Apex- PONV

Question 1

Which agent pimarily targets the chemoreceptor trigger zone:
A. Odanestron
B. Scopalamine
C. Dexamethasone
D. Hydroxyzine

Answer 1

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

Question 2

Where does the vomitting center reside?

how does it relate to the chemoreceptor trigger zone?

Answer 2

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

Question 3

Which dopamine receptors contribute to PONV D1 or D2

Answer 3

D2

but H1 and M1

Question 4

3 areas that send afferents to the vomitting center (NTS)

Answer 4

1. Vestibular apparatus (via CN8)
2. CTZ (area postrema)
3. GI tract (CN X)

Question 5

CTZ and GI tract are both densly populated with what 2 receptors

what 2 other receptors does the CTZ have

Answer 5

Serotonin receptors and Substance P (NK-1) receptors

Dopamine and Opiod receptors

Question 6

The vestibular apparatus is heavily populated with what 3 kinds of receptors

Answer 6

1. histamine 1 receptors
2. acetylcholine/muscarinic (M1) receptors
3. opioid receptors

Question 7

If somone has a history of motion sickness, what should you be thinking?

Answer 7

Motion sickness = vestibular apparatus = H1 and muscarinic receptors

-incorporate drugs to target that area: benadryl 12.5mg and/or scopalamine patch

Question 8

Zofran should be administered when

Answer 8

30 mins prior to emergence

Question 9

T/F: decadron should be administered during induction

Answer 9

true

Question 10

Which antiemetic has a black box warning for QT prolongation

Answer 10

droperidol

dopamine antagonist

Question 11

Which antiemetics are contraindicated in pts with parkinsons disease?

Answer 11

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)

Question 12

Pt’s undergoing middle ear surgery should have wich antiemetics incorproated into their anesthetic

Answer 12

M1 and HI blockers
scop and benadryl
want to targe the vestibular system

Question 13

Scopalamine should be applied how long before induction of anesthesia

how long does it last

Answer 13

> 4hrs

72 hrs

Question 14

Prochlorperazine vs Promethazine

Answer 14

prochlorperazine = compazine = dopamine antagonist
Promethazine = Phenergan = H1 blocker

phenergan = meth
ProCHLOR = COMPazine

Question 15

Problem with prochlorperazine

Answer 15

compazine
dopamine antagonist
caues significant sedation

Question 16

How much propofol caues an antiemetic effect

Answer 16

10-20mg

Question 17

T/F: midazolam may reduce PONV

Answer 17

true- by decreasing DA activity in the CTZ

Question 18

How would IM Ephedrine reduce PONV?

dose?

Answer 18

by maintaining BP and cerebral perfusion

25mg

Question 19

Where is the P6 accupressure point

Answer 19

3 thingerbredths below the wrist on the inner forearm between the two tendons

Question 20

What are 5 patient risk factors for PONV

Answer 20

1. female
2. non-smoker
3. motion sickness
4. previous PONV
5. young

So just being a young, non-smokking female gives your 3 risk factors - think im falling short on my ponv for these chickies

Question 21

5 surgical risk factors for PONV

3 more specific to peds

Answer 21

1. laproscopic
2. GYN
3. > 1hr
4. breast
5. plastics

strabismus, orchioplexy, T&A

Question 22

What are 5 drugs we give that directly contribute to PONV

Answer 22

1. halogenated agents
2. nitrous > 50%
3. opioids
4. etomidate
5. neostigmine