also require FEV1%.
• According to the ERS criteria, it is FEV1% predicted that defines when a patient has COPD, that is, when FEV1% predicted is < 88% for men, or < 89% for women.
• Spirometry can help to determine the severity of COPD.^[4]
• The FEV₁ (measured after bronchodilator medication) is expressed as a percentage of a predicted "normal" value based on a person's age, gender, height and weight:
• The severity of COPD also depends on the severity of dyspnea and exercise limitation. These and other factors can be combined with spirometry results to obtain a COPD severity score that takes multiple dimensions of the disease into account.^[5]

References[edit | edit source]