PONV pt2 Flashcards
What is P-6 stimulation?
Radial compression
How is P-6 manipulation thought to treat PONV?
P-6 compression → Hypophyseal secretion of β-endorphins → inhibition of CTZ.
Is P-6 manipulation good at treating nausea and vomiting?
Not really, better at inhibition. More time-limited
What are the subtypes of anti-dopaminergics that are used to treat PONV?
- Butyrophenones (haloperidol, droperidol…)
- Phenothiazines (promethazine, chlorpromazine…)
What are the side effects of dopamine receptor antagonists? (2)
- Drowsiness/sedation
- Extrapyramidal s/s [parkinsonism, dystonia, dyskinesia]
What mentioned drugs are butyrophenones? (2)
- Haloperidol
- Droperidol
What black box warning exists for Droperidol?
Torsades de Pointes and sudden death.
More than ______mg of droperidol should never be given.
0.625mg
Droperidol is as effective as ___________ for treatment of PONV.
Ondansetron 4mg
Droperidol also has effects as a ______________ thus resulting in hypotension.
weak ⍺ blocker ⇒ hypotension
What drugs are phenothiazines that were mentioned? (3)
- Prochlorperazine
- Chlorpromazine
- Promethazine
What black box warnings are there for promethazine? (2)
- Tissue damage
- Resp arrest for < 2yo’s
What receptors does promethazine act on? (4)
- Anti-dopamine
- Anti-histamine
- ⍺ adrenergic antagonist
- muscarinic cholinergic antagonist
What are known side effects of promethazine? (3)
- Sedation
- Hypotension
- Extrapyramidal side effects (EPS)
How do 5HT3 Antagonists work in the treatment of nausea/vomiting?
Antagonize serotonin receptors on the vagal nerve and CTZ
Chronic use of 5HT3 antagonists can result in mild elevation of what? Other side effects include? (2)
- elevation of Liver enzymes
- headache
- constipation
What timeframe should ondansetron be given?
4mg within 15 - 20 min of surgery end.
What anticholinergic is given for PONV prophylaxis?
What dose and route is utilized? How long should it be left in place? What are some side effects that may occur? (3)
Scopolamine
- 1.5mg transdermal patch
- Should be left in place for 48-72 hours
- May cause drowsiness, dizziness, or dry mouth
What is the PONV rescue dose of dexamethasone?
Trick question. Dexamethasone should be used for prophylaxis only, not useful as a rescue.
What timeframe is dexamethasone given and what dosage is utilized?
- Given during or immediately after induction (~2hours before end of surgery).
- 4mg (just as effective as 8mg)
How does metoclopramide combat PONV? What dose is given? What side effects can occur?
- Increases LES tone and GI motility.
- 10 - 20mg IV
- May cause restlessness, EPS
Less efficacious than droperidol, studies showing 50% effect compared to placebo.
What NK-1 antagonist is given for PONV? How does it work?
Aprepitant:
- antagonizes substance P in the emetic center.
- Depresses Nucleus tractus solitarius neural activity
- Blocks afferent messages from enterochromaffin cells
What is the aprepitant dose? What time frame should it be given?
- 40mg or 125mg
- given 2-3 hours prior to induction (preop)
How does propofol prevent/treat PONV?
Blocks serotonin release in subhypnotic doses.
May also inhibit CTR? CTZ?.
What is the subhypnotic dose of propofol?
16.7 mcg/kg/min
What drug needs to be given alongside propofol? Why?
Glycopyrrolate (to counteract bradycardia)
______ ______ has been associated with a 50% reduction in nausea.
Isopropyl alcohol
Droperidol can be given with _____ to provide better effect
Droperidol can be given with metoclopramide 10mg to provide better effect
What are other 5HT3 antagonist drugs that were mentioned along with ondansetron? (3)
- Dolasetron (anzemet)
- Granisetron (kytril)
- Palonosetron
What should be considered when choosing to administer aprepitant?
- has greater anti-vomiting effects than anti-nausea
What other complications should be considered by the CRNA as causes of N/V? (5)
- Hypotension
- Hypoxemia
- ↑ICP
- Gastric bleeding
- Hypoglycemia
What overall anesthetic management changes can be made to reduce the risk of PONV?
