Intravenous anesthetics

Question 1

What is the mechanism of action of propofol?

Answer 1

GABA-A agonist

Question 2

What is the onset of action of propofol?

Answer 2

30-60 seconds

Question 3

What is the duration of action of propofol?

Answer 3

5-10 minutes

Question 4

What is the clearance of propofol?

Answer 4

liver+ extra hepatic metabolism

Question 5

What is the active metabolite of propofol?

Answer 5

None

Question 6

What is the induction dose of propofol?

Answer 6

1.5-2.5 mg/kg IV

Question 7

What is the maintenance dose of propofol?

Answer 7

25-200 mcg/kg/min

Question 8

What are the respiratory effects of propofol?

Answer 8

decreased respiratory drive

Question 9

What are the CV effects of propofol?

Answer 9

decreased BP, SVR, preload, and contractility

Question 10

What are the CNS effects of propofol?

Answer 10

decreased ICP & IOP, no analgesia, +/- seizure activity
decreased CBF, decreased CMRO2

Question 11

What is the pKa of propofol?

Answer 11

11

Question 12

GABA-A receptor stimulation leads to

Answer 12

hyperpolarization of the neurons by increasing Cl- conductance; more Cl- inside the cell makes the cell more negative; this reduces resting membrane potential leading to prevention of action potential

Question 13

With propofol, there is a rapid redistribution

Answer 13

from the blood to the vessel rich group
redistribution from the VRG to the muscle and fat follows

Question 14

The brain concentration of propofol peaks at

Answer 14

~1 minute

Question 15

How does propofol affect the CO2 response curve?

Answer 15

shifts CO2 response curve down and to the right (less sensitive to CO2)–> respiratory depression and/or apnea

Question 16

Can myoclonus occur with propofol?

Answer 16

yes

Question 17

Does propofol provide analgesia?

Answer 17

no

Question 18

How can propofol infusions change the color of urine?

Answer 18

green urine= phenol excretion
cloudy urine= increased uric acid excretion

Question 19

Propofol has _______ properties.

Answer 19

antioxidant properties- free radical scavenging properties

Question 20

What organs are primarily responsible for propofol metabolism?

Answer 20

liver (CYP 450)
lungs

Question 21

Name 2 preservatives that may be added to the propofol vial.

Answer 21

disodium edetate (diprivan)
sodium metabisulfate (generic formula)

Question 22

Propofol infusion syndrome is categorized by the presence of:
a. hypokalemia
b. bradycardia
c. respiratory failure
d. metabolic acidosis

Answer 22

b. bradycardia
d. metabolic acidosis

Question 23

Propofol infusion syndrome presents with

Answer 23

acute refractory bradycardia–> asystole + at least one of the following:
metabolic acidosis (base deficit > 10 mmol/L)
rhabdomyolysis
enlarged or fatty liver
renal failure
hyperlipidemia
lipemia (cloudy plasma or blood)

Question 24

Propofol may be safely administered to patients allergic to

Answer 24

soy, peanuts, and probably egg

Question 25

Most people with egg allergies are allergic to the__________. Egg lecithin found in propofol is derived from

Answer 25

albumin in egg whites; derived from the yolk

Question 26

Risk factors for propofol infusion syndrome include

Answer 26

children receiving high doses (4 mg/kg/hr) over long periods of time (>48 hours) sepsis (inadequate oxygen delivery) continuous catecholamine infusions high-dose steroids significant cerebral injury

Question 27

Treatments for propofol infusion syndrome include

Answer 27

discontinuing propofol and initiating cardiac pacing, PDE inhibitors, and ECMO maximize gas exchange glucagon renal replacement therapy

Question 28

Propofol increases the risk of ______ contamination.

Answer 28

bacterial and fungal

Question 29

What measures should be taken to reduce the risk of bacterial contamination with propofol?

Answer 29

propofol syringes must be discarded within 6 hours infusions (and the tubing) must be discarded within 12 hours

Question 30

_______ to generic propofol preparations can cause complications.

Answer 30

Additives

Question 31

Describe two additives to generic propofol that can lead to complications.

Answer 31

metabisulfite--> bronchospasm in asthmatics benzyl alcohol--> should be avoided in infants

Question 32

Propofol also has the following properties:

Answer 32

antipruritic and antiemetic

Question 33

Pain on injection with propofol is reduced by

Answer 33

lidocaine, opioids and administration through larger and more proximal veins

Question 34

How does propofol cause propofol infusion syndrome?

Answer 34

propofol contains long-chain triglycerides (LCT) and an increased LCT load impairs oxidative phosphorylation and fatty acid metabolism. this starves cells of oxygen particularly in cardiac and skeletal muscle

Question 35

Fospropofol is: a. prepared as a lipid emulsion b. metabolized by alkaline phosphatase c. a prodrug d. associated with pain at the injection site

Answer 35

b. metabolized by alkaline phosphatase c. a prodrug

Question 36

What is the mechanism of action of fospropofol?

Answer 36

GABA-A agonist

Question 37

What is the onset of action of fospropofol?

Answer 37

5-13 minutes (much longer than propofol)

Question 38

What is the duration of action of fospropofol?

Answer 38

15-45 minutes

Question 39

What is the clearance of fospropofol?

Answer 39

liver+ extrahepatic metabolism

Question 40

What is the active metabolite of fospropofol?

Answer 40

propofol (fospropofol is a prodrug)

Question 41

What is the induction of fospropofol?

Answer 41

6.5 mg/kg IV

Question 42

What is the repeat dose of fospropofol?

Answer 42

max 1.6 mg/kg every 4 minutes

Question 43

What are the respiratory effects of fospropofol?

Answer 43

similar to propofol

Question 44

What are the CV effects of fospropofol?

Answer 44

similar to propofol

Question 45

What are the CNS effects of fospropofol?

Answer 45

similar to propofol

Question 46

What are other side effects of fospropofol?

Answer 46

genital and anal burning

Question 47

Advantages of fospropofol over propofol include

Answer 47

prevents burning doesn't support microbial growth in the same way as lipid emulsion (no preservative)