3/27 Lecture Flashcards
1
Q
T/F: Carbamino groups form on anything that has an exposed terminal amine group.
A
T
2
Q
At a PCO₂ of 45 mmHg, in a 70% saturated oxyhemobglobin sample, what the average total venous CO₂ content?
A
52.5 mL CO₂/dL
3
Q
At a PCO₂ of 40 mmHg, in a 70% saturated oxyhemobglobin sample, what the average total arterial CO₂ content?
A
48 mL CO₂/dl
4
Q
The difference between the arterial and venous curves of the CO₂ dissociation curve is ________ mL CO₂/dL
A
4.5 CO₂/dL
4
Q
The difference between the arterial and venous curves of the CO₂ dissociation curve represents CO₂ being ___________
A
unloaded into the lungs
5
Q
The difference between the arterial and venous curves of the O₂ dissociation curve represents O₂ being ___________
A
Onloaded into the blood
6
Q
The difference between the arterial and venous curves of the O₂ dissociation curve is ________ mL O₂/dL
A
5 mL O₂/dL
7
Q
CO₂ Dissociation Curve
What is the cause of the difference between the arterial and the venous curve?
A
Oxyhemoglobin saturation levels
8
Q
What is the Haldane effect?
A
This relates to deoxygenated blood having more room to transport CO₂
9
Q
What has more room to transport CO₂, oxygenated or dexoygentated blood?
A
Deoxygenated blood
10
Q
The amount of CO₂ that can be transported is dependent on ___________________
A
Oxyhemoglobin saturation levels
11
Q
Gas Transport in the Tissues
What happens to CO₂ after it leaves the tissues and enteres the CV system?
A
- Some dissolves in the plasma
- Most of it dissolves into a RBC
12
Q
In peripheral tissues (ex, muscle, foot), CO₂ is produced as a byproduct of _____________.
A
metabolism
13
Q
What enzyme breaks down or rebuild carbonic acid from bicarbonate and a hydrogen proton?
A
Carbonic anhydrase
14
Q
Bicarbonate leaves RBCs via the ______________
A
Bicarbonate-chloride exchanger
15
Q
What ion is bicarbonate exchanged for?
A
chloride
16
Q
The most notable proton buffer in the red blood cell is __________
A
Hemoglobin
17
Q
Protons (H⁺) in the blood can be buffered with what types of proteins in the blood? Whhic is the most notable
A
- Hemoglobin (most notable)
- Immuniglobulins
- Clotting factors
18
Q
A substance that is prone to accepting protons (H⁺) is considered a ________ acid.
A
weaker
19
Q
A substance that is prone to donating protons (H⁺) is considered a ________ acid.
A
stronger
Hint: remember strong acids want to dissociate!
20
Q
T/F: Deoxyhemoglobin (HHb) is less prone to accepting protons (H⁺) making it a weaker acid than Oxyhemoglobin (HbO₂)
A
False.
Deoxyhemoglobin (HHb) is MORE prone to accepting protons (H⁺) making it a weaker acid than Oxyhemoglobin (HbO₂)
21
Q
T/F: Oxyhemoglobin (HbO₂) does not accept protons (H⁺) very well because there isn’t room to effectively bind, making it a stronger acid than Deoxyhemoglobin (HHb)
A
T
22
Q
Breathing in CO₂ adds more CO₂ to the plasma and into RBCs making RBCs more acidic. This increased acidity (INCREASES/DECREASES) hemoglobins affinity for O₂, shifting the CO₂ dissociation curve to the (LEFT/RIGHT), and helps (ON/OFF)-load O₂ into the tissues
A
increases; left; offload
23
Q
The bicarbonate-chloride exchanger does the following:
* Brings bicarbonate in from the plasma into an RBC
* Removes chloride from an RBC to put into the plasma
Is this process happening in the tissue or the lungs?
A
In the lungs
24
The bicarbonate-chloride exchanger does the following:
* Removes bicarbonate from an RBC and puts it into the plasma
* Brings chloride from the plasma into an RBC
Is this process happening in the tissue or the lungs?
In the tissue
25
As CO₂ is blown off and protons are removed from the RBC, hemoglobin’s affinity for oxygen ________
increases
26
Deoxyhemoglobin has a ________ affinity for oxygen when there are fewer protons/less acid
higher
27
The speed or direction of the chemical reactions in the blood buffer chemical formula depends on the _____________________
concentration of substrates and products (CO₂, bicarbonate, and protons in the blood and alveolar air)
28
Under normal conditions, how long does it take for gas exchange to happen in the pulmonary capillaries?
