Exam 4 - Lecture 3 Flashcards
1
Q
What is the formula for the Alveolar Gas Equation as given in the sources?
A
PAO2 = [(PB - PH2O) x FiO2] - PaCO2 / R.
2
Q
What is the normal value for ‘R’ in the Alveolar Gas Equation?
A
R is normally 0.8.
3
Q
What does ‘R’ stand for in the Alveolar Gas Equation?
A
R is the Respiratory Exchange Ratio (RER).
4
Q
What is ‘R’ also called?
A
The respiratory quotient.
5
Q
What is the Respiratory Exchange Ratio (RER) or Respiratory Quotient (RQ) typically a ratio of?
A
How much O2 is used and how much CO2 is produced.
6
Q
Is the RER/RQ usually one-for-one?
A
They are usually pretty close to one-for-one.
7
Q
Why do planes typically fly at high altitude?
A
Planes fly at high altitude because the air is thinner, and you get better gas mileage.
8
Q
Modern jets are typically pressurized to mimic the environmental conditions at what altitude?
A
They are pressurized to basically mimic an 8,000 feet environmental condition.
9
Q
What is the approximate PO2 at 40,000 feet?
A
The PO2 at 40k feet is only 29mmHg.
10
Q
What happens to the blood vessels in your lungs at high altitude, and what is this process called?
A
The blood vessels in the lungs can constrict via HPV (hypoxic pulmonary vasoconstriction) if breathing air with lower than normal PO2.
11
Q
How does hypoxic pulmonary vasoconstriction (HPV) affect a bad right heart?
A
This constriction puts an excessive load on the right heart.
12
Q
What triggers the chemical reaction in the metal container attached to the mask?
A
Pulling on the mask triggers the chemical reaction in the box.
13
Q
During sudden depressurization at 40,000 feet, what is the PO2 in the cabin?
A
The PO2 in the cabin is 29mmHg.
14
Q
What happens to gas exchange in the lungs due to the large difference in PO2 between pulmonary capillary blood and alveoli at 40,000 feet during depressurization?
A
The gas exchange is actually going to happen in reverse since there is more oxygen in your lungs than the outside environment.
15
Q
What effect does the reversal of gas exchange have on consciousness?
A
That’s going to lead to rapid consciousness loss.
16
Q
Does depressurization and the reversal of gas exchange affect oxygen bound to hemoglobin?
A
Yes, it pulls it off hemoglobin too.
17
Q
What type of chemical reaction occurs in the oxygen mask container?
A
It’s an exothermic reaction, which gives off alot of heat.
18
Q
What is the risk if the chemical reaction in the oxygen mask container goes off at the wrong time?
A
If it goes off at the wrong time, heat + oxygen = fire.
19
Q
Why do most airlines not allow beards for pilots?
A
Most airlines don’t allow beards for pilots because of fitting for the mask.
20
Q
What type of oxygen source do pilots typically have, and why do they need a tightly fitting mask?
A
Pilots typically have a source of compressed 100% oxygen.
21
Q
What is the normal arterial pH?
A
Normal arterial pH is 7.4.
22
Q
What is the normal range for arterial pH?
A
The normal range is 7.35 - 7.45.
23
Q
What is acidity typically dependent on in body fluids?
A
Acidity is typically dependent on hydrogen activity.
24
Q
What is the main ‘volatile’ gas in the body?
A
CO2 is the main ‘volatile’ gas.
25
What does it mean for a gas to be 'volatile'?
Volatile just means it can go airborne.
26
What is the main acid in the body? Weak or strong?
CO2 is the main acid in the body. (weak acid)
27
Is carbonic acid (H2CO3) a strong or weak acid?
Carbonic acid is also a weak acid.
28
How are acids sometimes written in shorthand?
HA
29
When an acid dissociates (HA ⇌ H+ + A-), what is the A- called?
This A- is called a conjugate base.
30
Should the conjugate base (A-) be able to recombine with H+?
Yes
31
What happens when a strong acid like HCl dissociates in solution?
Very prone to donating protons.
32
Is the conjugate base of a strong acid like HCl (chloride) strong or weak, and why?
The resulting conjugate base (chloride) is very weak.
