General Anesthesia

Question 1

What are the 5 major effects of general anesthetics?

Answer 1

Unconsciousness
Amnesia
Analgesia
Attenuation of autonomic reflexes
Skeletal muscle relaxation

Question 2

What is an ideal general anesthetic?

Answer 2

Rapid, smooth loss of consciousness
Rapidly reversible on discontinuation
Wide margin of safety

Question 3

What is the goal of balanced anesthesia?

Answer 3

Minimize side effects, maximize efficacy

Question 4

What is balanced anesthesia?

Answer 4

Use small doses of multiple agents, inhaled and IV

Question 5

What is conscious sedation?

Answer 5

Use minimal amnestic and opioid

Patient can converse, respond to stimuli/commands, able to protect airway and maintain ventilation

Question 6

When is anesthesia considered general?

Answer 6

Once the patient has lost the ability to protect the airway

Question 7

What are the 3 phases of general anesthesia?

Answer 7

Induction
Maintenance
Emergence

Question 8

What is the difference in phase state for gaseous vs. volatile inhaled anesthetics?

Answer 8

Gaseous: gas at room temp
volatile: liquid at room temp

Question 9

What are the ideal PK for inhaled anesthetics?

Answer 9

Ideal agent is fast on/fast off

Adequate potency

Question 10

What is the driving force for the uptake of inhaled anesthetics?

Answer 10

Alveolar fraction/partial pressure

Question 11

What are the anesthesiologist controlled paramaters of an inhaled anesthetic?

Answer 11

1. Increase Fi (inspired fraction or partial pressure)

2. Increased alveolar ventilation

Question 12

What are the agent dependent parameters of inhaled anesthetic?

Answer 12

Solubility of inhaled anesthetic

Question 13

How does solubility affect onset?

Answer 13

More insoluble agent have a faster onset

Question 14

What the most important factor of emergence?

Answer 14

Alveolar ventilation

Question 15

What is the measure of potency of inhaled general anesthetics? What does it tell you?

Answer 15

Minimal alveolar ccn - ccn at which 50% of non-relaxed patients respond

Question 16

How do inhaled anesthetics affect CV system?

Answer 16

Decrease BP

Question 17

How do inhaled anesthetics affect respiratory system?

Answer 17

Decrease minute volume

Question 18

How do inhaled anesthetics affect hepatic system?

Answer 18

Decrease in portal vein flow

Question 19

How do inhaled anesthetics affect uterine smooth muscle?

Answer 19

Decrease in uterine tone, may increase uterine bleeding

Question 20

What is a potential toxicity of nitrous oxide?

Answer 20

Decrease in methionine synthase –> megaloblastic anemia

Question 21

What is malignant hyperthermia?

Answer 21

Hypermetablic syndrome: genetically susceptible patients after exposure to trigger (halogenated inhalationals/succinylcholine)

Question 22

What causes malignant hyperthermia?

Answer 22

Decrease in the reuptake of Ca2+ from sarcoplasmic reticulum

Question 23

What can malignant hyperthermia lead to?

Answer 23

Hyperthermia
Hypercapnia
Hypoxia
Hyperkalemia

Question 24

What is the antidote to malignant hyperthermia?

Answer 24

Dantrolene - inhibits release of Ca2+ from sarcoplasmic reticulum

Question 25

How can we prevent malignant hyperthermia?

Answer 25

Ask about family history of reaction to GA

Question 26

What is the preferred method of induction?

Answer 26

IV anesthetics

Question 27

What are the 3 major general IV anesthetics?

Answer 27

Propofol, etomidate, ketamine

Question 28

What is a major chemical property of the IV anesthetics? Why is this property beneficial?

Answer 28

lipophilic - preferential partitioning into highly perfused lipophilic tissues = brain/SC

Question 29

How can we describe the onset and elimination of IV anesthetics?

Answer 29

Rapid, for both

Question 30

What is the context sensitive half time?

Answer 30

Describes elimination half time after continuous infusion

Question 31

What does the context sensitive half time tell us?

Answer 31

Drug's suitability for maintenance sedation

Question 32

What is the mechanism of propofol?

Answer 32

GABA agonist

Question 33

What are the effects/benefits of propofol?

Answer 33

Non analgesic Amnestic Anti-emetic (small doses)

Question 34

What are the uses of propofol?

Answer 34

induction/maintenance of GA | sedation

Question 35

How does propofol affect the CV system?

Answer 35

Decrease in BP

Question 36

How does propofol affect the respiratory system?

Answer 36

Decrease in Vt, RR and minute volume, decrease in upper airway reflexes

Question 37

What is the time limit for using propofol after dispensing? Why?

Answer 37

8 hours - bacterial contamination

Question 38

What is etomidate used for?

Answer 38

Induction and short sedation

Question 39

What is the mechanism of etomidate?

Answer 39

GABA agonist

Question 40

What are the clinical effects/benefits of etomidate?

Answer 40

Non analgesic

Question 41

What organ effects result from etomidate? (3)

Answer 41

minimal hemodynamic Endocrine: may inhibit 11 B hydroxylase (chol to cortisol) Respiratory depressant

Question 42

What are the effects from ketamine?

Answer 42

dissociative anesthesia with nystagmus - freak out or great | analgesic

Question 43

What is the mechanism of ketamine?

Answer 43

NMDA receptor antagonist

Question 44

What are the organ effects of ketamine?

Answer 44

Increases in BP, CO and HR | Minimal respiratory depression

Question 45

Why use benzodiazepine with ketamine?

Answer 45

Hallucinations and unpleasant emergence may occur

Question 46

How can ketamine aid in opioid addiction?

Answer 46

Sub analgesic doses may help to limit or reverse opioid tolerance

Question 47

What is dexmedetomidine used for?

Answer 47

Sedation or adjust to GA

Question 48

What is the mechanism of dexmedetomidine?

Answer 48

Alpha-2 agonist

Question 49

What are the clinical effects of dexmedetomidine?

Answer 49

Sedative, analgesic

Question 50

What are the organ effects of dexmedetomidine?

Answer 50

Decrease BP, HR | Presserves respiratory drive