IV Anesthesia

Question 1

What will balanced anesthetia do?

Answer 1

relax muscles, relieve anxiety, prevent secretions, induce unconsciousness
- several drugs are used together

Question 2

Why do you need to worry about formulations for IV anesthesia drugs?

Answer 2

• are lipophilic (stuck for injecting) so pH must be adjusted or a surfactant needs to be added to make them more suitable.

Question 3

What are the side effects of adding surfactants?

Answer 3

thromblophlebitis

- concentration and speed sensitive

Question 4

general MOA of IV anesthetics?

Answer 4

• reinforce inhibitory action of GABA and glycine

Question 5

MOA of ketamine

Answer 5

activate GABA and glycine

-inhibit NMDA by physically occluding the channel

Question 6

MOA of propofol

Answer 6

activate GABA and glycine

- inhibit NMDA by blocking the binding of glutamate to the receptor

Question 7

MOA of barbiturates and benzodiazepine and etomidate

Answer 7

reinforce inhibiting effects produced by endogenous GABA binding

• barbs = prolong binding of GABA to R
• bezno = allosteric change in receptor activty
• both require endogenous GABA

Question 8

time course of IV anesthetics

Answer 8

• effects are almost instantaneous
• drug rapidly distributes out of plasma and into high flow organs and then re-distributes to other organs –> skeletal muscle and fat tissue

Question 9

pharmoknetic profiles of IV anesthetics

Answer 9

• awakening of the pts is due only to drug re-distribution making their clinical duration short but increasing length of elimination from non-active stores

Question 10

context sensitive half lives of IV anesthetics

Answer 10

• some drugs half lives increase w/ longer infusion times (thiopental, diazepam)

Question 11

what pharmacologic effects of thiopental

Answer 11

increase HR

- porphyria, enzyme induction

Question 12

what pharmacologic effects of etomidate

Answer 12

no effect on CV

- inhibits steroidogenesis, not used in ICU

Question 13

what pharmacologic effects of ketamine

Answer 13

increase CBF, ICP, MAP, HR, CO

• intact pharyngeal/laryngeal reflexes
• bronchodilator for refractory asthma
• hallucinations w/ emergence
• causes dissociative states (eyes open)

Question 14

what pharmacologic effects of propofol

Answer 14

increase HR

- antiemetic, infusion syndrome

Question 15

what is the long acting and short acting benzo

Answer 15

long = diazepam
short = midazolam

Question 16

What are the good attributes of benzodiazepine

Answer 16

• when analgesia not required
• anticonvulsants, amnesia
• wide therapeutic saftety margin
• minimal CV and respiratory depression if used alone
• Specific antagonists – Flumazenil

Question 17

What the is elimination of benzodiazepines?

Answer 17

1. Diazepam - 3 active metabolites
2. Lorazepam - conjugated for elmination
3. Midazolam - rapidly inactivated

Question 18

Opioid use during surgery

Answer 18

• CV effects - bradycardia, HypoTN, HTN, respiratory depression (less response to increase in PaCO2), muscle rigidity, increase ICP and CBF
• coma triad
  N/V, constipation

Question 19

Neurolept analgesia

Answer 19

use of drug combination that produces pain relief and provides a state of indifference

• Droperidol - state of indifference
• Fentanyl - analgesia
• Add N20
• Atropine

Question 20

How to chose opioid for surgery?

Answer 20

• for long lasting analgesia – morphine is ideal

- fentanyl for short duratio

Question 21

What happens in malignant hyperthermia?

Answer 21

• increase in end tidal CO2
• total body rigidity
• unexpected tachycardia, tachypnea
• respiratory and metabolic acidosis

Question 22

What is the cause of malignant hyperthermia?

Answer 22

succinylcholine - increases IC Ca release from SR

- can be caused by volatile gases

Question 23

how to treat malignant hyperthermia?

Answer 23

Danrolene
Stop giving trigger agent, hyperventilate w/ O2
- correct hyperkalemia and acidosis, cool core temperature