pulmonary anatomy - exam 3 Flashcards
(79 cards)
How much CO2 would you expect to be in the beginning of expiration?
none - anatomical dead space
When is expired CO2 highest during expiration?
at the end
why is expired CO2 sloped?
still passing deoxygenated blood the whole time (continuous blood flow) - averaged out at 40 mmHg
How do you calculate PCO2 after inspiration?
- calculate fraction of CO2 = 40/760 = 5.263%
- multiple by FRC (5.263% * 3L = 158 mL = between breaths)
- calc new volume in lungs = 3.35 L
- new concentration of CO2 (158/3.35 = 4.7%)
- new PCO2 = 4.7%*760 = 36 mmHg
What would an inverted slope of mixed expired CO2 mean?
late stage emphysema - small airway collapse, base collapses 1st, CO2 higher at base and lower at top compared to normal - CO2 higher at first bc base expired first
How is alveolar dead space calculated?
Bohr equation: arterial CO2 - end-tidal CO2
How would alveolar dead space impact end title CO2?
lower end-title CO2
What is the Bohr equation?
VDCO2/VT = (PaCO2 - PECO2)/PaCO2
end-title CO2 should equal ______ CO2 as long as there’s no _______
arterial, shunting
what is the total compliance equation?
1/compliance = 1/lung compliance + 1/chest wall compliance
are the lungs and chest wall in series or parallel?
series
what is the normal compliance at FRC of the chest wall? of the lung? total compliance?
0.2 L/cmH2O each
total = 0.1 L/cmH2O
the chest wall wants to recoil _____, while the lung wants to recoil ______
outwards
inwards
both outward recoil and inward recoil will determine _______ and ________
pleural pressure and lung volume
how does barrel chest occur in COPD?
loss of elastic recoil; chest recoils outward and more positive pleural pressure; inc lung volume
what is the pulmonary compliance at FRC?
compliance = ΔV/ΔP
0.5L/2.5 cmH2O = 0.2 L/cmH2O
ΔP = (-5) - (-7.5)= 2.5 = 2.5 cmH2O
What is the difference between lung volumes supine vs upright/standing?
Supine has dec FRC and ERV, inc IRV
What is the FiO2 of humidified air? Dry air?
19-20%, 21%
how much oxygen is in the lungs between breaths?
PAO2 = 100 mmHg/760 = 13.16% * 3L = 0.395 L O2
How long can you go without breathing?
a little less than 2 minutes
0.395 L O2 between breaths
use 250 mL/min
What are the differences between the R and L lungs?
R - larger, heavier, 3 lobes
L - taller, 2 lobes
what structure divides the lobes of the lungs?
fissures
What are the 2 fissures of the right lung called?
horizontal and oblique
What are the segments within the lobes of the lungs called?
Bronchopulmonary segments
