Obstructive and Restrictive Pulmonary Disease Flashcards
pulmonary function test
- Inspiration is represented by the part of the PFT that lies below the x axis
- Expiration is represented by the part of the PFT that lies above the x axis
- Patient inhales then exhales
- Curve starts at the left, moves to the right, and then back to the left (clockwise progression
pulmonary function test: different conditions
differently shaped curves and values relative to the normal ranges
obstructive pulmonary disease
- airflow is impeded during expiration
- obstruction of the small airways, which compromises airflow out of the lungs
- abnormally high amount of air left in the lungs at end-expiration
airflow is impeded during expiration major examples
COPD, asthma, cystic fibrosis, bronchiectasis
restrictive pulmonary disease
lungs cannot fully expand during inspiration
mechanisms of restrictive pulmonary diseases
lungs and/or chest wall stiffness, nerve and/or muscular damage, muscular weakness
primary causes of restrictive pulmonary disease
pulmonary fibrosis, tuberculosis, respiratory distress syndrome
secondary causes of restrictive pulmonary disease
certain neuromuscular diseases (e.g. myasthenia gravis, muscular dystrophy, ALS), obesity, ascites, diaphragmatic hernia
obstructive disease: effects on pulmonary compliance
- generally increased
- magnitude depends on the specific diease
explanation for obstructive disease: effects on pulmonary compliance
- lungs have become overstretched from chronic coughing and congested airways, so lungs are very distensible and easy to inflate
- elastic recoil is reduced and so additional effort is required to force air out of the lung
restrictive disease: effects on pulmonary compliance
- Generally decreased
- Magnitude depends on the specific disease
restrictive disease explanations: effects on pulmonary compliance
- Decreased elasticity of the lungs (e.g. from the formation of scar tissue)
- Decreased surfactant in the alveoli
- Decreased ability for the chest wall to move
- Muscular weakness
- Nerve and/or muscular damage
obstructive disease: effects on pulmonary resistance
- generally increased
- amgnitude depends on the specific disease
explanations for obstructive disease: effects on pulmonary resistance
Excessive narrowing of airways due to inflammation
Thickened airway epithelium
Smooth muscle spasm
Increased mucus
restrictive disease: effects on pulmonary resistance
generally unchanged
