Test 4 🥳 Flashcards
(791 cards)
1
Q
What is the name of the cartilaginous structure that floats in the middle of the neck?
A
Larynx
2
Q
Where does the larynx connect superiorly?
A
Hyoid bone→ Through a number of ligaments and pharyngeal skeletal muscles that secure larynx to hyoid bone
3
Q
Why is it useful that that trachea is not a continuous piece of cartilage?
A
- Opening on the back side of the cartilage
- Helps with swallowing→ easier for food moving through esophagus
- Enfolding in connective tissue with coughing→ increases velocity to clear mucus in upper respiratory system
4
Q
The _________ is anterior to the esophagus
A
Trachea
5
Q
Which area of the trachea are the rings not continuous?
A
Posterior side of tracheal cartilage
6
Q
How does the enfolding made in posterior tracheal cartilage aid in clearing secretions?
A
- Creates 2 smaller sections which allows for faster flow
- Smaller vessels generates faster expiration velocity
7
Q
What is a function of many lung cells that helps to move mucus in the respiratory tract?
A
Cilia
8
Q
What is the function of cilia and where are these ciliated cells located?
A
- Located around goblet cells
- Help to sweep out mucus in upper airway
9
Q
What happens if mucus builds up in the upper airway and the cilia arent able to sweep is all out?
A
Requires a cough to clear the mucus
10
Q
At what speed can we generate air flow when coughing?
A
100mph
11
Q
A
12
Q
What is the green circle showing?
A
Thyrohyoid membrane
13
Q
What view is being shown of the larynx?
A
Posterior view (back of trachea without cartilage)
14
Q
What is the function of the thyrohyoid membrane?
A
Connects top of thyroid cartilage to the hyoid bone at the front of larynx
15
Q
What is the only piece of continuous cartilage in the larynx?
A
Cricoid cartilage
16
Q
What is the narrowest point in a patient <10 years old?
A
Cricoid cartilage
17
Q
What is the narrowest point in an adult patient?
A
Transglottic space (area between the vocal cords
18
Q
Where does an ETT cuff sit in relation to the larynx?
A
Cuff sits below the larynx
19
Q
What is one way you could manually palpate ETT in the correct position?
A
Can palpate the cuff inflating at the sternal notch→ top of sternum trachea sits right underneath that
20
Q
What is the average length and width of the trachea?
A
- 10-13 cm long
- a couple cm wide
21
Q
Where does the trachea connect to the larynx?
A
At the base of the larynx
22
Q
Most of the trachea is __________ the thorax
A
Inside (intrathoracic)
23
Q
How much of the trachea is extrathoracic?
A
4cm at the top of the trachea that is accessible in the neck
24
Q
What is responsible for connecting each piece of tracheal cartilage together?
A
Annular ligaments (connective tissue)
25
How many pieces of tracheal cartilage do adults have?
20 pieces of tracheal cartilage all connected by annular ligaments
26
What is the shape of tracheal cartilage?
C-shaped
27
Why is is helpful to have cartilage in the trachea?
- It can bend and is resilient
- Helps to have a little bend so the structure doesnt break under pressure
28
How many bronchopulmonary segments does the right lung have?
10
29
How many bronchopulmonary segments does the left lung have?
8→ 4 segments that fuse into 2 segments during development
30
How does the right mainstem compare to the left mainstem?
- Right mainstem is wider since right lung is larger
- Right mainstem is shorter and branches almost immediately
31
How long is the right mainstem?
Only a few cm long
32
How long is the left mainstem?
4-6cm: More narrow and longer than the right mainstem
33
Why is the left mainstem longer than the right mainstem?
Longer length because the heart is positioned on the left and we need to route the air past where the heart is sitting
34
How does the angle of the right mainstem compare to the left?
- Right mainstem is more vertical (25 degrees)
- Left mainstem is more horizontal (45 degrees)
35
Why is the left mainstem more horizontal?
Winding around the heart
36
What is the total bifurcation angle and what is it measuring?
- 70 degrees (25 +45)
- The angle between the 2 mainstem at the tracheal bifurcation
37
What is the carina?
- Bottom of the tracheal cartilage that serves as bifurcation point for 2 mainstems
- The cartilage that is the start of the bifurcation
38
What are some locations for invasive airways?
- Trachea (tracheostomy)
- Median cricothyroid ligament
39
Where in the trachea would a tracheostomy be placed?
Top of the trachea (upper 4cm) that is extrathoracic
40
What is the median cricothyroid ligament?
Piece of connective tissue that connects front of cricoid cartilage to the front inside of the thyroid cartilage
41
What is the blue circle showing?
Median cricothyroid ligament
42
Why would you want to provides humidified air to patient with invasive airways (tracheostomy)?
Bypassing the nose so air is not being humidified→ humidify inspired air to help prevent airway from drying out
43
Where is the incision made of a tracheostomy?
Trachea
44
Where is the incision made if accessing an airway around above the trachea?
Cricothyroid ligament
45
What can change the length of the trachea?
- Changing head position
- stretching head back→ makes trachea longer and more narrow
- flexing head forward makes internal trachea diameter wider
46
What is the purple highlight showing?
Supraglottic space
47
What is the green highlight showing?
Transglottic space (vocal cords)
48
What is the pink highlight showing and what view is this?
- Subglottic space
- Posterior view
49
What part of the cricoid cartilage is the blue circle showig?
Anterior arch (where you apply cricoid pressure)
50
What can cricoid pressure be useful in preventing?
Gastric content aspiration (not without risk)
51
What is the muscle that connects the front of the cricoid cartilage to the rear of the thyroid cartilage?
Cricothyroid muscle
52
What happens when the cricothyroid muscle contracts?
Pulls the front of the larynx down
53
Where do the vocal cords attach?
Within in thyroid cartilage the vocal cords attach to the laryngeal prominence (also attached at the arytenoid cartilage)
54
What happens if the cricothyroid muscle contracts and the arytenoid cartilage doesnt move?
Vocal cords tighten up
55
Can the cricothyroid cartilage open and close the vocal cords?
No, it only tighten the cords by stretching them forward
56
Why do we care if the vocal cords are tighter?
Cricothyroid muscle contraction= More tension on the cords = More difficult to pass ETT through the cords
57
What view is this diagram of the larynx showing?
Superior
58
Which laryngeal muscles open the rima glottis?
Posterior cricothyroid muscles
59
What is another name for the Rima glottis?
Rima Glottidis
60
Laryngeal muscles are all ___________ muscles
Skeletal
61
What is the name of the opening between the vocal cords?
Rima Glottis
62
How many laryngeal muscle sets do we have?
6
63
What are the only laryngeal muscles that are fully exterior outside the larynx? (only extrinsic laryngeal muscles)
Cricothyroid muscles
64
What effect do the cricothyroid muscles have on the rima glottis?
No effect on rima glottis (just tighten the cords when flexed)
65
What are the muscles that run parallel to the vocal cords?
Vocalis Muscles
66
What happens with contraction of the vocalis muscles?
- Tightens the cords
- No effect on the rima glottis
67
Which muscle attaches to the thyroid cartilage and the arytenoid cartilage?
Thyroarytenoid muscles (articulates with the back part of the arytenoid cartilage)
68
What happens when the thyroarytenoid muscle contracts?
Arytenoid cartilage swivels to close the cords
Left cartilage swivels clockwise
Right cartilage swivels counterclockwise
69
What is another term to describe the cords closing?
Adduction of the cords
70
What does adducting the vocal cords mean?
Brings them together aka closes them when both arytenoid cartilage adduct at the same time
71
Which muscle attaches between the arytenoid cartilage?
Transverse arytenoid muscle (blue)
72
What is the only unpaired muscle in the larynx?
Transverse arytenoid muscle
73
What happens when the transverse arytenoid muscle contracts?
Bends the arytenoid cartilage to pull then closer together and closes the vocal cords
74
What parts of the arytenoid cartilage are flexible?
- The cartilage itself is flexible
- The swivel point is flexible
75
Which laryngeal muscle connects the cricoid cartilage to the arytenoid cartilage?
Posterior cricoarytenoid cartilage (pink)
76
What happens when the posterior cricoarytenoid muscle contracts?
Arytenoid cartilage back processes are pulled together and it pulls the vocal cords apart
77
What does abduction of the vocal cords mean?
Rima glottis is open
78
Why is it an issue if the posterior cricoarytenoid muscle has a problem?
Makes it difficult to breathe since its the only laryngeal muscle that opens the vocal cords
79
What are the connection points for the lateral cricoarytenoid muscles?
Posterior arytenoid and lateral (side) of cricoid cartilage (purple)
80
What happens when the lateral cricoarytenoid muscles contract?
Pulls back corners of the arytenoid cartilage causing rotation of the cartilage to close the vocal cords
81
What is the muscle with the purple dot?
Lateral cricoarytenoid muscle
82
What is the muscle with the pink dot?
Posterior cricoarytenoid muscle
83
What is the muscle with the blue dot?
Transverse arytenoid muscle (wrapped around the back part of the 2 pieces of arytenoid cartilage)
84
What is the muscle with the pink dot?
Posterior cricoarytenoid muscle (wraps around the back)
85
What is the muscle with the green dot?
Thyroarytenoid muscle
86
Which one of these show how the cords look with normal breathing?
Gentle abduction
87
Which position would the cord be in for a true whisper?
Full abduction?→ cords are not vibrating when whispering (wide opening for air to go through)
88
What position are the cords in during phonation?
Close together almost totally closed→ hard to take a deep breath in when talking
89
How does cord tightness relate to pitch?
- Tight closure allows us to form different pitches with our voice
- Tighter cords= higher pitch
- Looser cords= lower pitch
90
Which nerves innervate and control most of the muscles in the voice box?
Inferior laryngeal nerves
91
What are the inferior laryngeal nerves a derivation of?
Recurrent laryngeal nerve (comes from vagus nerve)
92
What happens if 1 laryngeal is injured and is dysfunctional?
- Still able to get cords tight enough to speak but usually have a raspy voice
- More muscles that close the cords than open the cords
93
94
Which nerve is responsible for sensory perception of the front 2/3 tongue?
Cranial nerve V (Trigeminal nerve)
95
Where is the trigeminal nerve located and how many division does it have?
Located on the side of the face
3 divisions
96
What are the divisions of the trigeminal nerve?
- V1: Top division→ophthalmic division
- V2: Maxillary division→ upper mouth and nose
- V3: Mandibular division→Mandible sensory function
97
Label the purple, green, and orange sections of the trigeminal nerve:
98
What causes atmospheric pressure?
Result of gravity and the weight of atmosphere between us and outer space
99
What is atmospheric pressure at sea level?
760mmHg
100
What is atmospheric pressure in space?
0
101
What happens to atmospheric pressure when there is more air between us and outer space?
Higher atmospheric pressure
102
How does atmospheric pressure change at higher altitudes?
Lower atmospheric pressure (less air above us)
103
What is another term for atmospheric pressure?
Barometric pressure
104
How does atmospheric pressure change at lower altitudes?
Higher atmospheric pressure (more air above us)
105
What is barometric pressure at the peak of Mt Everest?
253mmHg
106
How does inspired O2 change from sea level to the peak of Mt Everest?
Same O2 concentration (21%) but at Mt Everest peak there is less pressure available to push gas into our lungs
107
If barometric pressure at the peak of Mt Everest is 253mmHg and atmospheric O2 concentration is 21% what is the partial pressure of dry O2?
(253)(.21)= 53mmHg
108
If barometric pressure at the peak of Mt Everest is 253mmHg and atmospheric O2 concentration is 21% what is the partial pressure of inspired O2?
(.21)(253-47)= 43mmHg
PiO2= 43mmHg
109
What happens in the body when the partial pressure of O2 is low (like at the summit of Mt Everest)?
Arterial PO2 will likely be very low from the low pressure driving O2 into the system
110
What is the best way to look at barometric pressure in relation to the impact on the body?
Barometric pressure effects the pressure available to push O2 into your blood
111
How long can most humans tolerate a PiO2 of 43mmHg?
A couple hours→ that low of PO2 will not support life for a long period of time
112
What is the pressure generated by water vapor?
Always 47mmHg at any altitude
113
Why does it feel like you are out of breath at higher altitudes?
People tend to hyperventilate when first exposed to high altitude as a compensation to low PiO2
*over a few days ventilation rate comes back to normal levels*
114
What are longer term compensations to low PO2 in the blood when living at high altitude?
- Less O2 in the kidney= inner medulla O2 sensors increase EPO production
- Increased alveoli during development
115
How does increased EPO aid when at high altitude?
High EPO expands the hematocrit to help with O2 delivery in a low pressure environment
116
How does the respiratory system develop differently for people who grow up in high altitude climates?
These people have increased surface area for gas exchange in the lungs→ for more alveoli
117
Why do athletes who live at high altitudes have advantage in athletics/running marathon etc at sea level?
They have more surface area for gas exchange
118
What is a common place that has lots of people who win races?
Ethiopia or Kenya (countries are at high altitude)
119
What is the limiting factor to exercise performance?
Heart (cardiac output)→ not the lungs
120
We usually have ______x more lung area than we need for gas exchange
3X
121
How is it that someone who smokes for a few years then quits probably wont have much different lung quality than a healthy person?
The safety factor in the lungs with more area for gas exchange than we need→ short term damage in the lungs is usually tolerable
122
Why do some people get altitude sickness and others don't?
Genetic→ reason to increase altitude and allow time to adjust between each ascent bc people find out what they can tolerate at different altitudes
123
How many meters high is the summit of Mt Everest?
