Pulmonary Function Testing measures how well you are breathing. There are different types of pulmonary function tests that can be done. Spirometry is on type of pulmonary function test. This is a simple test to measure how much (volume) and how fast (flow) you can move air into and out of your lungs.
Why test my lung function?
Through routine spirometry, lung diseases can often be diagnosed in the early stages when treatment is most effective. Once a lung disease is diagnosed and treated, routine spiromety tests can monitor changes in lung functions with specific treatment. This will help your doctor find the best treatment plan for you.
What happens during the spirometry test?
You will be instructed how to perform spirometry. Basically, you will take in a deep breath and blow into a mouthpiece attached to the spirometer. You will blow out as hard and as fast as you can until your lungs feel absolutely empty. You will be asked to repeat the test several more times until there are two to three good efforts. You will be coached and encouraged to do your best during the test. A good effort during the test is important to get good results.
A computerized sensor (which is part of the spirometry) calculates and graphs the results. The results demonstrate a persons air flow rates or the colume forced out within the first second. This is the Forced Expiratory Volume in the first second (FEV1). This indicates whether or not there is airway obstruction. Spirometry also records the total volume of air forced out of the lungs. This is the forced Vital Capacity (FVC).
Ask your doctor about having your lungs tested with Spirometry to identify any lung flow problems.
The measurement, by a form of gas meter, of volumes of gas that can be moved in or out of the lungs. The classical spirometer is a hollow cylinder (bell) closed at its top. With its open end immersed in a larger cylinder filled with water, it is suspended by a chain running over a pulley and attached to a counterweight. The magnitude of a gas volume entering or leaving is proportional to the vertical excursion of the bell. Volume changes can also be determined from measurements of flow, or rate of volume change, that can be sensed and recorded continuously by a transducer that generates an electrical signal.
The flow signal can be continuously integrated to yield a volume trace.The volume of gas moved in or out with each breath is the tidal volume; the maximal possible value is the vital capacity. Even after the most complete expiration, a volume of gas that cannot be measured by the above methods, that is, the residual volume, remains in the lungs. It is usually measured by a gas dilution method or by an instrument that measures blood flow in the lungs. Lung volumes can also be estimated by radiological or optical methods.
At the end of an expiration during normal resting breathing, the muscles of breathing are minimally active. Passive (elastic and gravitational) forces of the lungs balance those of the chest wall. In this state the volume of gas in the lungs is the functional residual capacity or relaxation volume. Displacement from this volume requires energy from natural (breathing muscles) or artificial (mechanical) sources.