intravenous sedation - WATCH LECTURE

Question 1

Ideal features of an iv sedation agent

Answer 1

anxiolytic
sedation
ease of administration
non-irritant
quick onset
quick recovery
no side effects
low cost
amnesia?

Question 2

Benzodiazepines - mechanism of action

Answer 2

Acts on receptors in CNS to enhance effect of GABA
- prolongs time for receptor depolarisation
mimics effects of glycine on receptors

Question 3

What is GABA?

Answer 3

an inhibitory CNS neurotransmitter

Question 3

What is present in all active benzodiazepines and why?

Answer 3

benzene ring
allows attachment to receptors

Question 4

Benzodiazepines - effects on respiratory system

Answer 4

respiratory depression
- CNS depression and muscle relaxation
- decreases cerebral response to carbon dioxide
synergistic relationship with other CNS depressants
= increased respiratory depression in already compromised patients

Question 5

Benzodiazepines - effect on cardiovascular system

Answer 5

Reduced blood pressure by muscle relaxation decreasing vascular resistance
- increased heart rate as baroreceptor reflex compensates for fall in bp

Question 6

Benzodiazepines - side effects

Answer 6

drug interactions
- other CNS depressants
- erythromycin
- antihistamines
tolerance
dependence
sexual fantasies
- important that seditionist is never alone with patient

Question 7

Features of diazepam

Answer 7

first widely used BZD
insoluble in water
preparations:
- organic solvents (propylene glycol = pain on injection)
elimination half life = 43 +/- 13 hours
risk of rebound sedation
long recovery
unpredictable

Question 8

midazolam (hypnovel) features

Answer 8

present gold standard
water soluble at Ph >4
painless on injection