Apfel Score for PONV Risk Assessment
The Apfel simplified risk score is the best validated and most widely recommended tool for assessing postoperative nausea and vomiting (PONV) risk in adult surgical patients, including those with comorbidities such as cardiovascular disease or diabetes. 1
Understanding the Apfel Score
The Apfel score assigns one point for each of four risk factors present 1:
- Female gender 1, 2
- Non-smoking status 1, 2
- History of PONV or motion sickness 1, 2
- Postoperative opioid use 1, 2
The baseline PONV risk with zero factors is approximately 10%, and each additional risk factor increases the risk by approximately 20%, reaching up to 80% when all four factors are present 3, 4.
Risk Stratification and Clinical Application
For patients with an Apfel score ≥2 (two or more risk factors), prophylactic antiemetic therapy is strongly recommended. 1
The prophylaxis intensity should match the risk level 1:
- Moderate risk (2 risk factors): Administer 2 antiemetics from different drug classes 1
- High risk (3-4 risk factors): Administer 2-3 antiemetics from different drug classes 5, 1
Research confirms this approach is clinically accurate: patients with Apfel score III experienced 59.7% PONV incidence and those with score IV experienced 91.3% incidence, closely matching predicted values 3.
Antiemetic Drug Classes for Prophylaxis
Select from six first-line drug classes 1:
- 5-HT3 receptor antagonists (ondansetron, granisetron, ramosetron) 1, 6
- Corticosteroids (dexamethasone 4-8 mg IV preoperatively) 1, 6
- Dopamine (D2) antagonists 1
- Neurokinin-1 receptor antagonists (aprepitant) 1, 6
- Antihistamines 1
- Anticholinergics 1
Additional Risk Reduction Strategies
Beyond pharmacologic prophylaxis, implement these evidence-based interventions 1:
- Use total intravenous anesthesia (TIVA) with propofol instead of volatile anesthetic gases 1, 6
- Avoid nitrous oxide 1, 6
- Implement opioid-sparing multimodal analgesia 1, 6
- Maintain mildly positive fluid balance to prevent hypovolemia-induced splanchnic hypoperfusion 5, 1
- Consider preoperative carbohydrate loading 1
Important Clinical Caveats
The definition of "postoperative opioid use" varies significantly in clinical practice - it can mean either "anticipated" opioid use (54% of studies) or "actual" opioid use (18% of studies), creating potential inconsistency in risk assessment 7. In practice, assume all surgical patients will receive opioids unless a completely opioid-free technique is planned 8.
Comorbidities such as cardiovascular disease and diabetes do not directly modify the Apfel score, but these patients often require opioid analgesia, which contributes one point to their risk assessment 1, 2.
Rescue Treatment Protocol
If breakthrough PONV occurs despite prophylaxis, administer a different drug class than what was used prophylactically, as using the same class significantly reduces effectiveness 1, 6. Consider continuous infusion antiemetics for persistent symptoms 6.
Timing of PONV Risk
The Apfel score primarily predicts early PONV (0-24 hours postoperatively) 8. Patients with three or four risk factors experience significantly higher emesis rates at 0-6 hours (11-22%) and 6-24 hours (13-27%) compared to lower-risk patients, but late PONV (24-72 hours) shows low incidence regardless of Apfel score 8.