Spirometry – course, indications, preparation [EXPLAINED]

Proven content

Spirometry is a test that allows you to check the volume of the lungs and detect possible pathological changes. Thanks to this test, serious respiratory diseases can be diagnosed early and treatment initiated. It is a very important tool in the diagnosis of asthma and chronic obstructive pulmonary disease.

Unfortunately, although fewer and fewer people smoke, still almost one in four regularly uses cigarettes. Remember that smoking is still the main factor contributing to the development of the most serious respiratory diseases, i.e. lung cancer and chronic obstructive pulmonary disease (COPD). That is why the role of prophylaxis is so important.

At that time, tuberculosis was a major threat. It was suspected that it had a negative effect on lung function. The task of the spirometer was initially to test lung function in patients with tuberculosis. The measured lung volume was called vital capacity because low capacity was associated with premature death of patients.

Spirometry to measurement of lung volume and capacityand airflow through the lungs and bronchi. The test involves taking a few deep breaths followed by full exhales. During spirometry, the volume of air inhaled and exhaled from the lungs through a special mouthpiece is assessed. The physician must obtain a minimum of three airflow-lung volume curves. In this way, it is possible to determine the ventilation reserves of the respiratory system and determine whether asthma or COPD is developing.

The measurement is performed by the static (basic) or dynamic method. Static spirometry provides the following data: Tidal Volume (TV), Inspiratory Capacity (IC), Backup Inspiratory Volume (IRV), Backup Expiratory Volume (ERV), Vital Capacity (VC).

To obtain a flow-volume curve and a volume-time curve, execution is required dynamic spirometryduring which you make quick and heavy breaths. The test measures parameters such as Forced Vital Capacity (FVC), Forced Expiratory Volume in One Second (FEV1), Peak Expiratory Flow (PEF), and Forced Expiratory Duration (FET).

Commonly used include:

1. thermal spirometer – this large temperature-sensitive device measures the air flow with high accuracy, using the current, cooling process and keeping the temperature difference constant;
2. pressure spirometer – this type of spirometer measures the flow velocity on the basis of changes in pressure and temperature; another name for this kind of spirometer is pneumotachometr;
3. ultrasonic spirometer – the device uses the Doppler effect, is accurate and insensitive to changes in the environment (such as temperature or humidity), it is also lightweight and – unlike the pressure and thermal spirometer – it does not need to be calibrated;
4. turbine spirometer – air velocity measurement is carried out thanks to the operation of a turbine driven by exhaled air.

The spirometers listed above operate in an open system. Alternatively, but rarely, volumetric spirometers, such as cylindrical or bellows, are used.

Spirometry – COPD and asthma

Although modern spirometers differ from its first version, its task has remained the same. Today, spirometry is mainly used to identify changes caused by asthma and COPD. Thanks to it, the doctor acquires knowledge about any pathological changes in the patient’s respiratory system. It is also used for professions that require good health, such as professional athletes, firefighters, etc.

In Poland, spirometry is rarely performed, despite the fact that the test is readily available. Doctors emphasize that spirometry should be a standard part of prophylaxis, as well as blood count, sugar, blood pressure and hemoglobin control.

Spirometry – contraindications

Spirometry is a safe and painless test, but some people should not do it. Spirometry should be abandoned by:

1. people with diagnosed aneurysm of the aorta or cerebral artery,
2. people after a recent ophthalmic surgery,
3. people after retinal detachment,
4. people who have recently had a stroke or heart attack,
5. people with increased intracranial pressure.

There are also some relative contraindications for performing a spirometry test. These include conditions such as pain after abdominal or chest surgery that would interfere with full inhalation and exhalation, as well as stress urinary incontinence and dementia (dementia).

Spirometry – preparation for the test

There is no need to prepare yourself for spirometry. The correct reading of the result will be possible when the patient’s weight and height are measured. The examination itself is painless. Before spirometry, however, it is worth remembering the following:

1. do not smoke or drink alcohol for at least 4 hours, preferably one day in advance,
2. put on something comfortable, not restricting the movements of the torso,
3. do not eat heavy meals 2 hours before the test,
4. do not perform intense exercise immediately before spirometry (at least 30 minutes before),
5. Certain asthma medications must be discontinued if the test is performed after inhalation of the bronchodilator. In such a situation, the registrar will inform about the need to discontinue drugs.

At first, we breathe calmly. Then we take a deep breath and exhale as much as possible. Most often, it is difficult for patients to exhale for a long time, when we have the impression of empty lungs and lack of air. However, we can only stop at the sign of the person conducting the examination. This is very important. 3 attempts are made without interruptions. The determinant of a correctly performed spirometry are three similar results.

The results of spirometry are assessed by a doctor. The result is given in numbers and in the form of a graph. Most often we will see the so-called flow – volume curve. In this graph, the flow is marked on the vertical axis, and the volume of inhaled and exhaled air is marked on the horizontal axis. The curve has a characteristic shape that allows for quick interpretation of the test.

Spirometry in children

In the case of preschool children, spirometry is difficult to perform. This is mainly due to the need to exhale intensively. In adults, it should last six seconds, while a child has a lower tidal volume and therefore exhalation takes less time. Performing a spirometric test, even with the criteria changed due to age, requires proper cooperation between the child and the doctor.

If a spirometric test in a child is preceded by appropriate preparation (interactive games related to breathing, eg blowing up balloons, explaining the course of the study), there is a chance that they will be able to be properly carried out in children aged 3-6 years. Older children aged 7-10 have a greater chance of success.

Children’s respiratory tests are useful in the diagnosis and monitoring of diseases such as cystic fibrosis and bronchial asthma. Other possible respiratory tests include plethysmography, pulse oscillometry or the technique of forced oscillation

Read also:

1. Chest computed tomography – how to interpret the results?
2. Smog is killing Poles. Why is it dangerous?
3. Pulmonology – what is worth knowing?

The results of the spirometry test

The results of spirometry should be presented to the doctor who will interpret the graph and the values ​​of individual parameters. The standards of spirometry testing differ for men and women, but also for adults, children and seniors. For the correct reading of the results, e.g. age and height formulas are used to calculate the RDS (Residual Standard Deviation). Ultimately, norms are presented in percentiles:

1. adult norm: 5-95 percentile range;
2. norm for children: range of the 3rd to 97th percentile.

Based on the results, the doctor can diagnose diseases of the lung parenchyma, pleura, chest, asthma and chronic obstructive pulmonary disease.

The content of the medTvoiLokony website is intended to improve, not replace, the contact between the Website User and their doctor. The website is intended for informational and educational purposes only. Before following the specialist knowledge, in particular medical advice, contained on our Website, you must consult a doctor. The Administrator does not bear any consequences resulting from the use of information contained on the Website.