CAPA Nausea & Vomiting Prevention 2 — Questions and Answers
Question 1: A patient with a documented history of motion sickness is scheduled for laparoscopic cholecystectomy. Which combination prophylaxis is most appropriate?
- Ondansetron alone 30 min before emergence
- Dexamethasone at induction plus ondansetron near end of surgery (Correct answer)
- Scopolamine patch applied the night before plus metoclopramide at induction
- Droperidol alone at induction
Correct answer: Dexamethasone at induction plus ondansetron near end of surgery
Multimodal prophylaxis using dexamethasone at induction and a 5-HT3 antagonist near emergence is the evidence-based standard for high-risk patients.
Question 2: Which patient characteristic is NOT an independent risk factor in the Apfel simplified risk score for PONV?
- Female sex
- Non-smoker status
- History of motion sickness
- Use of regional anesthesia (Correct answer)
Correct answer: Use of regional anesthesia
The Apfel score uses female sex, non-smoking status, history of PONV/motion sickness, and postoperative opioid use — regional anesthesia is not one of its four factors.
Question 3: A patient receives ondansetron 4 mg IV at the end of surgery. Two hours later in the PACU they are vomiting. What is the most appropriate rescue antiemetic?
- Repeat ondansetron 4 mg IV
- Promethazine 12.5 mg IV
- Metoclopramide 10 mg IV (Correct answer)
- Dexamethasone 8 mg IV
Correct answer: Metoclopramide 10 mg IV
When a 5-HT3 antagonist fails or its duration has elapsed, a drug from a different class such as metoclopramide (dopamine antagonist) should be used for rescue.
Question 4: Which anesthetic technique most significantly reduces the baseline risk of PONV compared to general anesthesia with volatile agents?
- Using desflurane instead of sevoflurane
- Total intravenous anesthesia (TIVA) with propofol (Correct answer)
- Adding nitrous oxide to the volatile agent
- Using high-dose inhalation agents to deepen anesthesia
Correct answer: Total intravenous anesthesia (TIVA) with propofol
TIVA with propofol eliminates exposure to emetogenic volatile agents and nitrous oxide, significantly lowering the incidence of PONV.
Question 5: How does scopolamine transdermal patch work as a PONV prophylactic?
- Blocks dopamine D2 receptors in the chemoreceptor trigger zone
- Antagonizes muscarinic cholinergic receptors in the vestibular system (Correct answer)
- Inhibits serotonin reuptake at the vagal nerve endings
- Blocks histamine H1 receptors in the vomiting center
Correct answer: Antagonizes muscarinic cholinergic receptors in the vestibular system
Scopolamine is an anticholinergic agent that reduces PONV by blocking muscarinic receptors in the vestibular apparatus and central nervous system.
Question 6: A nurse notes a patient is at high risk for PONV (Apfel score 3). Which intervention addresses the anesthetic plan rather than pharmacologic prophylaxis?
- Adding droperidol to the antiemetic regimen
- Minimizing intraoperative and postoperative opioids (Correct answer)
- Administering dexamethasone at induction
- Using a combination of ondansetron and dexamethasone
Correct answer: Minimizing intraoperative and postoperative opioids
Reducing opioid use through multimodal analgesia (NSAIDs, regional blocks) addresses a modifiable risk factor and reduces PONV without adding another drug.
Question 7: Dexamethasone given for PONV prophylaxis should be administered at which point in the anesthetic?
- Immediately before emergence
- At induction of anesthesia (Correct answer)
- During the middle of surgery
- In the PACU upon arrival
Correct answer: At induction of anesthesia
Dexamethasone is most effective for PONV prevention when given at induction due to its delayed onset of action, requiring time to reach peak efficacy.
CAPA Nausea & Vomiting Prevention 2
A patient with a documented history of motion sickness is scheduled for laparoscopic cholecystectomy.
Which combination prophylaxis is most appropriate?