8848m
124
As barometric pressure decreases PiO2 ___________
Decreases
125
Where is the lowest altitude on earth?
Death Valley (higher atmospheric pressure)
126
How does scuba diving affect atmospheric pressure?
Water is very heavy→ If we are to dive to deep depths that subjects the body to a lot of pressure
127
What is the pressure at an underwater depth of 500 feet?
16x sea level = 16 (760) = 12,160mmHg
128
1 atm = ______ mmHg
760
129
How does increased barometric pressure affect our breathing?
- At increased pressure we would have to be breathing from a source where high pressure is available
- EX: Scuba equipment tanks are pressurized at a high level
130
How does breathing from a high pressure source when under high pressure affect blood gases? (ex: divers)
Blood gas will increase in proportion to the total environmental pressure
131
How does the pressure outside of the body compare to the blood gases before decompression when scuba diving?
- Pressure in the atmosphere: PO2 10x normal at 1000mmHg and PN2 is 4000mmHg
- Body gas pressures: H2O= 47mmHg, PO2= 60mmHg, PCO2= 40mmHg, PN2= 3918mmHg
132
What type of gas is usually in a scuba tank?
Atmospherics gas
- 79% N2
- 21% O2
133
What are the reasons for using atmospheric air in a scuba tank?
- Cheapest
- Not as explosive as 100% O2
134
Why is nitrogen partial pressure so high when total atmospheric pressure is high?
80% of the air in the tank is nitrogen→ high atmospheric pressure leads to high partial pressure of N2 (4000mmHg)
135
Is nitrogen soluble or insoluble?
Insoluble
136
What could partial pressure of N2 get to at deeper diving depths?
Partial pressure of N2 could exceed 10,000mmHg
137
Why does deeper dive create higher amount of N2 in the blood?
High pressure will push more N2 into the blood even though N2 is relatively insoluble→ creates concern with N2 toxicity and AMS bigger concern is resurfacing too quickly
138
Why is it a concern coming back to the surface too quickly when diving?
- Deep depth= really high pressures are larger than normal N2 in your system
- If surface too quickly the pressures adjust and the only way to do this is for gas to come out of solution
- N2 goes back to gas phase and into the body
- N2 can form air emboli in the circulatory system
139
How do we prevent N2 dissolved in the blood from going into a gas phase when decreasing barometric pressure?
Gradually decrease barometric pressure (give body time to adjust)
140
What is a potential fix if you have an emergency and have to rapid come to the surface when scuba diving?
Hyperbaric chamber→ put patient back into high pressure environment to make changes more gradual
141
Why do some people call sudden decompression "blood boiling"?
N2 hops out of solution back to gas form from the rapid decompression similar to water boiling
142
What do outside pressures and ABGs look like after sudden decompression?
gradient creates where N2 wants to leave pt blood and it goes back to gas phase
143
Aside from surfacing gradually, what is another way to get around N2 toxicity with sudden decompression?
If N2 isnt included in inspired gas mixture in scuba tank
- Other issues associated with too much O2 (could be bigger problem than increased N2)
144
If the scuba tank was filled with 100% O2 how would this affect ABGs?
SUPER high PO2 levels (40x normal)→ could create bigger problem than high N2 levels
*pros and cons to keeping N2 in inspired gas mixture when scuba diving*
145
What type of environment do hyperbaric chambers simulate?
3x normal sea level (3 atm)
146
_________ hyperbaric chambers can go to higher pressures; but more dangerous and risk for explosion
Military
147
What are hyperbaric chambers useful for?
- Bad immune system
- Bad CV system
148
What can hyperbaric chambers be used to treat?
- Rapid decompression
- Problems with wound healing→uncontrolled DM and immune system attacking the body and destroying CV system
149
How does a hyperbaric chamber aid in wound healing?
- Push more O2 into the blood to be used in the body as oxidative stress to destroy things that can't handle the increased O2 (Ex: viruses)
- Immune system can use O2 as a way to destroy things when there is increase levels of O2 in the blood
150
What example discussed in lecture could it be indicated to have an entire hyperbaric room at high pressure?
- Found at oil rigs
- Active divers: can be healthier for these people who are frequently diving to live at high pressures all the time so the body doesnt have to adjust as much with each dive
- Very expensive and dangerous
151
A lot of the time hyperbaric chambers are __________.
Mobile: More cost effective for smaller areas/hospitals
152
What do the mobile hyperbaric chambers do to provide O2 to patients without pumping O2 into entire chamber?
Enrich the environment immediately around the patient→ adjust O2 levels in the bubble around the patient
*monitored by a nurse*
153
What are 2 ways we can pack O2 into the tissues int he blood in a dissolved state?
- Increase environmental pressure
- Giving 100% FiO2
154
Which celebrity had a hyperbaric chamber at his house?
Michael Jackson
155
How do we increase O2 in the blood past what Hb can carry?
- Increase PAO2 = Higher FiO2 than 21%
- Hyperbaric chamber = increase environmental pressure
- Or combo of both of these
156
If we are pushing more O2 into the blood with hyperbaric chamber or increase FiO2, what form is the O2 in?
Dissolved form
*Once Hb binding sites are full with O2 the only way to increase O2 in the blood is to increase pressure to convince O2 to go into the blood*
157
Which gas is an acid and can also be toxic in vast excess?
CO2
158
What is the typical amount of O2 we use in the OR?
- 30%→ too much O2 is toxic
159
Why do we use a little more than 21% O2 when inducing someone with general anesthesia?
GA messes with hypoxic pulmonary response and airway reactivity→ use a little higher than 21% O2 to offset that
160
How many O2 molecules are reactive?
4 oxygen molecules that are all very reactive
161
What is O2- ?
- Superoxide: O2 with an extra electron
- Unpaired extra electron and is very reactive
162
What does superoxide do in the body?
Can be used to degrade a lot of different compounds with the unpaired electron
163
What enzyme can break down superoxide?
Superoxide Dismutase
164
Why is it a bad thing is the body has too much nitric oxide (NO)?
Too much NO can react with other molecules and create dangerous compounds like OONO-
165
What is OONO-?
Peroxynitrite
166
What compounds form peroxynitrite?
Large amounts of NO and oxidative stress/superoxide
167
What is the MOA of peroxynitrite (OONO-)?
- Interact and mutate DNA and destroys DNA
- Messes up cells
- Long term leads to cancer
168
How does hydrogen peroxide (H2O2) function as reactive O2 species?
Used as aseptic to tame infection
169
What are the 4 different reactive O2 species?
- Superoxide (O2-)
- Nitric oxide (NO)
- Peroxynitrite (OONO)
- Hydrogen peroxide (H2O2)
170
Is it always a bad sign when reactive O2 species are around in the body?
No, in limited amounts in specific places having some ROS around is a good thing because the body can use them to destroy things
EX: macrophages, immune killer T cells
171
What enzyme breakdown H2O2 and other peroxides?
Peroxidases
172
What enzymes can form or degrade Hydrogen peroxide?
Catalase
173
What is the function of acetylcysteine?
Good at destroying reactive O2 species
174
What is used in Tylenol OD?
N-acetylcysteine→ destroys reactive O2 species and cuts down on liver damage
175
When did the iron lung come about and what was the main use for it?
1960's d/t polio
176
What is polio?
Infection that destroys the ability of the nervous system to communicate with skeletal muscles
177
What is the pressure in the iron lung compared to the environment?
Pressure seal that creates lower than normal pressure inside the iron lung when the bottom cap is pulled out with inspiration
178
Why is the iron lung potentially better than positive pressure mechanical ventilation?
- Less trauma compared to PPV
- Iron lung mechanics are closer to how the body normally functions
179
How do the lungs fill with air in someone in an iron lung?
Alveoli at the superficial border of the lung tissue will fill first (closest to the negative pressure that is pulling on the lung)→ base of the lung/deep alveoli get stretched out and fuller
180
How do the lungs fill with air in someone on mechanical positive pressure ventilation?
- Pushing air into the lungs fills the alveoli closest to the large airways first
- Deep inner alveoli fill first and push on the other alveoli between them and the border of the lung
181
How does PPV compare to normal breathing?
Reverse of normal breathing but more mobile (positive aspect)
182
Who did he give as an example of a famous actor on PPV?
Christopher Reeves
183
What is the R variable in the alveolar gas equation?
Respiratory quotient / respiratory exchange ratio
R= 0.8
184
What does the respiratory quotient measure?
How much O2 is used and how much CO2 is produced
(not a 1:1 ratio)
185
What is the alveolar gas equation?
186
How tall is the summit of Mt Everest?
8,800m or 9km high
187
Why do airplanes fly at altitudes of 40,000 feet?
Cheaper to fly at 40,000ft→ better gas mileage because the air is thinner
188
What conditions are airplanes pressurized to mimic?
8,000ft environmental conditions
189
Why isnt the airplane cabin pressurized to sea level conditions?
Would require more pressure = more dangerous
190
Why does the air in the airplane cabin need to be pressurized?
Pump air in from outside the plane
- Still 21% O2
- PO2 is way too low → reason why it is pressurized
191
What is PO2 in the air at 40,000ft?
PO2 in the air = 29mmHg
192
What happens to arterial O2 sat if the cabin depressurizes at 40,000ft and you dont have supplemental O2?
O2 sat drop to 15%
*inspired PO2 is even lower in the lungs after diluted with water vapor→ delta P making O2 want to move from the blood (40mmHg) to the alveoli (23mmHg)*
193
What is typical cabin pressure when flying in a plane at 40,000ft when the cabin is adequately pressurized?
- Around 118mmHg
- Pressurized to mimic 8,000ft environment
194
Why is it a risk for people with a bad heart or lungs to fly?
- PO2 is lower than normal which causes hypoxic pulmonary vasoconstriction
- Lungs recognize the air we are breathing is lower than normal PO2
- Blood vessels in the lungs constrict because they sense "hypoxia"
- Makes it hard for the right heart to pump
- Right heart isn't that strong to begin with so don't want to put that load on the heart if we don't have to
195
How do the overhead masks on a plane create O2 flow?
Masks are hooked up to a container with chemicals→ when you ug on the mask it combines the chemicals in the box to produce O2 → Exothermic reaction
196
What is a concern if the chemicals in the O2 mask box get set off unintentionally?
Exothermic reaction→ O2 and heat could cause fires and create a chain reaction with the tanks next to them
197
If the PO2 in the air in the airplane cabin is 29mmHg then what will our inspired O2 be?
FiO2= (.21)(141-47) = 20mmHg
*Delta P for O2 to move out of pulm capillary into the alveoli*
198
What happens to gas exchange when PAO2 is lower than systemic venous PO2?
-Gas exchange happens in reverse
- O2 will move from the higher concentration in the capillary to the lower concentration in the alveoli
- O2 is pulled out of pulmonary capillary and also off Hb
199
What leads to the rapid loss of consciousness when the PO2 in the air is super low?
When O2 gas exchange moves from the pulmonary capillary to the alveoli (pulling O2 out of the circulation)
200
How does the supplemental O2 on a plane compare for the passengers and the pilots?
- Passengers get enough to stay conscious
- Pilots get compressed 100% O2 and a tight fitting mask to giver higher O2 and pressure in the lungs
201
What is normal pH range for our class?
7.35-7.45 (7.4)
202
Any pH lower than 7.35 = __________
Acidosis
203
Any pH higher than 7.45 = _________
Alkalosis
204
What does the variable "𝛼" stand for?
Acidity
205
What is the acidity of a mixture dependent on?
Hydrogen activity
206
What does "𝛼H+" stand for?
Proton activity
207
How does the activity of protons relate to the concentration of protons in the body?
- Activity of protons is directly related to concentration of protons in the body
- Solution in the body is relatively dilute of free hydrogen activity (H+)
208
What is the main volatile gas in the body?
CO2 (volatile acid)
209
What does volatile mean?
Can be airborne/ move into a gas phase
210
What is the main acid in the body?
CO2
211
What type of acid is CO2?
Weak acid
212
What is CO2 basically always in the presence of in the body?
Water
213
CO2 + H2O = ________
H2CO3 → Carbonic acid
214
Carbonic acid is a _______ acid
Weak
215
What does the variable "HA" stand for?
Short hand for acid
216
What are acids in a solution in equilibrium with?
H+ and the conjugate base of the acid
217
What does a weak acid dissociate into when its in solution?
- H+ falls off the acid
- A- is the conjugate base
218
What functions are associated with the conjugate base of an acid?
- A- can recombine with a proton
- Anything that has the potential to recombine with a proton is a base
219
What is the term for a base that is formed from an acid falling apart?
Conjugate base
220
What is an example used in class of a strong acid?
HCl (hydrochloric acid)
221
How do strong acids behave in aqueous solutions?
- Easily dissociate
- Likely to fall apart in aqueous solution
- Prone to donate a proton (produce lots of H+)
222
What does the process of donating protons involve?
Dissociation in solution
223
Why is it a concern when strong acids dissociate and easily produce a lot of protons?
Potentially cause a lot of damage in the wrong environment
224
What are the products of HCl when it is added to an aqueous solution?
- Cl- and H+
- Cl- do not like to accept protons→ wants to donate protons (weak conjugate base)
225
What makes Cl- a weak conjugate base when HCl dissociates?
Cl- does not like to accept protons
226
What type of bases do strong acids have?
Weak conjugate bases (wants to donate H+ not accept them back)
227
What are weak acid examples discussed in lecture?
