Hypoxemia prediction in pediatric patients under general anesthesia using machine learning: A retrospective observational study and external validation - Sujin Baek; Jung-Bin Park; Jihye Heo; Kyungsang Kim; Donghyeon Baek; Chahyun Oh; Hyung-Chul Lee; Dongheon Lee; Boohwi Hong (PLoS ONE, 2026)