Cardiovascular

Explainable machine learning-based prediction of postoperative pulmonary infection after aneurysmal subarachnoid hemorrhage clipping and exploratory analysis of enteral nutrition timing: a dual-cohort retrospective study.

TL;DR

An explainable Naive Bayes model temporally validated for early risk stratification of postoperative pulmonary infection after aSAH clipping (validation AUC 0.811), and an exploratory analysis found a nonlinear association between enteral nutrition start time and PPI risk with an inflection near 24 h, which needs prospective validation.

Key Findings

The Naive Bayes model showed the best overall performance among nine machine-learning algorithms for predicting postoperative pulmonary infection in the temporal validation cohort.

  • Validation cohort AUC was 0.811 (95% CI, 0.755-0.855).
  • Nine machine-learning algorithms were compared on discrimination, calibration, and clinical utility using decision-curve analysis.
  • The model was developed and temporally validated in a dual-cohort retrospective design.

Candidate predictors were selected with a combined LASSO regression and random-forest importance strategy.

  • This feature-selection approach fed the nine candidate algorithms.
  • The primary prediction model was a 24-h model.

SHAP analysis was used to identify the major contributors to the primary 24-h prediction model, making the model explainable.

  • SHAP provided interpretability of the model's predictions.
  • The abstract states that major contributors were identified but does not list them.

A secondary exploratory analysis found a nonlinear association between continuous enteral nutrition initiation timing and subsequent PPI risk, with an inflection point near 24 hours.

  • The bootstrap median model-derived inflection point was 24.0 h.
  • The 95% bootstrap interval was 23.0-27.0 h.
  • The analysis treated EN initiation time as a continuous variable and was explicitly labeled secondary and exploratory.

The authors conclude the model may support early PPI risk stratification after aSAH clipping, but the EN timing finding is exploratory and requires prospective validation before clinical use.

  • The study was retrospective and reported following TRIPOD+AI principles.
  • The EN timing signal should not be interpreted as establishing a causal or clinical threshold.

What This Means

This study looked at patients who had surgical clipping of a ruptured brain aneurysm (aneurysmal subarachnoid hemorrhage). Lung infection after surgery is a common complication in these patients and is linked to slower recovery and greater use of hospital resources. The researchers built and compared nine machine-learning models to predict who would develop a postoperative lung infection, and tested the best one on a later group of patients. The best model, based on Naive Bayes, correctly separated patients who did and did not develop infection reasonably well (AUC 0.811 in the validation group). The researchers used an explainability method (SHAP) to show which factors drove the predictions. This research suggests such a tool could help identify higher-risk patients early, so that clinicians can focus monitoring and preventive efforts. The researchers also explored when tube or enteral feeding was started. They saw a nonlinear pattern, with the risk pattern changing around 24 hours after the start of the observation period (estimated 24.0 hours, range 23.0-27.0 hours). This was a secondary, exploratory finding from a retrospective study, so it cannot show that starting feeding at a certain time prevents infection. The authors say prospective studies are needed before this is used in practice.

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Citation

Li L, Li X, Shi S. (2026). Explainable machine learning-based prediction of postoperative pulmonary infection after aneurysmal subarachnoid hemorrhage clipping and exploratory analysis of enteral nutrition timing: a dual-cohort retrospective study.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1873566