This prospective observational cohort study will evaluate the incidence and independent predictors of clinically relevant hypotension and hypoxemia during propofol-based diagnostic gastrointestinal endoscopy in adult patients at a tertiary referral hospital in Vietnam. Participants undergoing diagnostic upper gastrointestinal endoscopy, colonoscopy, or combined diagnostic procedures with propofol administration will be followed from pre-procedure assessment through the early recovery period. The study will assess demographic, clinical, airway, procedural, and sedation-related variables associated with clinically relevant cardiopulmonary adverse events.

Propofol is widely used for diagnostic gastrointestinal endoscopy because of its rapid onset and recovery profile, but it may be associated with cardiopulmonary adverse events, particularly hypotension and hypoxemia. The reported incidence of these events varies substantially across studies because of differences in patient populations, definitions, monitoring intensity, and sedation/anesthesia practice.

This single-center prospective cohort study will enroll adult patients undergoing diagnostic gastrointestinal endoscopy with propofol as the primary sedative/anesthetic agent. Eligible participants will be consecutively recruited at Bach Mai Hospital. Baseline demographic characteristics, comorbidities, airway assessment findings, obstructive sleep apnea risk, procedural characteristics, and sedation/anesthesia-related variables will be collected using a standardized case report form.

The two co-primary outcomes are clinically relevant hypotension and clinically relevant hypoxemia during the peri-procedural period. Participants will be monitored from pre-procedure baseline through the procedure and until discharge from the recovery area. If early post-procedure observation is prolonged because of a sedation/anesthesia-related event, follow-up for that participant will continue until initial stabilization and an immediate post-procedure management decision are completed.

Two separate multivariable logistic regression models will be developed to identify independent predictors of clinically relevant hypotension and clinically relevant hypoxemia. The study is intended to inform risk stratification and improve patient safety during propofol-based diagnostic gastrointestinal endoscopy

Inclusion Criteria:

• Age 18 years or older
• Scheduled for diagnostic esophagogastroduodenoscopy, diagnostic colonoscopy, or combined diagnostic upper and lower gastrointestinal endoscopy
• Planned use of propofol as the primary sedative/anesthetic agent for diagnostic gastrointestinal endoscopy
• American Society of Anesthesiologists physical status I to III
• Able to provide informed consent or has legally authorized representative consent according to local regulations

Exclusion Criteria:

• Therapeutic or interventional gastrointestinal endoscopy, including ERCP, EUS-guided intervention, EMR, ESD, endoscopic hemostasis, or polypectomy
• Planned sedation/anesthesia without propofol as the primary sedative/anesthetic agent
• Known allergy or contraindication to propofol
• Pregnancy or suspected pregnancy
• Emergency condition requiring immediate advanced airway control before the procedure
• Inability to obtain essential baseline or outcome data required for the study

Adult patients undergoing Propofol-Based Diagnostic Gastrointestinal Endoscopy at Bach Mai Hospital, a tertiary referral center in Vietnam.

The investigators have not yet finalized a plan for sharing individual participant data. Any future decision will be subject to institutional approval, participant confidentiality safeguards, applicable ethics requirements, and journal or data-sharing policies in effect at the time of publication.