Vomiting upon waking is one of the things patients fear most, sometimes even more than pain. Since 1999, a simple, four-question score has existed to estimate this risk: the Apfel score . It is used worldwide by anesthesiologists, and it is almost impossible to find in a form that a patient can fill out themselves.
Post-operative pain : Another fear upon waking: pain. What 50,000 surgical patients actually reported, and how to express it to find relief. Read the page.
Answer the four questions. The important thing is not the number itself, but what it allows you to ask your anesthesiologist during the consultation.
Answer all four questions to see the result. As long as an answer is missing, no number will be displayed: a partial score is meaningless.
Score of 0 out of 4
In the validation study, 10% of people with this number of risk factors experienced nausea or vomiting. This is a frequency observed in a group, not a prediction for you.
| Number of factors | Estimated risk | What this means in concrete terms |
|---|---|---|
| 0 | 10% | About one in ten people in your situation. |
| 1 | 21% | About one in five. |
| 2 | 39% | Nearly two out of five. That's the most frequent case. |
| 3 | 61% | More than one in two people. |
| 4 | 79% | Nearly four out of five. Prevention is becoming crucial. |
Figures taken from the validation article: « the incidences of PONV were 10%, 21%, 39%, 61% and 79% if zero, one, two, three or four of the mentioned risk factors were present, respectively ». Pierre S, Benais H, Pouymayou J. Apfel's simplified score may favorably predict the risk of postoperative nausea and vomiting. Canadian Journal of Anesthesia, 2002;49(3):237-242. DOI
A low score is not a reason to refuse prevention. This is the most important point on this page, and it goes against intuition. Recent recommendations advocate broad prevention, including when no risk assessment has been carried out. The consensus summary published in The Anaesthetist formulate it as follows: « a liberal PONV prophylaxis is encouraged for adult patients and children, which should also be administered when no risk assessment is made »and adds that the basis for every adult should be prevention with two antiemetics.
What this score doesn't tell us, and what almost no one mentions
The Apfel score is the most widely used in the world for assessing this risk. An Australian analysis published in 2021 examined how its four criteria were actually defined in the studies that used it. The result is disconcerting: out of 255 studies that included the four factors, smoking was defined in only 4, motion sickness in only one, and a history of vomiting in none.
The fourth factor is the most ambiguous of all. Postoperative morphine was counted as "anticipated" in 54% of studies and as "actually administered" in 28%, and in 18% of studies it was impossible to determine which of the two had been used. In other words, two teams can calculate a different score for the same patient, and both are correct according to the literature.
Darvall J, Handscombe M, Maat B, So K, Suganthirakumar A, Leslie K. Interpretation of the four risk factors for postoperative nausea and vomiting in the Apfel simplified risk score: an analysis of published studies. Canadian Journal of Anesthesia, 2021;68(7):1057-1063. DOI
This is why this page displays an order of magnitude, not a prediction. A score of 3 does not mean you have a 61% risk; it means you belong to a group where prevention truly makes a difference.
What this score allows you to ask
This is where it becomes useful. During the anesthesia consultation, you can ask three specific questions instead of saying "I'm afraid I'll vomit."
- What preventative measures are planned for me? The consensus synthesis recommends two antiemetics from different classes as a baseline in adults, and more if the risk is high.
- Can my risk of leaving be reduced? The recommendations cite regional anesthesia and non-morphine analgesics in a multimodal approach, which reduce the risk even before considering antiemetic drugs.
- What if I still vomit? The rule cited by the summary is to then use an antiemetic from a different class than the one received for prevention.
Kienbaum P, Schaefer MS, Weibel S, Schlesinger T, Meybohm P, Eberhart LH, Kranke P. Update on PONV: what is new in prophylaxis and treatment of postoperative nausea and vomiting? Der Anaesthesist, 2022;71(2):123-128, posted online October 1, 2021. DOI . References found via PubMed.
The limits, tell them frankly
- The score has been calculated and validated in adultsIn children, the risk factors are not the same and this calculation does not apply.
- It does not take into account the type of surgery, the duration of anesthesia, or the agents used, whereas the consensus synthesis cites them all as risk factors.
- He is assessing a group risk. He is not predicting what will happen to you personally.
Other tools on the site
- What time should I stop eating and drinking before an operation?, calculated from the time of your intervention.
- The APAIS preoperative anxiety test, for the other major apprehension before an operation.
- The reference framework for recovery times, for the aftermath: 90 recommendations gathered from twelve health institutions.
This page does not replace your anesthesia consultation. It presents a published score and has no knowledge of your medical history, your procedure, or the medications that will be used. Your anesthesiologist considers many more factors than these four questions.
If you have ever had a very bad experience waking up, say so explicitly in consultation, even if your score is low: this is information that changes the treatment.
