Anesthesia - Lichtblau

Question 1

Difference between anesthesia and analgesic

Answer 1

Complete loss of sensations/unconscious

Just loss of pain sensation

Question 2

What are the main stages of anesthesia?

Answer 2

1) Analgesia and Amnesia (good)
- goes unconscious

2 )Delirium (bad. get thru here fast)

• unconscious
• can be agitated or combative
• blood pressure and respiration can happen

3) Surgical Anesthesia (good)

4) Medullary Depression (bad, overmedicate)
- could lead to cardio/resp. collapse

Question 3

What 4 drug types are combined in order to achieve the aims of a balanced anesthesia?

Answer 3

General anesthetic - Loss of awareness or consciousness
Benzodiazepine - Amnesia
Opioid – Analgesia, BANS
Neuromuscular blocker - Skeletal muscle relaxation

Question 4

With gas anesthetic, why can’t you go higher than about 79% gas concentration?

Answer 4

You need 20.9% oxygen at least to survive

Question 5

If you want your anesthetic to be fast-acting, do you want the anesthetic to be highly soluble or less soluble in blood?

Answer 5

Less soluble

Question 6

What is the difference between how anesthesia perfuses and leaves alveolar, vessel-rich, muscular, and fatty areas??

Answer 6

Alveolar and vessel rich areas enter and exit tissue quickly

Muscle group is much more gradual incline and decline of perfusion

Fat is extremely in allowing drug to enter and exit

Question 7

What is the MAC?

No, not the computer smart alek… (alek? what is that)

Answer 7

MInimum Alveolar Concentration

• It is the does of anesthetic producing surgical anesthesia in 50% of patients
• To be sure this means you want to do about 1.3-1.5 MACs for surgical anesthesia

Question 8

Greater lipid solubility in an anesthetic =

Answer 8

Greater lipid solubility in an anesthetic = greater potency

Question 9

Increasing the partial pressure of a drug in the blood is much easier when:

Answer 9

The drug is less blood soluble

hard to increase partial pressure of drug in the blood when it is dissolves easily in blood

Question 10

What’s the second gas effect?

Lichtblau thinks its garbage…

Answer 10

Often N2O is used, it rapidly enters blood and it creates a “negative pressure” in the alveoli that allows the second gas to enter more quickly

Question 11

What is toxologically important about the way that anesthetic is eliminated from the body?

Answer 11

If you are working in the OR you need to be careful because reactive chemical metabolites can be eliminated through the skin and cause exposure

Question 12

CNS and Cardio effects of haogentaed hydrocarbon anesthetics?

Answer 12

CNS

• Decrease brain metabolic rate
• Increase Cerebral blood flow
• Increase intracranial pressure

Cardio

• Decrease myocardial contractility
• Decrease stroke volume

Question 13

What are the advantages and disadvantages of halothane?

Answer 13

Advantages:

• Potent
• Rapid induction/recovery
• inexpensive
• no larynx irritation

Disadvantages:

• Inadequtes analgesis and muscle relaxation
• depress cardiac output, blood pressure, and respiration
• sensitize myocardium to catecholamines
• hepatic toxicity risk (a lot of metabolism)
• Malignant hyperthermia

Question 14

How do you treat maligant hyperthermia caused by halothane?

Answer 14

Cool patient, treat with dantrolene

Question 15

So how is isoflurance in comparison to halothane?

Answer 15

Pretty similar.
Advantage - doesn’t sensitize myocardium to catecholamines
Disadvantage - Pungent odor!

Question 16

What anesthetic was recently voted “nearly perfect?”

Answer 16

Sevoflurane

• low blood solubility
• high potency

Question 17

Why is it impossible to use nitrous oxide by itself as an anesthetic?

Answer 17

MAC = 104%

So its impossible because you need 20.9% oxygen just to stay alive…

Question 18

What happens if you discontinue nitrous oxide very rapidly during recovery?

Answer 18

hypoxia can occur

Question 19

Advantage of nitrous oxide as anesthesia?

Answer 19

Very rapid onset due to low blood solubility

Question 20

Why are intravenous drug anesthetics not useful by themselves for surgery?

Answer 20

Can do short procedures, but they don’t maintain anesthesia for long AND muscle relaxation is poor with them

Usually used to induce anesthesia

Question 21

What is the mechanism of action for barbituates like thiopental, etomidate, and methohexital?
Why is toxicity an issue?

Answer 21

Mech: Facilitate GABA-induced Cl entry into neurons

Toxicity: Watch out because the anesthetic dose is between 50 and 75% of the LD50 (thats the dose that will kill 50% of people)

Question 22

What do you use benzodiazepines like midazolam for?

What is their mechanism of action?

Answer 22

Use: Most important for amnestic action

Mech: Facilitates GABA-induced Cl entry into neurons

Question 23

Name 1 advantage and 1 disadvantage of propofol for injection anesthesia:

Answer 23

Advantage: patients awake more clear-headed and not nauseous

Disadvantage: Pain at injection site

Question 24

Principal drawback of using ketamine?

What kind of anesthesia does it produce?

Answer 24

Occurrence of emergence reactions (delirium and hallucinations)
Abuse

Produces dissociative anesthesia