induction agents

Question 1

Is propofol an acid or a base and what is its PKA?

Answer 1

weak acid
11

Question 2

what chemical is propofol derived from?

Answer 2

phenol derivative

Question 3

what is the Vd for propofol?

Answer 3

4L/kg

Question 4

how much protein binding does propofol have?

Answer 4

98%

Question 5

what is the elimination half life of propofol?

Answer 5

5 hours

Question 6

how does propofol work as an anti-emetic?

Answer 6

D2 antagonism

Question 7

at what effector site target conc of propofol will patients be asleep?

Answer 7

2.5-3ug/ml

Question 8

which has more incidence of allergy thiopentone or methohexital?

Answer 8

methohexital

Question 9

which has more tissue damage on intra-arterial injection thiopentone or methohexital ?

Answer 9

thiopental

Question 10

how do Thiopental and pentobarbital compare?

Answer 10

both derived from barituric acid
thiopentone is a sulphur analogue of pentobarbital
pentobarbital has a =0 instead of S

Question 11

how does solubility of thiopental change in different pHs?

Answer 11

The solubility of barbiturates increases on transformation from the keto to enol form, called tautomerism

Question 12

what is barbituric acid derived from?

Answer 12

Barbituric acid is a condensation product of urea and malonic acid.

Question 13

what is the pka of thiopentone? at what pH is it kept in solution?

Answer 13

7.6 - weak acid
pH 10.5 - ionised so soluble

Question 14

in what form is thiopentone soluble?

Answer 14

enol form

Question 15

which has a faster clearance thiopental or methohexital?

Answer 15

methohexital

Question 16

what is the dose of thiopentone and methohexital?

Answer 16

he dose of thiopental for induction is 3-7 mg/kg. Methohexital has an induction dose of 1-2 mg/kg.

Question 17

what is the use of methohexital out of hospital?

Answer 17

ultra short acting

Question 18

does methohexital cause pain on injection?

Answer 18

yes

Question 19

which of the barbiturates cause osteomalacia?

Answer 19

phenobarbital

Question 20

how does thiopentone affect intra occular pressure?

Answer 20

reduces it

Question 21

which induction agents promote bronchospasm/ laryngospasm?

Answer 21

thiopentone

Question 22

how do the induction agents - propofol, thio, ketamine and etomidate effect seizures?

Answer 22

propofol and thio - reduce
ketamine - no effect
etomiidate increases

Question 23

which opioid med induces seizures?

Answer 23

pethidine (a.k.a meperidine)

Question 24

what is the major flaw of etomidate?

Answer 24

Etomidate is known to cause dose dependant adrenal suppression via reversible inhibition of the 11-beta hydroxylase enzyme.

Question 25

does etomidate have analgesics properties or cause thrombophlebitis?

Answer 25

no

Question 26

what chemical is etomidate?

Answer 26

imidazole

Question 27

how many isomers does etomidate have ?

Answer 27

2

Question 28

at physiological pH is etomidate water or lipid soluble?

Answer 28

lipid

Question 29

how does etomidate effect cerebral blood flow and metabolism

Answer 29

reduced ICP, CBF, CMRO2

Question 30

which induction agents precipitate porphyria?

Answer 30

thio ketamine etomidate

Question 31

what type of chemical is ketamine?

Answer 31

phencyclidine derivative

Question 32

what is the size of ketamine?

Answer 32

Its molecular weight is 238, making it relatively small and easier to diffuse across membranes.

Question 33

which receptor does ketamine bind?

Answer 33

NMDA

Question 34

what is the protein binding of ketamine

Answer 34

around 30%

Question 35

what is the elimination half life for ketamine?

Answer 35

2-3 hours

Question 36

can ketamine be derived via TCI?

Answer 36

yes - domino model

Question 37

how does ketamine effect CVS and resp systems?

Answer 37

CVS - tachycardia, increased BP Resp - increased RR, maintains airway reflexes, bronchodilator

Question 38

At what does is ketamine an analgesic?

Answer 38

0.15-0.25mg/kg

Question 39

glycopyrolate can be given with ketamine at induction - why?

Answer 39

ketamine increases secretions

Question 40

what is the IM induction dose of ketamine?

Answer 40

4-10mg/kg

Question 41

which isomer of etomidate is more active?

Answer 41

R

Question 42

which induction agent has lowest incidence of hypersensitivity?

Answer 42

etomidate

Question 43

which form of etomidate reduces pain on injection?

Answer 43

Etomidate-lipuro

Question 44

how does the Sulphur in thiopentone affect its speed of onset?

Answer 44

increases it

Question 45

what is the therapeutic index for thiopentone?

Answer 45

low

Question 46

how is thiopentone prepared?

Answer 46

500 mg thiopental is mixed with 20ml water This produces a 2.5% solution The powder contains 6% anhydrous sodium carbonate The pH of this solution is approximately 10.5 The ampoule contains nitrogen gas