This randomized controlled trial compared the efficacy of a nasal mask versus a standard nasal cannula for oxygen delivery during gastrointestinal endoscopic procedures performed under target controlled propofol infusion anesthesia with SedLine brain function monitoring. Hypoxemia during procedural sedation is a common and clinically relevant event, especially during upper endoscopy and combined procedures. The study aimed to determine whether nasal mask oxygenation reduces hypoxemia compared with nasal cannula oxygenation when sedation depth is guided with electroencephalography based monitoring.

Eligible adult patients undergoing gastrointestinal endoscopic procedures were randomly assigned to receive oxygen either via a nasal mask or via a nasal cannula. Oxygen was administered at a fixed flow rate according to the study protocol. Sedation was provided with target controlled propofol infusion, and SedLine monitoring was used to guide sedation depth throughout the procedure.

The primary outcome was the occurrence of hypoxemia, defined as peripheral oxygen saturation at or below 90 percent. Secondary outcomes included severe hypoxemia, duration of hypoxemia, lowest peripheral oxygen saturation value, need for airway interventions, other adverse events during the procedure, procedure time, recovery time, and operator satisfaction ratings. The study has been completed.

This study was a prospective randomized controlled trial designed to compare two oxygen delivery approaches during gastrointestinal endoscopic procedures performed under target controlled propofol infusion anesthesia with SedLine brain function monitoring. The main objective was to evaluate whether nasal mask oxygenation provides better protection against hypoxemia than standard nasal cannula oxygenation when sedation depth is actively guided with electroencephalography based monitoring.

Adult patients scheduled for gastrointestinal endoscopic procedures were assessed for eligibility and enrolled after appropriate ethical approval and informed consent procedures in accordance with local regulations. Participants were randomly assigned to one of two groups. In the nasal mask group, oxygen was delivered using a nasal mask device. In the nasal cannula group, oxygen was delivered using a standard nasal cannula. Oxygen flow was administered as specified in the protocol. Sedation for all patients was provided with target controlled propofol infusion. SedLine brain function monitoring was used to guide and standardize sedation depth during the procedure to reduce variability related to over sedation or under sedation.

The primary outcome was hypoxemia, defined as peripheral oxygen saturation at or below 90 percent. Secondary outcomes included severe hypoxemia, duration of hypoxemia, the minimum peripheral oxygen saturation recorded, need for airway support or rescue interventions, procedure related adverse events such as cough, hiccup, nausea, vomiting, reflux, aspiration, and laryngospasm, total procedure time, recovery time, and satisfaction ratings by the anesthesiologist and the endoscopist. All outcomes were assessed during the procedure and the immediate recovery period based on standardized definitions in the study protocol. The study has been completed, and the collected data are intended to support evaluation of the comparative effectiveness and safety of nasal mask versus nasal cannula oxygenation in this clinical setting.

Inclusion Criteria:

• Adults aged 18 years or older.

Scheduled for gastrointestinal endoscopic procedures (upper endoscopy and or colonoscopy) under propofol sedation using target controlled infusion with SedLine monitoring.

American Society of Anesthesiologists (ASA) physical status I to III.

Provided written informed consent.

Exclusion Criteria:

• Refusal or inability to provide informed consent.

Known allergy or contraindication to propofol or study related materials.

Severe cardiorespiratory instability or conditions judged by the investigator to increase procedural risk.

Pregnancy.

Requirement for tracheal intubation or general anesthesia at the outset of the procedure.

Significant anatomic or clinical factors precluding use of the assigned oxygen delivery device.

Open label due to the visible nature of the oxygen delivery device. Outcome measures were based on objective pulse oximetry and standardized definitions.