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
PFT Fowler: Describe the 1st portion of expiration
0 N2 should be present bc this was the 100% O2 that was inhaled left in the anatomic dead space
PFT Fowler: What is Alveolar plateau?
When N2 levels out
T/F: During PFT Fowler test, N2 should rise immediately during expiration
F
the beginning of expiration is 100% O2 from deadspace – N2 should be 0 and NOT rise at the beginning
PFT Fowler: Where does N2 come from 1st when meter starts to detect it? Where does it the rest of it come from?
Transitional zone
The deeper portion of the lungs
Remember these areas had N2 in them prior to inhaling 100% O2
PFT Fowler: How can you calculate anatomic dead space from the graph?
It is the point where theses 2 lines intersect:
-volume expired
-midpoint of transitional phase
The volume of deadspace is on the followed on the L vertical axis
_______ increases your anatomical deadspace. What will this require? Why?
Height (Being super tall)
An increased VT
You need an increased breath size to open to alveoli because there’s more air lost in the deadspace –> less air making it to the deeper parts of the lungs.
_______ PFT is fimilar to Fowlers PFT
Nitrogen Washout Test
PFT Nitrogen Washout: What is happening during this test? Describe inspiration/expiration.
- Breathing at normal VT w/ 100% O2 (multiple breaths)
- Each new inspiration is 100% O2 –> Nitrogen deep in lungs is diluted more with 100% O2 w/ each inspiration
- With each expiration a portion of diluted nitrogen is exhaled (this is all from the original N2 that was in the lungs)
PFT Nitrogen Washout: When does the greatest decrease in nitrogen concentration happen? Why?
On the 1st inhale
This is when N2 concentration is the highest – about 75% – and there’s the most to be diluted/displaced
PFT Nitrogen Washout: a ______ line = equal ventilation. What does the opposite mean?
smooth line
A not smooth line = unequal ventilation.
PFT Nitrogen Washout: What items do you need for this test?
Pt
100% O2 source
N2 meter
PFT Nitrogen Washout: This test ends when the patient is _______ nitrogen at _______%
exhaling
2.5%
PFT Nitrogen Washout: How long should this test last? What does an abnormal result look like & indicate?
In less than 7 mins the concentration of exhaled N2 should be 2.5%
Anything greater than 7 mins is abnormal.
PFT Nitrogen Washout: What is the normal time for this test? In real-life, how quickly is this test normally done if you’re 20yo & in perfect health?
< 7 mins
< 3.5 mins
PFT Nitrogen Washout: How will COPD affect this test? Why?
Increase the # of breaths it takes to washout Nitrogen to an exhaled concentration of 2.5%
COPD = larger lungs = more air in the lungs in general –> more nitrogen in the lungs dt the lungs having more air
PFT Nitrogen Washout: What do the dots on the plot represent? How do normal vs abnormal plots look?
Each dot = a breath
abnormal: scattered data plots w/ curved line; longer line
normal: more straight line w/ even plots; shorter line
PFT Nitrogen Washout: What causes the data points to be scattered when the test is abnormal?
Air being directed diff places in lungs on diff breaths –> uneven ventilation = sick lung
uneven ventilation = _________
sick lung
Flow Volume Loops: What do they show?
Speed at which air is coming out/in of the lung (at max effort & different efforts)
Flow Volume Loops: The main focus is __________ curves during ______
max effort
exhalation
Flow Volume Loops: explain the vertical line? horizontal?
Vertical: Volume in the lung
L of graph is TLC
R of graph is RV
Horizontal: Airflow in L/secs
Top is expiration
Bottom is insipiration
Flow Volume Loops: The L side of the graph is effort _______. What does this mean?
dependent
Effort applied dictated airflow rate
Flow Volume Loops: expiration starts off _______ with max effort. What happens after the peak?
rapidly
after the peak, expiration speed decreases even w/ max effort (effort independence)
What is vital capacity?
Max amount you can exhale after inhaling the max amount (TLC)
or the max amount you can exhale from TLC
Equation: RV =
TLC - VC
Flow Volume Loops: The R side of the graph is effort _______. What does this mean?
independence
Expired airflow is capped even with max effort –> Airflow will decrease even when applying increased airflow
Flow Volume Loops: Expiration goes from ______ to ________. Inspiration goes from _______ to ________.
Expiration: L to R ( TLC –> RV)
Inspiration R to L (RV –> TLC)
What is the difference between TLC and RV?
TLC = 6L
Total lung capacity
Cannot take any more volume in
RV = 1.5 L
Residual volume
Cannot exhale anymore
Flow Volume Loops: when does the max speed occur during inspiration when using max effort? how much air is in the lung at this point? What is the max speed (peak inspiratory flow)?
About 1/2 way between TLC and RV
TLC - RV = VC
6 - 1.5 =4.5
4.5/2 =2.25
1.5 + 2.25 =3.75 L is in the lung
About 10 L/sec (a little less)
Flow Volume Loops: Which side of the graph is skewed? why?
Top
This is dt fast expiration
Flow Volume Loops: combined inspiratory/expiratory loops are shaped like an _______
upside down ice cream cone
Flow Volume Loops: The distance on the horizontal line between TLC and RV is ______
VC
What happens if you cant exhale fast?