- Carbonic acid (H2CO3)
- Acetic acid (HC2H3O2
- CO2 (can be thought of as a weak acid)
228
What is the conjugate base for H2CO3?
HCO3-
229
Why is bicarb a strong conjugate base for H2CO3?
HCO3- likes to accept protons = strong base
230
Why can CO2 be thought of as a weak acid?
CO2 is always in the presence of water so always forming H2CO3 (weak acid)
231
Why is it easier to look at CO2 concentration than H2CO3?
- Carbonic acid in the body is in low concentrations (very dilute)
- H2CO3 either moves back to CO2 phase for into HCO3/H+ quickly
- H2CO3 is hard to measure
232
For every 1 H2CO3 there are ______ CO2 molecules?
1000
233
Why can we think of CO2 as an equivalent to H2CO3?
- Every time there is a carbonic acid that dissociates into HCO3- and H+ there is opportunity for CO2 to combine with water to replace carbonic acid
- Carbonic acid is in low concentration but it can be quickly replaced by CO2 in the environment
- Can use the kinetics of CO2 to replace H2CO3 bc H2CO3 is hard to measure
234
Why can we think of CO2 as a weak acid even though it doesnt have a proton on it?
CO2 can rapidly turn into carbonic acid which is a weak acid
235
What are common non-volatile acids produced in the body?
- Sulfuric acid (sulfate)
- Phosphoric acid (phosphorate)
- Hydrochloric acid (HCl)
- Lactate (lactic acid)
- Salicylic acid (salicylate)
- Ascorbic acid (ascorbate)
- Acetoacetic acid
- Butyric acid
236
What non-volatile acids is produced in people with poor blood sugar management?
- Acetoacetic acid
- Butyric acid
237
Why are nonvolatile acids produced in patients with poor diabetes management?
- Metabolism is messed up and they cant process sugar normally→ have to use different metabolic pathways to generate energy
- Creates nonvolatile acid byproducts
238
What is a clinical finding associated with acetoacetic acid?
Similar chemical structure and smell to acetone→ these DM patients can have this smell
239
What other pathway besides uncontrolled diabetes produced acetoacetic acid?
- Produced by the body after drinking a lot of alcohol
- Alcohol usually broken down in liver by alcohol dehydrogenase and acetaldehyde and often times creates acetoacetic acid
- causes hangovers
240
Which nonvolatile acids discussed in lecture are pathological?
- Acetoacetic acid
- Butyric acid
*Usually do not have these floating around in the body*
241
Which suffix is indicative of an acid?
-ATE
242
What type of elimination do nonvolatile acids go through? How does this compare to volatile acids (CO2)?
- Nonvolatile acid elimination has to go through the kidneys sometimes liver
- Volatile acid can turn into CO2 and be removed via the lungs
243
All nonvolatile acids can interact with CO2 and are all potential proton _________.
Donors
244
Which type of person might you expect to see more nonvolatile acid production?
Unhealthy people (typically we dont produce very much nonvolatile acids)
245
Where do nonvolatile acids come from?
Breakdown of proteins
246
What is one nonpharmacologic way to cut down on nonvolatile acid production?
Vegetarian diet→ no protein in your diet can cut down on these acids since a lot are formed through protein breakdown
(example of a big change in the body from a behavior change which isnt too common to have)
247
What are common weak bases discussed in lecture?
- NaF
- KF
*fluoride in toothpaste→ used to buffer pH in the mouth and prevent acid from breaking down teeth*
248
What is a strong base discussed in lecture?
NaOH→ sodium hydroxide → main component of drain cleaner (very toxic if ingested)
*dissociates very easily in solution*
249
What is a protein made from?
Combination of amino acids connected to each other and folded to perform a task (structural, enzymatic)
250
What are the charges of amino acids?
Amino acids have different charges→ some positive, some negative, some neutral
251
What is the structure of the protein dependent on?
Depends on a normal amount of protons interacting with some of the negatively charged areas on the proteins
(accustomed to being in an environment with a pH around 7.4)
252
What happens to proteins when the amount of protons in the environment changes?
More protons interacting with proteins = changes the shape and it will not function normally
253
What happens if oxyhemoglobin comes into an environment with more H+?
More H+ interacting with the protein changes the shape of the protein and causes O2 to fall off
*Based on how many protons are associated with the protein*
254
What need to be within normal values for hemoglobin to maintain normal function?
Normal and constant pH to maintain hemoglobin protein function
255
What is the bohr effect?
Term used to talk about O2 unloading at the tissues
*when there is more protons interacting with HbO2 the O2 unloads*
256
What pump does everything in the body run off of?
Na/K ATPase → 2K+ in for 3Na+ out
257
What happens to the Na/K ATPase if someone is acidotic?
Extra protons associated with the protein that makes up the pump→ structure if no longer optimal and it wont function efficiently (Pump slows down)
258
What are all ATPase pumps?
Proteins
259
What happens if Na/K ATPase slows down in an acidotic environment?
K+ that is normally tucked back into the cell by the pump will be in the environment/ leak out
260
Why is acidosis usually associated with hyperkalemia?
Due to ineffective Na/K ATPase with acidosis
261
What is the name for proteins that produce ATP?
ATPase
262
How do ATPase produce ATP?
Harness electron transport chain to turn energy from O2 into ATP
*Make ATP compared to the other pump we talk about that utilize ATP*
263
Where are many ATPases located?
Mitochondria
264
What happens if there are extra protons interacting with ATPase pumps?
ATP production will be decreased→ leading to further issues with ATP dependent pumps (Na/K ATPase) → worsening hyperkalemia
265
What happens to breathing if CO2 or H+ levels in CSF are a little higher?
Causes increase in respiration
266
What happens if there is an obscene increase in CSF acidity?
Can affect the brainstem ability to adjust ventilation (tissue no longer works)
*A few extra protons the body can handle→ excess protons make it difficult for the body to keep things normal*
267
How are drugs effects connected to the pH of the environment?
- Dissociation of compounds/drugs is affected by acid/base
- Need normal pH to have drug effects work
- If system isnt normal need to adjust which drugs we are giving, how they are given, or the dose
268
Why are drugs often packed with HCl salt?
HCl salt can help with absorption or distribution of the drug
269
What is an example from lecture of a super basic drug?
Sodium Pentobarbital→ Careful at the rate you infuse it, can be painful if infused too quickly
270
How do we quantify the acidity of body fluid?
Look at the concentration of H+ in solution
271
What is the formula to calculate pH when given H+ concentration?
pH= -log [H+]
*pH changes based on how much H+ in solution*
272
What values can overall pH range between?
1-14
273
What is a neutral pH?
7
274
What is a pH of <7 considered?
Acidic
275
What is a pH >7 considered?
Alkaline
276
What is happening if pH in an environment changes from 9 to 7?
More acidic conditions
277
What is happening if an environment goes from a pH of 7 to 9?
More alkaline conditions
278
What is the pH of gastric acid?
1
279
What is the most acidic area of the body?
Stomach= Gastric acid pH is 1
280
Why is the stomach able to tolerate a low pH?
- Stomach has a tough lining (like thick leather)
- Stomach tissue is specialized to produce lots of acid and be resistant to the acid
281
What are of the body produces the most alkaline secretions?
Pancreas→ pancreatic secretions pH can be as high as 8
282
Where is the pancreas in relation to the stomach?
After the stomach→ situated like this so the pancreas can neutralize the acid from the stomach so it doesnt rip apart the intestines (intestines are soft and fragile and cant handle a pH of 1)
283
What is the ratio of gastric acid secretions compared to pancreatic secretions needed to neutralize the acid?
Gastric acid pH is 1 (very acidic) and pancreatic secretions pH is alkaline but only 8 → Would need MUCH higher pancreatic secretion volume to neutralize what is coming out of the stomach
*Pancreatic secretions are functioning as a buffer for stomach acid*
284
Why can high intestinal motility lead to acidosis?
over production of gastric acid and pancreas is trying to buffer it with HCO3→ losing bicarb from the pancreas when trying to buffer acid coming from stomach
285
What pH disturbance can happen from an intestinal obstruction causing vomiting?
Losing large amount of acid from the stomach→ alkalosis
286
What does it mean that pH is a logarithmic scale?
- Log10
- Looking at 1x10^-1 (for gastric pH of 1)
287
What is the formula to find the concentration of protons in mmol/L?
1 x 10^-pH
288
What is the proton concentration of a pH=7?
1 x 10^-7 = 0.0000001
= 100 nmol of protons/L
289
What is the concentration of protons in stomach acid?
1 x 10^-1 = 0.1 mmol of protons/ L
290
What is the increase associated with base 10 logs?
- pH difference of 1 = 10 fold change in proton concentration
- Small changes in pH = HUGE changes in proton concentration
291
How does proton concentration at a pH of 6 compare to pH of 7?
- pH of 6 has 10x higher proton concentration than proton concentration at pH of 7
- pH 6 = 1000nmol/L
- pH 7 = 100nmol/L
292
What is the proton concentration at normal pH in the body?
10^-7.4 = 40 nmol/L
293
What is the proton concentration at pH= 7.7?
20 nmol/L
294
Why is a drastic change in proton concentration bad?
Bad for the body and affects all the chemistry in the body
295
What are the upper and lower limits of pH before causing death?
pH 6.9 and pH 7.8
296
What is the role of a buffer in solution?
Help stabilize pH by donating or binding to protons
297
What components of the buffer determine what pH it is trying to reach?
- Buffer pKa
- Chemical structure of the buffer
298
What is the main extracellular fluid buffer?
Bicarb
299
What are the 3 most important buffers?
- Bicarb
- Proteins (Hb)
- Phosphate
300
How do proteins function as buffers?
H+ that are in close contact to proteins are taken out of solution and reduce H+ overall activity
301
What is one of the most important protein buffers?
Hemoglobin
302
Where does phosphate function as a buffer?
Important intracellular buffer AND important plasma buffer despite lower concentrations in the plasma
303
What is phosphate used for in the cells?
- Energy storage in the cell in the form of ATP
- Each phosphate stuck to adenosine takes energy to attach them to adenosine and releases energy when you take the phosphates off
- Phosphates also turn things off and on by phosphorylation of dephosphorylation
304
When is the body able to have buffers that are functioning at the optimal level?
When bicarb, proteins and phosphates are all working together under normal conditions
305
What is the body dependent on to make quick adjustments to pH?
Ability to get rid of CO2
306
What is the predominant acid in the blood?
CO2 → if the lungs cant get rid of CO2 it hinders the ability of the buffers
307
What organ in the body can be thought of as a buffer for CO2?
Lungs→ if the lungs dont work then ther other buffers have to try to do more but they usually font work well if the lungs arent working to get rid of the CO2
308
How can the kidneys help as buffers?
Can produce more bicarb→ would be better if the lungs work to get rid of CO2
309
What happens if the body loses a bunch of proteins?
- Bicarb and phosphate are less effective buffers when we dont have proteins around
- Reason why hemoglobin is important for acid/base balance in addition to O2 transport
310
What does lower hemoglobin do to the buffer capacity in the body?
Less steep slope= Less effective buffer system
311
What does increase in hemoglobin do to the buffer capacity in the body?
- Steeper slope= increased/better buffer capacity
- Increased hemoglobin in the blood (protein) helps the chemical buffers be more effective
312
What does the utility of basic chemical buffers depend on?
Organic state of the blood (how much protein we have in the blood)
313
How does the kidney utilize ammonia based compounds?
Buffer the urine to help with excretion
314
Why isnt albumin a big component of buffer proteins?
Even though albumin is a plasma protein the amount in out plasma is small comapred to hemoglobin in RBCs
315
Where is hemoglobin located?
- Inside RBCs
- Not found in the plasma
- Component of intracellular fluid in RBCs (in HCT portion of the blood)
316
Does albumin have any proton buffer ability?
Might have some→ more important for osmotic pressure and keeping fluid inside CV system
317
What volume would contain hemoglobin with hematocrit is 0.4?
Every L of blood we have 400mL RBC volume containing Hb
318
What happens to the slope of the buffer line when Hb is reduced?
Flattens out= worse buffer
319
What happens to the isobars when Hb is low?
Isobars are stretched further than normal because we arent seeing as much of a change in bicarb with pH changes that we normally would
320
What is the graph illustrating?
- Poor buffer system that wont be able to cope with changes in pH if it is not able to take bicarb out of solution or add bicarb to solution
- A given PCO2 change will cause larger change in pH if buffer system is less effective
321
What can cause an increase in slope the buffer line?
Increase in amount of hemoglobin
322
What happens to the CO2 isobars if the buffer slope is increased?
Isobars get closer together (closer to normal) but stay the same shape
323
What happens to bicarb when pH is increased or decreased in a system that has increased amount of Hb?
- Greater change in the amount of bicarb when we add or take away CO2 from the mixture
- Increase pH = less bicarb
- Decrease pH = more bicarb
324
What is normal bicarb level when blood pH is 7.4?
24 mmol/L
325
What changes would we expect in bicarb if pH is 7.6 and CO2 is 40mmHg?
- Increase in bicarb→ 38mEq/L
- Lots of bicarb and fewer H+ in the blood
326
Would could be the reason for elevated bicarb levels with normal CO2 at a pH of 7.6?
Lack of protons should be why HCO3- levels are high
327
Which way does the isobar shift if blood PCO2 is increased?
Left
328
Which way does the isobar shift if blood PCO2 is decreased?
Right
329
At a pH of 7.6 what would you expect HCO3- to be if PCO2 is 20mmHg?
