PONV (Exam III) Flashcards

1
Q

When does nausea peak in patients post-operatively?
How long does nausea/vomiting typically last post operatively?

A

Peak: 6 hours
Persists for 24 - 48 hours

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2
Q

What are the four major inherent (patient-specific) risk factors for PONV?

A
  • Female
  • Non-smoker
  • PONV history
  • History of motion sickness

Opioid use not an inherent risk factor.

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3
Q

What factor is the greatest cause of PONV?

A

Intraoperative and postoperative opioids.

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4
Q

What is the full list of anesthetic-technique risk factors for PONV? 7 (4+3)

A
  • VAA’s
  • Nitrous > 50%
  • Opioids
  • Neostigmine
  • Gastric distention
  • Anesthesia duration
  • Forced PO fluids prior to discharge
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5
Q

What surgeries place a patient at higher risk for development of PONV?

A
  • ENT surgeries
  • Neuro surgeries
  • Belly surgeries
  • Breast, plastic, strabismus surgery (girly sx’s)
  • Long surgeries
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6
Q

Pediatric PONV incidence increases with age until _______.

A

puberty

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7
Q

Which pediatric procedures are noted to have a higher incidence of PONV? 5

A
  • Adenotonsillectomy
  • Strabismus repair
  • Hernia repair
  • Orchiopexy
  • Penile surgeries
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8
Q

Will increased O₂ concentrations increase or decrease PONV occurrence?

A

decrease

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9
Q

Will adequate hydration increase or decrease PONV occurrence?

A

decrease

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10
Q

Will nitrous use increase or decrease PONV occurrence?

A

increase

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11
Q

Will neuromuscular blockade reversal with acetylcholinesterase inhibitors increase or decrease PONV occurrence?

A

Increase

↑ neostigmine = ↑ PONV

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12
Q

Will minimized motion/ambulation increase or decrease PONV occurrence?

A

decrease

Let patient guide movement based on how they feel.

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13
Q

Where is the emetic center of the brain located?

A

Lateral reticular formation of the brainstem

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14
Q

Which substances act directly on receptors of the lateral reticular formation of the brainstem?

A

Trick Question. No substances act directly on the emetic center.

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15
Q

Where does afferent input originate (prior to arrival at the emetic center)? 5

A
  • Pharynx
  • GI tract
  • Mediastinum
  • Afferent nerves of CTZ and 8th CN
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16
Q

Where does CNS afferent input to the emetic zone come from?

A
  • Chemotactic Zone (CTZ) of the area postrema
  • Vestibular portion of Vestibulocochlear nerve (CN VIII)
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17
Q

The CTZ of the area postrema does not have the ______.
What are the implications of this?

A

Blood brain barrier (BBB)

No BBB means chemicals and drugs in the blood or CSF can trigger N/V.

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18
Q

What receptors are located in the Chemoreceptor Trigger Zone?

A
  • Dopamine
  • Serotonin 5-HT3
  • Opioid
  • Histamine
  • Muscarinic
  • Neurokinin-1
  • Cannabinoid
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19
Q

What drug is the gold standard for PONV prophylaxis and treatment?

A

Trick question. No single drug is gold standard.

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20
Q

Patients (should / should not) receive the same drug for prophylaxis and treatment of PONV.

A

Should not.

Ex. If ondansetron is used for prophylaxis, use promethazine for treatment

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21
Q

When it comes to anti-emetics more is _______ (better, or worse.)

A

Better

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22
Q

Opioid premedication will ______ risk of PONV.
Benzodiazepine premedication may ______ risk of PONV.

A

Increase

Decrease

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23
Q

What induction drug(s) increase risk of PONV?

A
  • VAA’s
  • Etomidate
  • Ketamine
24
Q

What induction drug(s) decrease risk of PONV?

A

Propofol

25
Q

What volatile agent is associated with PONV (especially in concentrations greater than 50%)?

A

Nitrous Oxide

26
Q

One single dose of an opioid is not enough to cause PONV. T/F?

A

False. A single dose can cause PONV.

27
Q

Greater than ____mg of Neostigmine is associated with increased PONV risk.

A

> 2.5mg

Dose dependent: ↑ neostigmine = ↑ PONV.

28
Q

What drug could reduce the PONV associated with neostigmine?

A

Atropine

29
Q

What is the mechanism of action of PONV induced by neostigmine?

A

Though to be muscarinic actions on the GI tract

30
Q

At how many risk factors is PONV prophylaxis indicated?

A
31
Q

What is P-6 stimulation?

A

Radial compression

32
Q

How is P-6 manipulation thought to treat PONV?

A

P-6 compression → Hypophyseal secretion of β-endorphins → inhibition of CTZ.

33
Q

Is P-6 manipulation good at treating nausea and vomiting?

A

No really, better at inhibition.

34
Q

What are the subtypes of anti-dopaminergics that are used to treat PONV?

A
  • Butyrophenones
  • Phenothiazines
35
Q

What are the side effects of dopamine receptor antagonists?

A
  • Drowsiness/sedation
  • Extrapyramidal s/s
36
Q

What drugs are butyrophenones?

A

Haloperidol
Droperidol

37
Q

What black box warning exists for Droperidol?

A

Torsades de Pointes and sudden death.

38
Q

More than ______mg of droperidol should never be given.

A

0.625mg

39
Q

Droperidol is as effective as ___________ for treatment of PONV.

A

Ondansetron 4mg

40
Q

Droperidol also has effects as a ______________ thus resulting in hypotension.

A

weak α blocker

41
Q

What drugs are phenothiazines?

A

Prochlorperazine
Chlorpromazine
Promethazine

42
Q

What black box warnings are there for promethazine?

A
  • Tissue damage
  • Resp arrest for < 2yo’s
43
Q

What receptors does promethazine act on?

A
  • Anti-dopamine
  • Anti-histamine
  • α adrenergic
  • muscarinic
44
Q

What are known side effects of promethazine?

A
  • Sedation
  • Hypotension
  • EPS
45
Q

How do 5HT3 Antagonists work in the treatment of nausea/vomiting?

A

Antagonize serotonin receptors on the vagal nerve and CTZ

46
Q

Chronic use of 5HT3 antagonists can result in mild elevation of what?

A

Liver enzymes

47
Q

When should ondansetron be given?

A

4mg within 15 - 20 min of surgery end.

48
Q

What anticholinergic is given for PONV prophylaxis?
What dose and route is utilized?

Non-Neostigmine adjunct…

A

Scopolamine 1.5mg transdermal patch

49
Q

What is the PONV rescue dose of dexamethasone?

A

Trick question. Dexamethasone should be used for prophylaxis only.

50
Q

When is dexamethasone given and what dosage is utilized?

A

Given during or immediately after induction. 4mg (just as effective as 8mg)

51
Q

How does metoclopramide combat PONV? Dose/Route

A

Increases LES tone and GI motility.

Not very efficacious. 10 - 20mg IV

52
Q

What NK-1 antagonist is given for PONV? How does it work? 3

A

Aprepitant:

  • antagonizes substance P in the emetic center.
  • Depresses NTS activity
  • Blocks afferent messages from enterochromaffin cells
53
Q

What is the aprepitant dose?

A

40mg or 125mg

54
Q

How does propofol prevent/treat PONV? 2

A

Blocks serotonin release in subhypnotic doses.

May also inhibit CTR.

55
Q

What is the subhypnotic dose of propofol?

A

16.7 mcg/kg/min

56
Q

What drug needs to be given alongside propofol?

A

Glycopyrrolate (to counteract bradycardia)

57
Q

______ ______ has been associated with a 50% reduction in nausea.

A

Isopropyl alcohol