Estimates baseline 24-hour risk of postoperative nausea and vomiting (PONV) in adults undergoing inhalational general anaesthesia without routine antiemetic prophylaxis.

The simplified Apfel PONV score was derived and cross-validated in two adult centres (Oulu, Finland and Würzburg, Germany; n=2,722) using multivariable logistic regression. Four equally weighted predictors were retained: female sex, history of PONV or motion sickness, current non-smoking, and planned postoperative opioid use.

Number of Apfel factors	Approximate 24-hour PONV incidence without prophylaxis	Consensus risk category
0	~10%	Low
1	~21%	Medium
2	~39%	Medium
3	~61%	High
4	~79%	High

The 2025 fifth consensus guideline highlights the Apfel score as a simple, well-validated adult risk tool and classifies 0, 1–2 and ≥3 factors as low, medium and high risk respectively.

The percentages shown here reflect the original no-prophylaxis cohort. Absolute PONV rates are typically lower when total intravenous anaesthesia, regional techniques and multimodal prophylaxis are used, but the relative risk gradient across Apfel factors remains useful for tailoring prophylaxis intensity and counselling.

The score was developed for adults under general anaesthesia. Performance is less certain in paediatric, obstetric, sedation or regional anaesthesia cases, and additional factors (such as age <50 years and highly emetogenic surgery types) should also inform local risk assessment and management.

Apfel Score for Postoperative Nausea and Vomiting