| FEF50 | forced expiratory flow at 50% of forced vital capacity |
|---|---|
| FEF50/FIF50 | ratio of expiratory flow to inspiratory flow at 50% of forced vital capacity |
| FIF50 | forced inspiratory flow at 50% of forced vital capacity |
| FIVC | forced inspiratory vital capacity |
| FOAVF | failure of all vital forces |