1. POSTOPERATIVE NAUSEA AND VOMITING Risk Factors and Prevention Plan

2. Cost Postoperative nausea and vomiting incidence 25-30% Leads to poor patient satisfaction Delayed discharge Hospital admission Aspiration Disruption of suture lines

3. Risk Factors Female Gender History of motion sickness or postoperative N/V Pain High levels of anxiety Long surgical procedure Type of surgery (intra-abdominal, gynecologic, laparoscopic, breast, ENT, strabismus) Incidence of postoperative N/V 0 risk factor -10% 1 risk factor -20% 2 risk factors -40% 3 risk factors -60% 4 risk factors -80%

4. Prophylatic Agents Dopamine receptor antagonists Promethazine long duration of action, may delay recovery from anesthesia Droperidol NNT 5-7 excellent for nausea prophylaxis FDA black box for QTc prolongation Side effects: sedation, restlessness, hypotension, extrapyramidal

5. Prophylatic Agents Anticholinergic Scopolamine transdermal offers long duration of action, often used with opioid premedication Side effects: sedation, dry mouth, dizziness, restlessness

6. Prophylatic Agents 5 HT3 receptor antagonists Ondansetron, Dolasetron, Granisetron NNT 5-6 binds to chemoreceptor trigger zone and vagal afferents, specific Effectiveness is similar for all three, difference is cost Side effects: headache, constipation, elevated liver enzyme

7. Prophylatic Agents NK-1 receptor antagonist Aprepitant Better efficacy for vomiting vs ondansetron up to 72 hours Long duration of action

8. Prophylatic Agents Corticosteroids Dexamethasone Long duration of action NNT for late postoperative N/V 4.3 NNT for early postoperative N/V 7.1

9. Postoperative N/V Prevention Strategy 1-2 risk factors 5HT3 antagonists Dexamethasone Scopolamine Droperidol 2-4 risk factors Droperidol + 5HT3 antagonist Dexamethasone + 5HT3 antagonist Droperidol + dexamethazone Greater than 4 risk factors Combination antiemetics and IV anesthesia with propofol

10. References Habib, AS; Gan, TJ. What is the Best Strategy to Prevent Postoperative Nausea and Vomiting? Evidence-Based Practice of Anesthesiology. Chapter 40 Van Erdewyk, JM. Postoperative Nausea and Vomiting. Anesthesia Review. Chapter 233