intravenous sedation

Question 1

Name 4 ideal properties of an IV sedation agent

Answer 1

Any from:
- anxiolytic
- sedative as a side effect
- easy to administer
- non-irritant
- has a quick onset
- has a quick recovery
- low cost

Question 2

Describe the effects of benzodiazepines on the nervous system

Answer 2

Act on receptors in the CNS to enhance the effect of GABA
This prolongs the time for receptor repolarisation
They mimic the effect of glycine on the receptors

Question 3

In which ways can benzodiazepines cause respiratory depression?

Answer 3

• CNS depression and muscle relaxation
• Decreased cerebral response to CO2
• Synergistic relationship with other CNS depressants
• Causes further respiratory depression in already compromised patients

Question 4

What are the cardiovascular effects of benzodiazepines?

Answer 4

• Decreased BP by muscle relaxation which decreases vascular resistance
• Increased HR due to baroreceptor reflex compensatin for BP fall

Question 5

Name 4 drug interactions with benzodiazepines

Answer 5

Any other CNS depressant eg - opioids
Erythromycin
Antihistamines
Alcohol

Question 6

Name 3 other side effects of benzodiazepines

Answer 6

Tolerance
Dependance
Sexual fantasy

Question 7

Name 4 disadvantages of diazepam as a sedative

Answer 7

Any from:
- pain on injection
- long elimination half life
- risk of rebound sedation
- long recovery
- unpredictable

Question 8

What is the dose, and pH of midazolam used for sedation?

Answer 8

5mg/ml
pH 3.5

Question 9

What is the onset and elimination half life of midazolam?

Answer 9

Rapid onset
90-150 minutes

Question 10

Name 4 people involved in the sedation team?

Answer 10

Operator/sedationist
Second sedation trained person eg - dental nurse
Someone else in the practice for reception and as a runner
Patients escort present

Question 11

What are the different cannulation sites for IV sedation?

Answer 11

Dorsum of hand
Antecubital fossa

Question 12

What are the advantages of using the dorsum of the hand for a cannulation site?

Answer 12

Accessible
Superficial and visible

Question 13

What are the drawbacks of using the dorsum of the hand for a cannulation site?

Answer 13

Poorly tethered
Affected by peripheral vasoconstriction so may need to warm up hand

Question 14

How much midazolam is administered at a time?

Answer 14

2mg bolus, then 1mg increments every 60 seconds until suitable level of sedation

Question 15

Give 4 ways you can tell if a sedated patient is ready to start treatment?

Answer 15

Any from:
- they are willing to start treatment
- relaxed
- delayed response to commands
- slurring and slowing of speech
- Verrill’s sign of ptosis
- Eve’s sign - loss of motor coordination

Question 16

What is the maximum dose of midazolam generally recommended?

Answer 16

7.5mg

Question 17

How long is a patient likely to be sedated for with midazolam?

Answer 17

30-45 minutes

Question 18

What are the recovery steps after IV sedation?

Answer 18

Escort can be with the patient
60 minutes after last increment of midazolam
Cannula needs to be removed before leaving
Ensure patient can walk unaided
Escort given post operative instructions

Question 19

What should you do if the patient goes into respiratory depression during IV sedation

Answer 19

Talk to the patient and shake them
Head tilt, chin lift, jaw thrust
Oxygen 2L per minute via nasal cannulae
Oxygen, max you can give vis Hudson mask
Flumazenil
Call and ambulance

Question 20

What is the dose of flumazenil and how much is given?

Answer 20

500mcg in 5ml
Dose given is 200mcg (2ml) then 100mcg (1ml) every 60 seconds until a response is seen

Question 21

What is the risk of flumazenil?

Answer 21

Re-sedation

Question 22

What is the elimination half life of flumazenil?

Answer 22

50 minutes