33
What happens when a weak acid like carbonic acid dissociates?
A weak acid (such as carbonic acid) dissociates into a proton and its conjugate base.
34
What is the conjugate base of carbonic acid?
The conjugate base in this case is bicarb (HCO3-).
35
Is the conjugate base of carbonic acid (bicarb) strong or weak, and why?
Bicarb likes to accept protons, so it is considered a strong conjugate base.
36
For every 1,000 CO2 molecules, about how many carbonic acid molecules are present at any given time, and why?
For every 1,000 CO2 molecules, we might have one carbonic acid molecule. Its rapidly broken down.
37
For practical purposes in acid-base math, what can CO2 be considered equivalent to?
For practical purposes, we can think of CO2 as basically being the equivalent of carbonic acid.
38
Name some examples of non-volatile acids found in the body.
Other non-volatile acids include Sulfuric acid, Phosphoric acid, Hydrochloric acid, and Lactic acid (Lactate).
39
What does it generally mean if a word ends in the '-ate' suffix in acid-base terminology?
If they end in -ate suffix, generally means acid.
40
What produces much of the non-volatile acids in the body?
Much of the production involves the breakdown of food, typically proteins.
41
How can the production of non-volatile acids be reduced?
If you have a low protein diet, you'll have a lot less of these acids.
42
Is the effect of diet on non-volatile acid production described as a big change in the body's normal function?
Yes, this is one area where a simple behavior change (diet) can cause a big change.
43
Are pathological acids normally found in high amounts in the body?
No, pathological acids are typically not found in high amounts normally.
44
Name an example of a pathological acid associated with poor blood sugar management in diabetes.
Acetoacetic acid.
45
What does acetoacetic acid smell like?
It's kind of like acetone and is what produces that smell coming off diabetic patients.
46
When is acetoacetic acid also produced?
Excessive alcohol consumption
47
What alcohol breakdown products in the liver are associated with acetoacetic acid production?
Alcohol is broken down by alcohol dehydrogenase in the liver which results in acetaldehyde and acetoacetic acids.
48
Name another example of a pathological acid produced in people in poor health, particularly with poorly managed diabetes.
Butyric acid.
49
What is the general property of all the acids mentioned (volatile and non-volatile)?
All of these acids are potential proton donors.
50
What primary organs take care of non-volatile acids?
Non-volatile acids must primarily be taken care of by the kidney or liver.
51
Name an example of a strong acid.
Hydrochloric acid is a strong acid.
52
Name an example of a weak base mentioned in the sources.
Sodium fluoride. Toothpaste is a weak base, to buffer the acidity on the teeth.
53
Name an example of a strong base.
NaOH is a STRONG BASE. Sodium Hydroxide.
54
How easily does sodium hydroxide (NaOH) dissociate in solution? What is this a main component of?
It dissociates really easily in solution. Drain cleaner.
55
How do the properties of amino acids differ?
Charge and solubility.
+/-, lipid or water soluble.
56
What does the structure of a protein depend on in relation to protons?
The way the protein is structured depends on a normal amount of protons interacting with some of the negatively charged areas on the protein.
57
What happens to the shape of a protein if the amount of protons changes? What does this result in?
If we change the amount of protons, the shape of the protein will change. Then, it will not function normally.
58
Provide an example of a protein mentioned that is affected by proton concentration changes.
Hemoglobin and the Na+/K+ ATPase pump.
59
How does increased free proton activity affect oxyhemoglobin?
If oxyhemoglobin goes into an environment with a lot of free proton activity, more protons than usual will interact with the protein and change its shape, causing oxygen to fall off. (Bohr effect)
60
When the Na+/K+ pump slows down due to acidosis, what happens to potassium levels inside and outside the cell?
The potassium normally packed into the cell leaks out because the pump cannot sequester it. This leads to outwards leaking of K+ and hyperkalemia.
61
ATP that comes from proteins, these proteins are thought of as?
ATPases
62
Where are many ATPases that produce ATP located?
Mitochondria
63
How does the association of lots of protons with ATPase ATP-generating pumps affect ATP production levels? What pump is most affeted by this?
If we have lots of protons associated with ATPase ATP generating pumps, then ATP production drops.