About 0.25 seconds (a quarter of a second)
29
Under resting conditions, how long does blood typically hang out in the alveolus?
About 0.75 seconds
30
If cardiac output increases, ________ increase and the blood moves through the pulmonary capillaries ________ than normal.
recruitment and distension; faster
31
Under extreme conditions, increased cardiac output can lead to ________ blood flow through the capillaries, so much so that the time spent in the capillaries can drop to ________.
If this is a normal healthy patient, would this be a problem?
faster; 0.25
No
32
T/F: Normally, 0.25 seconds is **not** enough time for the blood to pick up oxygen and offload CO₂
F
It's enough time!
33
N₂O equilibrates very quickly in the capillary, with equilibration happening in _____________________
less than 0.25 seconds
34
Why does N₂O rapidly equilibrate into the capillary?
N₂O doesn’t have many places to bind/go and has low solubility in blood (won't stay dissolved in the blood).
35
T/F: N₂O has **low** permeability in blood has a tendency to leave the blood quickly to return back to alveolar gas.
T
36
T/F: N₂O is **more** soluble than O₂ in the blood
F
It's less! N₂O hates being in the blood
37
T/F: N₂O is more soluble compared to nitrogen
T
38
The diffusion of carbon monoxide is very similar to the diffusion of __________
oxygen
39
# DLCO
Why is the DLCO test performed?
To look at the diffusion capabilities of the lungs
40
# DLCO
The faster the body absorbs CO, the **____________** the diffusion capabilities of the lungs.
better
41
# DLCO
The slower the body absorbs CO, the **____________** the diffusion capabilities of the lungs.
worse
42
The ________ test measures how much CO is absorbed during a brief exposure, then a blood sample is taken to analyze the levels.
DLCO
43
# DLCO
A healthy person exposed to CO should show ________% CO in the blood sample.
0%
44
# DLCO
T/F: If the results of a DLCO test show 0% carboxyhemoglobin, this suggests exposure to CO.
F
0% is a normal reading. Anything above 0% is adnormal and suggests exposure to CO
45
T/F: Carboxyhemoglobin can be the blood, without exposure to CO.
F
Carboxyhemoglobin should not be present unless there has been exposure to CO (ex: smoking, working in high-CO environments).
46
During extreme exercise/marathon (arrow), blood spends ________ in the capillary. This is more than enough to bring on the oxygen that we need.
0.25 sec
47
What is the minimum diffusing capacity (time for gas exhange) of the lung?
What is the normal amount?
0.25 seconds
Normal = 0.75 seconds
48
The diffusing capacity (time for gas exhange) of the lung becomes 1/4th of normal time (0.75 sec). What disease process can cause this?
Mild PNA
49
The diffusing capacity (time for gas exhange) of the lung increases 1/8th of normal time (0.75 sec). What disease process can cause this?
Pulmonary edema
50
What is **diffusion**-limited gas exchange?
Diffusion-limited gas exchange occurs when the ability of a gas (like oxygen) to diffuse across the alveolar-capillary membrane is slower than the time it takes for blood to pass through the pulmonary capillaries.
So gas exchange is restricted by the ability of the gas to diffuse across the alveolar membrane (ex: due to lung disease or damage, fibrosis, emphysema).
51
What is **perfusion**-limited gas exchange?
Gas exchange that is dependent on blood flow through the lungs, and the only way to increase gas absorption is by increasing blood flow (ex: increasing cardiac output)
52
If Gas Y does not have a plateau phase and does not equilibrate with alveolar air, this is ____________-limited gas exchange.
diffusion
53
If Gas X does reaches a plateau phase and equilibrates between the pulmonary capillary blood and the alveolar air, this is ____________-limited gas exchange.
perfusion
54
In this graph, what gas or gasses reflects diffusion-limited gas exchange and explain how you came to this conclusion.
CO
CO doesn't have a plateau phase, it just keeps going up without ever reaching a plateau, hence it is a diffusion limited gas.
This is what make it is useful for testing the diffusion capacity of the lungs.
55
In this graph, what gas or gasses reflects perfusion-limited gas exchange and explain how you came to this conclusion.
N₂O and O₂
Both have a plateau phase
56
In a healthy patient, lungs have the surface area about the size of _________________
a tennis court (70 m2)
57
More surface area = ________ Gas Diffusion
More
58
What is something simple we can do to increase the surface area for gas exchange inteh lungs?
