Apex- PONV Flashcards
Which agent pimarily targets the chemoreceptor trigger zone:
A. Odanestron
B. Scopalamine
C. Dexamethasone
D. Hydroxyzine
A. Odansetron
5Ht-3 antagonist - treats PONV by antagonizing serontinin receptors in 2 places:
-CRTZ (area postrema) and peripheral receptors in the GI tract and vagus nerve
Scopalamine - M1 antagonist
Hydroxyzine - H1 antagonist
–> boht primariily target the vestibular apparatus in the inner ear
Dexamethasone binds to intracellular stereoid receptors and it’s exact site of a ction is unknown
Where does the vomitting center reside?
how does it relate to the chemoreceptor trigger zone?
In the Nucleus tractus solitarius of the medulla
(visceral control)
CTZ is in the area postrema of the medulla and is not protected by the BBB , so when expsoed to noxious substances, it sends affarents to the NTS and elicits vomitting
Which dopamine receptors contribute to PONV D1 or D2
D2
but H1 and M1
3 areas that send afferents to the vomitting center (NTS)
- Vestibular apparatus (via CN8)
- CTZ (area postrema)
- GI tract (CN X)
CTZ and GI tract are both densly populated with what 2 receptors
what 2 other receptors does the CTZ have
Serotonin receptors and Substance P (NK-1) receptors
Dopamine and Opiod receptors
The vestibular apparatus is heavily populated with what 3 kinds of receptors
- histamine 1 receptors
- acetylcholine/muscarinic (M1) receptors
- opioid receptors
If somone has a history of motion sickness, what should you be thinking?
Motion sickness = vestibular apparatus = H1 and muscarinic receptors
-incorporate drugs to target that area: benadryl 12.5mg and/or scopalamine patch
Zofran should be administered when
30 mins prior to emergence
T/F: decadron should be administered during induction
true
Which antiemetic has a black box warning for QT prolongation
droperidol
dopamine antagonist
Which antiemetics are contraindicated in pts with parkinsons disease?
dopamine antagonists
Butyrophenones, phenothiazines, and metoclopramide)
can cause extrapyramidal symptoms
(PD= low dopamine, dont wnna block the receptors responding to the little bits they have)
Pt’s undergoing middle ear surgery should have wich antiemetics incorproated into their anesthetic
M1 and HI blockers
scop and benadryl
want to targe the vestibular system
Scopalamine should be applied how long before induction of anesthesia
how long does it last
> 4hrs
72 hrs
Prochlorperazine vs Promethazine
prochlorperazine = compazine = dopamine antagonist
Promethazine = Phenergan = H1 blocker
phenergan = meth
ProCHLOR = COMPazine
Problem with prochlorperazine
compazine
dopamine antagonist
caues significant sedation