Lung function test or spirometry is a test used to check the condition and function of the respiratory tract. In this test, the amount and speed of air that is inhaled and breathed by the patient will be measured. Spirometry helps doctors diagnose diseases related to the respiratory tract, and observes the development of the patient's condition for the therapy given
Spirometry is carried out using an instrument called a spirometer. Some parameters that can be measured by the spirometer include:
- Forced expiratory volume in one second (FEV1). FEV1 is the amount of air that is blowing in one second.
- Forced vital capacity (FVC). FVC is the amount of air that can be breathed in one breath.
- The FVC / FEV1 ratio is a value that indicates what percentage of lung air capacity can be exhaled in 1 second.
Spirometry examination is performed to assess respiratory disturbances, which are divided into two, namely:
- Obstructive airway disease. In this case, the body's ability to exhale is impaired due to narrowing of the airways. For example, asthma and chronic obstructive pulmonary disease.
- Restrictive airway disease. This condition illustrates the reduced capacity of the air in the lungs to expand and hold an amount of air in the lungs. Conditions of changes in lung tissue itself result in restrictive pulmonary disease, such as changes in lung tissue to scar tissue (pulmonary fibrosis).
Lung Function Test Indications
Spirometry is used to determine the condition and function of the lungs if the patient has a cough or shortness that lasts a long time or is at risk of suffering from lung disease, for example, over 35 years of age and smoking. In addition, the spirometry examination is done as a basic examination before surgery. Spirometry can also be used to diagnose diseases, such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, or pulmonary fibrosis, as well as observe the development of the condition and the body's response to the therapeutic treatment given.
Lung Function Test Warning
This test can increase pressure on the head, chest, stomach and eyes. Therefore, consult with a pulmonary doctor first before doing spirometry tests if you have conditions, such as:
- Angina
- Pneumothorax
- Heart attack
- Stroke
- Coughing up blood
- Tuberculosis (TB)
- Hypertension
- Respiratory tract infections
In addition, this test is not recommended for patients who have just had eye surgery and abdominal surgery. Heavy smokers and patients over the age of 70 should consult a doctor first, because this test has the potential to cause complications.
In certain cases, patients will be given inhaled breathing medications (bronchodilators) as a comparison of test results before and after the drug is given. Patients who are allergic to bronchodilators, should tell their doctor. Examples of bronchodilator drugs are beta-2 agonists (for example salbutamol, formoterol, or salmeterol), theophylline, and anticholinergics (for example tiotropium or ipatropium).
Lung Function Test Preparation
Before spirometry is scheduled, the doctor will ask the patient whether he is using bronchodilator drugs. If so, the doctor will ask the patient to stop using the drug before the test, because it can affect the results.
In addition, patients must also prepare for the following:
- Do not smoke, at least for 1 day before the examination.
- Avoid consuming alcohol.
- Do not eat too much. It will interfere with breathing.
- As much as possible avoid using clothes that are too tight, so that you can breathe more easily.
Lung Function Test Procedure
Spirometry examinations are generally carried out in a sitting position. The doctor will ask the patient to puff out the chest, and place himself in the most comfortable position possible. Patients will be provided with a clip (pinch) that is used to pinch and close the nostrils, so that no air comes out of the nostrils and spirometry results can be maximized. Next, the doctor will ask the patient to place the spirometer tube in the mouth. The patient must place the tube as close as possible with the mouth.
After the device is mounted, the patient will be instructed to take a deep breath, hold it for a few seconds, then exhale as hard as possible on the tube. This process is usually repeated up to 3 times. This was done to see if the results of each test were carried out the same. If the results obtained are too varied, the doctor will ask the patient to repeat the process. The doctor will take one of the results with the highest value to be the final result of the examination.
Spirometry tests usually take around 15 minutes. But in certain cases, the time required can be longer. For example if the doctor asks the patient to do a second session using bronchodilators, to compare the results with those obtained in the first session.
After Lung Function Test
After the test, the patient is allowed to go home and move as usual. But for patients who have never used breathing remedies, it will be advisable not to go home immediately so that the doctor can see if there is an allergic reaction to the drug given.
In addition, in patients who have respiratory problems, this test may make the body feel tired. Such patients will be advised to rest for a while before returning home.
The final results of spirometry examination cannot be immediately concluded on the same day. The data obtained must be further discussed by a pulmonary doctor. Inspection results will be compared with predictions of normal conditions. Prediction of the value of normal conditions in each patient can vary, depending on age, weight, and gender. If the spirometer shows results below 80% of the predicted value, then the patient can be said to have a disorder in the respiratory tract.
Risk of Lung Function Tests
Spirometry is a procedure that is relatively fast and safe to do. However, after the examination takes place, the patient can feel some side effects caused by the examination process or the drug used. Among others are:
- Headache
- Diarrhea
- Tremor
- Nausea and vomiting
- Cough
- Dry mouth
