Table 25-1.
Terms Used for Spirometric Measurements
| Term | Previously Used Terms | Description |
|---|---|---|
| Vital capacity (VC) | Largest volume measured on complete exhalation after full inspiration | |
| Forced VC (FVC) | Timed VC, fast VC | VC performed with forced expiration |
| Forced expiratory volume with subscript indicating interval in seconds (FEVt) (e.g., FEV1) | Timed VC | Volume of gas exhaled in a given time during performance of FVC |
| Percentage expired in t seconds (FEVt%) (e.g., FEV1%) | Timed VC | FEVt expressed as percentage of FVC |
| Forced midexpiratory flow (FEF25%–75%) | Average flow rate during middle 50% of the FVC | Maximal midexpiratory flow |
| Forced expiratory flow with subscript indicating volume segment (FEFV1–V2) (e.g., FEF200–1200) | Maximal expiratory flow rate | Average rate of flow for a specified segment of FVC, most commonly 200–1200 mL in adults |
| Maximal voluntary ventilation (MVV) | Maximum breathing capacity (MBC) | Volume of air a subject can breathe with voluntary maximal effort for a given time |
Modified from Kory RC: Clinical spirometry: recommendation of the Section on Pulmonary Function Testing, Committee on Pulmonary Physiology, American College of Chest Physicians. Dis Chest 43:214, 1963.