Na+/K+ pump
64
What happens if there is extreme acidity in the CSF surrounding the brainstem and nervous system?
If we have extreme acidity in CSF surrounding the brain and NS, then it can completely shut down nervous system. An obscene amount can make tissue stop working entirely.
65
What substance is typically packaged with a drug to help with absorption/distribution?
Hydrochloride salt is typically packaged with a drug to help with absorption/distribution.
66
Name a drug mentioned that is extremely basic.
Phenobarbital. Sodium phenobarbital is extremely basic. Causes pain on administration.
67
Is the pH scale logarithmic or linear?
pH is logarithmic. It's a base 10 log.
68
What kind of changes in proton concentration result from small changes in pH?
Small changes in pH = LARGE changes in [H+]. For relatively small changes in pH, there are drastic, huge changes in proton concentration.
69
Are the overall concentrations of free protons in body fluids described as high or low?
Overall, very low concentrations.
70
What determines the pH in body fluids?
pH is dependent on how many protons we have in solution.
71
What is the approximate pH of gastric acid?
Gastric acid has a pH of 1. This is about as acidic as you can get in the body.
72
Why can the stomach handle a pH of 1?
Stomach can handle this because it has very tough lining, like thick leather. Its tissue is specialized to be resistant to that acid.
73
What part of the body has the most alkaline secretions, and what is their approximate pH? Why?
The pancreas has a pH of 8. To secrete and neutralize stomach acid.
74
Why don't we want our intestines to be super acidic?
We don't want our intestines to be super acidic, since they are more fragile.
75
Given the pH difference between gastric acid (pH 1) and pancreatic secretions (pH 8), what is needed to neutralize the stomach acid?
Going to need A LOT more pancreatic secretions to normalize pH, since 8 isn't that alkaline but 1 is. Since the pH numbers are so lopsided (pH 1 vs pH 8), the pancreatic secretions need to have a much higher flow rate or volume than what is coming from the stomach to adequately neutralize the acid.
76
If you have really high intestinal motility, what can happen to your acid-base status, and why?
If you have really high intestinal motility, you can become acidotic because the pancreas is having to work extra and utilizing a lot of bicarb. Losing a lot of the bicarb produced by the pancreas leads to acidosis.
77
If you have an intestinal obstruction and are constantly vomiting stomach contents, what can happen to your acid-base status, and why?
If you have an intestinal obstruction and constantly vomiting, you'll also be losing large amounts of acid and make us more alkalotic. Repeatedly vomiting stomach contents leads to loss of large amounts of acid, which can swing things towards alkalosis.
78
What is the formula for pH using proton concentration?
pH = -log [H+] or 'base 10 log'.
79
What is the proton concentration in mmol/L at a pH of 1?
At pH 1, [H+] = 1 x 10^-1 = 0.1mmol/L.
80
What is the proton concentration in mmol/L at a pH of 7?
At pH 7, [H+] = 1 x 10^-7 = 0.0000001mmol/L.
81
How many zeros after the decimal point correspond to milli, micro, and nano prefixes?
3 zeros after '.' is milli, next 3 is micro, next 3 are NANO.
82
What is the proton concentration in nmol/L at a neutral pH?
The proton concentration at pH 7 (this is neutral) is 100 nanomoles/L (nmol/L).
83
What is the approximate survivable pH range for humans according to the sources?
The survivable pH range is 6.90 - 7.80
84
What happens to proton concentration for every one unit change in pH (e.g., from 7 to 8)?
If we have a pH difference of 1 (pH of 7 to 8), results in 10x the difference. A change of one pH unit is basically a 10-fold change in proton concentration.
85
What is the proton concentration in nmol/L at a pH of 8 compared to pH 7?
pH of 7 is 100 nmol/L, while pH of 8 is 10nmol/L.
86
What is the proton concentration in nmol/L at a pH of 6?
At a pH of 6, it’ll be 1000nmol/L.
87
1000 nmol/L is equivalent to how many micromoles per liter?
1000nmol/L would ALSO be 1micromoles/L.
88
If pH changes from 7.4 to 7.7, what happens to the proton concentration in nmol/L?
