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In this new informative capsule we discuss the importance of spirometry in Cystic Fibrosis with Josep L. Valera, nurse at Hospital Son Espases.
What is spirometry?
A spirometry test measures the health of the lungs and helps diagnose and monitor lung disease.
The test consists of a forced expulsion of air in a device called a spirometer. This test measures the air that enters and exits the lungs and how fast it can do so.
How is a spirometry test prepared?
It does not require special preparation, but the results may be altered by certain activities such as smoking, drinking coffee, strenuous exercise or eating a large meal before the test. Therefore, it is advisable not to do any of these activities two hours before the test.
In any case, it is important to talk to the healthcare professional team beforehand to clarify any doubts.
How is spirometry performed?
The health personnel will demonstrate how to blow into the spirometer before the test. Once the person is ready, he/she will put on a nose clip, take a deep breath in as much air as he/she can and then blow out as fast and hard as he/she can at least three times.
During the test, you will be asked to breathe in as deeply as you can, place your lips around the mouthpiece tightly, do your best to expel air as quickly as possible, and keep breathing out until your lungs are empty and until the health personnel tells you to stop.
How do you know if spirometry is properly performed?
In order for spirometry to be evaluated, it must meet internationally established quality criteria. Furthermore, there should be no major differences between the different tests performed.
What results does a spirometry test measure?
Two main outcomes are measured:
- FEV1: It is the amount of air expelled in a forced way during the first second of expiration. According to parameters such as age, height and gender, there are established values considered “normal”.
- FVC: Expresses the Forced Vital Capacity, that is, the maximum volume of air exhaled, with the maximum possible effort, starting from a maximum inspiration.
If a person obtains a low FEV1 result, he/she may be suffering from airway narrowing, possibly due to some respiratory pathology.
Is spirometry a reference test?
Although spirometry provides results that should be taken into account, there are other tests that can give a relative value to the FEV1 and FVC data obtained. To give an example that can be seen in Cystic Fibrosis, a person with CF with a higher FEV1 than another person with CF may have less endurance capacity than the latter.
Therefore, it is important to relativize the data obtained from spirometry with other tests such as plethysmography.
Is it good to have a spirometer at home?
Advances in technology allow us to know many more things that we did not know before. Having a spirometer at home is not a bad thing, as long as you know how to use it and, above all, that it is not taken as the only reference test to know if a person is well or not.
A specific case could be that the person who performs spirometry at home does not apply the steps well and the result is unreliable. In this case, if a person takes this value as a single reference, he may have an unrealistic idea of his or her physical condition.
In addition, spirometry should be used as a time trend test, because the person’s conditions can vary in a short time for good and for not so good, so the test done in short periods of time would give disparate results.