PONV Flashcards

1
Q

When does PONV peak PONV and persist

A

Peaks 6 hours postop
Persists 24-48 hours

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2
Q

Risk Factors for Adults PONV: Patient Specific (6)

A

*Female
*Non-smokers
*History of PONV
*History of motion sickness
Delayed gastric emptying
Preoperative anxiety

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3
Q

Risk factors for Adults PONV: Anesthesia/PACU (8)

A

Volatiles
Nitrous oxide >50%
*Intra/Postop opioids
Neostigmine
Preanesthetic medication
Gastric distention
Duration of anesthesia
Mandatory po fluids before discharge

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4
Q

Risk Factors for Adults PONV: Surgical Factors

A

Longer duration of surgery

High-risk surgery;

Laparoscopy
Ear, nose, throat surgery
Neurosurgery
Laparotomy
Breast, strabismus, or plastic surgery

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5
Q

Risk factors for peds PONV

A

Increases with age until puberty
Male = female
Vomiting 2x adults
Specific pediatric procedures;
-Adenotonsillectomy
-Strabismus repair
-Hernia repair
-Orchiopexy
-Penile surgery

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6
Q

Strategies to reduce risk of PONV

A

Regional anesthesia

Propofol for induction and maintenance

Intraoperative supplemental O2

Adequate hydration

Avoid nitrous

Avoid volatiles

Minimize opioids

Minimize neostigmine

Minimize mandatory motion and early ambulation

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7
Q

Emetic Center location

A

Located in lateral reticular formation of brainstem

No substances act directly on the emetic center

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8
Q

Incoming stimuli to the emetic center come from where? (4)

A

(afferent input)
Pharynx
GI tract
Mediastinum
Afferent nerves from higher brain centers

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9
Q

Afferent nerves from higher brain centers that cause PONV (2)

A

CTZ (chemotrigger tactic zone) from area postrema

Vestibular portion of 8th CN (auditory nerve-> inbalance)

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10
Q

Chemoreceptor Trigger Zone features and receptors

A

Has no BBB
Chemicals, drugs in blood or CSF can trigger

Receptors;
Dopamine
Serotonin (5-HT3)
Opioid
Histamine
Muscarinic
Neurokinin-1?
Cannabinoid?

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11
Q

Data on management of PONV

A

No single drug is gold standard

Patients should not receive the same drug for prophylaxis and treatment

Work on identifying and preventing as treating is +/- effective

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12
Q

Preoperative Prevention of PONV

A

Opioid premedication ↑ risk
BZD may ↓

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13
Q

Induction prevention of PONV

A

Volatiles, ketamine, etomidate ↑ risk

Propofol ↓…short duration; better if used induction and maintainence

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14
Q

nitrous and PONV

A

Associated with PONV
50% and greater

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15
Q

Opioid avoidance and PONV

A

Single dose of morphine associated with…
Regional nerve blocks, high dose acetaminophen, wound infiltration

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16
Q

Nursing protocols for PONV

A

Forcing position changes
Forcing ambulation/early po fluids

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17
Q

Reversal of NMBD and PONV

A

Anticholinesterases: muscarinic actions on GI

Dose related (> 2.5mg of neostigmine-> PONV)

Atropine reduces PONV (give instead of robinol w/ neostigmine)

Give NMBD that aren’t reversed

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18
Q

Apfel score

A

Predictors: female, hx, postop opioids, nonsmoker
Identified high risk procedures: breast, dental, ENT, lap BTL

0 risk factors: 10%
1 risk factor: 20%
2 risk factors: 39% *** prophylaxis indicated
3 risk factors: 60 %
4 risk factors: 79%

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19
Q

Low risk surgery with Low risk of medical sequela treatment for PONV

A

5Ht3 antagonsit

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20
Q

Low risk of PONV with High risk of medical sequela PONV prevention and treatment

A

Prophylaxis; 5HT3

treatment; phenothiazine
antihistamine
metroclopramide

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21
Q

Moderate risk for PONV and any risk of medical sequela Prevention and treatment of PONV

