Sedation during upper gastrointestinal endoscopy may lead to respiratory events not only during the procedure but also in the early recovery period. Although most hypoxemic episodes are considered transient, their frequency, duration, and clinical consequences during recovery remain insufficiently defined.

This prospective observational study aims to evaluate the incidence, duration, and clinical impact of recovery-period hypoxemia following sedated upper gastrointestinal endoscopy. Hypoxemia is defined as SpO₂ <90% lasting ≥10 seconds. Associated respiratory events and potential risk factors will be analyzed without altering routine clinical practice.

Inclusion Criteria:

• Adults aged ≥18 years
• Scheduled for upper gastrointestinal endoscopy (EGD) under anesthesiologist-administered sedation
• Able to undergo post-procedure monitoring in the recovery unit
• Provided written informed consent for participation and data use

Exclusion Criteria:

• Colonoscopy or combined procedures (EGD + colonoscopy)
• Emergency procedures or procedures performed under intensive care conditions
• Requirement for endotracheal intubation, noninvasive ventilation, or advanced airway support during the procedure
• Known severe upper airway anatomical abnormalities, facial deformity, or tracheostomy
• Inability or refusal to provide informed consent
• Incomplete or unavailable recovery-period oxygen saturation monitoring data

Adult patients undergoing elective upper gastrointestinal endoscopy (EGD) under anesthesiologist-administered sedation at a single tertiary care endoscopy unit. Participants will be enrolled consecutively and followed prospectively during the immediate recovery period without alteration of routine clinical management.