IV sedation Flashcards
1
Q
ideal IV sedation agent properties
A
- Anxiolysis
- Sedation (side effect)
- Ease of administration
- Non-irritant
- Quick onset
- Quick recovery
- No harmful side effects
- Amnesia (side effect)
- Low cost
2
Q
action of benzodiazepines
A
- Acts on receptors in CNS to enhance effect of GABA (gamma-amino butyric acid)
- Prolongs time for receptor repolarisation
- Mimics effects of glycine on receptors
3
Q
GABA
A
- cerebral cortex and motor circuits
- inhibitory CNS neurotransmitter
4
Q
glycine
A
- brainstem and spinal cord
- inhibitory CNS neurotransmitter
5
Q
3 main effects of benzodiazepines
A
Respiratory depression careful with resp disease pt
- CNS depression and muscle relaxation
- Decreases cerebral response to increase CO2
- Primary drives breathing
- Synergistic relationship with other CNS depressants
- Enhance their effects
- increase respiratory depression in already compromised patients
Cardiovascular
- decrease BP by muscle relaxation decreasing vascular resistance
- increase HR due baroreceptor reflex compensating for BP fall
6
Q
4 side effects of benzodiazepines
A
- Drug Interactions
- Any other CNS depressants
- Erythromycin
- Antihistamines
- Tolerance
- Dependence
- Sexual fantasies
- Males and females
- inc dose = inc chances
- Usually opposite sex
- Very important that seditionist is never alone with patient –always need a second person present
7
Q
first widely used BZD
A
diazepam
8
Q
properties of diazepam
A
- Insoluble in water
- Preparations
- Organic solvents (propylene glycol), 5mg/ml, - Valiumâ
- Propylene glycol = pain on injection
- Emulsified in soya bean oil 5mg/ml, - Diazemulsâ
- Organic solvents (propylene glycol), 5mg/ml, - Valiumâ
- Elimination half life = 43 +/-13 hrs long
- Redistribution (alpha) half life = 40 mins
- Metabolites
- Desmethyldiazepam = 73hrs
- Oxazepam = 7hrs
- Risk of rebound sedation
- Dose =0.1-0.2mg/kg
- Long recovery
- Unpredictable
9
Q
current BZD
A
midazolam
10
Q
properties of midazolam
A
- Hyponovel
- Water soluble imidazobenzodiazepine
- water soluble at pH < 4.0
- Lipid soluble at physiologic pH allowing crossing of BBB.
- Painless on injection
- One preparation 5mg/ml
- pH=3.5
- more rapid onset and 2-3 times more potent than diazepam
- elimination half life = 90-150mins
- less working time but safer for pt
- metabolised in liver
- extra-hepatic metabolism in bowel so less affected by liver disease than some
11
Q
midazolam vs diazepam
A
- Painless
- Quicker onset
- Quicker recovery
- More reliable
12
Q
the sedation team
A
- Operator-sedationist
- Second sedation trained person eg dental nurse
- Neither of these people can leave the surgery while patient sedated
- Must also have someone else in the practice for reception and as a runner
- If using separate recovery area must have nurse and patient’s escort present at all times
- All must have appropriate sedation training
- Must be able to manage sedation related complication and emergencies
- Annual ILS training and sedation scenario training
13
Q
cannulation
A
in-dwelling Cannula used (not butterfly)
- More secure
- Teflon
- Rarely blocks
- Blue – pink – green- etc
14
Q
2 cannulation sites
A
dorsum of hand
antecubital fossa
15
Q
dorsum of hand as a cannulation site
A
- Accessible e.g. when clothed
- superficial and visible
- poorly tethered
- affected by peripheral vasoconstriction so may need to warm up hand
16
Q
antecubital fossa as a cannulation site
A
- brachial artery and median nerve
- Keep lateral
- Second choice
- Less stable – immobilisation of joint
