Spirometry – Lung function testing: Pulmo Sleep Elixir✓

Spirometry is a standard test that doctors, most often pulmonologists, use to measure how optimal a patient’s lung function is, i.e., how good their respiratory functions are.

Spirometry results provide data that helps monitor lung health and diagnose lung diseases. Spirometry tests thus reveal many useful facts about the lungs and their performance. 

Common questions from patients who have received a referral for spirometry or believe they should undergo it include: How is spirometry performed?, Is it advisable and possible for patients to interpret spirometry results?, What indications should be present for a patient to decide on a spirometry test?

We provide answers to common questions about spirometry below.

What is spirometry?

We have already mentioned that spirometry is a test whose results provide an image of lung function, but how exactly does it achieve this, i.e., on what principle does it work? The spirometry test measures the airflow through the lungs, through inhalation and exhalation, thus determining both lung capacity and potential problems in function. 

More technically: spirometry determines lung volumes (expiratory reserve volume, inspiratory reserve volume, tidal volume) and capacities (inspiratory capacity, vital capacity), as well as the volumes of respiratory organs over time (forced expiratory volumes). During forced expiration, the vital capacity is obtained, marked here as forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), as well as flow rates in the flow/volume curve. 

Other designations used in spirometry that should be known are: VC –  vital capacity of the lungs and PEF – peak expiratory flow rate.

When should you go for a spirometry test – indications

Since the spirometry test is a specialist type of test, it is performed when a problem with lung function is noticed and does not fall into the category of tests that everyone should undergo periodically. 

Therefore, when a general practitioner or pulmonologist notices certain indications that may suggest some type of lung problem – they will refer the person for spirometry testing.

Additionally, a person who believes they have breathing problems can personally schedule a spirometry examination at a private clinic or inform their doctor that they believe they need a test, and be referred for spirometry.  

Spirometry is used to confirm or detect: asthma, chronic bronchitis, chronic obstructive pulmonary disease (COPD), pulmonary emphysema, and pulmonary fibrosis. Doctors will, based on certain symptoms, notice indications suggesting one of these diseases (shortness of breath, breath loss, coughing up..), and refer the patient for this diagnosis. 

Also, spirometry tests are mandatory for monitoring the condition in patients who already suffer from such diseases.

How to prepare for spirometry?

Since the preparation instructions for a spirometry test may vary depending on individual patient characteristics (for example, if the patient is on certain medication, it may be recommended to take it earlier or later that day)  – we advise consulting with a doctor about the proper preparation for spirometry .

Generally, it is advised to: not smoke, avoid coffee, and not consume anything that might affect breathing and lung capacity several hours before the test. Intense physical activity, heavy meals, and breathlessness from rushing to the clinic can also affect spirometry results. 

How is spirometry performed?

Spirometry is a non-invasive diagnostic method, and completely painless for the patient, and it is performed quickly. It usually takes about 10-15 minutes.

The spirometry test is performed using a device “spirometer,” into which you breathe through a tube (a clean mouthpiece with an antibacterial filter placed on the device), while the nose is clamped with a small clip to prevent the breathing function of this organ during testing. 

The person being tested should sit upright, with their legs slightly apart on the ground. The pulmonologist gives instructions to the patient on how and when to breathe into the tube during the test. 

Doctor’s instructions given before and during the test must be fully followed to obtain accurate results. These will most often include: inhaling or exhaling as forcefully as possible, keeping lips firmly on the tube to prevent air leakage, and blowing until the lungs are completely emptied. 

Spirometry results and whether patients should interpret them

Spirometry test results will typically not be available immediately after the test, and even if you receive them right away, if you are not a pulmonologist – there is a high chance you will not be able to interpret them. We advise against trying, as the results show several different values that together may indicate a certain diagnosis, so it is best to leave the interpretation to the doctor. 

Additionally, test references vary according to: gender, age, height, and weight of the tested person, so only a specialist doctor can provide a relevant diagnosis. A spirometry result is considered normal if 80% or more of the factors are within the reference values. When the percentage of FVC values is lower – the results are considered abnormal and indicate issues with lung functions. 

Basic units that are useful to know if you have undergone a spirometry test are: 

• FVC (Forced vital capacity) – The maximum amount of air that can be exhaled after the deepest breath. Lower than normal values ​​indicate that there are limiting respiratory functions.
• FEV (Forced expiratory volume) – How much air can be exhaled from the lungs in one second. This information gives the pulmonologist the opportunity to determine a number of specifics about the respiratory problems of the tested person. Low FECV-1 values ​​indicate more significant obstruction.

How safe is spirometry?

Spirometry is considered a very safe diagnostic method. Some people may experience short-term dizziness, trembling, or nausea after the test, and that is perfectly normal. 

The spirometry test involves no risk to health and is entirely non-invasive. The patient’s only task is to follow the doctor’s instructions and perform the test correctly.