3 - Overview of Obstructive & Restrictive Disease Flashcards
What type of lung disease does turbulence on physical exam suggest?
Obstructive
A(n) [increase/decrease] in smooth muscle tone of large/medium airways will decrease the radius, [increasing/decreasing] the resistance.
increased tone –> smaller radius –> increased resistance
Parasympathetic stimulation of smooth muscle will result in a(n) [increased/decreased] airway radius.
more tone –> decreased radius
Low PaCO2 levels will affect airway smooth muscle to result in a(n) [increased/decreased] airway radius.
decreased radius (hypocapnic bronchoconstriction)
High PaCO2 levels will affect airway smooth muscle to result in a(n) [increased/decreased] airway radius.
increased radius
Sympathetic stimulation of smooth muscle will result in a(n) [increased/decreased] airway radius.
decreased tone –> increased radius
What are some factors that affect airway resistance in disease?
- smooth muscle (hypertrophy and contraction)
- mucus (hypersecreted, gland hypertrophy)
- airway wall infiltrated
- epithelium desquamated
What is the major driving force of expiration?
Elastic recoil (from elastic fibers and surface tension)
Why does emphysema lead to hyperinflation?
Decreased alveolar pressure because of lost elasticity and surface tension –> not enough pressure gradient to get air out before hitting equal pressure point (EPP) –> EPP happens at compressible part of respiratory system –> airway collapse –> trapped air
What are the two stages of forced expiration in regards to effort?
Early phase: flow is effort dependent
Late phase: flow is effort independent
Why is there increased expiration resistance in emphysema?
The lung lacks enough alveoli to pull on the bronchiole to keep it open –> narrowed/collapsed airway = increased resistance
What two things limit expiratory flow in emphysema?
- loss of radial traction from surrounding alveoli –> airway collapse
- loss of elastic recoil –> decreased alveolar driving pressure
Reduced compliance is seen in [obstructive/restrictive] lung disease.
restrictive
In restrictive disease, resistance is [decreased/normal/elevated] because of [no/some] airway involvement.
normal resistance because of no airway involvement
Wheezing [is/is not] seen with restrictive lung disease.
is not (because there is no turbulent flow)
What four factors contribute to FEV1 and FVC values?
- age
- sex
- height
- race / racial health disparities
What FEV1/FVC ratio is diagnostic of obstructive lung disease?
FEV1/FVC < 0.7
In a flow volume loop, obstructive disease shows [increased/decreased] TLC, [increased/decreased RV], and ___. Why do you see this increase/decrease?
increased TLC, increased RV, expiratory scooping
Lung cannot expire all of the air –> hyperinflation –> increased TLC and RV over time
In a flow volume loop, restrictive disease shows [increased/decreased] TLC and [increased/decreased RV]. Why do you see this increase/decrease?
decreased TLC, decreased RV
Problem with compliance –> need more effort to breathe in the same amount –> reduced volume over time
What determines the diffusion of a gas?
- ventilation
- perfusion
- hemoglobin
- surface area, solubility, pressure gradient, thickness of interstitium (all part of diffusion equation)
What is the equation for diffusion?
D = [area * gas *(pressure 1 - pressure 2)]/Thickness
gas = solubility / MW
What three lung disease categories have reduced diffusion? Which is the only obstructive disease?
- emphysema (obstructive)
- alveolar filling
- interstitial
Asthma results in [normal/reduced] diffusion.
normal
Chronic bronchitis results in [normal/reduced] diffusion.
normal
Upper airway obstruction results in [normal/reduced] diffusion.
normal
Small airways disease results in [normal/reduced] diffusion.
normal
Pleural disease results in [normal/reduced] diffusion.
normal
Neuromuscular disease results in [normal/reduced] diffusion.
normal
Chest wall abnormalities result in [normal/reduced] diffusion.
normal
Emphysema results in [normal/reduced] diffusion.
reduced
Alveolar filling disease results in [normal/reduced] diffusion.
reduced
Interstitial lung disease results in [normal/reduced] diffusion.
reduced
What factors affect diffusion?
- surface area
- thickness of interstitium
- hemoglobin content
- perfusion
What factors cause expiratory flow limitation?
- increased resistance
- decreased radial traction
- decreased elastic recoil
What factors affect diffusion?
- surface area
- thickness of interstitium
- hemoglobin content
- perfusion
- pressure gradient
