Ventilation/Perfusion

Question 1

When does quality Gas Exchange occur?

Answer 1

When V/Q match and equal 1.

Question 2

When blood flow> ventilation, what is VQ?

Answer 2

V/Q«<1

Question 3

When blood low<ventilation, what is VQ?

Answer 3

VQ»»1

Question 4

What is Pa, PA, and PV?

Answer 4

Pa = Pulmonary arterial pressure (coming in)

PA = Alveolar pressure (inside alveoli)

Pv = Pulmonary venous pressure (outflow)

Question 5

Top of the lung (Zone 1) Pa, PA, and Pv relation

Answer 5

PA>Pa>Pv
Inflating lung, closes the artery
No flow
Gravity works against

Question 6

Middle of the lung (Zone 2) Pa, PA, and Pv relation

Answer 6

Pa>PA>Pv

V/Q =1

Question 7

Bottom of the lung (Zone 3) Pa, PA, and Pv relation

Answer 7

Pa>Pv>PA
Gravity works w us
More blood flow, excess perfusion
Mixed venus concetration
No gas exhange

Question 8

What element can be used to take imaging of the perfusion of the lung?

Answer 8

133 Xe

Question 9

What is the V/Q values at the top, middle and bottom of the lung?

Answer 9

Top: VQ>1
Middle: 1
Bottom VQ<1

Question 10

Hypoxic Pulmonary Vasoconstriction

Answer 10

Principle mechanism of V/Q match through Constriction if a part doesnt breath well(ventilation)
Other part that breathes well will dilate to have more ventilation?

poorly executed tho

Question 11

What is nitrogen washout

Answer 11

measures FRC

Question 12

On the nitrogen washout graph, what is x and y axis? what does slope represent?

Answer 12

Number of breath(x) vs N%(y)
Rate of the line is the ventilation perfusion match

Question 13

What is shunt?

Answer 13

low V/Q; Qs<Qt

Question 14

What stage is the goal for Anesthesia?

Answer 14

Stage 2 or 3

Question 15

What are the effects of the anesthetic state? Secondary effects?

Answer 15

Anesthetic State
Loss of consciousness
Amnesia
Immobility (lack of response to noxious stimuli)
Not necessarily complete analgesia
Secondary effects
Muscle relaxation, Loss of autonomic reflexes,Analgesia, Anxiolysis

Question 16

What are the 4 stages of anesthesia?

Answer 16

Stage I : Analgesia
Stage II : Excitement
Stage III : Surgical Anesthesia
Stage III : Surgical Anesthesia w repirtory arrent (DONT WANT THIS)

Question 17

How do you control Palv?

Answer 17

Pi (inspired partial pressure)

Question 18

What is MAC?

Answer 18

considered to be the lightest possible level of anesthesia

Question 19

If MAC is small that potency is _____

Answer 19

high

Question 20

What is the equation for MAC?

Answer 20

MAC=1.3/λ

Question 21

What is an example of a high potent anesthetic?

Answer 21

Halothane

Question 22

What is the rate limiting step of the transfer of anesthetic?

Answer 22

Its the rate of equilibration between
Palv and Pi
Ptissue and Part

Question 23

τ (the time constant) is the time required for equilibration between areas to be _____.

Answer 23

63%

Question 24

After how many T’s is it considered to be 95% complete

Answer 24

3 T’s

Question 25

What is T =?

Answer 25

τ = λ(tissue) x (Volume Capacity/Flow Rate)

Question 26

How does VRG, MG, Fat group and VPG uptake anestheia?

Answer 26

VRG--> fast and first; bc 10% mass buut 75% of VO MG-->slower uptake Fat group-->slow uptake and slow release VPG-->almost no blood flow so neglible

Question 27

Which are ventilation limited anesthetics?

Answer 27

High potency; Diethyl ether, Halothane, enflurane, isoflurane; HIGH lamba

Question 28

Which are perfusion limited anesthetics?

Answer 28

Low potency; nitrous oxide, desflurane, sevoflurane LOW lambda induction and recovery fast

Question 29

What increases the induction of anesthesia? What decreases it?

Answer 29

Increasing ventilation accelerates induction of anesthesia Increasing blood flow reduces induction rate

Question 30

What can Alter Induction? too fast

Answer 30

Hyperventilation Decreased CO Young Age Shock Thyrotoxicosis Pi higher than desired PCNS

Question 31

What can Alter Induction? Too slow

Answer 31

Hyperventilation Hypoventilation Increased CO COPD Right to left shunt

Question 32

Higher the lamda, ____ the recovery time

Answer 32

higher

Question 33

How are Intravenous Anesthetics helpful?

Answer 33

Fast induction BUT can't breathout! so if Stage 4 reached, super hard to reverse

Question 34

What are the Intravenous Anesthetics?

Answer 34

Barbiturates- Thiopental etc. GABA activators Propofol- Lipid-soluble Etomidate- Imidazole with similar kinetics to propofol (limited sympathetic and cardiac func) Ketamine- Produces dissociative anesthesia, highly analgesic and amnesic, increases CO by increasing sympathetic nervous output