HCO3- 19mmol/L (lower)
330
What happens to HCO3- concentration at a higher PCO2 and a lower pH?
- HCO3- is a little higher than normal
Reason:
- extra CO2 results in more HCO3- being produced from that reaction with H2CO3
- Not enough bicarb to correct pH problem
331
What are changes in pH correlated with?
Changes in H+ concentration
332
What is the proton concentration at a pH of 8?
10nmol/L
333
What do isobars correspond to?
PCO2 levels
334
What does the buffer line incorporate?
Represents normal blood buffering system→ combo of bicarb + proteins + phosphate
*Normal amount of proteins is super important at managing stress to the system*
335
What factors influence how a system behaves?
- PCO2
- HCO3-
- pH
336
What changes occur with uncompensated respiratory acidosis (acute)?
- Higher CO2 in the blood causing lower than normal pH (7.1)
- Curve shifts to the left and pH is lower
- HCO3- is acutely elevated bc CO2 is high (before kidney tries to adjust)
337
What changes occur with uncompensated respiratory alkalosis (acute)?
- Low PCO2 causing pH to be higher than normal
- Curve shift to the right
- HCO3- will be slightly lower than normal d/t low CO2 in blood (less CO2 in reaction creating bicarb)
- before kidney tried to adjust
338
Why are uncompensated respiratory issues more short term?
Take a little time before the kidney kick on and can adjust for the issues (kidney adjusts because there is an issue with the lungs functioning as buffer)
339
What is associated with poor lung function and CO2 building in the blood?
Respiratory acidosis
340
What do most anesthetics have the potential to cause by knocking out ventilatory drive?
Respiratory acidosis→ Reason why we have them on mechanical ventilation
341
How is decreased ventilation correlated with increased PCO2 in the blood?
Not enough fresh O2 in the lungs causes high PCO2 in the blood (doesnt dilute out the CO2)
342
What are some examples of things that could result in decreased ventilation leading to respiratory acidosis?
- Brain injury/disease
- Brainstem injury
- Spinal cord injury
- Stroke
- Upper thorax sc injury
- Kyphoscoliosis
- Extreme obesity
- Opiates
- Barbiturates
- Volatile Anesthetics
- Phrenic nerve injury/block
- Poliomyelitis
- Tetanus/botulism
- MG
- Curare like drugs
- Chest wall restrictions
- Lung problems
- Pna
- Upper airway obstruction
343
Which area, if injured, would cease innervation to the diaphragm by the phrenic nerve?
Injury above C3
344
What would happen if pt has a C4 injury?
Might have some diaphragm function but might not be normal
345
Which motor neurons innervate accessory muscles?
Lower SC levels
346
What might be an issue if an older person has a spinal cord injury in the upper thorax?
- Accessory muscles are innervated by upper thorax nerves→ older adults rely on accecssory muscles more than younger people because their lungs arent as healthy
- Would expect ventilation to be affected in older people if the accessory muscles arent working
347
What plane is the abnormal curvature located in someone with kyphoscoliosis?
- Abnormal curve in coronal and sagittal plane
348
What can be done to help correct kyphoscoliosis? How can this create further problems?
- Correct with plates/rods in the spine to help align better→ hardware put in isnt flexible like the normal spine
- Can make it hard to breath normally from reduction of chest wall compliance (chest wall restriction)
349
Why is respiratory acidosis a potential concern for patients who are obese laying supine?
Chest wall compliance is low from the weight of the tissue on top of them (would be even lower compliance when on OR table paralyzed)
350
How do opioids impact gas exchange?
Can cause respiratory insufficiency and knock out respiratory centers in the brain when given at high doses
351
Do Benzos cause respiratory depression?
- Not common to cause respiratory depression and death from just a benzo (usually in combo with a direct GABA agonist like alcohol)
- Benzos augment amount of GABA already in the system (not pure GABA agonist)
352
Which direct GABA agonist discussed in lecture has massive impact on respiratory control centers?
Barbiturates (Pentobarbital)
353
What is a concern when performing a scalene block?
- Area we are trying to block is close to the phrenic nerve→ If the phrenic nerve gets saturated with anesthetic that could knock out the phrenic nerve activity on that side of the body
- Should still be able to move air in and out of the lungs with one phrenic nerve working (not as effective ventilation)
- Would be a BIG issue if the patient is older
354
What is poliomyelitis?
Musculoskeletal issue that prevents CNS from talking to muscles its supposed to control
355
How can tetanus cause respiratory acidosis?
Causes tetanic contraction of muscles→ If the muscles are always contracting then we cant move air in and out we need the muscles to contract and relax at a pace to maintain ventilation
355
What causes chest wall restrictions?
- Compliance issue with problems of the rib cage
- Less flexible thorax= less compliant chest wall = less compliant system = harder to breathe
356
What type of lung problems can cause respiratory acidosis?
- COPD, Asthma, Fibrosis, Sarcoidosis
- Not ventilating effectively and not getting rid of CO2 = V/Q mismatch as well as not bringing on O2
357
How does pneumonia cause CO2 retention?
CO2 is able to move through fluid better than O2 but if there is too much fluid in the lungs (PNA) then there will be a problem getting rid of CO2
358
What are some examples of upper airway obstructions that could lead to respiratory acidosis?
- Paralyzed/collapsed vocal cords
- Scar tissue from prior trach
- Tumors in upper airway
359
What are majority of the issues leading to respiratory alkalosis a result of?
Neurological or psychological issues→ Less common, and most pts in the OR are under anesthesia so we dont see this too much by taking the nervous system out of the picture
360
What are some things that can cause respiratory alkalosis?
- Extreme anxiety
- Congenital hyperventilation syndromes
- Inflammation of brain or meninges (encephalitis, meningitis)
- Salicylates acid toxicity
- Brainstem tumors
- Progesterone
- High altitude
- Acute asthma exacerbation
- Overventilation with mechanical ventilation
361
How can brain stem tumors cause respiratory alkalosis?
If they cause problems with increase respiratory drive
362
What is the MOA of inflammation in the brain creating potential for respiratory alkalosis?
Problems with neural activity in the brain
363
How does progesterone affect breathing?
- Increases breathing rate and depth when pregnant
- Surges with pregnancy
- Any drug/tumor that increases amount of estrogen or progesterone has potential to cause increased ventilatory drive
364
How does acute asthma exacerbation affect ventilation compared to chronic asthma?
- Acute asthma attack: hyperventilation when they feel like they cant get enough air in and out →Respiratory alkalosis
- Chronic asthma: Not ventilating effectively to get rid of CO2 causes V/Q mismatch and not bringing in enough O2→ Respiratory acidosis
365
How do strong acids behave in solution?
Very likely to have proton fall off→ strong acids have weak conjugate bases
366
How do weak acids behave in solution?
Less likely to have proton fall off→ Weak acids have strong conjugate bases
367
How do strong bases function in solution?
Strong bases want to hang on to protons (would create weak conjugate acid)
368
How do weak bases function in solution?
Weak bases are less likely to combine with a proton (any conjugate acid that is formed will be a strong conjugate acid)
369
What do buffers combine with?
H+ to neutralize the acid
*Buffers tend to correct problems in either direction of the chemical equation*
370
What form of a buffer in solution is capable of binding a H+?
- Ionized buffer in solution
- HBuffer (H+ combined with buffer) in solution
371
How does the body respond if the pH is increased?
Hbuffer in solution can dissociate back into H+ and the buffer to even out the pH
372
How does the body respond if the pH is decreased?
Ionized buffer in the solution can combine with H+ → When protons are bound to the buffer they dont count toward acidity because their activity is low when bound to a chemical
373
What is the pK of a buffer equal to?
pK of a buffer is equal to the pH when the buffer had equal quantities or ionized components and nonionized components
374
What is the pK of bicarb as a buffer?
6.1
375
What does it mean that the pk of bicarb is 6.1?
Bicarb will be the most effective buffer if the pH of the system is 6.1→ but normal body plasma pH is 7.4 (bicarb is still extremely effective buffer at preventing acidosis)
376
What is the isohydric principle?
All of the buffers working together and interacting with the same pool of protons even though each buffer may have different pKs
*Combined activity of the buffer is greater and more effective than any of their individual activity*
377
What can the nomogram be used for?
Figure out cause of acid based issue and treatment plan
378
What do we have to consider when someone has an acute respiratory issue?
Acute= happened rapidly so the kidney hasnt been able to adjust yet
378
What happens to blood gases with acute respiratory acidosis?
- Ventilatory drive is reduced
- PCO2 is elevated→ generates acidosis
- H+ lowers pH
- HCO3- also formed but not able to buffer all of the H+ (its a weak base)
- Some excess bicarb in the blood
379
How does elevated PCO2 generate acidosis?
Any excess CO2 in aqueous solution can combine with water then dissociate into H+ and HCO3-
380
How does respiratory alkalosis impact PCO2 and the isobar on the graph?
Lower PCO2 levels correspond to isobars further to the right
381
What happens to blood gases in acute respiratory alkalosis?
- Low PCO2
- Isobar moves to the right
- Low bicarb
- Higher pH than norm
382
What causes pH to rise with acute respiratory alkalosis?
Blowing off CO2 = less H+ = higher pH
383
What happens with blood gases in chronic respiratory acidosis?
Kidney steps in to compensate by
increasing bicarb and secrete acid
- High PCO2
- Higher Bicarb
- more normal pH
384
What is the gain of a control system?
- How much of a problem it can correct for
- Most systems in the body can correct for half the problem (require multiple controllers to get a better correction)
385
What do blood gases look like the chronic respiratory alkalosis?
- pH much more normal
- More reduction in arterial bicarb from less CO2 and kidney stepping to no reabsorb bicarb
- Kidney can also retain protons by turning off H+ secreting activity
386
Why don't metabolic issues have acute and chronic phases like respiratory issues?
- The lungs step in to buffer pH vary quickly
- Compensation mechanism (lungs) activated almost immediately
387
What causes ABG changes in metabolic acidosis?
Lack of bicarb→ rapidly corrected by the lungs increasing ventilation which moves isobar to the right = lower PCO2
388
What causes ABG changes in metabolic alkalosis? (Not common)
Too much bicarb→ Corrected by the lungs decreasing ventilation which moves isobar to the left = higher PCO2 levels
389
How can the body lose bicarb with metabolic acidosis?
- Producing too much acid
- Consuming acids from diet/drug
390
What are some causes of metabolic acidosis?
- Increased GI motility (diarrhea)
- Pancreatic fistula (more than one output duct= losing more bicarb)
- Renal dysfunction (not producing new bicarb)
391
What are some ingested substances that could cause metabolic acidosis?
- Methanol
- Salicylates
- Ethylene glycol
- Ammonium chloride
392
What is methanol? What is the MOA of how it can cause acidosis?
- Byproduct of fermentation (moonshine)
- Methanol intoxication can make you go blind
- Increased alcohol consumption could cause acidosis
- Methanol and ethanol stimulate the pancreas→ overstimulation of pancreas will produce more bicarb which is lost as diarrhea
393
What are salicylates? What issues can they cause if consumed?
- Aspirin compounds→ Can be found in skin cleaners/ acne reduction with weak acid solution
- If consumed could cause metabolic acidosis
394
What is ethylene glycol a component of? What issues can it cause?
- Antifreeze→ found in cooling system of cars to prevent freezing over
- Sweet smelling
- Very little is too much if consumes and could cause metabolic acidosis
395
What color is ethylene glycol in European cars?
Blue
396
What color is ethylene glycol in Japanese/American cars?
Green
397
What is ammonium chloride a component of?
Fertilizer→ can be dangerous with high dose exposure (metabolic acidosis)
398
What is the most effective way to produce ATP in the body?
- Oxidative metabolism→ bypasses lactic acid production
- Produces 38 ATP per molecule of glucose
399
What does the body do to create ATP if there is an O2 deficit and it cant use oxidative metabolism like normal?
- Glycolytic metabolism→ backup source of energy that isnt as efficient
- Produces 2 ATP for each glucose molecule (burns glucose very fast if needing ATP)
- By product of glycolysis is lactic acid
400
What type of acid is lactic acid? How does this impact the body?
- Lactic acid is non-volatile acid
- Harder for the lungs to get rid of
401
What O2 deficiencies can cause change to glycolytic metabolism and lactic acid production?
- Hypoxemia
- Anemia→ decrease carrying capacity of O2
- Carbon Monoxide→ takes up binding sites of Hb and prevents other O2 on Hb from releasing
- Shock (hypovolemic, cardiogenic, septic)
402
What happens if carbon monoxide binds to one of Hb binding sites?
Renders that hemoglobin inoperable→ increases O2 affinity for Hb which prevents O2 release at the tissues (leading to O2 deficit)
403
How can hypovolemic, septic, and cardiogenic shock create an O2 deficit/ lead to lactic acid production?
- Inadequate volume/pressure makes it difficult to deliver O2 to the tissue
- Lack of O2 to the tissues the body switches to glycolytic metabolism and produces lactic acid→ metabolic acidosis
404
Explain how severe exercise can cause metabolic acidosis?
Increased amounts of lactate produced
405
What is a common ABG issues with ARDS?
Lungs are really sick so they arent bringing O2 on→ O2 deficit and tissue switches to glycolysis for ATP production→ produces more potent acids (lactic acid)
*Metabolic acidosis*
406
What is happening with ketoacidosis?
Primary issue with uncontrolled DM→ Problem getting energy to the cells that cant take in glucose so switch to other forms of metabolism→ formation of acetoacidic acid and ketones (acids)
*metabolic acidosis*
407
What is a concern for blood gases in a patient who is an alcoholic?