A

Prophylaxis; 5HT3 & Steroid

Treatment; Phenothiazine, antihistamine, metroclopramide

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22
Q

History of PONV with any risk of medical sequela PONV prevention and treatment

A

Prophylaxis; 5HT3, steroid, Propofol TIVA, Scop

Treatment; Phenothiazine, antihistamine, metroclopramide

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23
Q

Acupuncture and Acupressure MOA

A

P 6 stimulation

Results in hypophyseal secretion of beta-endorphins -> And subsequent inhibition of CTZ

Decreases acid secretion

Better at inhibiting nausea than vomiting

24
Q

Anti-dopaminergics Subtypes

A

Butyrophenones
Phenothiazines

25
Anti-dopaminergics MOA
Receptor antagonists are anti-emetic Also antipsychotic and neuroleptic
26
Anti-dopaminergics Side effects
Can cause drowsiness, sedation, EPS effects
27
Butyrophenones drugs
Haloperidol Droperidol
28
Haloperidol PONV characteristics
Not really approved for PONV Not approved for IV use
29
Droperidol (inapsine) PONV characteristics/ dose/ side effects and adjuncts
never > 0.625 mg As effective as Ondansetron 4mg With metoclopramide 10mg more effective Weak alpha blocker...hypotension Black box: torsades de pointes and sudden death
30
Phenothiazines Drugs
Prochlorperazine (Compazine) Chlorpromazine (thorazine) Promethazine (Phenergan)
31
Torsades characteristics
type of polymorphic v tach (coming from different places) -> qrs is different (up and down) Qt is long and being twisted around the horizontal axis
32
Polymorphic v tach from MI treatment
Lidocaine procaindamide
33
Torsades treatment
Isoproterenol (speed up atrial rate and over drive the qrs) Magnesium
34
Promethazine PONV characteristics/ dose/ side effects
Also antagonizes alpha adrenergic, histamine, muscarinic cholinergic receptors Sedation, hypotension, EPS 12.5-25 mg Black box: tissue damage; respiratory arrest < 2 y/0
35
5HT3 antagonists MOA
Antagonize serotonin On vagal nerve and CTZ
36
Side effects of 5HT3 antagonists
Side effects HA, constipation, mild elevation in liver enzymes
37
Examples of 5HT3
Dolasetron (Anzemet) Granisetron (Kytril) Ondansetron (Zofran) Palonosetron
38
Ondansetron (zofran) dose
4mg within 15-20 of surgery end; data unclear on 4mg vs. 8mg
39
Scopalamine dose and placement
1.5 mg transdermal patch; leave in place 48-72 hours placement; upper chest, upper outer arm, lower abdomen, hip
40
Scopolamine MOA
blocks ach
41
Scopolamine SE
Causes drowsiness, dry mouth, dizziness Care with handling
42
Dexamethasone on PONV and dose
Decrease postop pain and edema Anti-inflammatory reaction No adverse side effects Not useful for rescue Glycemic effect? Dose: 4mg as effective as 8mg Given during/just after induction
43
Gastrokinetics drugs
Metoclopromide (Reglan)
44
Metoclopromide (Reglan) effect
Increases LES tone and GI motility Less efficacious than droperidol
45
Metoclopromide (Reglan) dose and SE
½ of studies indistinguishable from saline Restlessness, EPS Dose: 10-20mg IV Short ½ life…dosing closer to the end of surgery
46
NK-1 antagonists drugs for PONV
Aprepitant
47
NK-1 antagonists MOA
Antagonize Substance P in the emetic center; Depress neural activity of the nucleus tractus solitarius May also interfere with afferent messages from enterochromaffin cells
48
Dose, effects and when to give for Aprepitant
Dose 40mg or 125 mg Greater anti-vomiting than anti-nausea Given 2-3 hours prior to induction
49
Propofol MOA on PONV
Blocks serotonin release at 5HT3 receptors In subhypnotic doses May also inhibit CTz
50
Propofol for PONV dose
Dose 16.7 mcg/kg/min (subhypnotic) or TIVA dose
51
What to give with prop for PONV for associated bradycardia
Glycopyrrolate
52
Prehydration to prevent PONV
Adequate pre-hydration 10-30 ml/kg
53
Isopropyl Alcohol on PONV
Isopropyl alcohol: 50% reduction in nausea
54
Chewing gum on PONV
Potential improvement in nausea; stimulates motility
55
What else could cause PONV (5)
Hypotension Hypoxemia Elevated ICP Gastric bleeding Hypoglycemia
56