Spirometry is often used in the Pulmonary Function Tests for measuring the lung function. This is particularly performed for measuring the amount and/ or speed of air flow during exhalation and inhalation. This is the most useful tool for generating pneumotachographs. These graphs are used in assessing the conditions like pulmonary fibrosis, asthma, COPD and cystic fibrosis.
SPIROMETRY TESTING:
- Spirometry is done with spirometer. This is available in several varieties. Most spirometers display the results in the form of graphs called spirograms.
- A volume-time curve shows volume in liters along the y-axis and time in seconds along the X-axis.
- A flow volume loop depicts the airflow rate on Y-axis and total volume expired or inspired on X-axis.
European Respiratory Society (ERS) and American Thoracic Society (ATS) usually sets guidelines for spirometric interpretation and testing.
WHAT DOES SPIROMETRY MEASURE?
Spirometry not only measures airflow, but also measures airflow per unit volume. Some examples that measure spirometry include:
- Forced Vital Capacity (FVC): Total air volume that a person can exhale after taking a large breath.
- Forced Expiratory Volume at 1 second (FEV1): Amount of air that a person exhales at 1 second.
PRECAUTIONS:
Patient should inform health care provider about the health conditions as these may affect the results. Smoking habits and history of the patient should be documented. Patient should understand and respond to the instructions of breathing maneuvers. Hence, this test is not suggested for physically impaired or unresponsive persons and young people.
People with following conditions should avoid the spirometry test:
- Unstable angina
- Recent heart attack
- Hemoptysis: Spitting blood from bronchial tubes or lungs
- Thrombotic condition: Blood clotting in vessels
- Vomiting or nausea
- Recent abdominal or thoracic surgery
- Aneurysm: Cranial, Abdominal or thoracic
- Pneumothorax: Gas or air in the pleural cavity
Test should be performed if the patient shows symptoms like chest, abdominal or headaches while the test is in progress. Patient’s emotional state should also be considered while performing the test.