- Alcohols are acidic→ Liver exposed to large amounts of alcohol over a longer period of time then the liver will not be able to work to regulate blood sugar
- Liver is a large storage place for sugar (glycogen)
- Liver not working interferes with normal pathways → alternate metabolic pathways produce ketone acids (ketones)
*Metabolic acidosis*
408
Which 2 places in the body have glycogen?
- Liver
- Skeletal muscles
409
What can starvation do to the body?
- No energy coming in so the body starts to use other break down pathways→ leads to metabolic acidosis
410
Explain how renal failure can cause metabolic acidosis?
Kidneys not working to remove protons→ protons build up and cause metabolic acidosis
411
What are causes of metabolic alkalosis?
- Repeated vomiting
- GI fistulas
- Diuretics
- Increased aldosterone
- Increased mineralocorticoid (Cortisol)
- Too many alkaline products (tums)
412
How do GI fistulas cause metabolic alkalosis?
- Pathways for H+ to leave the stomach and for the body to get rid of
- Getting rid of more gastric acid = alkalosis
413
How does diuretic therapy cause metabolic alkalosis?
- Most are K+ wasting
- Getting rid of K+ means also getting rid of H+= decreases acidity
414
If K+ is low what is also likely low?
H+ (K+ and H+ follow eachother)
415
How does increased aldosterone or cortisol cause metabolic alkalosis?
- Increased Aldo= more K+ leaving and H+ follows
- Cortisol can function as also in high quantities
416
Which organ system functions as a short term buffer for metabolic issues?
Lungs
417
Which organ system functions as a long term buffer from respiratory problems?
Kidneys
418
Acute respiratory acidosis is the same as _____________________
Uncompensated respiratory acidosis
419
What happens with uncompensated metabolic acidosis?
Lungs are not compensating→ decreased pH from increased H+ and decreased bicarb
420
What happens with uncompensated metabolic alkalosis?
Increased pH from less protons and excessive bicarb
421
What is happening with partially compensated respiratory acidosis (chronic)?
- Partially compensated by the kidney
- Still small drop in pH from increased CO2
- Extra bicarb as side effect from increase CO2
422
How does partially compensated respiratory acidosis compare to uncompensated respiratory acidosis?
After partial compensation→ pH change is less, kidney in increasing bicarb more than with uncompensated
423
What is happening with partially compensated respiratory alkalosis?
- Long term hyperventilation
- High pH low CO2
- kidney steps in to remove greater amount of HCO3-
424
What is the compensatory mechanism for partially compensated metabolic acidosis?
Lungs increase ventilation (wont get all the way back to normal but very effective)
425
What is the limitation to partially compensated metabolic alkalosis?
Respiratory system compensates by decreasing ventilation to increase CO2 and even out pH → It can only reduce ventilation so much (dont want to reduce O2 content)
426
What treatment is necessary for combined respiratory and metabolic acidosis?
Medical treatment (acidosis is more pronounced when both metabolic and respiratory)
427
What can cause combined respiratory and metabolic alkalosis?
If kidneys are messed up and the respiratory system is in overdrive that will produced a more pronounced alkalosis
428
Does blood have a charge associated with it?
No, there are equal quantities of positive charged ion and negatively charged ions
Cations in blood are balances by anions in the blood
429
What are the 3 main ions that make up blood?
- Main cation: Sodium
- Main anions : Chloride and bicarb
[Na+] = [Cl-] + [HCO3-]
430
What is a normal value for Na+?
142mEq/L
431
What is a normal value for Cl-?
106mEq/L
432
What is normal value for HCO3-?
24mEq/L
433
What happens when you set normal values for Na, Cl, and HCO equal to each other?
142= 106 + 124
142 = 130 → Gap of 12 (from unmeasured proteins negative charge)
434
What is the formula for anion gap? What is the typical margin of error?
- AGap= [Na+] - [Cl- + HCO3-]
- Margin of error +/- 4mEq/L → lots of unmeasured ions that are not accounted for in the equation that make up the difference
- Short on negative species (from proteins)
- Most proteins have multiple net negative charges
435
How can we account for the unmeasured cations and anions in the Anion gap formula?
[Na+] + [Unmeasured cations] = [Cl-] + [HCO3-] + [Unmeasured anions]
436
What are the unmeasured anions in the agap formula?
- Proteins
- Sulfur species
- Phosphate species
437
What are the unmeasured cations not included in Agap?
- K+
- Ca2+
- Mg2+
438
What happens if there is an increase in the unmeasured cations with nothing changing on the anion side?
Will have to have a reduction in Na+ in the solution to balance out
439
What change has to be made to maintain equilibrium?
Increase in Na+
440
What has to happen to maintain equilibrium in this situation?
Either Cl- or HCO3- or both have to increase to maintain electrical neutrality
441
What has to happen to maintain equilibrium in this situation?
Cl-, HCO3- or both have to decrease to maintain balance
442
What happens if the ions on either side of the equation for AGAP increase or decrease in the same proportions?
Anion gap will be normal
443
Which ions are usually the issues if the anion gap is increased?
Cl- and HCO3- → associated with nonvolatile acid production and results in increased anion gap
444
What can the anion gap look like in metabolic acidosis?
Normal or increased AGap
445
What is happening in someone with metabolic acidosis and a normal anion gap?
The kidney is healthy and can make up for the Cl- with increased HCO3-
→ Loss of HCO3- from diarrhea or pancreatic fluid loss (need kidney help to keep agap norm)
446
Why is it a bigger issue when kids have significant fluid loss like diarrhea?
- More dangerous in kids d/t lack of ability to manage changes from not having fully developed kidneys
- EX: reason why babies have specific formula or breastmilk because they do not have the ability to get rid of extra water (can cause volume overload and stretch out the heart)
- Kids cant cope with massive changes and volume loss
447
What is happening in a patient with renal tubular acidosis?
Cl- retention causing metabolic acidosis→ kidney could be healthy just experiencing temporary change (Agap commonly normal)
448
T/F: The body is usually able to keep anion gap normal if the problem is more common and less severe
True
449
What is usually associated with and increased anion gap?
Production of nonvolatile acids→ causes increase in anion gap
450
Metabolic acidosis with increased anion gap could be from:
- Unmeasured metabolic anions (nonvolatile acids)
- Ketoacidosis (DM, Alcoholism, Starvation)
- Lactic acidosis (hypoxemia, anemia, CO, hypovolemia, cardiogenic shock, septic shock)
- Renal insufficiency (Kidney cant maintain balance)
- Ingested drugs/toxins (methanol, ethanol, salicylates, ethylene glycol, ammonium chloride)
451
What are the plasma values for Na+, K+, Ca2+, Mg2+, Cl-, HCO3-, HPO42-, SO42-?
452
What amount of air is a loud cough equivalent to?
About 2L of air moving in and out of the lungs
453
Why is a muffled cough not good?
As people get sicker the cough becomes more muffled and not able to move the same lung volume as before
454
How is breathing regulated day to day?
Automatically→ the place in the brainstem where regulation happens is the medulla
455
What are the 3 sections of the brainstem?
- Top: Midbrain (mesencephalon)
- Middle: Pons (olive shape)
- Bottom: Medulla oblongata
456
What are the primary things chemoreceptors are looking at in the body?
- pH (H+ concentration)
- PCO2 (arterial)
- PO2
457
Is there crossover between respiratory chemoreceptors and CV sensors (baroreceptors)?
Yes
458
What is the definition of a chemoreceptor?
Looking for changes in chemicals
459
Where are the main peripheral chemoreceptors located?
1) Carotid receptors at carotid bifurcation
2) Aortic arch
460
Where are central chemoreceptors primarily located?
Brainstem (part of CNS)
461
What do central chemoreceptors respond to?
Changes in protons
462
What is located underneath the CNS meningies?
CSF→ all brain tissues are bathed in the CSF
463
What is the main trigger that regulates most of our breathing?
Changes in pH in the CSF from proton concentration changes
464
How does the body adjust to extra protons in the CSF?
Respiratory rate increases
465
Why is a change in CO2 easily sensed by the central chemoreceptors but not non-volatile acid increases?
- Nonvolatile acids do not cross BBB easily→ may take time before the central chemoreceptors are set off
- CO2 easily cross BBB so central responses to PCO2 are much faster than responses to nonvolatile gases
466
How do the chemicals looked at by chemoreceptors rank in effect on ventilation?
1) pH (proton concentration)→ strongest effect on ventilation in peripheral and central chemoreceptors
2) PCO2
3) PO2→ last thing to go low before reflexes kick in, usually O2 deficit comes with increased PCO2
467
How low can PO2 drop before peripheral chemoreceptors kick in?
PO2 70mmHg → have to have a big decrease in PO2 to have increased ventilation
468
What is the controller of breathing where all of the information from the chemoreceptors is fed into?
Medulla (brainstem) to respiratory control neurons
469
How does planned exercise impact the chemoreceptors?
- Frontal brain makes the decision to start exercising and can send that to the cerebral cortex
- Cerebral cortex tells the brainstem to pick up ventilation to the exact degree its needed to prevent changes in blood gases
- We have almost instantaneous increase in ventilation with PLANNED increased activity
470
What happens if higher order function in the brain are offline?
Rely more of the chemoreceptors to sense changes→usually don't have to do a lot if the person in healthy
471
How does the respiratory control system functions as a big negative feedback loop?
- Lots of pathways to correct for imbalances
- Kidney
- Fluid shifts
472
How does the respiratory control center typically respond to increases in metabolism?
- Tidal volume adjusted first (deeper breath)
- Increase resp rate second
473
If you have a pt on mechanical ventilation with a little off blood gases what should you try to manipulate first?
Tidal volume→ helps to fine tune the blood gases and changing respiratory rate can sometimes create more dead space ventilation
474
What is the downside to adjusting tidal volume?
Might have to change inspiratory pressure a little bit (ex: by 1 cmH2O)
475
If you have a pt with known right heart failure and they are in a procedure on mechanical ventilation with off blood gases what should you try to do to fix their ABG?
Would want to try to keep Vt as low as possible to prevent further lung injury (increase VT can increase PAP)→ maybe would manipulate rate
476
How does the body manipulate tidal volume on its own?
- Brain stem generates stronger inspiratory signal
- Increases amount of motor neurons connected to skeletal muscles
477
What type of motor neurons are almost all motor neurons in the respiratory system?
A-Alpha (myelinated)
478
What are the characteristics of A-alpha motor neurons?
- Large
- Fast (myelinated)
- Send messages to muscles quickly to contract
479
Which neurons control tidal volume in the respiratory system? How can increased force (VT) be generated?
A Alpha→ can generate more for force by recruiting more motor neurons or by increasing the frequency of firing of motor neuron
480
What governs the respiratory rate?
Interval/ amount of time it takes for the inspiratory centers to fire, the expiratory centers to fire, and a brief pause between respiratory attempts
481
How does the body increase respiratory rate?
Shortens amount of time for inspiratory and expiratory impulses → more time to fit in more breaths per minute
482
What type of fibers (neurons) are associated with pain transmission?
C-fibers and A-delta (smaller)
483
How do A-alpha fibers compare to pain fibers and how can this guide us when providing nerve blocks?
- A alpha are motor and are much larger than the pain fibers
- If trying to block a mixed nerve and you knock out motor then pain is more than likely blocked
- A-alpha (motor) are big and hard to block
484
Which type of neuron is harder to block: motor or pain?
Motor (a alpha)
485
What is the lowest portion of the brainstem before it turns into the spinal cord?
Medulla
486
What is the function of the motor cortex in ventilation?
Decides to recruit a set of muscles → Connections between thinking and motor areas of the brain and brainstem
487
What tells the brainstem to set a change in ventilation?
Higher order from the brain
488
What are the different reflexes involved in the respiratory system?
- Arterial Chemoreceptors
- Central Chemoreceptors
- Baroreceptors
*Cross talk between CV and respiratory systems→both controlled at the brainstem*
489
Where are irritant sensors located and what do they do?
- Sensors in the lungs and airways that monitor for things such as irritants
- Can get rid of large irritants with a cough
490
What is the largest airway?
Trachea
491
Where is trachea sensory info sent through?
Vagus nerve
492
Where are stretch sensors located and what is their purpose?
- Located in the lungs
- Stretch sensors give brainstem feedback on how much the lungs have stretched with each breath
- As lungs fill with air it stretches out and stretch sensors can be useful to provide feedback when to shut down inspiration
493
How can pain impact breathing?
- Causes sudden increases in breathing or brief periods of apnea
- Causes disruption and changes to normal ventilation
494
What is the main muscle of breathing?
Diaphragm
495
What is the second most involved muscle in breathing?
External intercostal muscles
496
What muscles get involved with breathing after the diaphragm and external intercostal muscles?
Internal intercostal muscles and accessory muscles
497
What muscles are included in the accessory muscles?
- Sternocleidomastoid
- Scalenes
- Abdominal
- Pectoralis minor
498
What muscle is involved in quiet breathing?
Usually only the diaphragm involved (only 1 or 2 muscles involved)
499
How is the timing of all the skeletal muscles involved with breathing coordinated?
Brainstem coordinates the timing
500
What is the function of accessory muscles for respiration?
- Good for backup to help with breathing
- Step in if we need to increase breathing
- Allow for faster inspiration and expiration
- If we increase breathing rate it requires coordinated efforts from lots of muscles (passive recoil of the lung isnt enough)
501
What are neurons in the medulla known as?
