General Anesthetics

Question 1

What are the two ways that anesthetics can effect organs?

Answer 1

1) Strengthening inhibition

2) Diminishing excitation

Question 2

What are the two inhibitory ion channels that are legitimate candidates for anesthetic action?

Answer 2

1) GABAa Cl channel

2) K+ channels

Question 3

What are the three excitatory channels that are legitimate candidates for anesthetic action?

Answer 3

1) nACHRs/mACHRs
2) NMDA
3) 5-HT

Question 4

What is the driving force for uptake of an inhaled anesthetic?

Answer 4

Alveolar Concentration

Question 5

What two factors determine how quickly the alveolar concentration changes?

Answer 5

1) inspired concentration or partial pressure

2) alveolar ventilation

Question 6

What is the blood:gas partition coefficient?

Answer 6

Defines the relative affinity of an anesthetic for the blood compared with that of inspired air (i.e. Blood solubility)

Question 7

What type of drugs will induce anesthesia via a fast onset of action?

Answer 7

Agents with low blood solubility–> small blood:gas partition coefficient.

Question 8

What type of drugs will induce anesthesia via a slow onset of action?

Answer 8

Agents with a high blood solubility–> Large Blood:Gas coefficient

Question 9

What is the MAC?

Answer 9

Minimum Alveolar Concentration is the concentration of inhaled anesthetic that prevents movement in response to surgical stimulation in 50% of subjects (measure of potency).

Question 10

What effect does Cardiac Output have on anesthetic distribution?

Answer 10

• Increase in pulmonary blood flow (inc. CO) will increase uptake and decrease the rate at which Fa/Fi rises, which will decrease induction.
• Increase uptake into the blood, causes dilution of the anesthetic into the blood.
• This results is a slower rise in partial pressure in the blood due to a greater volume of distribution.

Question 11

What are the three factors controlling uptake of an anesthetic?

Answer 11

1) blood:gas partition coefficient
2) Cardiac output
3) Alveolar-venous partial pressure

Question 12

What is a potential toxicity of Halothane?

Answer 12

Hepatitis with or without exposure (anorexia, nausea, myalgias, arthralgias, and rash)

Question 13

What two drugs can cause malignant hyperthermia?

Answer 13

• Succinylcholine and inhaled volatile anesthetics.

- Antidote is dantrolene.

Question 14

What is the induction/recovery, assumed MOA, and important features of Propofol?

Answer 14

Induction/ recovery-> rapid onset and recovery.
MOA-> agonists of GABAa receptors.
Features-> antiemetic, rapidly metabolized in liver, can cause hypotension

Question 15

What is the onset/recovery and general characteristics of Fosopropofol?

Answer 15

• Water-soluble prodrug of Propofol that is rapidly metabolized by alkaline phosphatase.
• Similar effects of Propofol but onset and recovery are prolonged.

Question 16

What is the onset/recovery, MOA, and general characteristics of Etomidate?

Answer 16

• rapid onset and moderately fast recovery.
• Potentiates GABA on GABAa receptor.
• causes minimal CV and respiratory depression

Question 17

What is the onset/recovery, MOA, and general characteristic of Ketamine?

Answer 17

• Modertly rapid onset and recovery.
• NMDA receptor antagonist.
• CV stimulation, increased cerebral blood flow, dissociative anesthetic state–>catatonia, amnesia,analgesia.

Question 18

What is the MOA and use of Dexmedetomidine?

Answer 18

• alpha 2 andrenergic agonist that produces hyponosis.

- principally used for short-term sedation of incubated patients in the ICU or as an adjunct to general anesthesia.

Question 19

What are some opioid adjuncts that can be used in addition with general anesthesia?

Answer 19

Fentanyl, sufentanil, remifentanil, morphine

Question 20

What are some barbiturates that can be used in adjunct to general anesthesia?

Answer 20

-Thiopental (prototype) and methohexital

Question 21

What are some benzodiazepines that can be used in adjunct with general anesthesia?

Answer 21

-Diazepam, lorazepam, midazolam