PONV

Question 1

5 Primary afferent pathways involved in vomiting stimulation:

Answer 1

Chemoreceptor Trigger Zone (CTZ)

Vagal mucosal pathway in the GI system

Neuronal pathways from the vestibular system (Inner Ear)

Reflex afferent pathways from the cerebral cortex

Midbrain afferents

Question 2

Stimulation of the afferent pathways stimulating vomiting can be activated by four receptor types

Answer 2

Cholinergic (muscarinic)
Dopaminergic
Histaminergic
serotonergic

Question 3

Vomiting center is located

Answer 3

It is located within the reticular formation of the brainstem

Question 4

Vomiting center can also be stimulated by

Answer 4

gut, oropharynx, movement, pain, hypoxemia, and hypotension

Question 5

Efferent signals are directed to the following nerves:

Answer 5

Glossopharyngeal (IX)
Hypoglossal (XII)
Trigeminal (V)
Accessory(XI)
Spinal segmental
Flood states  V, VII, IX, X, XII

Question 6

Outside the BBB
Has contact with CSF and allows substances in blood and CSF to interact.
Toxins and/or drugs in the blood can stimulate the____causing n/v
This stimulation may send emetogenic triggers to the vomiting center activating the vomiting reflex

Answer 6

CTZ

Question 7

Vomiting is associated with marked vagal and sympathetic activity causing:

Answer 7

Sweating
Pallor
Bradycardia

Question 8

PONV is influenced by multiple factors that are r/t:

Answer 8

Patient
Surgery
Anesthesia

Question 9

PONV: PATIENT FACTORS

Answer 9

Sex: Women > Men (strongest predictive factor)
Motion Sickness: Previous history motion sickness or PONV from previous surgeries
Smoking: Nonsmokers > Smokers due to gradual desensitization of the CTZ
Age: < 50 years of age is a significant factor
Obesity: recent studies demonstrate BMI is not a factor
Delayed Gastric Emptying:
MD
Hypothyroidism
Pregnancy
Increased ICP
Swallowing blood
Full stomach

Question 10

PONV:
PRE-OP AND INTRA-OP FACTORS
Surgical: ______________
During Surgery: _______________

Answer 10

Surgical: Type of surgery: cholecystectomy, gynecological and lap surgeries have high incidents of PONV
During Surgery: Long duration; Increasing by surgery time by 30 minutes may increase PONV risk by 60%

Question 11

Significant decrease in vomiting when avoided in lap procedures.

Answer 11

Nitrous oxide

Question 12

_________ and ________ cause higher PONV d/t increase in endogenous catecholamines

Answer 12

Ether and Cyclopropane

Question 13

_________, _______, _______, ______. and _______ are associated with lesser degree of PONV

Answer 13

Sevoflurane, Enflurane, Desflurane, and Halothane

Question 14

Continuous infusion markedly increases post-op emesis

Answer 14

Etomidate

Question 15

When used for induction, its been known to delay D/C d/t vivid dreams, hallucinations, and higher incidence of PONV (20 to endogenous catecholamine release) when compared to giving barbiturates and nitrous oxide

Answer 15

Ketamine

Question 16

reduced PONV

Answer 16

Propofol

Question 17

increase incident of PONV d/t directly stimulating the CTZ

Answer 17

Nitrous-Opioid-relaxant technique

Question 18

Emesis caused by stimulation of opioid receptors in the CTZ. Using intraoperative ______ shows a weak contribution to PONV

Answer 18

opioids

Question 19

Incidence of PONV is uncertain

Answer 19

Neuromuscular Reversal Agents

Question 20

Risk for PONV is 9 times less than with ______than with general anesthesia

Answer 20

regional

Question 21

Nausea after epidural may be less with ______ ________ opioids such as _______ and ________d/t less rostral spread from lumbar epidural injection site to CTZ and vomiting center than the less lipid soluble such as morphine

Answer 21

lipid soluble, fentanyl and sufentanil

Question 22

______ or _____ is common cause of post op emesis

Answer 22

Visceral or pelvic pain

Question 23

Sudden motion, changes in position, and/or transport from PACU to patient floor can precipitate n/v after receiving ______

Answer 23

opioids

Question 24

Post-op opioids ______ risk for PONV in dose dependent manners. This effect can last as long as opioids are used in the post op period

Answer 24

increase

Question 25

________ can be used perioperatively to reduce need for opioids.

Answer 25

Non-steroidal

Question 26

__________ is no longer recommended for PONV prevention

Answer 26

Supplemental O2

Question 27

Genes/receptors regarded as r/t PONV or opioid induced N/V:

Answer 27

``` 5-HT3 Muscarinic type-3 Dopamine type 2 Catechol-o-methyl transferase Alpha-2 adrenoceptor Adenosine triphosphate binding cassette subfamily B member Cytochrome P450 superfamily enzyme Uridine 5’-diphospho-glucuronosyltransferae ```

Question 28

5-hydroxytryptamine subtype 3 receptor antagonists:

Answer 28