Nuclei → clusters of cell bodies in the CNS where decision are made
502
How many groups of neurons are located in the medulla?
2 (DRG and VRG)
503
What are the 3 respiratory groups in the brainstem?
- Dorsal respiratory group (back)
- Ventral respiratory group (front)
- Pontine respiratory group
504
Where is the pontine respiratory group located?
Highest point for brainstem control of breathing located at the base of the pons (between pons and medulla)
505
Where does most of the regulation of breathing happen?
Medulla
506
What does rostral mean?
Front and forward (beak)
507
What does caudal refer to?
Lower and to the rear (tail)
508
Which respiratory group is involved in modulating the activity of the dorsal and ventral respiratory groups?
Pontine respiratory group
509
Which respiratory group is in charge of inspiratory signals?
Dorsal respiratory group
510
Which respiratory group is in charge of expiratory signals?
Ventral respiratory group
511
What is reciprocal inhibition?
When one of the respiratory centers activates it sends inhibitory signals to the other center
EX: when expiratory center is activated it inhibits the inspiratory center and vice versa
*dont want both groups active at the same time*
512
What type of neurons are all of the brainstem respiratory groups?
Motor neurons→ most motor function has a crossover point at the end of the medulla/ beginning of spinal cord
513
What is the point called where motor neuron cross over at the beginning of the SC?
Decussation of the pyramids
514
Which muscles does the right brainstem control?
Respiratory muscles on the left side of the body (contralateral) from cross over at decussation of the pyramids
515
Which pathway does the phrenic nerve follow?
Crosses over at the decussation of the pyramids (most other respiratory motor neurons cross over as well)
516
Where specifically is the dorsal respiratory group located?
Nucleus Tractus Solarius→ area within the reticular formation
517
Where are inspiratory signals generated?
Dorsal respiratory group
518
How do inspiratory signals from the DRG travel to the muscles?
Through many motor nerves (phrenic nerve most important)
519
Where is the primary location where gas sensors are feeding information into?
Dorsal respiratory group→ PO2, PCO2, and pH sensors feed in here via the vagus nerve and glossopharyngeal nerve
520
What else is the DRG responsible for while generating inspiratory signals?
Projections to expiration areas to inhibit those signals
521
What would cause the DRG to increase the speed that it is initiating respirations?
- Low PO2
- Low pH
- High PCO2
522
Where do baroreceptors provide input to?
Dorsal respiratory group (same place where gas sensors feed into)
523
Which nerve does the DRG control?
Phrenic nerve (and several accessory muscles involved in inspiration)
524
What 2 groups of expiratory neurons are controlled by the DRG?
- Abdominal muscles
- Internal intercostal muscles
*these are forced expiratory muscles but still controlled by DRG*
525
What is the purpose of the ventral respiratory group?
Site of respiratory rhythmogenesis and helps open upper airway muscles
526
What is the place within the VRG that controls respiratory rate by feeing over to the DRG and controlling the pace at which DRG is firing?
Bötzinger complex/ Pre Bötzinger complex (site of respiratory rhythmogenesis in VRG)
527
What part of the brainstem specifically controls respiratory rate through reciprocal innervation of DRG?
Botzinger complex in the VRG
528
What motor output from VRG ensures we have an open airway?
Innervation of skeletal muscles around the larynx→ pharyngeal constrictor muscles
529
What part of the brainstem helps keeps upper airways open?
Ventral respiratory group
530
What is the function of the pontine respiratory group?
Limits inspiration→ important place where irritant receptors send information
531
Where are irritant receptors located?
Trachea, lungs, airways, PRG
532
Under normal conditions the PRG can limit the time spent in _______________
Inspiration→ makes sure inspiration isnt too long
533
How does the PRG know when inspiration needs to be cut off?
- Stretch sensors imbedded in lung tissue→ limits the length of time spent in inspiration by talking to DRG
- Helps fine tune breathing to make sure the planned amount of air went into the lungs via stretch sensors located in PRG
534
What happens if the pons and medulla pathway is lesioned?
Breathing will be abnormal since we cut off the pathway where the PRG can tell the DRG to stop inspiration
- Would see super prolonged inspiration and short expiration
535
What is the term for prolonged inspiration and short expiration?
Apneustic breathing→ sign that something is seriously wrong in the CNS (death reflexes)
536
- Orange: pontine respiratory group
- Pink: DRG; Nucleus tractus solitarius
- Green: VRG; Botzinger and pre botzinger complex
- Red: Decussation of the pyramids
- Yellow: Phrenic nerve
537
538
539
Where does all of the sensory info feeding into the brainstem and into the medulla come from?
Vagus nerve (X)
540
What nerve do gas sensors and irritant sensors feed into?
Vagus (aortic arch) and glossopharyngeal (carotid bodies)
541
Why is the trigeminal nerve so large?
It covers a large surface area on out face and our face is very sensitive = lots of pressure sensors
542
Where is the trigeminal nerve in relation to vagus and glossopharyngeal?
Higher than vagus and glossopharyngeal
543
Where is the general area where control of breathing center is located?
Lower parts of the reticular formation
544
What is the broad term for a slough of tissue in the lower parts of the brain stem?
Medullary area / medullary respiratory center → Place where groups of inspiratory and expiratory neurons are located
545
How does the brain know when CO2 increases in the tissues?
CO2 easily crosses BBB since its a gas and the central chemoreceptors sense it→ Brain responds to increased CO2 almost instantaneously
546
What makes nonvolatile acids hard to cross BBB?
They are charged H+ so they need help from a transport protein→ H+ can influence how much CO2 we have
547
Why is there a delay in the respiratory response to nonvolatile acids?
They dont cross BBB because they are charged → more difficult for the central chemoreceptors to process and creates a delay in brainstem responses to nonvolatile acids (may take a few minutes for brain to repsond)
548
What are the normal conditions of CSF?
- Clear (no proteins)
- pH 7.31 or 7.32
- Higher proton concentration
- CSF has own buffering system
549
What is the pH of CSF?
7.31 or 7.32
550
How does CSF buffering system work?
- Bicarb levels managed by glial cells
- Bicarb levels in CSF different from plasma
- Bicarb cant cross BBB (only can cross in the form of CO2)
551
How can bicarb work as an effective buffer in the CSF if there normally arent other proteins around?
Bicarb is a less effective buffer in the CSF explains why pH is a little lower in CSF compared to arterial blood (optimum pH for bicarb function is 6.1)
552
How does PCO2 in the brain compare to arterial PCO2? Why is this set up important?
- PCO2 in the brain is higher than arterial PCO2→ Working neurons produce CO2
- Neurons generate CO2 which increases levels in the CSF and creates a gradient for CO2 to be carried away in the blood
553
What is normal PCO2 in CSF?
50mmHg
554
How does proton concentration in the CSF compare to the blood?
- Proton concentration is higher in CSF than blood → proton concentration is in line with CO2 concentration
- Lower pH in CSF d/t higher CO2
555
What directly activates the medullary respiratory centers of the brainstem?
Protons
556
What do high levels of CO2 cause in the brain?
- Increased brain blood flow→ smooth muscle controlling the arteriolar tone of brain blood vessels dilates in response to increased CO2
- More blood flow helps wash out CO2 in the brain to bring conditions back to normal
557
Where are peripheral chemoreceptors located?
Same place as baroreceptors (carotid bifurcation, aortic arch)
558
What are chemoreceptors in the periphery called?
Bodies
559
Where are the 2 carotid bodies located?
One on each side of the neck at the bifurcation of internal and external carotid arteries
560
Where are the aortic bodies located and how many are there?
3-5 aortic bodies located on aortic arch
561
What blood do the aortic bodies monitor?
Blood coming out of the left ventricle
562
What blood do the carotid bodies monitor?
Blood before it heads up to the brain
*strategic placement of the peripheral chemoreceptors to monitor blood gases of whats coming out of the heart and whats heading to the brain*
563
What nerve do aortic bodies transmit info back to the brainstem through?
Vagus nerve (X)
564
What nerve do the carotid bodies transmit info back to the brainstem through?
Glossopharyngeal nerve (9)→ Herrings nerve is a component of the carotid body pathway
565
Where do both the vagus nerve and the glossopharyngeal nerve carry impulses from chemoreceptor?
Medullary parts of the brainstem
566
Where in the brain do irritant and stretch receptors feed back into?
Pontine respiratory group (higher location on the brainstem)
567
Where in the brain does blood gas and acid/base information get relayed to?
Medullary respiratory groups
568
Are chemoreceptors always working to maintain balance?
No, in a healthy system the chemoreceptors are not super active→ they step in if they sense the chemistry is off (safety system of the body)
569
How does the body adjust if there is a lot of extra metabolism producing excess CO2?
Would probably increase VT and RR
570
How does the heart try to compensate for a decrease in pH or increase in PCO2?
- Cardiac output increases and BP increases→ Pumping more blood into the lungs to increase recruitment of alveoli and increase surface for gas exchange (more CO2 removed)
- More carbonated blood going through the lungs = more CO2 removed
571
What 2 ways can the body compensate for decreased pH or PCO2 increase?
- Increase ventilation→ blow off excess CO2
- Increase cardiac output→ more blood in the lungs increases gas exchange surface area blows off more CO2
572
What is a simple way to adjust BP for a short period of time without drugs?
Adjust ventilation
573
How does hypocapnea impact BP?
Lowers BP
574
How does hypercapnia impact BP?
Increases BP
575
Why should we probably not use ventilation adjustments to adjust BP in pts with heart problems?
- If we blow off a bunch of CO2(H+) then more negative charges free up on proteins
- Proteins (albumin) has negative charges that are usually occupied by H+ and calcium
- If H+ are blown off then more binding sites on albumin for Ca2+
- Less free calcium= drop in ionized calcium
- Less Ca2+ available to help with cardiac function
576
What chemical changes is the body least sensitive to to change respiration?
- Changes in O2→ Graph showing PO2 around 70mmHg before the chemosensors increase firing frequency
577
What 2 versions of the polio vaccine where created during the polio outbreak in the 1960s?
- Attenuated: dead virus injected into patients
- Engineered virus that is less potent
578
Where did polio trace back to?
Swimming pools
579
What characterizes emphysema?
- Inside of the lung is shredded, lower surface area for gas exchange, and increasing lung compliance
- Lung is more compliant and easier to fill but more difficult to empty
580
What happens to alveoli in obstructive diseases like emphysema and COPD
- Lose alveoli and elastic tissue→hard to get air out
- Alveoli are arranged right next to each other in the lungs → emphysema alveoli merge together and the walls have less recoil
581
How do the lungs manage to clear debris and excess fluid in the lungs?
Digestive enzymes in the lungs that can destroy debris → trypsin
582
How does trypsin function in healthy lungs?
Should have low activity when there is no work for it in healthy lungs through the action of alpha 1 antitrypsin
583
What is trypsin capable of if left unchecked in the lungs?
Enzyme that destroys things→ would be destroying things in the lungs
584
What molecule is responsible for inhibiting trypsin in the lungs when its not needed?
Alpha 1 antitrypsin
585
Where is alpha 1 antitrypsin found?
Found floating in the blood and can deposit in the lungs to keep trypsin activity low
586
What are the consequences for someone who has alpa 1 antitrypsin deficiency where the body doesnt produce it or the molecule doesnt work?
- Trypsin will not be repressed and will have high activity in the lungs→ Wall of alveoli are makes of stretchy proteins and high trypsin might start breaking those walls down leading to loss of recoil force in the lungs
- Similar to autoimmune disorder where the body's own defense systems are destroying things it shouldn't
587
What are causes of alpha 1 antitrypsin deficiency?
- Inherited genetic disorder
- Smoke
- Liver problems
588
How many people have inherited alpha 1 antitrypsin deficiency?
1:3000 → don't make the enzyme of the version they have doesnt work
589
What is the treatment for pts with genetic alpha 1 antitrypsin deficiency?
- Causes emphsema→ treatment is lung transplant or will cause death by age of 30
- Even after transplant they still have the deficiency so would be breaking down new lungs as well
590
What is a chemical inhibitor of alpha 1 antitrypsin?
Smoke; also increases activity of trypsin since it can get into the lungs
591
Where is alpha 1 antitrypsin produced?
Liver
592
How can liver disease impact alpha 1 antitrypsin?
If you dont have normal liver function then usually lack alpha 1 antitrypsin production
EX: alcoholism, congenital liver issues
593
What element does hemoglobin have?
Iron
594
Fe2+ = _____________
Fe3+ = _____________
Fe2+: ferrous (good version of iron)
Fe3+: ferric
595
Which version of iron is capable of binding and later releasing O2?
Ferrous (Fe2+)
596
How does ferrous become ferric?
Oxidative stress→ Lots of oxidation involves removing an electron/ adding a positive charge on an atom
Fe2+ → Fe3+
597
What is hemoglobin with Fe3+ bound to it called?
Methemoglobin→ not functional and does not let O2 delivery to the tissues
598
How does Fe3+ bind to hemoglobin?
- Cant release O2 and binds permanently
- Takes up a spot for other O2
599
What percent of circulating Hb is in the ferric form?
1.5%→ Always some bad Hb around
600
What is normal hemoglobin saturation in healthy arterial blood sample? Why isnt it 100%?
97.4% → not 100% because a portion of this is from the venous add mixture coming from bronchiolar circulation and mixing with oxygenated blood in left atrium AND portion of Hb is going to be in state of oxidation where it cant do any work (Fe3+)
601
What is always being produced in the body that is usually handled quickly to avoid problems?
