Pulmonary Function Test

Detailed Information:
In order to accurately measure the ability of the lungs, the patient must not have had any outside stimulation from smoking, heavy eating or asthma drugs, for several hours before the test.

During the test, a clip is placed on the patient's nose so that none of the exhaled air escapes measurement. Lung function is measured with a spirometer. The spirometer consists of a tube attached to a small machine that measures the force of the exhaled air. The patient is asked to take deep breaths and exhale forcefully into the tube. The test will last for up to 45 minutes, because three or more repititions must be administered to assure the validity of the results.

The spirometer measures the following:

• The vital capacity (VC), or the maximum volume of air that can be inhaled or exhaled from the lungs
• The peak expiratory flow rate (PEFR), or the maximum flow rate generated during forced exhalation
• The forced expiratory volume (FEV1), or the amount of air expired in one second.