Lung Function Tests
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Several different lung function tests are used to diagnose diseases such as asthma or COPD. To find out more about these tests, watch this video.
Transcript: The contraptions you see in your pulmonologist's exam room AREN'T there to scare you - they have a real...
The contraptions you see in your pulmonologist's exam room AREN'T there to scare you - they have a real purpose! First, let's talk about the SPIROMETER. This device helps doctors diagnose ASTHMA, chronic obstructive pulmonary disease, BRONCHITIS and emphysema. During a spirometry test, a patient exhales HARD into the device several times. The results tell a doctor MANY things about your lung function-but the two MAIN measurements show how much air you can exhale after INhaling deeply, and the amount of air you can exhale in ONE SECOND. Spirometry is useful to give an initial diagnosis of disease, to gauge the SEVERITY of disease, and to determine whether or not medications-such as bronchodilators-are working. The measure of what is called FEV1 or the forced expiratory volume in 1 second, let's you know how you are doing. If, after using a bronchodilator, you can blow out less than 30% of the expected volume of air, you have severe lung dysfunction; if you can blow out 80% or MORE then it is mild. A methacholine challenge test HELPS CONFIRM AN ASTHMA DIAGNOSIS. Before and after spirometry, you inhale increasing amounts of methacholine-a substance known to cause airway spasms. If spirometry shows it reduces your lung function by 20% or more, your diagnosis of asthma is confirmed. A bronchodilator is always provided afterwards to stop the reaction. A NITRIC OXIDE TEST also helps a doctor diagnose asthma, as well as COPD and chronic bronchitis. When there is airway inflammation, a person exhales nitric oxides. The amount exhaled indicates the extent of inflammation A lung DIFFUSION test evaluates how well the lungs can SEND oxygen to the blood and DIFFUSE carbon dioxide out of it. This test HELPS diagnose COPD, emphysema, pulmonary hypertension and other lung conditions. COPD patients and doctors use PULSE OXIMETERS to make TREATMENT decisions. This non-invasive device is placed on your finger, toe or earlobe. It emits infrared beams of light that measure how much oxygen is in the blood. Doctors use pulse oximetry to see if oxygen therapy is working, and patients can use it at home to find out if they need to adjust their oxygen flow during exercise or sleep. An arterial blood gas test also measures the amount of oxygen AND CARBON DIOXIDE in the blood, but it's more ACCURATE than pulse oximetry. This test is done in a doctor's office because it involves drawing blood. It's used to initially decide if a patient needs oxygen therapy or later to CONFIRM the results of pulse oximetry. To learn more about your respiratory health, watch other videos in this series.More »
Last Modified: 2012-11-17 | Tags »
spirometer, nitric oxide test, methacholine, forced expiratory volume, pulse oximeter, arterial blood gas test, diagnosing asthma, diagnosing copd, finger pulse oximeter, incentive spirometer, pulmonary function test asthma, copd, lung function, coughing, wheezing, peak flow meter, lung volume respiratory, respiratory system, respiratory problem