Oxidative stress
602
What enzyme is in charge of reducing ferric iron into ferrous iron?
Methemoglobin reductase (reduction process: gaining electron)
603
What is the reaction of iron going from Fe2+ to Fe3+?
Oxidation reaction (removing an electron)
604
What are the 4 chains of adult hemoglobin?
- 2 Alpha
- 2 Beta
605
How much O2 can each chain on Hb carry?
Each chain can carry 1 O2 molecule→ 4 total O2 molecules
606
What is the most known Hb defect?
Sickle Cell Anemia
607
What are the primary issues associated with sickle cell anemia?
- Issue with O2 carrying (causes CO2 issue)
- Hemolytic anemia
- Painful
*Tissues switch to anaerobic metabolism*
608
What is the defect in pts with sickle cell anemia?
Defective beta chains on Hb → genes that code for these are passed down by parents
609
What causes the anemic component of sickle cell anemia?
Eventually sickled RBCs will be taken out of circulation and the body will have to build new RBCs → losing RBCs with this disease as a result of the blood getting stuck in the capillaries
610
What drives the "sickling" of the RBCs?
Deoxygenation (O2 unloading)
611
What are special tubes in the body specialized for gas exchange?
Capillaries
612
How does the internal diameter of a capillary compare to the diameter of a floating RBC?
Internal diameter of a capillary is less than RBC → Healthy RBCs have to be flexible to get through the capillaries and the walls of the RBC are right up against the capillary wall (good for gas exchange)
613
If the RBC has sickle Hb what happens as the O2 is unloading from the RBC in the capillary?
- The shape of the RBC changes into a sickle shape (more rigid and impossible to get through the capillary)
- The sickle RBC is stuck and blocking blood flow, have to look for nutrients from collateral flow (eventually capillary goes away since body cant use it but will be an issue until a new capillary is formed)
614
What does it mean if you have one defective beta gene?
Sickle trait: Minor not as bas a having full blown disease
615
What disease are people with sickle cell trait more resistant to?
Malaria
616
How can you manage symptoms if you have sickle cell trait?
Limit activity→ keep metabolism low the O2 unloading around 5mlO2/dL (what we unload at rest) then there isnt too much sickle cell issue
617
What happens if you increased your O2 consumption in a patient with sickle cell trait/disease?
Will cause a massive increase in amount of sickled RBCs: dangerous because of lack of perfusion through capillary and RBC would need to be rebuilt which is time consuming and dangerous if happening too much at the same time
618
Can supplemental O2 help with sickle cell?
Can be useful to try to limit BUT supplemental O2 doesnt raise O2 very much since its not very soluble
619
What does it mean if you have 2 defective beta chains?
Full blown sickle cell anemia
620
What are the treatment options for sickle cell anemia?
- Replace RBCs with donor (would need lots of transfusions: blood supply issue and risk for infection)
- Hydroxyurea (turns on fetal HB genes that are usually repressed in adults: replace defective sickle Hb with fetal Hb)
621
How do fetal Hb and adult Hb differ?
Fetal Hb has 2 alpha and 2 gamma subunits and higher affinity for O2
622
What is the function of myoglobin?
Uses iron to pull O2 into tissues where its needed (usually in skeletal muscles)
623
What is HbA1C?
Accetalated Hb→ sugars in the blood that are sticky and can stick to Hb (uncontrolled DM will have more sugars in blood and HbA1c higher)
624
What does the A1C mean in HbA1C?
A= adults hemoglobin
1C: Extra sugar group at 1C position on hemoglobin
625
What is a normal HbA1C level?
5 or less
626
What is HbCO and is it normally present in the body?
- We produce a little bit of CO from the chemical reactions in our body
- 1% Carbon monoxide occupied Hb would be normal
627
What percent of carboxyhemoglobin is abnormal?
4%: must have come from another source (smoking, working on cars)
628
What is the name for CO occupied on hemoglobin?
Carboxyhemoglobin
629
When comparing HCO3- and CO2 how can we decide which is the acid and base and whether it is strong or weak?
- Strong/weak is relative based on the chemical reaction and what you are comparing it to
- HCO3- is much stronger CB than CO2 which is an acid
630
In some reactions HCO3- can be considered a strong base, but it s a weak base compared to ____________
Sodium hydroxide (NaOH)
631
What is normal arterial blood CO2 content?
48 mLCO2/dL
632
What is normal venous CO2 content?
52.5 mLO2/dL (less O2 in deoxygenated sample allows for more room for CO2 transport)
633
What type of blood gas problem is emphysema?
O2 and CO2 problem
*any time we have something creating an issue with O2 transport we run into CO2 problem as well*
634
What are the long term adaptations to messed up blood gases with emphysema (chronically high H+ and CO2)?
- Tertiary gas sensor system kicks in (O2) if H+ remains chronically high
- Become reliant on O2 sensor feedback to control ventilation (respiratory drive is dependent on low O2 levels in the blood)
- Reliant on hypoxia sensors that are looking for PO2 of 70mmHg to drive ventilation
635
What happens if you give someone with emphysema 100% O2?
They will probably stop breathing because the PO2 will have increased and they dont have that hypoxia that was driving their brainstem reflexes to breathe→ acidosis issue from apnea which creates respiratory acidosis
636
What is the average surface area of alveoli?
Tennis court
637
What is important for O2 gas exchange in the lungs?
Surface area→ O2 is constantly being used and its not very soluble so we need a lot of surface area to suck in all the O2 needed each minute in the body
638
How much O2 is used by the lungs per minute in a healthy person?
250 mLO2/min (a little less than a can of soda)
639
Do the lungs utilize all of the alveoli all the time?
- No, We dont always have every pulmonary capillary in use or every alveoli in use→ body blocks off some alveoli to limit dead space ventilation
- Unused alveoli have no blood flow and now airflow if there is no dead space
640
How does the body limit damage to the lungs if in a toxic environment breathing harsh chemicals?
- By not always ventilating and perfusing every alveoli→ limits the amount of damage to the lungs
- Not all of the alveoli are always exposed to the environment (protection mechanism)
- A lot of alveoli kept in reserve which is a good thing to help limit the damage that can be done by environmental contaminants
641
How often do adults sigh?
- 12-15x per hour (built into resp control centers)
- Unnoticed occasional deep breath
642
What does the breath before a sigh likely look like?
Deeper breath before the sigh→gives extra volume that you can let out as a sigh
643
What is the purpose of the sigh function built into new anesthesia machines (button on older equipment)?
Ups inspiratory pressure and and puts more air in the lungs then goes back to normal→ useful to maintain patency of most alveoli (deep breath makes sure surfactant levels in the lungs are normal and prevent areas from collapsing)
644
Why is the sigh function important with mechanical ventilation?
Positive pressure ventilation doesnt release surfactant like normal breathing → changing lung volumes every so often helps free up surfactant (anything to get extra surfactant in the lung is a good thing)
645
Why cant we inject surfactant in the ETT if someone is intubated on the vent?
The surfactant would just be pushed to areas where the alveoli are already open (doesnt help open up areas of atelectasis because they arent getting any air if already collapsed)
646
What do all lung issues have in common?
Surfactant deficiency
647
What does the body generate yawns?
Prepare for lower lung volumes when sleeping →Deep breath before anticipation of laying on back/supine where lung volumes will decrease
648
How does FRC change when going from upright to supine?
From 3L down to 2L
649
If the PRG isnt function, what type of breathing do we have?
Apneustic
650
What can happen if someone has a really bad traumatic brain injury/ GSW to the head?
Can cause pontine respiratory groups to be separated from the DRG and VRG further in medulla (often lesion is right under the pons)→physical separation leads to apneustic breathing
651
652
What is likely the cause of the picture on the left?
Decades of chemicals/smoke destroying the lungs → mediated by inhibition of alpha 1 antitrypsin
653
What happens to blood vessels in obstructive lung disease?
Decreased in blood vessels as the alveoli decrease (BV is attached to each alveoli)
654
What is departitioning in the lungs?
- Decreased surface are for gas exchange and reduced alveoli
655
What happens to volume when the lungs have reduction in alveoli causing decreased area for gas exchange?
- Lungs get stretched out and volume increases
656
What makes it difficult to get air out of the lungs with emphysema?
Decrease in alveoli = decrease in elastic recoil = harder to get air out of lungs without elastic recoil
657
What does this image show?
normal alveoli
658
What trends in histology happen with alveoli breakdown in the lungs?
659
What problem does decreased blood vessels in the lungs cause?
- Harder for the right heart to pump
- People with emphysema eventually go into right heart failure
660
What is the specific name for the enzyme in the lungs that destroys elastic tissue when not in check? What keeps it in check?
- Neutrophil elastase
- Alpha 1 antitrypsin
661
What type of enzyme is trypsin and neutrophil elastase?
Protease→ break down proteins
662
What is neutrophil elastase normally inhibited by?
Alpha 1 antitrypsin
663
How do lung volumes change with emphsema?
- Increased RV
- ERV and IRV reduced
- Increased TLC (from increased RV)
- slightly increase VT
664
What happens to lung volumes as emphysema gets worse?
- RV will keep increasing until VT is right up against TLC (no ERV, IRV, or IC)
665
What happens when emphysema is so bad that ERV and IRV are gone?
Tidal volume = Inspiratory capacity
666
What is the limit to increased RV with emphsema?
- Lung cant get any bigger
- Chest wall maximally bowed out (VT up against TLC)
667
What is the issue in a patient who cant get very much air in on inspiration?
Inspiratory capacity issue (obstructive disorder)
668
What causes slight increase in tidal volume with emphsema?
Alveolar dead space
669
What is the easiest fix for alveolar dead space?
Expand VT (deeper breaths)
670
What happens to lung volumes with restrictive disorders?
All lung volumes decrease
671
What barrier do inhaled particles have to make it though in order to get past nasopharynx and into oropharynx?
Turbinates (concha)→ big particles get collected in the mucus at the back of the nose, small particles can make the turn down the airway
672
What happens to particles that get trapped in the nose mucus?
Brought into GI system and broken down/recycled
673
How does smoke make it into the airway without being trapped by mucus in the nose?
Small particles no much mass→less inertia (less momentum) so they are able to make the turn down the airway
674
What is the name for the group of 4 muscles that are found between the hyoid bone and the mandible?
Suprahyoid muscles
675
What is the name for the group of 4 muscles that attach to the hyoid and structures below it?
Inferior hyoid muscles
676
What part of the trigeminal nerve has irritant receptors?
V2 (maxillary division)→ sensory portion that have irritant receptors in V2 can relay info to brainstem about contaminants
677
What nerve is the sneezing sensation routed through?
Cranial nerve 7, V2 sensory branch (top part of face and nose)
678
What part of the skull dose CN5 V3 innervate?
Mandibular division (V3)→ everything below the jaw
679
How can you stop a sneeze if you feel it coming on?
Manipulate the tissue close to the nose to shut down the reflex via lateral inhibition
* Drink water (stimulate sensors in mouth)
* Pinch upper lip (fed through V2 pathway)
680
Which main nerve innervates the larynx and surrounding muscles?
Vagus nerve
681
Which nerve control sensory for the lung?
Vagus
682
What is the name for the branch of vagus nerve that curves around before heading up to the larynx?
Right and left recurrent laryngeal nerves
683
Where does the recurrence happen for right and left recurrent laryngeal nerves?
Left: Wraps under aortic arch
Right: More superior than left (aortic trunk)
684
What is the function of the recurrent laryngeal nerves?
Control the ability to speak→ innervation to the voice box
685
What does the recurrent laryngeal name change to after the turn it makes to head up to the larynx?
Inferior laryngeal nerve (coming from below the larynx)
686
Orange: Right recurrent and inferior laryngeal nerves
Blue: Left recurrent and inferior laryngeal nerves
Green: vagus nerve
687
What type of muscles are the muscles in the larynx?
Skeletal muscles→ inferior laryngeal nerve is the motor neuron the makes contact with 5 of the skeletal muscles in the larynx
688
Which muscles in the larynx does the inferior laryngeal nerve innervate?
All except cricothyroid muscle
689
Which branch of the vagus nerve provides motor function to the cricothyroid muscle?
Superior laryngeal nerve exterior branch→ 2 segments (internal and external branch)
690
Which nerve is responsible for sensory function in the larynx?
Superior laryngeal nerve internal branch→ if something is stuck controls coughing it out (goes internal through opening with blood vessels)
691
What happens when the cricothyroid muscle is contracted?
Tightens up the vocal cords and makes it more difficult to intubate (want it to be relaxed to intubate easier)
692
Name for the place where inferior laryngeal nerve and superior laryngeal nerve internal branch have the potential to link:
- Galens anastomosis→ not functional just structural
- Not present in everyone but possibility as a lot of people have this
693
Which nerve is responsible fore sensory coverage to the trachea?
Vagus nerve→ early part of trachea this is accomplished through inferior laryngeal nerve
694
Label: What muscle is blue innervating?
cricothyroid muscle
695
Which side of the patient is this?
Left side
696
What is the name of the hole where the internal branch of the superior laryngeal nerve passes and where is it located?
* Above thyroid cartilage: Thyrohyoid membrane
* Foramen for internal branch of SLN
697
What does foramen mean?
Opening
698
Where are the pharyngeal constrictor muscles located?
Muscles that are wrapped around the larynx and the areas of the airway above the larynx
699
What are the names of the 3 muscles sets outside the upper airway?
