Respiratory Physiology Lecture 2 Part 10: Spirometry Tests to Determine Obstructive/Restrictive Diseases Flashcards
How is spirometry test performed?
patient is asked to make maximal inspiration and then exhale as much air as fast as possible
What data is collected from spirometry Test?
- Forced expiratory volume in 1 sec (FEV1)
- Forced vital capacity (FVC)
FEV1 of healthy person
A healthy person can normally blow out most of the air from the lungs within one second
Forced Vital Capacity
FVC
The total amount of air that is blown out in one breath after max inspiration as fast as possible
(TV + IRV + ERV) ~ VITAL CAPACITY
FEV1/FVC
Proportion of the amount of air that is blown out in 1 second
What three patterns does a spirometry test show?
- Normal (Age, gender, weight, height)
- An obstructive pattern
- A restrictive pattern
FVC for normal person
occurs quickly
What happens with an obstructive pattern respiratory system?
Patients affected by obstructive lung disease have shortness of breath due to difficulty in exhaling all the air from their lungs
Because of damage to the lungs or narrowing of the airways inside the lungs, exhaled air comes out more slowly than normal. At the end of a full exhalation, an abnormally high amount of air may still linger in the lungs
Physiological conditions of obstructive patterns
- Bronchial asthma
- chronic obstructive pulmonary disease
- cystic fibrosis
How are FEV and FVC effected by obstructive patterns?
FEV1 is significantly reduced
FVC is ~ normal/reduced
FEV1/FVC is reduced (< 0.7)
How is obstructive pattern breathing dealt with?
Asthma: β2 adrenergic agonists to reduce bronchospasm
- so spirometry test in normal state and do it again using drug to see if it makes a difference
What happens with an restrictive pattern respiratory system?
Patients affected by restrictive lung disease cannot fully fill their lungs with air. Their lungs are restricted from fully expanding
Restrictive lung disease most often results from a condition causing stiffness in the lungs themselves. In other cases, stiffness of the chest wall, weak muscles, or damaged nerves may cause the restriction in lung expansion
Physiological conditions of restrictive patterns
Lung fibrosis (abestos), neuromuscular diseases (ALS, muscular dystrophy) or scarring of the lung tissue
How are FEV and FVC effected by restrictive patterns?
- Reduced vital capacity
- FEV1 is reduced
- FVC is reduced
- FEV1/FVC almost normal (but both are reduced by themselves)
What volumes equal FRC?
FRC = RV + ERV
