Spirometers And What They Are Used For

By Marissa Velazquez


Spirometers are a very useful tool for a doctor to diagnose breathing conditions such as chronic obstructive disease (COPD) and lung capacity in general for those who present symptoms of concern. They are a great diagnostic tool for those who are currently under treatment for lung conditions to see if the treatment is effective. It measures the flow of air going in and out of the lungs and how fast it is moving.

If a doctor suspects symptoms are caused by such conditions as pulmonary fibrosis, emphysema, chronic bronchitis, COPD, or asthma, a test may be ordered. For those who have been diagnosed with one of these conditions, this test can be used to see how effective medication is working and to make sure symptoms are under control.

Prior to taking the test one will need to avoid using inhaled or other medications. Loose clothing should be worn that will not constrict the ability to take a deep breath and one should avoid eating a large meal before testing so that breathing will be easier.

When taking the test a soft clip will be placed on the nostrils to keep them closed and filtered mouthpieces may be used to prevent the spread of germs. The patient will then take a deep breath and breathe out as hard as possible for a few seconds into a tube that is attached to the spirometer. Dizziness or shortness of breath may be felt shortly after doing this. The test may need to be repeated up to three times to get consistent and accurate readings.

If inhaled medications are administered after the initial test to keep the lungs open, one should wait at least 15 minutes before taking another test. Comparison can then be made between the two tests to see if the medication improved airflow. Each test takes less than 15 minutes to do. The measurements include the largest amount of air that can be exhaled, called forced vital capacity (FVC), and another reading shows how much air can be exhaled in one second, known as forced expiratory volume (FEV-1).

A spirometer test is used to diagnose and provide asthma management, detect respiratory disease for those who show symptoms of breathlessness, and to distinguish between respiratory conditions and cardiac disease. It can measure bronchial responsiveness or differentiate between an obstructive and a restrictive lung disease. It is used to assess the impairment from occupational asthma or identify risk from pulmonary barotrauma while scuba diving. It is also used for risk assessment before the administration of anesthesia or prior to cardiothoracic surgery. This test can measure the treatment of conditions that it detects and diagnose the dysfunction of vocal cords.

In order for this test to show accurate results, the patient needs to be cooperative. It can be used on children, but it is advised that they be at least 6 years of age or more. It is not a good test for those who are heavily sedated, have limited respiratory effort, are unconscious, or cannot understand the instructions.

Spirometers can be a part of bronchial challenge testing, to check hyper-responsiveness to either inhalation of dry or cold air, during rigorous exercise, or the use of a medication such as a histamine or a methacholine agent. Other lung function testing can include a nitrogen washout or a plethysmography.




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