- Superior pharyngeal muscle constrictor sets (S1-4)
- Middle pharyngeal muscles constrictor sets (M1,M2)
- Inferior pharyngeal muscles constrictor sets (I1, I2)
*All skeletal muscles that squeeze the upper airway→ prefer then relaxed to intubate easier
700
Blue: Superior pharyngeal constrictor
Orange: Middle pharyngeal constrictor
Green: Inferior pharyngeal constrictor
701
Blue: Superior pharyngeal constrictor
Orange: Middle pharyngeal constrictor
Green: Inferior pharyngeal constrictor
702
How many suprahyoid and infrahyoid muscles do we have?
4 muscles for suprahyoid
4 muscles for infrahyoid
703
What happens when any of the suprahyoid muscles are contracted?
Brings the hyoid bone and the larynx up
704
What are the components of the Diagastric muscle?
- Anterior belly
- Posterior belly
- 3 tendons
705
What is the tendon called between the 2 bellies of the diagastric muscle?
Intermediate tendon
706
How does the Diagastric muscle connect to the hyoid bone?
- Connective tissue loop/sling from the hyoid bone that wraps itself around the middle tendon
- Used to fasten the hyoid bone to the other 2 attachment points on the skull
707
Where does the anterior belly of Diagastric muscle fasten on the skull?
Mandible
708
Where does the posterior belly of the diagastric muscle fasted to on the skull?
Mastoid process
709
What muscle is being shown?
Diagastric muscle
Green: Anterior belly
Blue: Posterior belly
Pink: Connective tissue sling from hyoid bone
710
Which suprahyoid muscle is this?
Stylohyoid Muscle→ Direct connection to styloid process and hyoid bone
711
Where does the styloid process sit in relation to the mastoid process?
Styloid process is in front (anterior) to the mastoid process
*Styloid process very fragile and usually in human skulls studied is broken
712
Where is the mylohyoid muscle located? Where does it attach?
- In the floor of the mouth
- Attaches inside mandible to top middle part and to body of hyoid bone
713
Orange: Mylohyoid
Purple: Geniohyoid
714
What suprahyoid muscle is on the floor of the mouth and runs midline to attach to middle part of top of hyoid and the mandible?
Geniohyoid
715
- 1a) Anterior belly of diagastric muscle
- 1b) Posterior belly of diagastric muscle
- 2) Stylohyoid muscle
- 3) Mylohyoid muscle
- 4) Geniohyoid muscle
716
What happens with contraction of the infrahyoid muscles?
Drops the hyoid bone and larynx down
717
Where do the infrahyoid muscles connect to the hyoid bone?
Somewhere at the bottom of the hyoid bone→ connect somewhere below hyoid bone
718
What are the components of the omohyoid muscle?
- 3 tendons
- Superior belly: belly higher up
- Inferior belly: belly lower
719
When tendon connects the 2 bellies of the omohyoid muscle?
Intermediate tendon
720
What anchors the omohyoid muscle to the upper thorax?
Intermediate tendon is tied down with connective tissue loop attached at the clavicle
721
Muscle that connects hyoid bone to sternum:
Sternohyoid muscle
722
Muscle that connects bottom of hyoid bone to thyroid cartilage?
Thyrohyoid muscle→ tendon where muscle attaches to cartilage
723
Which muscle is a continuation of the thyrohyoid muscle and fastens at the same place on thyroid cartilage and the sternum?
Sternothyroid muscle
724
- 5) Omohyoid muscle
- 6) Sternohyoid muscle
- 7) Sternothyroid muscle
- 8) Thyrohyoid muscle
725
726
727
Thick part of hyoid bone that makes up majority of the bone:
Body
728
What are the 2 horns on each side of the hyoid bone called?
- Greater horn (2)
- Lesser horn (2)
*Attachment points for muscles on different parts of the horns and body
729
What view is this?
- Anterior
- Green: Greater horn
- Pink: Lesser horn
- Purple: Body
730
What view?
Posterior view
731
What view?
Left lateral view
732
Periodic bursts of inspiration that get larger and larger then a period of apnea:
Cheyne-Stokes breathing
733
When is Cheyne-stokes breathing seen?
Brain damage or blunt force trauma to head
734
Bradypnea:
<10 breaths per minute
735
Tachypnea:
>20 breaths per minute
736
Hyperventilation:
Moving more air d/t excess metabolic needs
737
What distinguished hyperventilation from tachypnea?
Hyperventilation is in response to increase metabolism
*Nervous hyperventilation has potential for person to pass out
738
How does breathing pattern change with sighing?
Must have deep breath before to exhale larger amount (AKA sigh)
739
What type of breathing is Kussmal respirations?
- Hyperventilation (metabolic excess) as a result of DKA→ deep breaths at fast rate
- Body trying to buffer acidity (hard to blow off non volatile acids)
- Pt wouldnt pass out from this hyperventilation because underlying acidosis
740
What is another term for stretch receptors in the lung?
J-receptors
741
What is the function of J-receptors (stretch receptors)?
Shutting down inspiration once lung gets to a certain point→ J receptors sense when the lung is full
742
What happens with inspiration if the lungs are super stretched out all the time?
- Inappropriate size inspiration
- Sensors in periphery telling brainstem that the lungs are stretched out/ full
- Causes inspiratory problems and can lead to abnormal breathing patterns
743
What is the Hering Breuer Reflex:
Inflation reflex→ shuts down inspiration when the lungs get full via J receptors and limits further air coming in
744
What type of breathing is associated with opioid OD?
Biot breathing→ irregular interspersed breathing at lower than needed rate and depth
745
Why is capnography useful to us?
Shows us conditions inside the lungs and can give us an idea of what blood gases might be
746
What changes in capnography and blood gases occur with hypoventilation?
- Increase PCO2 in blood= more CO2 to unload in the lungs
- Elevated wave forms on ETCO2
747
What changes in capnography and blood gases occur with hyperventilation?
- Low PCO2 in blood
- Low CO2 in alveoli
- Capnography waveform lower than normal
748
What could be happening with an abrupt decrease in capnography wave form that is progressive and gets lower?
- EX: MI (left or right heart failure)
- Heart is unstable and not getting normal amount of blood through the lungs then ability to offload CO2 is reduced
- PCO2 levels in blood increase
- PO2 levels fall
- Capnograph shows reducing waveform on each subsequent ventilation because not enough blood is getting through the lungs
- Creates a difference between patients ABG and capnograph bc heart isnt pumping deoxygenated/carbonate blood through the lungs
749
How can increased metabolic rate impact capnography?
- Increased capnograph waveforms
- EX: malignant hyperthermia
750
What is the first warning sign of malignant hyperthermia?
Abrupt spike in ETCO2→ metabolic demands of the body cause increased metabolism
751
What causes hyperthermia associated with MH?
Increased metabolism can lead to overheating of the patient (excess Ca2+ causing increased muscle ridigity and metabolism)
752
What is the antidote for MH?
Dantrolene→ blocks Ca2+ channels
*Usually have heads up from patient history (genetic)*
753
What would be a good change in ETCO2 that reflects ROSC?
Increase in ETCO2 as the heart is able to pump more blood through the lungs
754
What pattern dose bronchospasm look like on ETCO2?
"Shark fin"→ from uneven emptying of the lung creating uneven expiration
755
What would ETCO2 look like with esophageal intubation?
Flat line→ sometimes we see a few wave forms from preoxygenation prior to intubate which pushes some air into the stomach
*May have a few waveforms but they will disappear quickly if you have esophageal intubation*
756
What are causes for an abrupt flat line to ETCO2?
- Usually mechanical→ Self extubation or disconnection, tubing disconnect
*Other issues are more of a gradual change rather than immediate flat line*
757
How can bicarb infusion affect ETCO2?
- Increase ETCO2 waveforms
- Portion of bicarb turn into CO2
758
How does releasing a tourniquet impact ETCO2 waveform?
Limb gets perfusion after not having it and will need to increase metabolism/generate lots of CO2 bc the tissue is getting up to speed on ATP levels
759
How does an acute increase in cardiac output impact ETCO2 waveform?
- Transiently pumps more blood through the lungs= more CO2 unloaded= higher ETCO2
- Non sustained because at some point we would be blowing off extra CO2 and changing our blood gases
760
What impact does increased BP have on ETCO2 waveform?
increase BP from increase CO= flow increases so able to unload more CO2 and increase waveform
761
What are changes the ETCO2 that happen with pregnancy?
- Body producing more CO2 than normal→ expect CO2 to be elevated even if rate and VT are normal
- End of wave form can have a little increase (operating at lower lung volumes in pregnancy d/t abd content shifted up)
762
How are lung volumes impacted by pregnancy?
Operating at lower lung volumes d/t abd contents shifted up
763
How can drinking a carbonated beverage impact waveform on ETCO2?
Someone who isnt intubated obvi→ increase in middle of waveform if CO2 expelled from stomach
764
What will ETCO2 look like if someone has 2 bad lungs but can only get one transplanted?
- Split in middle of ETCO2
- Good lung emptied first and bad lung empties second (shows separation in ETCO2)
765
Factors that can decrease EtCO2 waveform:
- Hypothermia
- Decreased CO
- Decrease BP
- PE
- Hyperventilation
- Extubation
- Airway obstruction
- Circuit disconnection
- Alveolar dead space development
- Esophageal intubation
766
How does decreased CO impact ETCO2 waveform?
EX: MI or anything that decreases CO= less blood being pumped through the lungs = less CO2 given off and reduced BP
*reduced BP lowers ETCO2 waveform for the same reason*
767
How does airway obstruction cause decrease ETCO2 waveform?
Obstruction to airflow so we wont see as much CO2 making it out
768
How does more alveolar dead space decrease ETCO2?
- More dead space caused by ventilation to areas that arent perfused
- When alveolar dead space empties on exhalation it will combine with air from good alveoli and drop CO2 average in the gas sample
769
_________ CO2 should always be equal or higher than _________ CO2
- a-A different
- arterial CO2 is always equal or higher than alveolar
- CO2 in blood cant be concentrated but there are lots of ways alveolar CO2 can be reduced (EX: Dead space emptying)
770
What is the gradient for O2 between alveoli and blood?
- A-a difference
- Alveolar O2 is always equal or higher than arterial O2
- O2 going in opposite direction
- The only thing that can happen to alveolar O2 gas in that its diluted out before it becomes systemic arterial gas
771
What happens to RV when sedated and paralyzed and on back on OR table?
- Abdomen pushes some of the air out of the lungs
- Skeletal muscles are paralyzed
- RV could be as low as 800cc -1L)
772
Can your body ever go below RV in the lung?
Yes when anesthetized and completely paralyzed on your back
*Overweight patients have added weight on them as well that contributes to low lung volumes*
773
What creates the pleural pressure gradient at low lung volumes when paralyzed anesthetized and on your back?
Gravity
774
What is the pressure in the anterior and posterior lung in a patient paralyzed on OR table?
Anterior: -13cmH2O
Posterior: +4cmH2O
More positive posterior pleural pressure because chest wall doesnt want to recoil out on someone who is overweight on their back
775
Where will air go when pushed into the lung of someone who is paralyzed on back and sedated/intubated?
- Most ventilation at Top/anterior parts first (similar to upright RV)
- Posterior parts will have some collapse bc underneath anterior and closer to the hearth so higher pressure
776
Where is blood flow in the lung the highest in paralyzed anesthetized pt on their back?
Posterior lung→ gravity dependent
under these conditions posterior lung has low ventilation and high perfusion→ V/Q mismatching
777
How can V/Q mismatch be fixed in a pt who is on back ventilated and paralyzed?
- Operate at higher lung volumes (get more air into the posterior/base)
- PEEP
778
How does PEEP improve VQ mismatch during surgery?
- More air directed to posterior lung by working at higher lungs volumes (preventing collapsed alveoli)
- More PEEP= Lung more full= more air directed to the posterior lung
779
Does every patient need same amount of PEEP with surgery under anesthesia?
- Healthy pt and quick procedure may not need PEEP
- Patients with sick lungs probably do or older patients
- Depending on pt history
780
What is another (aside from PEEP) way we try to lessen lung collapse during anesthesia?
30% FiO2 (try to keep more air in the lungs)
781
What is a negative aspect of PEEP?
Increases workload for right heart by increasing pressure in the lungs
(harder for R heart to pump against increased pressure)→ can be issue in someone with right heart failure
782
How does being supine but awake and spontaneously breathing impact gas flow in the lungs?
- Abdominal contents still shifted up on diaphragm reducing lung volume
- 2L (from 3L) → not even close to RV
- Decent VQ matching
- Anterior lung is full
- Posterior lung is most compliant and less full that anterior(fresh air directed here)
783
What might pleural pressures be in a patient who is going to sleep for the night?
- Anterior: -10 cmH2O
- Posterior: -2 cmH2O (negative pressure helps keep posterior alveoli somewhat full to direct air and blood flow here first= good V/Q matching)
784
How does just using sedation and mechanical ventilation affect the lungs compared to GA with paralytic?
- Sedation has similar mechanics to awake supine pt
- Not knocking out all skeletal muscles so lung volume is low but not SUPER low
- Things would operate pretty normal (similar to awake supine)
785
What is boyles law?
P1V1= P2V2
786
With is ficks law of diffusion?
787
What is Ohms law?
V (Pressure) = iR
i= Flow (blood flow or current)
R= Resistance (vascular resistance)
788
How did we utilize daltons law in our class?
PPgas= [gas] x Ptotal
789
What is grahams law of effusion?
- Movement of gases with similar solubility is dictated by SIZE of the molecule
- Smaller gas moves faster
- Larger gas moves slower
