PONV (Exam III) Flashcards
(37 cards)
What is the most common patient complaint regarding anesthesia? What is the incidence of this compaint?
PONV
- Overal incidence 20-30% (some reach 80%)
When does nausea peak in patients post-operatively?
How long does nausea/vomiting typically last post operatively?
Peak: 6 hours
Persists for 24 - 48 hours
What are the four major inherent (patient-specific) risk factors for PONV?
- Female
- Non-smoker
- PONV history
- History of motion sickness
Opioid use not an inherent risk factor.
What factor is the greatest cause of PONV?
Intraoperative and postoperative opioids.
What is the full list of anesthetic-technique risk factors for PONV? (7)
- VAA’s
- Nitrous > 50%
- Opioids
- Neostigmine
- Gastric distention
- Anesthesia duration
- Forced PO fluids prior to discharge
What surgeries place a patient at higher risk for development of PONV? (5)
- ENT surgeries
- Neuro surgeries
- laparoscopy/laparotomy
- Breast, plastic, strabismus surgery (girly sx’s)
- Long surgeries
Pediatric PONV incidence increases with age until _______.
Pediatric PONV incidence increases with age until puberty
Which specific pediatric procedures are noted to have a higher incidence of PONV? (5)
- Adenotonsillectomy
- Strabismus repair
- Hernia repair
- Orchiopexy
- Penile surgeries
In pediatrics, how does gender play a role in PONV risk?
In pediatrics, male risk = female risk
unlike with adults, where females have higher risk
Will increased O₂ concentrations increase or decrease PONV occurrence?
decrease risk
Will adequate hydration increase or decrease PONV occurrence?
decrease risk
Will nitrous use increase or decrease PONV occurrence?
increase risk
Will neuromuscular blockade reversal with acetylcholinesterase inhibitors increase or decrease PONV occurrence?
Increase risk
neostigmine = ↑ PONV
Will minimized motion/ambulation increase or decrease PONV occurrence?
decrease risk
Let patient guide movement based on how they feel.
How do volatiles affect risk for PONV?
Increase risk
may supplement with propofol which has antiemetic properties itself
Where is the emetic center of the brain located?
Lateral reticular formation of the brainstem
Which substances act directly on receptors of the lateral reticular formation of the brainstem?
Trick Question. No substances act directly on the emetic center.
Where does afferent input arrive from to the emetic center? (4)
- Pharynx
- GI tract
- Mediastinum
- Afferent nerves of CTZ and 8th CN
Where does CNS afferent input to the emetic zone come from?
- Chemoreceptor Trigger Zone (CTZ) of the area postrema
- Vestibular portion of Vestibulocochlear nerve (CN VIII)
The CTZ of the area postrema does not have the ______.
What are the implications of this?
Blood brain barrier (BBB)
No BBB means chemicals and drugs in the blood or CSF can trigger N/V.
What receptors are located in the Chemoreceptor Trigger Zone? (8)
- Dopamine
- Serotonin
- 5-HT3
- Opioid
- Histamine
- Muscarinic
- Neurokinin-1
- Cannabinoid
What drug is the gold standard for PONV prophylaxis and treatment?
Trick question. No single drug is gold standard.
Patients (should / should not) receive the same drug for prophylaxis and treatment of PONV.
Should not use the same drug for prophylaxis and treatment
Ex. If ondansetron is used for prophylaxis, use promethazine for treatment
When it comes to anti-emetics more is _______ (better or worse)
Better
hit as many receptors as possible
