Zones of the Lung Flashcards
How many Zones of the lung are there?
4
what is zone 1 called?
collapse
(b/c alveolar pressure collapses arterial)
what is zone 2 called?
waterfall
what is zone 3 called
Distension
what is zone 4 called
Interstitial pressure
what is the ideal Zone?
zone 3
state the pressures in each zone
- PA > Pa >Pv
- Pa > PA > Pv
- Pa > Pv > PA
- Pa> Pisf > Pv > PA
Zone 1:
Explain it
Pulm artery pressure negigilble bc Alveolar pressure exceeds it, the distensible cappilieries in the alveolar wall are collapsed. There is NO blood flow in Zone 1
it is normally not present.. its a pathological zone that develops with pulmonary HYPOtension
Zone 2:
explain it
Pa pressure exceeds PA pressure
after blood passes through the alveoli is “falls” into the venous system
Zone 3:
explain it
Blood flow is proportional to Pulm Artery pressure minus the pulmonary vein pressure.
Zone 4:
explain it
it’s a pathological zone that normally is not present. it is present with Pulmonary edema
the tip of the swan should be placed in what zone?
3
Must Know:
West’s zones describe the _____ in the lungs
perfusion
Must Know:
west’s zones are not “fixed” zones they are varible function zones. what does that mean
they are dependent on body position
Must Know:
why is zone 3 the best zone?
Zone 1 is found in the Non-dependent lung
Zone 3 is found in the dependent lung
hence zone 3 is better perfused and ventilated
