Have you ever wondered what all those lung capacities and volumes you hear so much about actually represent? We thought it might help you to have a visual aid to help define what they mean and how they work, so here you go!
Below is an explanation of what each volume/capacity title means. When performing a PFT your therapist will not only be recording what your flows are, but what your volumes and capacities are, as well. Hearing all of the titles and seeing the abbreviations can be difficult to understand, and we would like to make it easier.
Total Lung Capacity (TLC): The total volume of air your lungs are capable of holding after you inhale slowly and deeply.
Tidal Volume (Vt): The volume of air you breathe with each regular breath.
Functional Residual Capacity (FRC): The amount of air in your lungs after a regular exhaled breath.
Residual Volume (RV): The amount of air in your lungs after you exhale
completely. It can be measured by inhaling a gas and measuring how much of that gas is exhaled.
Expiratory Reserve Volume (ERV): The difference in the amount of air in your lungs after a normal exhalation (FRC) and the amount after you exhale with force (RV).