APEX Respiratory Physiology

Question 1

Where does dead space end?

Answer 1

Terminal bronchioles
Next is respiratory bronchioles, which is where gas exchange begins

Question 2

Muscles of expiration

Answer 2

“I let the air out of my TIRE”
internal intercostals
Rectus abdominis
external oblique/ internal oblique
Traverse abdominis

Question 3

Muscles of inspiration

Answer 3

Diaphragm
External intercostals
Sternocleidomastoid
Scalene muscles

Question 4

Primary determinant of CO2 elimination

Answer 4

Alveolar ventilation- more important than MV (Ve) bc it includes dead space

Question 5

Alveolar ventilation formula

Answer 5

Vt-Vd x rr

Question 6

What increases PaCO2/ETCO2 gradient?

Answer 6

Things that increase deadspace
PPV
Hypotension- decreased BP decreases ETCO2
Atropine- bronchodilator

Question 7

Normal Vd?

Answer 7

33%

Question 8

Define physiologic Vd

Answer 8

anatomical Vd + alveolar Vd

Question 9

Anatomical vs alveolar Vd

Answer 9

Body part is confined to conducting airways
alveoli has ventilation but no perfusion

Question 10

Things that change dead space

Answer 10

I- old age, copd, hotn, atropine, decreased co
D- ETT, LMA, Trach

Question 11

The base of the lung has more / less what in compared to the apex in the sitting position

Answer 11

More blood, more CO2,
Less PO2, Less Vq ratio

Question 12

The most compliant part of the lung

Answer 12

Base

Question 13

V/Q= infiniti cause

Answer 13

Dead space

Question 14

Does HPV minimize shunt or dead space?

Answer 14

Shunt!
Theres no shunting since theres no blood flow
It could be said that it increases Vd bc the air has to travel further for VQ

Question 15

VQ=0 means

Answer 15

Shunt

Question 16

The tendency of an alveolus to want to collapse is indirectly proportional to ____

Answer 16

Surface tension

Question 17

The tendency of an alveoli collapse is directly proportional to ______

Answer 17

Radius

Question 18

VQ ratio in Zone 1, does zone 1 always occur? how does lung combat this zone?

Answer 18

infinity / 0
Zero blood flow
Does not occur in normal lung
To combat, bronchioles constrict

Question 19

Zone 2 VQ ratio

Answer 19

1/1=1

Question 20

Zone 3 VQ ratio

Answer 20

0 / infinity
Although, zone 3 is good, most zone 3 is just “shunt-like” bc the Q is higher than V

Question 21

Anatomical shunts

Answer 21

Thesbian veins (drain L heart)
Bronchiolar veins (drain bronchial blood)
Pleural veins (drain bronchial blood)

Question 22

Zone 4 lung

Answer 22

Too much fluid, not enough removal by lymph
Fluid overload, pulmonary edema, Mitral stenosis,

Question 23

Aa gradient can be altered, meaning?

Answer 23

Can be increased
Can not be decreased, just stays “normal”

Question 23

Hypoxemia define

Answer 23

PaO2 <80mmHg

Question 24

Things that increase Aa gradient

Answer 24

VQ mismatch (too much V, COPD, embolism) Older age Shunt (Pneomonia, atelectasis, alveoli cant touch blood!) Diffusion impairment- Same as shunt! (Emphysema, ILD, Fibrosis)

Question 25

Aa gradient formula

Answer 25

PAO2-PaO2 Normal range is <15mmHg

Question 26

IRV, ERV, Vt, IC, FRC, RV, TLC

Answer 26

Question 27

What cant spirometery measure?

Answer 27

RV, FRC, TLC, CC, CV

Question 28

What inreases/ reduces FRC?

Answer 28

Age- Old people can sigh long af bc high FRC Sighs recruit alveoli COPD traps air in FRC Prone- thats why we do it PEEP adds air to FRC ----- Obesity/ pregnancy- no space left over! GA, light anesthesia, NMB- decreased muscles Supine- thats why we only prone under emergency

Question 29

CV, things that increase CV

Answer 29

The volume above RV where small airways begin to collapse, a bad thing! want it to be small COPD LV failure Obesity/ pregnancy Surgery Extremes of age

Question 30

Closing capacity (CC) formula

Answer 30

CV + RV Absolute volume of gas in lungs when collapse begins

Question 31

How does CC ratio to FRC

Answer 31

FRC should be higher If CC higher, more shunts

Question 32

DO2 definition and formula

Answer 32

Delivery of O2 CaO2 x CO x 10

Question 32

CaO2 definition and formula

Answer 32

Arterial oxygen content (AOC) (1.34 x hgb x SaO2) + (PaO2 x 0.003)