If we have a pH change from 7.4 to 7.7, this would cut nmol/L concentration in HALF from 40 to 20nmol/L.
89
What is the normal proton concentration at pH 7.4?
Normal proton concentration at pH 7.4 is 40 nmol/L.
90
What is the main extracellular fluid buffer?
The main extracellular fluid buffer is Bicarb (HCO3-).
91
Besides bicarb, what else is a very important buffer in the blood?
Proteins are a super important buffer in the blood.
92
How do proteins act as buffers?
Protons bind to proteins and takes them out of solution and reduces their overall activity. It effectively takes them out of solution and keeps them in check.
93
What specific protein is mentioned as a very helpful buffer?
Hemoglobin (Hb)
94
Where are phosphate buffers most important?
Phosphate buffers are most important for INSIDE the cells.
95
Can phosphate buffers also be useful in the blood?
Yes
96
What are considered the three most important buffers?
The three most important buffers are bicarb, proteins, and phosphate.
97
What ability of the body allows it to adjust pH quickly?
CO2 control via the lungs.
98
How does the effectiveness of other buffers change if the lungs don't work well?
The buffers won't work as well if the lungs don't work as well. Effectiveness of buffers is always correlated with other buffers available.
99
What role do the kidneys play in adjusting bicarb concentrations?
The kidneys can also produce bicarb to increase concentrations.
100
How does losing a lot of proteins affect bicarb as a buffer?
If we lose a bunch of proteins, then bicarb becomes a less effective buffer.
101
How does losing proteins affect phosphate as a buffer?
Phosphate also becomes a less effective buffer without proteins.
102
Do all buffers tend to work together?
All buffers tend to work together. All of these tend to work together with each other to stabilize our pH.
103
What units are used for Hemoglobin on the left and right sides of the Blood buffer system graph?
On the left side is Hb measured in g/100mL, and on the right side it's also Hb just measured in Hb (meq/L).
104
What variable is going through between the Hb measurements on the Blood buffer system graph?
Going through between them is the PCO2.
105
What is on the Y-axis and X-axis of the Blood buffer system graph?
The Y-axis is Bicarb concentration in mmol/L (from low to high). The X-axis is pH (7.0 on left, 7.8 on right).
106
On the Blood buffer system graph, what does a steeper slope represent?
Steeper the slope, the better the buffering capacity.
107
What does the Blood buffer system chart basically show about buffering capacity?
Basically, the chart is showing that increased amount of Hb and HCO3- has a better buffering capacity than low Hb and low HCO3-.
108
What do the blue lines on the Blood buffer system graph represent?
The blue lines represent deviations from normal Hb levels.
109
How does having extra protein (Hb) affect the line on the Blood buffer system graph?
If you have extra protein (Hb), it shifts the line up.
110
What is a PaCO2 curve on a buffer graph called?
PaCO2 curve is a isobar. It's a line that represents a specific arterial PCO2 level.
111
What are the normal values for PaCO2, pH, and HCO3- at the normal point on the PaCO2 isobar graph?
A normal PaCO2 is 40mmHg, with a pH of 7.4, and a HCO3- is 24mmol/L.
112
What is considered the normal arterial bicarb level for this class?
A NORMAL BICARB IS 24mmol/L.
113
What units can be used for normal bicarb levels?
The units can be mmol/L or milliequivalents per liter (meq/L).
114
On the PaCO2 isobar graph (slide 7), if pH stays at 7.4 but PaCO2 is 20, and Bicarb is around 37, what might this indicate about proton concentration?
With lots of bicarb (37ish), there are probably fewer protons floating around in the blood.
115
What are the two ways described to look at the relationship between high bicarb (e.g., 37) and low proton concentration?
Bicarb is high because proton concentration is low, OR proton concentration is low BECAUSE bicarb concentration is high.
116
In uncompensated respiratory acidosis, what are the expected changes in pH, PCO2, and Bicarb?
↓↓pH, ↑↑ PCO2, and ↑ Bicarb. Uncompensated respiratory acidosis results in a substantially lower pH, a substantially higher PCO2, and bicarb levels that are slightly elevated.
117
In uncompensated respiratory alkalosis, what are the expected changes in pH, PCO2, and Bicarb?
