Mrs. Hoffman's medical record indicates previous pulmonary function tests as follows: baseline FEV1 50.7L, FVC 51.5 L, FEV/FVC 46%. Define FEV, FVC, and FEV/FVC, and indicate how they are used in the diagnosis of COPD

Question

How can these measurements be used in treating COPD?

Answer 1

• These tests are types of spirometric measurements, which include:
- Forced expiratory volume (FEV1)
- Forced vital capacity (FVC)
- Ratio of FEV1/FVC: A ratio of less than 70% FEV1/FVC is generally indicative of obstructive disease
• These tests are used for diagnostic purposes, to assist in the prescription of therapy, and to evaluate responsiveness to treatment.
• In general, when treatment is effective, the FEV1/FVC should improve.
• FEV1
- Forced expiratory volume is the volume of air forcefully expired during the first second after a full breath.
- It usually accounts for >75% of the FVC.
- Expiratory flow rate is prolonged when there is an increase in secretions or loss of lung elastic recoil.
• FVC
- Forced vital capacity is the maximum volume of air that can be forcibly expelled after inhaling as deeply as possible.
- Patients with obstructive lung disease will have a normal or slight decrease in FVC due to their inability to exhale efficiently.
• Ratio of FEV1/FVC: This is the percentage of vital capacity expired in the first second of maximal expiration.
• In COPD, if the FEV1/FVC is less than 0.70, then COPD is indicated. Thereafter, the GOLD classification method can be used.
- GOLD 1 (Mild): FEV1 ≥ 80% predicted
- GOLD 2 (Moderate): 50% ≤ FEV1 < 80% predicted
- GOLD 3 (Severe): 30% ≤ FEV1 < 50% predicted
- GOLD 4 (Very Severe): FEV1 < 30% predicted