Thoracic PPT Flashcards
Ventilation (V) is approximately _ L /min and pulmonary blood flow (perfusion Q) is approximately _ L/min
4L/min (V) 5L/min
The V/Q ratio for the entire lung is _
0.8 (4/5)
V/Q must be matched with the lung at the _ - _ level for gas exchange to occur
alveolar-capillary
Perfusion in the _ portion of the lung have greater amount of blood flow than the _
dependent (bases)
apex
Ventilation is greater in more _ parts of the lung, which are _ portions of the lung
compliant
dependent (bases)
Alveoli in the non-dependent portions of the lung, like the _, is more inflated and _ compliant
apex
less compliant
Difference between ventilation and oxygenation:
ventilation - moving air in and out of lungs, delivers O2 to alveolar space and removes CO2
oxygenation - delivering O2 from the lungs to body’s tissues
When standing, most of the ventilation and perfusion occurs at the _
base / dependent portion / zone 3
Which portion of the lung is more compliant?
dependent portion / base / zone 3
Which portion of the lung is less compliant?
apex, superior portion, “up lung”
Which monitor measures ventilation and which one measures oxygenation?
V = capnography
O2 = pulse ox
Pa =
Pv =
PA =
pulmonary arterial flow = Pa
pulmonary venous flow = Pv
alveolar pressures = PA
In an upright pt, where does most of tidal volume breath distribute to and why?
dependent portion / bases
-perfusion increases from the top - down (apex to base), negative pulmonary pressure is highest at apex of lungs so alveoli are most distended there, dependent alveoli are less distended and more compliant
Lung zones:
Zone 1
alveoli are at a HIGHER resting volume, represents alveolar dead space
PA > Pa > Pv
When PA > Pa = perfusion is impeded
Lung zones:
Zone 2
Variable relationship between vascular and alveolar pressure; intermediate zone
Pa > PA > Pv
Lung zones:
Zone 3
dependent part of lung, alveoli rest at LOWER volumes than zone 1 + 2 so they are more compliant and allow continuous blood flow thru the respiratory cycle
Pa>Pv>PA
An alveolus that undergoes a _ (greater/lesser) degree of volumetric change during a breath is going to be better ventilated. (Q!)
greater
-these are the dependent parts of lungs
Ventilation is greatest at the lung _ due to a _ alveolar compliance
Perfusion is greatest at the lung _ due to _
base, higher
base, gravity
T/F An alveolus that undergoes a greater degree of volumetric change during a breath is going to be better ventilated than an alveoli that undergoes a smaller degree of volumetric chancge during that breath
true
-dependent!!! :)
Most of the Vt is distributed to the _ alveoli
dependent
At end expiration, the alveoli near the _ are the largest and the alveoli near the _ are the smallest
apex = largest
base = smallest
compliance equation
compliance = change in volume / change in pressure
Lung compliance concept that “will be on every test you take for anesthesia board prep” (Q!)
volume difference at end expiration and end inspiration is smallest difference at the apex of the lung and greatest in the base of the lung
additionally, the ventilation is greatest at end expiration from the base and smallest at the apex
The more volume change an alveoli experiences will have better ventilation/perfusion (dependent!)
_ and _ _ affect the distribution of blood flow to the lung.
Gravity
hydrostatic pressure