↑↑ pH, ↓↓ PCO2, ↓ Bicarb. Uncompensated respiratory alkalosis results in a higher pH, a lower PCO2, and bicarb levels that are lower than normal.
118
In uncompensated respiratory alkalosis, why are bicarb levels lower than normal?
Bicarb is lower because there's less CO2 available to form carbonic acid and then bicarb.
119
What happens to pH in acute respiratory acidosis according to the graph description (slide 10)?
In acute respiratory acidosis, the pH shifts to the left (becomes very low, e.g., 7.1 or lower).
120
What happens to arterial bicarb slightly in acute respiratory acidosis according to the graph description (slide 10)?
Bicarb levels are slightly higher.
121
Name some specific causes of respiratory acidosis related to poor lung function or decreased ventilation.
Respiratory disease, neuromuscular disorders, sedation. Anything that affects the strength of the lung muscles.
122
From what spinal nerves does the phrenic nerve arise?
C3 - C5
123
How can a high spinal cord injury (above C3-5) cause respiratory acidosis?
If we have an injury above that level, all of the phrenic nerve activity is going to cease. A high injury can stop phrenic nerve activity and cause complete cessation of respiration by impacting the phrenic nerve.
124
How can lower spinal cord injuries (C4 or upper thorax) affect ventilation?
Lower injuries (C4 or upper thorax) can affect diaphragmatic function and accessory muscles, impacting ventilation.
125
What is kyphoscoliosis?
Kyphoscoliosis is an abnormal curvature in both the coronal and sagittal planes. It is a crooked spine.
126
How can kyphoscoliosis lead to respiratory acidosis?
It can lead to respiratory acidosis by limiting lung function.
127
How can surgical correction of kyphoscoliosis using plates, screws, and rods affect breathing, and what is this related to?
Surgical correction using plates, screws, and rods can improve posture but make breathing difficult due to introduced rigidity. It's a reduction of **chest wall compliance.**
128
When is breathing especially difficult for a person with extreme obesity?
Especially when lying on the back.
129
How do opiates affect respiration?
Opiates can cause respiratory depression and insufficiency if given in high enough doses. They can lead to respiratory insufficiency.
130
What is a common cause of death in fentanyl overdoses?
Fentanyl essentially dying from respiratory insufficiency.
131
What specific area of the brain do opiates affect to cause respiratory insufficiency?
They knock out the respiratory centers in the brain.
132
Do all clinically used opiates have the potential to cause respiratory insufficiency?
Yes, all clinically used opiates have the potential to do that if given a high enough dose.
133
Name some other sedatives and drugs mentioned that can cause respiratory depression leading to acidosis.
Central nervous system injuries, benzodiazepines, alcohol, barbiturates, volatile anesthetics, and paralytics.
134
How do benzodiazepines (like valium or ativan) affect respiration?
Benzodiazepines function by augmenting GABA activity.
135
Are benzodiazepines likely to cause fatal respiratory depression alone?
Much less likely when used alone
136
When might fatal respiratory depression occur with benzodiazepines?
Usually, fatal respiratory depression with benzodiazepines occurs in some combination with something else that inhibits respiratory drive.
137
How does alcohol (ethanol) affect respiration?
Alcohol is a direct GABA agonist, decreasing respiratory effort.
138
Why can alcohol be fatal, especially in combination with other substances?
Respiratory acidosis, especially in combination with other substances that enhance GABA activity.
139
How do barbiturates (like pentobarbital) affect respiratory control centers?
Barbiturates have massive impacts on the respiratory control centers.
140
Are barbiturates described as dangerous direct GABA agonists?
Yes, barbiturates are highly dangerous direct GABA agonists.
141
What were barbiturates once prescribed for, and why are they rarely used now?
They were once prescribed for sleep but are rarely used now due to their severe risks.
142
Do volatile anesthetics affect respiratory function?
Yes, volatile anesthetics can affect respiratory function to some degree.
143
How can lying on the back on a surgical table, especially with extreme obesity or muscle paralysis, affect breathing?
Lying on the back on a surgical table, especially with extreme obesity or when skeletal muscles have been paralyzed during surgery, can also exacerbate breathing issues. It makes the chest wall compliance that much lower.
