The lung function test, also called spirometry, provides information on the current condition of both lungs and the bronchi within a few minutes.
The pulmonary function test is used for the diagnosis as well as for the follow-up and therapy control of existing lung diseases. Depending on the clinical picture present, it may even happen that patients have to undergo such a lung function test several times a week.
Whether a possible lung weakness is present, an already existing lung disease progresses or has come to a standstill, can be interpreted safely and quickly on the basis of the measured values of a lung function test.
Depending on the sex, age and size of a patient, the pulmonary function test provides individual information about the state of fitness and health of the lungs. Thus, based on the measured values can be read very quickly, for example, whether for years inhalative smoking has already led to permanent damage to the lungs.
Based on the values determined, the pulmonary function test allows accurate conclusions about the course and stage of chronic lung diseases such as asthma, bronchitis or pulmonary emphysema.
An initial diagnosis of these diseases is also possible through the parameters of the pulmonary function test. Over the years, the medical industry has developed very different devices to perform a pulmonary function test safely and easily. Simple spirometers for a quick check of the so-called vital capacity are as much a part of it as well as technically sophisticated devices, which are similar to a telephone booth on the outside.
As so-called bodypletysmography, this special and extensive lung function test is reserved for larger pulmonary practices and medical centers. The pulmonary function test is performed by connecting the patient to the spirometer through a mouthpiece. The nasal breathing is prevented by a special nose clip before the actual test, so that the patient can actually breathe only through the mouth.
Only when perfect test conditions are created can the actual pulmonary function test begin. Therefore, calibration is required for each measurement to calibrate the spirometer to the patient's individual breathing rhythm. A special software detects irregularities and includes them later in the test evaluation, so that the doctor always reliable readings.
In various breathing maneuvers, the patient is urged to inhale and exhale deeply or to hold the air. The lung function test measures both the volume and the force of the exhaled air. If the pulmonary function test is assessed, the ratio of two specific values is decisive. These are the vital capacity and the one second air.
Vital capacity refers to the maximum amount of air that can be exhaled after the deepest possible inhalation. The term of one second air is understood to mean an air volume which can be expelled forcibly within one second.
Based on these two parameters, the pulmonary function test now determines the ratio of the individual one-second air value to the normal value of the vital capacity for the corresponding age group and depending on gender and size. The pulmonary function test gives the ratio of both values in percent. The determined percentage value now only has to be compared with the standard value table in order to be able to make a reliable statement about the lung function of a patient.
Corresponding to the different lung capacities, the norm values for men and women are different. In patients with chronic lung or heart disease, the pulmonary function test is performed at regular intervals in consultation with the treating physician. In this therapy and follow-up, the medication used in each case can be constantly adapted.
The pulmonary function test is therefore a very important instrument for diagnosis and therapy in practice. The measured values are entered in a patient diary. In patients with chronic lung diseases, the pulmonary function test can also be performed at home with a so-called peak-flow meter. As soon as the readings worsen, the doctor must be consulted.