Question 33

VO2 meaning and range

Answer 33

Consumption of Oxygen 250ml/min

Question 34

Increase vs decrease P50

Answer 34

Decrease is actually a L shit- HALDANE HOLDS O2- holding stronger to O2 Haldane is about CO2, not O2 HGB F hypocarbia, carboxyhemoglobin, decreased CO, decreased 2,3 DPG (which is also in banked blood) decreased H ions- alkalosis, low Fio2 (gonna hold because its scarce) Increase is a R shift- BOHR BYE O2- letting go of O2 easily Bohr is about O2 not CO2 Acidosis, hypercarbia, increased 2,3 DPG (caused by hypoxia which tells body let go of O2!), hyperthermia, high fio2 (can let it go easily)

Question 35

Glucose ATP ratio

Answer 35

1:38 1 glucose converts to 38 ATPs

Question 36

What is the biggest ATP producer? lesser ones?

Answer 36

electron transport- 34 ATPs Krebs- 2 Glycolysis- 2

Question 37

The hamburger shift

Answer 37

Pertaining to CO2 production and elimination main character- Cl- For every molecule of HCO3 that leaves the RBC, a Cl is transported in

Question 38

Hypercarbia effects on O2 demand Other effects of Hypercarbia

Answer 38

Increases it! too much CO2 in blood Hypoxemia Hyperkalemia

Question 39

Salicylates effect on minute ventilation

Answer 39

Increase! "Aspirin makes you breathe!"

Question 39

Pacemaker for breathing

Answer 39

Dorsal Respiratory center in the medulla Although, new evidence says pre-botzinger complex in VRG Door cell- door opens for breathing

Question 40

CO2 Ventilatory response curve

Answer 40

Opposite of Bohr haldane L shift- prompts breathing R shift- stops the prompt to breathe

Question 41

Pacemaker for expiration

Answer 41

Ventral respiratory center in the medulla

Question 42

What inhibits the respiratory pacemaker?

Answer 42

Pneumotaxic center in the upper pons

Question 43

What stimulates the respiratory pacemaker?

Answer 43

Apneustic center in the lower pons

Question 44

What does the DRC respond to ?

Answer 44

pH of the CSH PaCO2 Although, stimulated by hypoxemia and hypercarbia, and is depressed by PROFOUND hypoxemia and hypercarbia

Question 45

Can CO2 cross BBB? (CCR)

Answer 45

Yes, but H can't

Question 46

What does the central chemoreceptor respond to?

Answer 46

H+, although h cant pass bbb, so when co2 diffuses across, it combines with h2o to form h and hco3

Question 47

Peripheral chemoreceptor location and purpose

Answer 47

Carotid arteries, transverse aortic arch monitor for hypoxemia PaO2<60mmHg (hypoxic ventilatory response)

Question 48

How does the peripheral chemoreceptors respond to hypoxemia

Answer 48

Raises RMP, opens CA channels, AP is sent down Herings nerve to CN9 to increase ventilation

Question 49

Things that impair hypoxic ventilatory response

Answer 49

Endarectomy cuts the limbs of the nerves Low anesthetic gases 0.1MAC Volatile anesthetics

Question 50

What prevents over inflation of the lung (reflex, nerve, etc.?)

Answer 50

Hering-Breuer Reflex

Question 51

J receptors

Answer 51

Hyperventilate, i cause ventilation o_o (side eye)

Question 52

Agents that causes shunt/ prevent HPV

Answer 52

DES prevents HPV TIVA agents will not increase shunts Vasodilators like dobutamine, CCB will Vasoconstrictors will cause fast BF and cause shunt

Question 53

How do the stupid lungs respond to zone 3?

Answer 53

HPV to prevent shunt

Question 54

Sepsis effect on P50

Answer 54

Right shift, take the O2! although it wont

Question 55

Whats another way to say increase dead space?

Answer 55

increase paco2 etco2 gradient

Question 56

Does hemorrhage effect Vd?

Answer 56

Yes, increases , adds more pathways in the body

Question 57

What drugs increase shunting?

Answer 57

Des, SNP

Question 58

VO2 formula

Answer 58

250ml/min 3.5ml/kg/min

Question 59

EMLA cream and oxyhemoglobin curve

Answer 59

Shifts to the left EMLA turns into methemoglobin which is a left shift