Anaesthetics
Apfel Score (PONV)
Risk of postoperative nausea and vomiting.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The Apfel score is a simplified tool that estimates a patient's risk of postoperative nausea and vomiting (PONV) after general anaesthesia. It uses four equally weighted risk factors: female sex, being a non-smoker, a history of PONV or motion sickness, and the expected use of postoperative opioids. Each present factor scores one point, giving a total from 0 to 4. It is used before surgery to identify patients who would benefit most from antiemetic prophylaxis.
Interpreting the result
Risk rises roughly linearly with the score. With 0, 1, 2, 3 and 4 factors the approximate risk of PONV is about 10%, 20%, 40%, 60% and 80% respectively. A score of 0–1 is low risk, 2 is moderate and 3–4 is high risk. The score is used to match the intensity of antiemetic prophylaxis to the patient, with higher scores supporting multimodal prophylaxis using several agents with different mechanisms.
Advice
Each risk factor adds roughly 20% absolute risk (≈10/20/40/60/80% for 0–4 factors). Use to guide multimodal antiemetic prophylaxis.
Worked example
A female non-smoker with a history of motion sickness, who is expected to need postoperative opioids: female sex (1) + non-smoker (1) + history of motion sickness (1) + expected opioids (1) = 4. This is high risk (around 80%), warranting aggressive multimodal antiemetic prophylaxis.
Pearls / pitfalls
- The four factors are equally weighted; do not give extra weight to any single one.
- It estimates risk, not certainty — patients with a low score can still develop PONV, and prophylaxis decisions consider the consequences of vomiting (e.g. certain surgery types).
- The score was developed for adults having general anaesthesia and does not directly apply to children, who have their own risk tools.
- Higher risk supports combining antiemetics from different classes and reducing emetogenic anaesthetic factors rather than relying on a single agent.
Evidence & validation
Derived and validated by Apfel and colleagues across multiple centres, the score is widely used in anaesthetic practice and underpins consensus guidance on PONV management, which recommends risk-based, multimodal prophylaxis.
Frequently asked questions
What are the four Apfel risk factors?
They are female sex, being a non-smoker, a history of postoperative nausea and vomiting or motion sickness, and the anticipated use of postoperative opioids. Each scores one point, giving a total from 0 to 4.
How does the score relate to risk?
Each additional factor adds roughly 20% absolute risk, giving approximate PONV rates of about 10%, 20%, 40%, 60% and 80% for scores of 0 to 4. Higher scores justify more intensive, multimodal antiemetic prophylaxis.
Does a low score mean no prophylaxis is needed?
Not necessarily. A low score means lower baseline risk, but prophylaxis may still be appropriate where vomiting would be particularly harmful, such as after certain types of surgery. Clinical judgement is required.
Can I use the Apfel score in children?
No. It was developed and validated in adults having general anaesthesia. Paediatric PONV risk is assessed using separate tools designed for children.
References
- Apfel CC, Läärä E, Koivuranta M, et al. A simplified risk score for predicting postoperative nausea and vomiting. Anesthesiology. 1999;91(3):693–700.
- Gan TJ, et al. Fourth Consensus Guidelines for the Management of Postoperative Nausea and Vomiting. Anesth Analg. 2020;131(2):411–448.
About the creator
Apfel CC et al.
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