Impact of Nasal Mask Versus Nasal Cannula Oxygenation on Hypoxemia in Gastrointestinal Endoscopy: A Brain Function Monitoring (SedLine)-Guided Randomized Controlled Trial (NAMSHIC)

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.

• Nasal Mask Oxygenation (Device): Oxygen supplementation delivered via a nasal mask at the protocol specified flow rate during the procedure.
• Nasal Cannula Oxygenation (Device): Oxygen supplementation delivered via a standard nasal cannula at the protocol specified flow rate during the procedure.

Primary outcomes

• Hypoxemia [During the endoscopic procedure and immediate recovery period (from start of sedation to discharge from the recovery area).]: Occurrence of hypoxemia defined as peripheral oxygen saturation (SpO2) ≤ 90% during the procedure

Secondary outcomes

• Severe hypoxemia [During the endoscopic procedure and immediate recovery period]: SpO2 ≤ 75% at any time, or SpO2 ≤ 90% lasting ≥ 60 seconds.
• Duration of hypoxemia [During the endoscopic procedure and immediate recovery period.]: Total duration (seconds) with SpO2 ≤ 90%.
• Minimum SpO2 [During the endoscopic procedure]: Lowest SpO2 recorded during the procedure.
• Need for airway interventions [During the endoscopic procedure and immediate recovery period]: Any airway rescue or supportive intervention required (e.g., airway repositioning, jaw thrust, increased oxygen, mask ventilation, or other emergency airway management).
• Procedure-related adverse events [During the endoscopic procedure and immediate recovery period.]: Cough, hiccup, nausea, vomiting, reflux, aspiration, laryngospasm, and other adverse events.
• Procedure time [During the procedure.]: Total procedure duration (minutes).
• Recovery time [Immediately after the procedure]: Time from end of procedure to readiness for discharge from recovery (minutes).
• Satisfaction ratings [mmediately after the procedure, during recovery (same day).]: Anesthesiologist and endoscopist satisfaction assessed using a 0-100 Numeric Rating Scale, where 0 = least satisfied and 100 = most satisfied (higher scores indicate greater satisfaction)

Sex: All, ages: 18 Years to any

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.

• Study Protocol and Statistical Analysis Plan (PDF, 2025-12-15)