Exercise
59
How dose exercise increase the surface area for gas exchange in the heart?
Exercise is going to increase blood flow, increasing distension and recruitment.
Recruitment activates more alveoli.
More active alveoli = more surface area for gas exchange
60
# Fick's Law of Diffusion
What is Fick's Law of Diffusion?
Define all variables
Fick's Law of Diffusion describes the rate at which a gas diffuses across a membrane (like the alveolar-capillary membrane in the lungs)
T = Thickness of the membrane through which the gas is diffusing (thicker membranes reduce diffusion rate
A = Surface area available for diffusion (the area of the membrane through which gases are diffusing)
D = Diffisivity, the diffusion coefficient of the gas (depends on the gas’s solubility and molecular weight)
(P1 - P2) = The partial pressure difference between the two sides of the membrane (for example, the difference between the partial pressure of oxygen in the alveoli and in the blood)
Vgas = Rate of gas diffusion (the volume of gas that diffuses per unit of time)
61
# Fic
How is diffusivity calculated?
(The solubility of the gas) / (the square root of the molecular weight of the gas)
62
What is the minute alveolar ventilation for a healthy patient?
This is the air Q portion would be 5000ml of blood that is going through the lungs each minute.
4.2 L/min
63
The normal V/Q ratio about _____________
0.85
(4.2 L of air per minute) / (5 L of blood per minute) = 0.85
64
In terms of **solubility**, CO₂ is ________ more soluble than oxygen
24x
65
In terms of **diffusivity**, CO₂ is ________ more soluble than oxygen
20 x
66
# V/Q Ratio
If there is no ventilation, what would be the expected values for pulmonary venous PO₂ and PCO₂? How would this affect the V/Q ratio?
PO₂ = 40 mmHg
PCO₂ = 45 mmHg
There's no fresh air for gas exchange to happen so whatever the gasses were that went into this part of the lung, their composition is being going to be unchanged if it's allowed to flow through alveoli that aren't ventilated at all.
V/Q ratio would decrease
67
If there is no perfusion, what would be the expected values for pulmonary venous PO₂ and PCO₂ (at sea level)? How would this affect the V/Q ratio?
PO₂ = 150 mmHg
PCO₂ = 0 mmHg
(if at sea level 760mmHg)
There is ventilation happening but no perfusion. Fresh air iis entering the lung, but there's no blood flow so the alveolar air would mimic the inspired air pressures
V/Q ratio would increase
68
If the V/Q ratio is normal, what would be the expected values for pulmonary venous PO₂ and PCO₂? What is the V/Q ratio number?
PO₂ = 100 mmHg
PCO₂ = 40 mmHg
0.85
69
Under the circumstances of no perfusion but ventilation, the V/Q ratio can be as high as ______________.
infinity
70
Blood flow through a non-ventilated alveolus is a called a ________.
shunt
71
Ventilating an alveolus that has no blood flow is called _____________.
dead space
72
What graph reflects a normal V/Q ratio?
Graph A
73
What graph reflects a pulmonary shunt?
Graph B
No Ventilation + Perfusion = Shunt
74
What graph reflects a dead space ventilation?
Graph C
Ventilation + No Perfusion = Dead Space
Ventilating an alveolus that has no blood flow
75
If someone is sitting upright and resting, the majority of the blood flow and fresh air in their lungs is going through the ____________ of the lung.
base
This patient is breathing at FRC
76
What is the **lowest** value a V/Q ratio can be?
0
77
What is the **highest** value a V/Q ratio can be?
Infinity
78
If a healthy patien is breathing to FRC, both blood flow and ventilation are higher at ________ of the lung.
base
79
The base of the lung has ____________________ blood flow than ventilation in comparison to the apex
a little bit more
80
The apex of the lung has ____________________ ventilation than blood flow in comparison to the base
a little bit more
81
T/F: In general, the base of the lung is a little bit under ventilated.
T
82
T/F: In general, the base of the lung is probably a little bit over ventilated. It gets more air than it really needs.
F
Apex of the lung
The apex of the lung is probably a little bit over ventilated. It gets more air than it really needs because the apex has less blood flow
83
What is the actual PO₂ at the **apex** of the lung?
What is the actual PO₂ at the **base** of the lung?
