General Anesthetics

Question 1

What are the characteristics of a general anesthesia?

Answer 1

1) amnesia
2) analgesia
3) unconsciousness
4) inhibition of sensory and autonomic reflexes
5) skeletal muscle relaxation

Question 2

How does GABA cause IPSP?

Answer 2

GABA receptors that are activated will open a Cl- channel. Cl- will enter the cell making it more negative which makes it more difficult to reach threshold and trigger an AP.

Question 3

What is the Minimum Alveolar Concentration?

Answer 3

Minimum Alveolar Concentration @ 1ATM that prevents movement during a skin incision in 50% of patients.

Question 4

What is the ED95 for the MAC?

Answer 4

1.3 times the MAC

Question 5

What is the MAC influenced by?

Answer 5

Temperature
Age
Other drugs

Question 6

What is the MAC NOT influenced by?

Answer 6

Sex
O2
pH
BP

Question 7

What happens to the rate of induction when CO increases?

Answer 7

It will cause slower induction

Question 8

What is the mechanism of inhaled anesthetics?

Answer 8

Act at the GABAa receptor-chloride channel and facilitate the GABA mediated neuronal inhibition at these receptor sites. Nevertheless, the exact mechanism of inhaled anesthetics remains unclear.

Question 9

What is a measure of potency of an anesthetic?

Answer 9

MAC

Question 10

What is cascade?

Answer 10

The faster the agent gets from one compartment to the next, the slower it reaches equilibrium.

Question 11

What are factors that determine anesthetic delivery to the brain?

Answer 11

(1) inspired concentration
(2) transfer of the gas to the arterial blood
(3) transfer of the agent to the brain

Question 12

What are the factors that determine uptake of anesthetic into the blood?

Answer 12

• 1. Solubility
• 2. Partial Pressure Difference
• 3. Cardiac Output

Question 13

What is the effect of solubility on equilibrium?

Answer 13

More soluble agents reach equilibrium slower than less soluble agents. Th blood compartment is “larger” for more soluble agents.

Question 14

What drives the movement of the inhaled drugs?

Answer 14

Partial pressure difference.

Question 15

What is the order of the organs receiving the drug?

Answer 15

Vessel rich organs first, then skin and muscle and fat is last.

Question 16

What happens with increased blood flow?

Answer 16

Increased blood flow near alveolus slows equilibrium because it increases uptake
•Therefore, it also slows FA/FI

Question 17

What will a venous blood sample of a patient under anesthetic look like?

Answer 17

Venous blood sample will be red in the patient because

the metabolic rate decreases and O2 consumption decreases

Question 18

How does ventilation affect the speed of induction?

Answer 18

The rate of rise of anesthetic gas tension in arterial blood is directly dependent on the minute ventilation.

Question 19

What is the blood/gas partition coefficient, λ?

Answer 19

It represents the ratio of anesthetic concentration in blood to anesthetic concentration in a gas phase when the two are in partial pressure equilibrium

Question 20

What are the IV drugs?

Answer 20

Propofol
Thiopental
Ketamine
Etomidate

Question 21

What are the effects of propofol?

Answer 21

Vasodilator leading to decreased BP

Respiratory depression causing apnea

Question 22

What is the emergence time from propofol like?

Answer 22

Rapid

Question 23

What are the effects of thiopental on the various organ systems?

Answer 23

Vasoconstrictor so it can cause limb ischemia
Puts the brain to sleep as it is lipid-soluble and diffusesrapidly through biological membranes, including the blood-brain barrier

Can take a long time for emergence though

Question 24

What is unique about ketamine and respiration?

Answer 24

Bronchodilator so it keeps patients breathing

Question 25

What is etomidate used for?

Answer 25

It is used only for induction. A primary advantage of etomidate is its ability to preserve cardiovascular and respiratory stability better than does thiopental.

Question 26

How does ketamine affect the HR and BP?

Answer 26

Increases HR and BP

Question 27

What are the anesthetic properties of NO?

Answer 27

AC for nitrous oxide is 110 percent of one atmosphere and thus it is incapable of independently producing surgical anesthesia outside of a hyperbaric chamber. It is used clinically as a supplement to other agents.

Induction and emergence are rapid