Lecture 3/6 - Pulmonary Flashcards
Test 3
A small amount of gas exchange happens at the _________. What areas are these?
Transitional zones
Respiratory bronchioles
How much of your tidal volume is dead space? What happens to the rest of it?
150 ml
350 ml is pushed into the lungs and used for gas exchange.
Describe what happens to your tidal volume using 500ml of an indicator gas
150 ml in dead space is same composition as indicator gas
350 ml is diluted in the lungs (mix of 3L of air in lungs & indicator)
_________ ventilation is the last portion of an inspired breath
dead space
What is the difference between alveolar and anatomic dead space?
Anatomic: conducting zones in upper airway
alveolar: dead space w/i lung that create patched that are ventilated but not perfused
T/F: Alveolar dead space can occur in healthy lungs
F
Only occurs in unhealthy lungs
When is an indicator gas MOST diluted?
During the 1st breath
If only using 150 ml of indicator gas inhaled, when you inhale, where does the indictor gas go?
It goes into the lung and is diluted
it does NOT stay in the anatomical headspace
What does PIN2 mean?
Pressure inspired of Nitrogen
This is a humidified pressure bc it is an inhaled gas pressure
PIN2 =
564 mmHg
Equation: Partial pressure of an inspired gas =
gas concentration x (atomspheric pressure - water pressure)
Ex) 149 = (0.21) x (760 - 47)
The total pressure of all gases in the lungs is ______ when at sea level
760 mmHg
Equation: Concentration of gas in lungs =
(partial pressure of gas in alveoli) / (total pressure of all gases in lungs)
PAN2 / PB
Ex) Nitrogen: 569 / 760 –> 0.7486 –> 74.9% or 75%
What is PAN2?
569 mmHg
PP of nitrogen in the alveoli
When would we be worried about nitrogen being absorbed by pt?
Deep sea diving
Deep sea diving has a major increase in pressure
Fowler’s test is a ______ test that looks at what?
PFT
How much nitrogen is coming out of the patient
PFT Fowler: What items are needed?
N2 meter
patient
source of 100% O2
What would a N2 meter read when breathing on RA?
74.9% (75%)
PFT Fowler: ________ analyzes the expired gas
N2 meter
PFT Fowler: How does it work?
- Hook pt up to 100% O2 source & N2 meter
- Tell them to take a deeper breath
- 100% O2 diluted w/ water vapors –> O2 concentration decreased
4. Did not inspire any N2 - pp thats already in the lung = 569 mmHg
- Exhale
6.
PFT Fowler: How much do you want them to increase their VT to?
Double = 1000ml
(tell them to take a little deeper breath)
PFT Fowler: How many breaths are taken in this test?
1
(just 1 deeper breath)
PFT Fowler: The last portion of inspired breath should have _____ N2
0
(100% O2)
PFT Fowler: Describe the 1st portion of inspired air
100% O2 is mixed with air thats already in lungs
Has N2