IV sedation

Question 1

ideal IV sedation agent properties

Answer 1

• Anxiolysis
• Sedation (side effect)
• Ease of administration
• Non-irritant
• Quick onset
• Quick recovery
• No harmful side effects
• Amnesia (side effect)
• Low cost

Question 2

action of benzodiazepines

Answer 2

• 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

Question 3

GABA

Answer 3

• cerebral cortex and motor circuits
• inhibitory CNS neurotransmitter

Question 4

glycine

Answer 4

• brainstem and spinal cord
• inhibitory CNS neurotransmitter

Question 5

3 main effects of benzodiazepines

Answer 5

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

Question 6

4 side effects of benzodiazepines

Answer 6

• 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

Question 7

first widely used BZD

Answer 7

diazepam

Question 8

properties of diazepam

Answer 8

• Insoluble in water
• Preparations
  
  • Organic solvents (propylene glycol), 5mg/ml, - Valiumâ
    
    • Propylene glycol = pain on injection
  • Emulsified in soya bean oil 5mg/ml, - Diazemulsâ
• 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

Question 9

current BZD

Answer 9

midazolam

Question 10

properties of midazolam

Answer 10

• 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

Question 11

midazolam vs diazepam

Answer 11

• Painless
• Quicker onset
• Quicker recovery
• More reliable

Question 12

the sedation team

Answer 12

• 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

Question 13

cannulation

Answer 13

in-dwelling Cannula used (not butterfly)

• More secure
• Teflon
• Rarely blocks
• Blue – pink – green- etc

Question 14

2 cannulation sites

Answer 14

dorsum of hand

antecubital fossa

Question 15

dorsum of hand as a cannulation site

Answer 15

• Accessible e.g. when clothed
• superficial and visible
• poorly tethered
• affected by peripheral vasoconstriction so may need to warm up hand

Question 16

antecubital fossa as a cannulation site

Answer 16

• brachial artery and median nerve
• Keep lateral
• Second choice
• Less stable – immobilisation of joint

Question 17

before cannulation appt ensure

Answer 17

• Assessment – should have been done on separate day
• Staff
  
  • Training
  • Second competent person
• Surgery / Recovery
  
  • Access for escort and emergencies

Question 18

on day of cannulation appt

but prior to cannulation

Answer 18

• Pre-op pulse and blood pressure
• Escort-must stay in the building
  
  • Travel arrangements for home
  • Responsibilities
• Consent
  
  • mandatory at separate visit but reconfirmed on the day
• High volume aspiration
• Monitoring- ‘to warn’
  
  • Staff assume responsibility for monitoring measurements every 5 mins
    
    • Pulse oximeter
    • NIBP
  • Acts as early warning system
    
    • Allow intervention before emergency develops
    • Minimise risk
• Emergency (revise management of medical emergencies)
  
  • Flumazenil
  • Means of ventilation

Question 19

cannulation procedure

Answer 19

• Correct place
  
  • Flush with saline to check
• Secure with elatoplast

Pulse oximeter and BP monitoring

• Drug administration - Midazolam
  
  • 2mg bolus
  • 1mg increments every 60 seconds
• INCREMENTS
  
  • Until suitable level of sedation

Question 20

end point for IV Sedation signs

Answer 20

• Slurring and slowing of speech
• Relaxed
• Delayed response to commands
• Willingness to accept treatment
• Verrill’s sign-ptosis (eyes drooping)
• Eve’s sign-loss of motor coordination.
  
  • Ask pt to try touch their nose with a finger on non-cannulated hand, often miss at end point

Shouldn’t lose verbal communication

Question 21

midazolam dose for IV sedation

Answer 21

Therapeutic dose varies

• sleep
• alcohol
• stress
• drugs

Maximum 7.5mg generally recommended-most people fine with a lot less

Approximately 30-45 minutes useful sedation

Question 22

IV sedation recovery

Answer 22

• Escort can be with patient at this stage and can be the second person
• 60 minutes after last increment – recording will indicate
• Cannula-needs to be removed before leaving
• Ensure patient can walk unaided
• Escort given post op instructions

Question 23

emegencies with IV sedation

Answer 23

all general medical emegencies

esp respiratory depression

Question 24

how to hand respiratory depression during IV sedation

Answer 24

• Talk and shake
• Head tilt, chin lift, jaw thrust
• Encourage them to take deep breathes
• O2 (2l/min via nasal cannulae)
• O2 (5l/min via Hudson mask)
• Flumazenil not given often
• Ambu bag
• Airways

Question 25

reverse drug for midazolam

Answer 25

flumazenil

Question 26

flumazenil

Answer 26

* Preparation * 500mcg in 5ml (micrograms) * Dose * 200mcg then 100mcg increments every 60s until a response is seen * Shorter half life than midazolam – 50mins * Risks of re-sedation * Keep pt for longer * is also a BZD

Question 27

overview of sedation procedure

Answer 27

* name and tx on white board * draw up drugs before – gloves, kidney bowls, notes expiry and batch, label syringes (NaOCl/saline, Midazolam) ensure air bubbles removed from syringe * BP * strap on forearm and tap hand and get pt to make fist to try and get vein visible * flush with water first then secure and add HR monitor to finger * record amount given * continually monitor – oxygen sat, resp rat, BP and HR made every 5 mins * wheelchair move them to recovery – keep cannula in

Question 28

what to do if pt oxygen saturation and arterial levels drop

Answer 28

tilt head nose cannula/piece with oxygen 3l/min