``` Ondansetron Dolasetron (ban d/t concerns of QT prolongation and torsade's de pointes) ```

Question 29

Blocks muscarinic receptors in the cerebral cortex and pons to induce antiemetic effects

Answer 29

Anticholinergic/Antimuscarinic | Transdermal Scopolamine

Question 30

Histamine Receptor Antagonists: Blocks acetylcholine receptors in the vestibular apparatus and histamine receptors in the nucleus tractus solitaries

Answer 30

Dimenhydrinate (Dramamine) Meclizine: Has longer during of PONV effect than ondansetron Promethazine

Question 31

Dopamine Antagonist:

Answer 31

Metoclopramide: Strong D2-receptor antagonist and blocks H1 and 5-HT3 receptors as well.

Question 32

Neurokinin-1 Receptor Antagonists: New group of drugs used for PONV thought to prevent both acute and delayed emesis. Act mainly at nucleus tractus solitaries and areas of reticular formation blocking NK-1 receptors. More effective in inhibiting emesis than nausea.

Answer 32

Aprepitant (Emend [PO], Cinvanti [IV]):

Question 33

Aprepitant (Emend [PO], Cinvanti [IV]): NK-1 receptor antagonist with a ____hours half life. Significantly more effective than ondansetron for preventing vomiting at 24 and 48 hour after surgery and in reducing nausea severity in the first 48 hours after surgery

Answer 33

40

Question 34

Blocks synthesis of prostaglandins which sensitized nerves to other commonly involved neurotransmitters in emesis control. May have central effect by antagonizing 5-HT3 receptors or corticosteroid receptors in the nucleus tractus solitaries

Answer 34

Corticosteroids: Dexamethasone:

Question 35

effective for late PONV prevention

Answer 35

Methylprednisolone:

Question 36

Butryphenones

Answer 36

Droperidol | Haldol

Question 37

Relatively selective D2 receptor antagonist. Use was stopped in 2001 due to black box warning related to CV events. A recent meta-analysis demonstrated at low doses of <1 mg or 15 mcg/kg IV there is significant antiemetic efficacy with low risk of adverse reactions.

Answer 37

Droperidol

Question 38

Haldol

Answer 38

< 2 mg reduces the risk of side effects and QT prolongation. Not DFA approved

Question 39

Phenothiazines

Answer 39

Perphenazine | Chlorpromazine

Question 40

Used to treat schizophrenia and n/v

Answer 40

Perphenazine

Question 41

a D2 receptor antagonist at CTZ. May treat schizophrenia; used to treat mental illness, behavioral disorders, tetanus, blood disorders such as porphyria and severe n/v. Severe sedation

Answer 41

Chlorpromazine

Question 42

Used in TIVA can reduce baseline risk of PONV

Answer 42

Propofol

Question 43

Has direct antiemetic effect along with opioid sparing effect. Clonidine and Dexmedetomidine (alpha-2-adrenceptor agonists) demonstrated a significant but weak and short lived antinausea effect (meta-analysis)

Answer 43

Alpha-2-agonists

Question 44

Antidepressant (specific serotonergic an noradrenergic antidepressant). The combination of _______30 mg PO and dexamethasone 8 mg decreases incidence of late PONV > 50%.

Answer 44

mirtazapine (remeron)

Question 45

_____600 mg 2 hours prior to surgery effectively decreases PONV. An hour before surgery ________ 800 mg PO is as effective as dexamethasone 9 mg IV and the combination is better than either drug given alone

Answer 45

Gabapentin

Question 46

_______: 2 mg 30 before end of surgery is as effective as ondansetron 4 mg. 2 mg 30 min before end of surgery is more effective against PONV than 35 mcg/kg premedication

Answer 46

Midazolam

Question 47

Effective for reducing the baseline risk for PONV.

Answer 47

IV Fluids:

Question 48

Strategies that do not work:

Answer 48

``` Music therapy Isopropyl alcohol inhalation Intraoperative gastric decompression The proton pump inhibitor esomeprazole (Nexium) Ginger root Nicotine patch to nonsmokers Cannabinoids ```

Question 49

Serotonin (5-hydroxytryyptamine subtype 3) antagoist examples

Answer 49

ondansetron, granisetron, dolasetron, ramosetron, palonsetron, tropistron, corticosteroids

Question 50

Antcholinergics. antimuscarinics (M)

Answer 50

Scopolamine

Question 51

Histamine (H1) antagonist

Answer 51

promethazine, perphenazine, dimenhdrinate, diphenhydramine, meclizine, chlorpromazine

Question 52

Dopamine (D2) antagonist

Answer 52

Domperidone, chlorpromazine, metoclopramide, drperidol, haloperidol

Question 53

Neurokinin-I antagonist

Answer 53

Apreitant, cospitant, rolapitant