6 - Intravenous sedation Flashcards
What is the action of benzodiazepines?
- act on receptors in CNS to enhance the effect of GABA (inhibitory neurotransmitter)
- mimics the effects of glycine
What effect do benzodiazepines have on respiratory depression?
- CNS depression and muscle relaxation
- decreases cerebral reposes to increased levels of CO2
- synergistic effects with other respiratory depressants (increased respiratory depression in already compromised patients)
What effect do benzodiazepines have on the cardiovascular system?
- decreased BP caused by muscle relaxation decreasing vascular resistance
- increased heart rate due to baroreceptor reflex to low BP
What drug interactions are common with benzodiazepines?
- CNS depressants
- erythromycin
- antihistamines
What is the brand name of midazolam commonly used?
Hypnovel
What is the elimination half life of midazolam?
90-150 mins
Where is midazolam metabolised?
Liver
What staff are required in intravenous sedation?
- operator
- sedation trained nurse
- a runner/receptionist available as above persons cannot leave the room
Describe the dorsum of the hand as a cannulation site.
- accessible
- superficial and visible
- poorly tethered
- affected by peripheral vasoconstriction when cold
What are the two cannulation sites used in dentistry?
- dorsum of the hand
- antecubital fossa
What increments do you use to administer midazolam?
- initial bolus 2mg
- 1mg increments every minute
What are the signs that adequate sedation has been achieved?
- slurring and slowing of speech
- relaxed
- delayed response to commands
- willingness to accept treatment
- ptosis (droopy eyes)
- loss of motor coordination
What is Verrill’s sign?
Ptosis
What is Eve’s sign?
- loss of motor coordination
- unable to touch nose with eyes closed
How long is the window of useable working time?
30-45 mins
When can patient be allowed to leave post-op?
- 60 mins after last increment
- ensure they can walk unaided
What are the stages of managing respiratory depression involving intravenous sedation?
- ask patient to take a deep breath
- talk, shake, hurt
- head tilt, chin lift, jaw thrust
- oxygen via nasal cannulae at 2l/min
- oxygen via Hudson mask at 5l/min
- flumazenil
- ambu bag
- airways
What is the preparation of flumazenil?
500mcg in 5ml
What dose of flumazenil do you administer?
- 200mcg initial bolus
- 100mcg increments every 60s until response seen
Why is there a risk of sedation rebound after flumazenil in given?
Shorter half life than midazolam (50mins)
What is the preparation of midazolam?
5mg in 5ml
