IV sedation Flashcards
main aim of IV sedation
anxiolysis
GABA
most common inhibitory neurotransmitter in the CNS
lessens ability for nerve cells to recieve, create or send chemical messages to other nerve cells
does this by prolonging time for receptor polarisation
glycine
inhibitory neurotransmitter acting in brain and spinal cord
cardiovascular effects of benzodiazepines on the body
decreased BP by muscle relaxation causing decreased TPR
increased HR due to baroreceptor reflex compensating for BP fall
respiratory effects of benzodiazepines on the body
CNS depressant and muscle relaxant
decreased cerebral response to CO2 the primary driver of breathing
name 3 side effects that may be experienced with benzodiazepines
amnesia
drowsiness
unsteadiness
name 2 drugs benzodiazepines may interact with
antihistamines
antipsychotics
antidepressants
why is diazepam painful upon injection
insoluble in water so prepared with propylene glycol whihc is painful upon injection
why is midazolam preferred to diazepam
painless to inject
faster onset
quicker recovery time
why should canula remain in place throughout treatment
in case emergency drug is required
why should butterfly cannulas be avoided
made of metal which increases risk of clotting, they are also easily dislodged
what material should a cannula ideally be made from to minimise risk of blockage
teflon
how many staff members must be present at a practice to carry out sedation
minimum of 3
2 sedation trained who must be with patient at all times throughout treatment
1 other for runner and emergencies
what monitoring of the patient should be done throughout the duration of treatment
pulse oximeter
blood pressure
signs that adequate IV sedation has been reached
slurring and slowing of speech,
relaxed,
delayed response to commands,
willingness to accept treatment,
eves sign (loss of motor control)
Eves sign
loss of motor control
ask patient to close eyes and put arms out to side then touch nose - sedated patient will miss
working time of midazolam
roughly 45 mins
how long should a patient be kept for after the last increment of midazolam has been given
at least 60 minutes after last increment of drug given
what should be done if someone experiences respiratory depression
stop procedure
talk and shake patient
head tilt, chin lift, jaw thrust to open airway
check if chest rising and falling
if O2 sats dont improve nasal cannula with O2 2l/ min
still no improvement then hudson mask 5l/min
if no improvement flumazenil reversible agent
what dose does flumazenil come in
500mcg per 5ml
what doses should flumazenil be given in
200mcg initial dose then 100mcg increments every 60s until response seen
why is there a potential risk of re sedation by midazolam even after flumazenil given
flumazenil has a shorter half life than midazolam
can midazolam cross the blood brain barrier
yes midazolam becomes lipid soluble at physiologic pH so able to cross BBB
where is midazolam metabolised
mainly liver but some extra hepatic metabolism in bowel
if cannulating in dorsum of hand, name 3 veins that could be cannulated
cephalic
basilic
metacarpal
dorsal venous arch
dose incremements of midazolam
2mg initial bolus and assess after 1 min
then 1mg increments every 60s until desired effect achieved
(very rarely go above 7.5mg)
name 3 things that may impact the therapeutic dose of midazolam required
stress
drugs
alcohol
sleep
