A Machine Learning Prediction Model for Delayed CIPONV

The website https://mvansmeden.shinyapps.io/BeyondEPV/ was used for sample size calculation, considering 6 candidate predictors, an event fraction of 0.14, and a criterion value for reduced mean predictive squared error of 0.03. The calculated sample size is 1080, with a minimally required expected event per variable of 25.1. Therefore, a sample size of 1154 patients is deemed sufficient to support the inclusion of 6 predictors in the development of the predictive model.

A total of 81 variables, including demographics, comorbidities, laboratory findings, as well as information related to anesthesia and surgery, are prospectively collected in the FDP-PONV trial and considered as potential predictive factors in this study. The least absolute shrinkage and selection operator method is used to identify clinically significant variables. Further selection of the final predictors is performed using stepwise regression based on the Akaike Information Criterion.

The entire dataset is randomly divided into a training set and a validation set in a ratio of 7:3. Six machine learning models, namely logistic regression, random, extreme gradient boosting, k-nearest neighbor, gradient boosting decision, and multi-layer perceptron, were developed to create risk prediction models for delayed CIPONV. The performance of the models is assessed by comparing the area under the receiver operating characteristic curve, accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1 score, Brier score and calibration curve. Bootstrap resamples is conducted 1000 times on the training cohort to evaluate the predictive model's performance. Decision curve analysis is conducted to assess the clinical applicability of the model. The SHapley Additive Explanations library (SHAP) is used to interpret the prediction model.

Inclusion criteria

a) age between 18 and 75 years, b) having 3 or 4 Apfel risk factors, and c) scheduled to undergo laparoscopic gastrointestinal surgical procedures under general anesthesia.

Exclusion criteria

a) American Society of Anesthesiologists (ASA) physical status greater than 3, b) severe hepatic dysfunction, c) contraindications to fosaprepitant, 5-HT3 receptor antagonist, or dexamethasone, d) preoperative use of medications known to have antiemetic properties, e) presence of mental disorders or inability to communicate, and f) pregnant or nursing women.