Airway dynamics Flashcards
2 ways airways can be decreased
- smooth muscles
2. edema
at what point does airway area signifacntly increase
after 10 generation
2 drug types that can dilate and constrict lungs
- beta blockers -constrict ,agonists dilate
2. parasymp antagonists - constrict
2 main types of flow
- laminar
2. tubulent
features of laminar flow
orderly
lowresitance
assymetric
features of turbulent flow
disorganized
higher resitance
what type of flow is generally present in small airways
laminar
what is pressure drop along a tube proportional to in laminar vs. turbulent flow
laminar - equal to flow rate
turbulent - 4 times the flow rate
what is more important in tubulent flow, viscosity or density
density
what is formula to determine flow type
Reynolds number
Re = 2rvd/viscosity
if >2000 – turbulent
what is more important in laminar flow, viscosity or density
viscosity
what will lower density favor
laminar flow
what is a method of lowering desnity and therefore creating laminar flow
give He
what size airway s site of major airway resitance
medium sized
why is med size the point of major resitance
smaller diameter, but not branched enough to create parallel lowering
at what lung volume is resistance lowest?
higher volumes -> pt. with resisitance breathe at higher volumes
where in a flow volume curve is effort dependant
first half - is dependant, second half is independant
what does the alveolar pressure equal
the elastic recoil pressure plus the pleural pressure
what will cause the airway to collape (2)
- increase airway resistance
2. decrease elastic recoil
what will be seen of F/V curve with upper airway narrowing
flattening in exp and inspiratory loop
what will happen if obstruction is intrathoracic
neg. pleural pressure will open airway on inspiration, but close it on expiration
what will happen in extrathoracic obstruction
no effect of pleuraal pressure
