Apex- PONV Flashcards

1
Q

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

A

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

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2
Q

Where does the vomitting center reside?

how does it relate to the chemoreceptor trigger zone?

A

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

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3
Q

Which dopamine receptors contribute to PONV D1 or D2

A

D2

but H1 and M1

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4
Q

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

A
  1. Vestibular apparatus (via CN8)
  2. CTZ (area postrema)
  3. GI tract (CN X)
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5
Q

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

what 2 other receptors does the CTZ have

A

Serotonin receptors and Substance P (NK-1) receptors

Dopamine and Opiod receptors

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6
Q

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

A
  1. histamine 1 receptors
  2. acetylcholine/muscarinic (M1) receptors
  3. opioid receptors
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7
Q

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

A

Motion sickness = vestibular apparatus = H1 and muscarinic receptors

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

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8
Q

Zofran should be administered when

A

30 mins prior to emergence

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9
Q

T/F: decadron should be administered during induction

A

true

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10
Q

Which antiemetic has a black box warning for QT prolongation

A

droperidol

dopamine antagonist

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11
Q

Which antiemetics are contraindicated in pts with parkinsons disease?

A

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)

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12
Q

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

A

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

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13
Q

Scopalamine should be applied how long before induction of anesthesia

how long does it last

A

> 4hrs

72 hrs

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14
Q

Prochlorperazine vs Promethazine

A

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

phenergan = meth
ProCHLOR = COMPazine

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15
Q

Problem with prochlorperazine

A

compazine
dopamine antagonist
caues significant sedation

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16
Q

How much propofol caues an antiemetic effect

A

10-20mg

17
Q

T/F: midazolam may reduce PONV

A

true- by decreasing DA activity in the CTZ

18
Q

How would IM Ephedrine reduce PONV?

dose?

A

by maintaining BP and cerebral perfusion

25mg

19
Q

Where is the P6 accupressure point

A

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

20
Q

What are 5 patient risk factors for PONV

A
  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

21
Q

5 surgical risk factors for PONV

3 more specific to peds

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

strabismus, orchioplexy, T&A

22
Q

What are 5 drugs we give that directly contribute to PONV

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