Unhealthy lungs
Most likely obstructive = lose of recoil
Peak expiratory flow depends on what 2 things? Describe them.
PER: helps get air out of the lung quickly
PPl: will be more positive if using max effort to get air out of lungs quickly
What will transpulmonary pressure be at TLC?
PTP = 30 mmHg
What are the additional muscles used in forced expiration? Besides the thorax, how do they help?
Diaphragm
Internal intercostal muscles: pulls ribs close together –> reduces chest volume –> increases PPl –> forces air out
Abdominal muscles: muscles contract –> push abd contents upward to diaphragm –> combined action with internal intercostal muscle contraction –> increased PPl –> forces air out
Where are the internal intercostal muscles located?
Inside thorax
Inside the rib cage
In between the ribs
In COPD, what is exhalation dependent on? Why? What problems does this create?
Entire entirely depending on pushing air out of lungs and NOT passive recoil
Recoil is weak dt spring being lost –> forced expiration is needed
Excessive force –> collapse small airways –> limits expiratory flow
How should ventilators settings look if recoil pressure is low?
Expiratory times should be longer than inspiratory
Paralyzed patients rely entirely on _________ pressure
lung recoil
Expiratory Flow Function Curves: These show the _______ flow volume loops only. This is the _____ of the flow volume loops.
Expired
Top
Expiratory Flow Function Curves: what is a normal peak expiratory flow in a healthy 20yo?
greater than 12 L/sec
Expiratory Flow Function Curves: What curves are shown? Which has the highest curve/airflow? Lowest?
Normal, obstructive diseases, restrictive disease diseases
Highest: normal
Lowest: obstructive
Expiratory Flow Function Curves: the slope for obstructive disease diseases is __________. Which side is this on? What does this indicate?
Concave (slight curve inward)
R side of curve
This indicated abnormal effort-independent phase
Expiratory Flow Function Curves: If the curve is lower than normal, what does that mean?
Some sort of pathology
Expiratory Flow Function Curves: The ________ of the curve tell us the behavior of the tissue during force expiration
Shape
Briefly describe the pathology of restrictive lung disease
More scar tissue –> difficult to fill the lungs with air –> less volume in lungs –> reduced expiratory flow
Expiratory Flow Function Curves: why is Max expiratory flow rate reduced in restrictive lung disease?
Less volume in the lung = less air volume available for expiration –> lower max expiratory flow rate
Expiratory Flow Function Curves: on restrictive lung disease, how does the effort – independent slope present?
convexed (slightly outward)
FVC =
Forced vital capacity maneuver
What is FVC?
Forced vital capacity maneuver: the expired portion of the flow volume loop
** the top portion of the graph on the flow volume loop**
** the expiratory flow function curves**
Expiratory Flow Function Curves: what does the right border of each loop represent?
RV
This is where the curve meets the x-axis on the right side
Expiratory Flow Function Curves: which loop has the lowest RV? Highest?
Lowest: Restrictive lung disease (right border furthest to the right)
Highest: obstructive lung disease (right border furthest to the left)
Expiratory Flow Function Curves: based on the diagram, restrictive lung disease, RV is equal to _____
1 L
What is the value of RV?
1.5 L
More elastic tissue = ______ lung volumes. They are _______ compliant. What type of pathology is this?
Lower lung volumes (Lower RV)
Less
Restrictive lung disease
Less elastic tissue = ______ lung volumes. They are ______ compliant. What type of pathology is this?
Higher lung volumes (Higher RV)
More
Obstructive lung disease
Equation: VC =
TLC - RV
Expiratory Flow Function Curves: The beginning of the loop is ______
TLC
Expiratory Flow Function Curves: how can we determine RV in pathologies?
- Maximum flow rate: height of the curve/plotted lines
- Shape: normal, concave, convex on R side (effort-independent side)
- Vital capacity: measure with scale; smaller = sicker
What causes effort independence during FVC?
Increased pleural pressure + decreased alveolar pressure = vulnerable point in the smaller airway –> small airway collapse
T/F: effort-independence affects the conducting zone. Why?
F
Conducting zone has Cartlidge that prevents collapse during FVC
Why are smaller airways more prone to collapse during FVC?
They do not have cartilage for structural stability (only soft tissue) –> creating a vulnerable point just before the Cartlidge
Where is the vulnerable point in the small airways during FVC? Why does this point exist?
Right before you get to the cartilage in the conducting zone
Pressure decreases as you go up the respiratory system from the alveoli &
Pleural pressure is high = vulnerable point
What types of pressure cause the vulnerable point during FVC?
When pleural pressure is HIGHER than pressure right before the conducting zone/cartlidge
What happens to pressure as we go further up the respiratory system from the alveoli?
Decreases
If pleural pressure is equal to lower air pressure at the vulnerable point, will it cause airway collapse during FVC?
No, Pleural pressure would need to be higher than lower airway pressure
T/F: internal airway pressure is enough to maintain opening of airway during FVC
F
Pleural pressure has to be lower than internal lower airway pressure
