Effect of ciprofol–etomidate mixtures for deep sedation during gastrointestinal endoscopy: Protocol for a three-arm, double-blind randomized controlled trial - Boxuan Xu; Min Niu; Xueling Zhu; Min Cui; Xiaona An; Tianhao Yu; Sihui Tang; Qiuyu Yang; Junjie Wang; Jiguo Si (PLoS ONE, 2026)