Background: Accurate diagnosis of acute appendicitis in children remains challenging due to variable presentations and limitations of existing clinical scoring systems. While machine learning (ML) offers a promising approach to enhance diagnostic precision, most prior studies have been limited by small sample sizes, single-center data, or a lack of external validation. Methods: This prospective, multicenter study included 8586 pediatric patients to develop a machine learning-based diagnostic model using routinely available clinical and hematological parameters. A separate, prospectively collected external validation cohort of 3000 patients was used to assess model performance. The Random Forest algorithm was selected based on its superior performance during model comparison. Diagnostic accuracy, sensitivity, specificity, Area Under Curve (AUC), and calibration metrics were evaluated and compared with traditional scoring systems such as Pediatric Appendicitis Score (PAS), Alvarado, and Appendicitis Inflammatory Response Score (AIRS). Results: The ML model outperformed traditional clinical scores in both development and validation cohorts. In the external validation set, the Random Forest model achieved an AUC of 0.996, accuracy of 0.992, sensitivity of 0.998, and specificity of 0.993. Feature-importance analysis identified white blood cell count, red blood cell count, and mean platelet volume as key predictors. Conclusions: This large, prospectively validated study demonstrates that a machine learning-based scoring system using commonly accessible data can significantly improve the diagnosis of pediatric appendicitis. The model offers high accuracy and clinical interpretability and has the potential to reduce diagnostic delays and unnecessary imaging.

Background: Central venous catheters are essential but associated with complications in premature infants. We compared the short-term outcomes of umbilical venous catheter (UVC) versus peripherally inserted central catheter (PICC) as the initial postnatal primary venous access in preterm infants. Methods: Preterm infants with a birth weight ≤ 1500 g within the first postnatal hours were included. Patients were randomly assigned to the UVC or PICC groups. Catheter insertion time, number of attempts, number of operators, duration of catheter use, reason for removal, and overall duration were recorded. Results: A total of 107 premature infants were included, with 63 receiving UVC and 44 receiving PICC. Nineteen infants who initially had UVC placement on day 1 required PICC placement on day 5. The number of attempts, number of operators, and insertion time were significantly higher in the PICC group compared with the UVC group (p < 0.001, p = 0.002, and p = 0.002, respectively). Catheter removal due to thrombosis or leakage occurred in 14.2% of UVC cases versus 40.1% of PICC cases (p = 0.002). Conclusion: UVC placement appears to be superior to PICC as the first venous access in preterm infants during the early postnatal period. PICC placement may be less advantageous in the first days of life due to a smaller catheter diameter, technical difficulty, and longer insertion time.

Background/Objectives: We aimed to describe the clinical, laboratory, and radiological characteristics of children with complicated pneumonia/empyema who underwent video-assisted thoracoscopic surgery (VATS) and to identify factors associated with length of hospital stay. Methods: We retrospectively reviewed 68 children who presented to the pediatric emergency department of a tertiary university hospital and underwent VATS between April 2015 and April 2025. Factors associated with length of stay were assessed using univariable and multivariable negative binomial regression. Results: Median age was 60 months (interquartile range 36–138), and 66% were male. On univariable analysis, C-reactive protein (CRP) was associated with length of stay (incidence rate ratio [IRR] = 1.03 per 100 mg/L; p = 0.034), whereas age was not (p = 0.542). In the multivariable model, CRP remained borderline associated (IRR = 1.03; 95% confidence interval [CI] 1.00–1.06; p = 0.049), whereas performance of computed tomography was not (p = 0.142). An atypical (gastrointestinal or pain-predominant) presentation occurred in 25%. Streptococcus pneumoniae was the most frequently detected bacterial pathogen, mainly by nasopharyngeal polymerase chain reaction. Conclusions: In this single-center, retrospective cohort, higher CRP at presentation, but not age, was modestly associated with a longer hospital stay; this small association needs confirmation in larger prospective studies, and most children (82%) were managed with VATS alone.