(Hint: It's not 100 mmHg)
Apex = 130 mmHg
Base = 90 mmHg, a little bit lower than average
84
What is the actual PCO₂ at the **apex** of the lung?
What is the actual PCO₂ at the **base** of the lung?
(Hint: It's not 40 mmHg)
Apex = 30 mmHg or a little higher
Base = A little bit higher than 40 mmHg, so a little bit higher than average
85
For the purposes of this class, the most important V/Q mismatch disorder for us as CRNAs is the development of ___________________
alveolar dead space
(Graph C)
86
How does age affect V/Q matching and what would the V and Q curves look like?
The older you become, the more mismatched the V/Q ratio and the curves would not be on top of each other as they would with a normal V/Q ratio
87
If PAO₂ = mmHg in a completely healthy patient, would age you would estimate the patient to be?
Around 55 years old
88
What does ZEEP mean?
Zero PEEP applied on the ventilator
89
Expiratory pressure and **not** using PEEP can lead to ________________ instantaneously!
atelectasis (lung collapse)
90
Age effects how patient will tolerate ZEEP during anesthesia.
How would a healthy 20 y/o tolerate ZEEP?
How would a healthy or unhealthy 90 y/o tolerate ZEEP?
20 y/o tolerate may tolerate it for very short 20-30 min procedure
90 y/o already has decreased lung function so probably they probably won’t tolerate this
91
Does this image show V/Q matching or mismatching? What is the condition of the patient?
V/Q matching
This is a normal patient at rest. The image shows the heart and 2 lungs that look healthy and full of air
92
How can atelectasis be prevented during anesthesia?
**giving PEEP**
PEEP holds the airways open preventing collapse
93
How does PEEP prevent atelectasis during anesthesia?
PEEP holds the airways open preventing collapse
94
Does this image show V/Q matching or mismatching? What is the condition of the patient?
V/Q mismatching
The red area is pointing to a collapsed lung (atelectasis). This patient may be under anesthesia with ZEEP
95
Alveolar collapse happens ____________ upon anesthesia induction
instantaneously
96
The pressure within a alveoli/balloon is dependent on it's ___________
radius
97
Which alveolus would have a higher pressure?
The smaller alveolus to the left
The pressure within the sphere with the smaller radius is going to be comparatively HIGHER than the pressure in the sphere with a larger radius
98
If the sphere to the left is inflate halfway full (50%) and the sphere to the right is inflated to 10% capacity, the ________ sphere will deflate and the air will go into the ________ balloon
left; right
99
What is Laplace's Law?
Air is going to flow from smaller spheres to larger spheres, provided the larger spheres are not completely full to 100%
100
There are two lungs and one of the lungs is collapsed. Would would LaPlace's prediction of this situation be?
What would happen under normal healthy conditions?
That the collapsed lung would remain collapsed and only the open lung would continue to be ventilated.
LaPlace's law predicts **uneven ventilation** and that in a collapsed lung, the pressure in the smaller alveoli would be much higher due to the reduced radius. This makes it harder for the lung to re-expand and could exacerbate the collapse until the radius increases and the pressure decreases.
**Under normal conditions, LaPlace's prediction is incorrect because of surfactant production**. Surfactant will break some of the surface tension to distribute things more evenly and all the collapsed lung to open up.
However, if there is no surfactant present, LaPlace's prediction is true
101
Which sphere has a **higher** surfactant concentration?
Left sphere
Smaller alveolus = less surface area = more concentrated surfactant
This sphere would be easier to air into because of this
102
Which sphere has a **lower** surfactant concentration?
Right sphere
If you have more surface area with the same amountt of surfactant,the surfactant will spread out more, lowering the concentration
103
Every single lung problem ever studied has a ____________________ problem
surfactant deficiency
104
Normal anatomical dead space = ______ cc
**150 cc** or **1 cc per lb if IBW**
105
T/F: A healthy 20 y/o patient's physiologic dead space should consistent of both anatomical and alveolar dead space.
F
A healthy 20 y/o patient's physiologic dead space should **ONLY** consistent of anatomical dead space.
There should be no alveolar dead space.
106
If a patient has a lot of alveolar dead space, what must be done to ompensate for the portion of the air not being used for gas exchange?
They must **get more fresh air into the lungs** to compensate for the portion of the air not being used for gas exchange
107
What does Mixed Expired (ME) gas consist of?
The entire tidal volume is analyzed (500 mL)
The 150 mL of air (anatomical dead space) and the other 350 mL of alveolar gas.
