What PONV risk does each Apfel score correspond to?

Score 0 = approximately 10% risk, Score 1 = 21%, Score 2 = 39%, Score 3 = 61%, Score 4 = 79%. These estimates come from the original Apfel et al. (1999) validation study in over 2,000 surgical patients.

Does the Apfel score apply to all types of anesthesia?

The Apfel score was validated for patients receiving inhalational general anesthesia. It is less applicable to total intravenous anesthesia (TIVA), neuraxial (spinal/epidural), or regional anesthesia, where baseline PONV risk is significantly lower.

What counts as a history of PONV or motion sickness?

Any prior episode of postoperative nausea or vomiting after a previous surgery, or a documented history of motion sickness (car, sea, or air sickness), qualifies as a positive criterion.

At what score should antiemetic prophylaxis be given?

SAMBA and ERAS guidelines generally recommend prophylaxis starting at a score of 1-2 (low to moderate risk). Patients with scores of 3-4 typically benefit from multimodal prophylaxis combining two or more antiemetic agents (e.g., ondansetron + dexamethasone + scopolamine patch).

Is postoperative opioid use the planned use or actual use?

For preoperative risk stratification, this criterion refers to the anticipated use of opioids for postoperative analgesia. If opioid-based analgesia is planned (e.g., PCA morphine), the point is assigned. Regional anesthesia or non-opioid analgesic plans may reduce this risk factor.

Is this tool a replacement for clinical judgment?

No. The Apfel score is a decision support aid. Clinical judgment, patient preferences, surgical type, and institutional protocols should all inform antiemetic management decisions. Always consult current anesthesiology guidelines and involve qualified clinicians in perioperative care.

Apfel PONV Score Calculator

Select the 4 Apfel risk factors to instantly calculate PONV risk percentage and guide antiemetic prophylaxis decisions.

Apfel Risk Factors (1 point each)

Female sex

Patient is female. Female sex is the strongest single predictor of PONV in adults.

Non-smoker

Patient does not currently smoke. Smoking appears to have a protective effect against PONV.

History of PONV or motion sickness

Prior episode of postoperative nausea/vomiting after a previous surgery, or documented history of motion sickness.

Postoperative opioid use (planned)

Opioid-based analgesia is planned for postoperative pain management (e.g., PCA morphine, IV opioids).

Factors selected 0 of 4

Apfel PONV Score

0 / 4

Very Low Risk

~10%

Estimated PONV probability

Prophylaxis Guidance

Score 0: Baseline risk. Routine antiemetic prophylaxis is generally not required. Consider TIVA or regional techniques when appropriate to further reduce risk.

PONV Risk Reference

Score	Risk Category	PONV Risk
0	Very Low	~10%
1	Low	~21%
2	Moderate	~39%
3	High	~61%
4	Very High	~79%

Risk estimates from Apfel et al., Anesthesiology 1999. Validated in patients receiving inhalational general anesthesia.

Medical Disclaimer: This tool is for educational and clinical decision support only. It does not constitute medical advice and must not replace individualized clinical judgment. Always consult current anesthesiology guidelines and involve qualified healthcare professionals in perioperative care decisions.

Summary

The Apfel Simplified Risk Score is a validated clinical tool developed by Christian Apfel and colleagues to predict the probability of postoperative nausea and vomiting (PONV) in adult patients undergoing general anesthesia. It uses four equally weighted binary risk factors: female sex, non-smoker status, history of PONV or motion sickness, and planned postoperative opioid use. Each factor present adds 1 point, yielding a score from 0 to 4 that corresponds to PONV risk estimates of approximately 10%, 21%, 39%, 61%, and 79%, respectively. The tool is recommended by the Society for Ambulatory Anesthesia (SAMBA) and other major anesthesiology guidelines to identify patients who would benefit from single or multimodal antiemetic prophylaxis.

How it works

Review the 4 Apfel risk factors listed on the left panel.
Check each factor that applies to the patient prior to surgery.
Each checked factor adds 1 point to the total score (range 0-4).
The results panel on the right updates instantly with the score and estimated PONV risk percentage.
Use the result alongside clinical judgment to decide on antiemetic prophylaxis strategy.
Click "Reset" to clear all selections for a new patient assessment.

Use cases

Preoperative anesthesia assessment to stratify PONV risk before elective or urgent surgery.
Guiding antiemetic prophylaxis decisions — low-risk patients may not need prophylaxis, while high-risk patients benefit from multimodal regimens.
Perioperative nursing and PACU staff education on identifying patients at elevated PONV risk.
Medical student and resident exam preparation for anesthesiology and perioperative medicine rotations.
Quality improvement and PONV reduction protocol development for surgical departments.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu