Uptake & Distribution

Question 1

We use ______ ________ to move our product.

Answer 1

concentration gradients

Question 2

Fd

Answer 2

Fraction of DELIVERED gas (percentage in the flow as it leaves the machine)

Question 3

Fi

Answer 3

Fraction of INSPIRED gas (the percentage as the patient ventilates)

Question 4

Fa

Answer 4

Fraction of ALVEOLAR gas (percentage in the alveoli; most closely reflects the concentration in the brain)

Question 5

What is our end-target organ with inhaled anesthetics?

Answer 5

THE BRAIN!!!!!

Question 6

Which anesthetic has the GREATEST uptake?

Answer 6

The one with the highest blood solubility; It piles up on the Blood Train when it leaves the Lung Station because it loves that fucking train! (HALOTHANE)

Question 7

Which anesthetic has the FASTEST uptake?

Answer 7

The one with the lowest blood solubility, meaning it jumps off the Blood Train when it reaches the Brain Central Station because it hates to be on that damn train. (DESFLURANE)

Question 8

What characteristic determines the rise of Fa?

Answer 8

Solubility (inverse relationship; most soluble raises Fa the slowest, and vice versa…)

Question 9

What are some factors that can speed up an inhalation induction?

Answer 9

• Low blood solubility
• Increased Fi of anesthetic
• Increased Vital capacity and Ventilation
• Less distribution to peripheral compartment
• Decreased CO (slower train means more chemical passengers can jump on that shit)

Question 10

What are some nifty factors that slow awakening?

Answer 10

• High tissue solubility
• Long anesthetic times
• Low gas flows
• Increased Cardiac Output

Question 11

What the heck is a time constant?

Answer 11

TC= Capacity/flow
1 TC exchanges 63%
2 TC exchanges 86%
3 TC exchanges 95%
4 TC exchanges 98%
TC for the lungs is approx. 30 seconds!

Question 12

Effect of ventilation on speed on anesthetic on or off?

Answer 12

Direct proportional relationship (The faster they ventilate, the faster the anesthetic goes on or off)

Question 13

Effect of CO on anesthetic?

Answer 13

Inverse relationship (The lower the CO (to a point…), the more inhaled anesthetic can make it into the bloodstream to then make its way to brain, like trying to jump on a moving train. If the train is moving faster, it’s harder to jump on)

Question 14

What are the 4 main groups of tissues we concern ourselves with?

Answer 14

Vessel-rich, muscle, fat, vessel-poor

Question 15

What is the % of body mass/% CO received of the vessel-rich group?

Answer 15

10%/ 75%

Question 16

What is the % of body mass/% CO received of the muscle group?

Answer 16

50%/ 19%

Question 17

What is the % of body mass/% CO received of the fat group?

Answer 17

20%/ 6%

Question 18

What is the % of body mass/% CO received of the vessel-poor group?

Answer 18

20%/ 0%

Question 19

In what order do the groups equilibrate?

Answer 19

1. Vessel-rich
2. Muscle
3. Fat
4. Vessel-poor

Question 20

Let’s think about the concentration effect (overpressurinzing) for a second. What is its significance?

Answer 20

By increasing the Fd, the Fa can reach desired concentrations faster.

Question 21

How is partial pressure measurement derived?

Answer 21

Concentration x Total pressure (760 mmHg at sea level)