uptake an distribution Flashcards

1
Q

Uptake =

A

ƛ * Q * (A-v)

Solubility * CO * difference in alveolar/venous partial pressures

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2
Q

Solubility’s effect on the rate of rise of FA/FI curve:

A

Less soluble = faster rate of rise

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3
Q

Over pressurization

A

The use of high FD to increase the speed of FA=FI equilibration

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4
Q

Effect of CO on induction speed:

A

Increasing Cardiac Output = decreased speed of induction

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5
Q

Tissue uptake equation:

A

Uptake = tissue/blood coefficient * flow * (a-t)

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6
Q

The coefficient that most influences FA/FI rise:

A

Blood/Gas

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7
Q

The coefficient that most influences the FA/FI tail:

A

Tissue-gas

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8
Q

MAC

A

Minimum alveolar concentration; ED50 of inhaled anesthetics. The concentration that will produce absence of movement in 50% of the population.

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9
Q

↑ ventilation will have more of an effect on FA/FI curve for this type of agent:

A

Highly soluble agent

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10
Q

Effect of both ↑ ventilation and ↑ CO:

A

↑ ventilation has more effect (to speed induction) than ↑ CO does (to slow it)

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11
Q

If only one lung is intubated, what is the effect on the rise in FA and rise in Pa?

A

FA rises faster than if the ETT was in the trachea

However, loss of uptake from unventilated lung leads to overall depressed ↑ in Pa

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12
Q

Higher blood-gas coefficient means:

A

Agent is more soluble

More agent in blood = less in alveoli/brain

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13
Q

Type of gas that will washout fastest:

A

Least soluble

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14
Q

N2O is ____x as soluble as nitrogen:

A

34x

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15
Q

Places that N2O can diffuse into during surgery:

A
  1. ETT cuff
  2. Bowel obstruction
  3. Pneumothorax/pneumocephalus
  4. Inner ear
  5. Ophtho procedures using gas bubbles
  6. Air embolus
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16
Q

Another name for blood-gas partition coefficient:

A

Oswaldt Solubility Coefficient

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17
Q

Brain-level activity of a highly vs. minimally soluble IA:

A

Highly soluble: low brain activity

Minimally soluble: high brain activity

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18
Q

Effect of solubility on emergence

A

Less soluble = faster induction/emergence

More soluble = slower induction/emergence

19
Q

Five partial pressure gradients between vaporizer and end-target tissue:

A

Vaporizer and inflow, Inflow and circuit, Circuit and alveoli, Alveoli and blood, Blood and tissues

20
Q

Impact of HCT on B/G coefficient:

A

↓ HCT = ↓ B/G coefficient
Dropping HCT from 21 –> 43 drops B/G coefficient by 20%
D/t less binding sites in the blood

21
Q

FA vs. FI:

A
FA = alveolar concentration 
FI = inspired concentration
22
Q

FD = FI when:

A

High flow rate with no re-breathing

23
Q

Make these changes to ventilation to ↑ uptake:

A

↓ TV, ↑ rate

24
Q

PA of volatile anesthetic is determined by (4):

A
  1. PI (inhaled partial pressure)
  2. Alveolar ventilation
  3. Breathing circuit
  4. FRC
25
Normal alveolar ventilation, minute ventilation and deadspace:
Alveolar Ventilation = 4 L/min Minute ventilation = 6 L/min Dead space = 2L/min
26
Solubility's effect on the rate at which FA approaches FI:
Less soluble agents will reach equilibrium faster | They have a faster rate of rise
27
Describe the FA/FI curve:
``` First rise: VRG uptake First knee: VRG at equilibrium Second rise: MG uptake Second knee: MG at equilibrium Third rise: FG/VPG uptake (very slow) ```
28
With lower solubility (
1. Gas phase | 2. Blood phase
29
What determines which direction the gas will move
pressure gradients
30
How long does it take the fat compartment to reach equilibrium?
24-48 hours
31
Rate of induction/emergence of an anemic patient
Faster induction and emergence
32
What determines how quickly FA= FI ?
Solubility - less soluble = faster equilibrium
33
Partial Pressure that represents anesthetic going to the brain
FA (fraction of alveolar concentration)
34
What do we as anesthetists control
FI (fraction of inspired concentration) - the % dials
35
What is out overall goal with induction
Get the FA/FI ratio to 1:1 quickly - the faster to equilibrium - the faster the induction
36
PA (alveolar pressure ) is used to estimate 3 things
1. Depth of anesthesia 2. Recovery from anesthesia 3. Anesthetic Potency (dose) or MAC (ED50)
37
Exhaled gas readings during induction and emergence. During induction readings will be ____________ than what is set on the dial d/t ________________. During emergence the readings will be higher than what is set on the dial d/t ___________.
Induction - lower; Uptake occurring in the tissues | Emergence - higher; tissue giving up previously absorbed IA
38
What has a faster induction, iso or des?
des- it is less soluble and has a faster rate of rise and therefore reaches equilibrium much faster.
39
Why does nitrous have a faster rate of rise than desflurane?
Despite des being less soluble nitrous will rise faster because of the concentration effect.
40
What opposes the effect of ventilation?
Uptake
41
A increase in CO will cause a ____________ in the FA/FI ratio. this means that the patient will be induced ___________.
Decrease | Slower
42
A decrease in CO will cause a ____________ in the FA/FI ratio. this means that the patient will be induced ___________.
Increase | Faster
43
Changes in CO will have a greater effect on the ____________ soluble agents. Why?
More soluble. They have more time to equilibrate with the passing blood.
44
Changes in ventilation will have greater effects on ______________ agents. Why?
More Soluble. Alveolar pressure will build up much faster in both, but the rate of rise will increase more for the highly soluble agents.