Changes in pulse oximetry levels and factors affecting oxygen saturation during routine upper gastrointestinal endoscopy with or without sedation - KILIÇ, Mehmet; BAYAN, Kadim; YILMAZ, Şerif; TÜZÜN, Yekta; DURSUN, Mehmet; CANORUÇ, Fikri (Turkish Journal of Gastroenterology, 2006)