Source and Necessity of Pulmonary Function Testing
Pulmonary Function Tests are important and highly useful examinations in the process of diagnosing, evaluating, and monitoring the treatment of respiratory system diseases such as asthma, chronic obstructive pulmonary disease, occupational lung diseases, etc. Additionally, pulmonary function tests can indicate lung function deterioration before clinical symptoms appear because the lungs have a high reserve capacity. Symptoms like shortness of breath usually appear after significant pathological changes have occurred in the lungs. Pulmonary function testing requires significant cooperation from the patient to perform maximal effort in breathing out and inhaling through the mouth, which is unfamiliar to most people. The timing of inhalation and exhalation is also very important. Therefore, the technician conducting the test must have understanding, expertise, and experience to ensure reliable test results.
Pulmonary Function Testing by Spirometry
This test measures the volume of air inhaled and exhaled from the lungs using a device called a Spirometer. This method is the most commonly used pulmonary function test because it is easy to perform, provides reliable and useful information, and uses uncomplicated equipment. The graph showing the relationship between volume and time is called a Spirogram.
Since spirometry provides several measured values, the main important values for assessing lung function are detailed as follows:
1. FVC (Forced Vital Capacity) is the volume of air forcefully and rapidly exhaled completely after a full inhalation. Interpretation: FVC represents nearly the total volume of air contained in the lungs. This value decreases when lung tissue undergoes fibrosis or the lungs cannot fully expand. This condition is called “RESTRICTIVE (limited lung expansion).” Normal value: greater than 80%
2. FEV1 (Forced Expiratory Volume in one second) is the volume of air forcefully and rapidly exhaled in the first second. FEV1 is the most frequently used data in pulmonary function testing. Interpretation: FEV1 is used together with FVC to calculate the FEV1 / FVC % ratio. Normal value: greater than 80%
3. FEV1 / FVC % is the percentage of air volume exhaled in the first second relative to the total volume of air forcefully exhaled. This is the best indicator of airway obstruction. Interpretation: The FEV1 / FVC % reflects the ability to exhale air from the lungs, depending on the patient’s effort and airway characteristics. If the airways are obstructed or have reduced elasticity, air passage is difficult, and this value decreases. This condition is called “OBSTRUCTIVE (airway obstruction or narrowing).” Normal value: greater than 70%
Types of Lung Abnormalities Detected, Divided into 3 Groups
1. Obstructive means airway obstruction, such as in patients with asthma, emphysema from smoking, or chronic bronchitis. This group shows FEV1 / FVC values below 70%, while FVC remains normal.
2. Restrictive means reduced lung elasticity, leading to decreased lung capacity, such as in patients with lung tissue diseases or abnormalities in the muscles or bones involved in breathing. This group has FVC values below 80% compared to the standard, but FEV1 / FVC is above 70%.
3. Combine means patients who have abnormalities of both types simultaneously.
Risk Groups That Should Undergo Pulmonary Function Testing
- Smokers or those regularly exposed to cigarette smoke
- Those with chronic cough
- Suspected asthma patients
- Suspected emphysema patients
- Occupations at risk, such as working in factories with dust and smoke, mining, or cement work
Complications from Spirometry
Although spirometry is relatively safe, some complications may occur as follows:
- Increased intracranial pressure, which may cause headaches
- Dizziness, lightheadedness, and in some cases, loss of consciousness
- Coughing
- Bronchospasm, especially in patients with asthma or poorly controlled chronic obstructive pulmonary disease
- Chest pain
- Pneumothorax (air leakage in the pleural cavity)
- Oxygen deprivation due to temporary breath-holding during the test
- Infection
How to Maintain Lung Health
- Maintain overall health by eating nutritious food, exercising to strengthen the lungs, getting enough rest, and reducing or quitting smoking
- If experiencing cold symptoms, chronic cough, excessive phlegm, wheezing, shortness of breath, or allergies, seek early medical evaluation and treatment
- Avoid crowded places with dust, aerosols, smoke, pollution, chemicals, and poor ventilation
- Those working with dust, chemicals, or hazardous substances should have annual health check-ups including chest X-rays and pulmonary function tests. If abnormalities are found, prompt treatment and prevention are necessary. Proper and consistent use of protective equipment against dust or chemicals during work is essential. Workers should be knowledgeable about hazards and prevention methods related to these substances
- Implement measures to control, block, or reduce dust and hazardous substances both at the source and in the air
