A risk score to predict the probability of postoperative vomiting in adults

Acta Anaesthesiol Scand. 1998 May;42(5):495-501. doi: 10.1111/j.1399-6576.1998.tb05157.x.


Background: The aim of this study was to identify factors most relevant for postoperative vomiting (PV) and to develop a risk score to predict the probability of PV.

Methods: Adult inpatients scheduled for elective ear, nose and throat (ENT) surgery under general anaesthesia were offered to participate in a prospective study for PV over 24 h. No prophylactic antiemetics were used. The data of 1137 patients were randomized and split into an evaluation set (n=553) and a validation set (n=584). The evaluation set was subjected to logistic regression analysis to quantify the relative impact of anaesthetic, surgical and individual factors and to develop a risk score. The score was then tested by applying it to the validation set. The area under a receiver operation characteristic (ROC) curve was calculated and the predicted and actual incidences of patients were correlated.

Results: In the evaluation set, patient-related factors (female gender, young age, non-smoking, history of PV or motion sickness) and a high duration of anaesthesia were independent risk factors for PV. The probability of PV could be estimated from the equation: PV=1/(1+exp(-z)) where z=1.28 (gender)-0.029 (age)-0.74 x (smoking)+0.63 x (history of PV or motion sickness)+0.26 x (duration)-0.92. In the validation set this score achieved an area under the ROC-curve of 0.78 and the actual incidence correlated strongly with the predicted risks (R2=0.93, P<0.001).

Conclusion: The data suggest that the probability of PV following ENT surgery under inhalational anaesthesia with low-dose opioids can be predicted by a score mainly based upon patient-related risk factors.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Age Factors
  • Algorithms
  • Anesthesia, General / adverse effects
  • Anesthetics, General / adverse effects
  • Anesthetics, Inhalation / adverse effects
  • Area Under Curve
  • Elective Surgical Procedures
  • Evaluation Studies as Topic
  • Female
  • Forecasting
  • Humans
  • Incidence
  • Logistic Models
  • Male
  • Middle Aged
  • Motion Sickness / complications
  • Narcotics / adverse effects
  • Otorhinolaryngologic Diseases / surgery
  • Postoperative Complications*
  • Probability
  • Prospective Studies
  • ROC Curve
  • Reproducibility of Results
  • Risk Factors
  • Sex Factors
  • Smoking
  • Time Factors
  • Vomiting / etiology*


  • Anesthetics, General
  • Anesthetics, Inhalation
  • Narcotics