Pulmonary function testing (PFT) is a process for assessing functional status of the lungs, for obstructive and restrictive lung disease screening, and for evaluating treatment response (e.g., medications, chest physical therapy). Spirometry, using a spirometer, is the most common of the pulmonary function tests and measures the amount (volume) and the speed (flow) of air that can be inhaled and exhaled. It is designed to measure changes in lung volume and can only measure lung volume compartments that exchange gas with the atmosphere. Graphical measurement of gas movement (in and out of the chest) is referred to as a spirograph, and the tracing is called a spirogram. Spirogram tracings typically include both predicted and observed values to aid in clinical diagnostic evaluation.
The spirometry procedure is highly dependent on individual effort and cooperation and to ensure reproducibility, is generally repeated three times. Typically, individuals are...