Pulmonary function tests measure airflow velocity, lung volume, gas exchange, and respiratory muscle function. Basic lung function tests include spirometry, bronchodilation test, and pulse oximetry.
These tests also provide insight into pulmonary physiology (function) and may serve to narrow the differential diagnosis and suggest further diagnostic and therapeutic strategies.
Spirometry is a painless method that measures lung capacity and airflow rate through the airways. It measures lung function, specifically the amount and/or speed of air that can be inhaled and exhaled. When performing the test, it is important that the person does not breathe through the nose, but that exhales the air from the lungs completely. The total duration of the test is about ten minutes.
The test needs to be performed 3 times in order to achieve greater accuracy of the results.
The nurse will give a plastic mouthpiece (probe) that is changed for each patient. The mouthpiece should be covered with the lips so that the tongue does not enter the opening of the mouthpiece, while the nose should be closed with a clip. According to the instructions of the medical staff, you will breathe into the mouthpiece releasing air from the lungs and inhaling again. It is important that the patient listens to the staff’s instructions during the test.
Bronchodilation test involves performing spirometry after inhalation of fast-acting bronchodilators. It is most often inhaled salbutamol. The test result is interpreted on the basis of the difference achieved between the first and the second test.