IV sedation Flashcards
What would you look for in an ideal IV sedation agent
anxiolysis
sedation
ease of use
Non-irritant
Quick onset
Quick recovery
No side effects
Low cost
What is Benzodiazepines method of action
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
GABA = cerebral cortex and motor circuits
GABA = inhibitory CNS neurotransmitter
Glycine = brainstem and spinal cord
All active BZD’s have benzene ring allowing attachment to receptors
What are the effects of BZD,s
Respiratory Depression
-CNS depression and muscle relaxation
-Decreases cerebral response to increase CO2
-Synergistic relationship with other CNS depressants
-Increases respiratory depression in already compromised patients
Cardiovascular
-Decrease BP by muscle relaxation decreasing vascular resistance
-Increase HR due baroreceptor reflex compensating for BP fall
What Drugs does BZD interact with
Any other CNS depressant
Erythromycin
Antihistamines
How long can you prescribe BZDs for
2 weeks
Whats the gold standard of BZD’s
Midazolam
Is Midazolam water soluble
Yes
If a BZD is water soluble what does that mean
Its painless on injection
What is the prep of Midazolam
5mg/5ml
pH 3.5
More rapid onset and 2-3 times more potent than diazepam
What is the elimination half life of Midazolam and where is it metabolised
Elimination half life = 90 - 150 mins
Metabolised in liver but also Extra-hepatic metabolism in bowel so less affected by liver disease than some
What cannulation is mandatory
In-dwelling cannula and may be needed for emergency
BUTTERFLY cannula not recommended
Where are the cannulation sites and why
Dorsum of hand
-accessible
-superficial and visible
-poorly tethered
Antecubital fossa
-brachial artery and median nerve
-keep lateral
-second choice
Whats essential doing sedation
High volume aspiration
Monitoring
-Pulse oximeter
-Non invasive BP measurements every 5-10 mins
-Acts as early warning system
-Allow intervention before emergency develops
What is the emergency reversal agent
Flumazenil
When administering drug what important
Give a 2mg bolus and observe for 1min to see how they respond before you give more and then give 1mg increments every 60s, don’t exceed 7.5mg
What can you check to test sedation
Eves sign loss of motor cordination
Check for Verrills sign ptosis
Slurring and slowing of speech
Relaxed
Delayed response to commands
Willingness to accept treatment
How long does sedation normally last
30-45 minutes of useful sedation
If there is respiratory depression what do you do
Talk, shake, hurt
head tilt, chin lift, jaw thrust
O2 (2l/min via nasal cannuae)
O2 (5l/min via hudson mask)
Flumazenil
Ambu bag
Check airways
What is the preperation of Flumazenil
500mg in fml
dose is 200mg then 100mg increments every 60s until response is given
