Multifunctional Oropharyngeal Airway and Hypoxemia in Sedated GI Endoscopy: A Multicenter RCT

Study Title Effect of a Novel Multifunctional Oropharyngeal Airway on Hypoxemia in Patients Undergoing Sedated Gastrointestinal Endoscopy: A Multicenter, Prospective, Randomized Controlled Trial

Principal Investigator Dr. Wu Jianbo, Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Shandong First Medical University (Shandong Provincial Qianfoshan Hospital)

Participating Centers A total of 29 centers across China (including Zhejiang University First Affiliated Hospital, Hebei Medical University Second Hospital, Qilu Hospital of Shandong University, etc.)

Study Objective To evaluate whether a novel multifunctional oropharyngeal airway (MOPA) reduces the incidence of hypoxemia compared to conventional nasal cannula with standard mouthpiece in patients undergoing sedated gastrointestinal endoscopy.

Study Design Multicenter, prospective, parallel-group, randomized controlled trial.

Sample Size 1,518 patients (759 per group), accounting for a 20% dropout rate. Power: 90%, two-sided alpha: 0.05.

Participant Criteria

Inclusion: Age 18-80 years; ASA I-II; scheduled for elective sedated gastroscopy + colonoscopy; written informed consent.

Exclusion: Known respiratory disease (asthma, COPD, moderate-severe OSA, etc.); bleeding tendency or oral/nasal mucosal injury; severe cardiac/renal/hepatic dysfunction; therapeutic endoscopy (e.g., polypectomy, EMR); pregnancy; known drug allergy; emergency procedure; alcohol abuse; psychiatric illness; myasthenia gravis; participation in another trial within 3 months; refusal.

Interventions

Experimental group (MOPA): After standard sedation (fentanyl 0.05 μg/kg + propofol 1.5-2.5 mg/kg, then propofol infusion 4-12 mg/kg/h), a novel multifunctional oropharyngeal airway (integrating a bite block, oropharyngeal airway, oxygen delivery channel, and CO₂ sampling port) is inserted. Oxygen 3-4 L/min is delivered via the device, and PETCO₂ is continuously monitored through the sampling port.

Control group (conventional mouthpiece): Same sedation regimen. Patients receive oxygen 3-4 L/min via nasal cannula. PETCO₂ is monitored via nasal cannula sampling line. No oropharyngeal airway is used.

Both groups receive standardized rescue interventions for hypoxemia or ventilatory abnormalities.

Primary Endpoint Incidence of hypoxemia defined as 75% ≤ SpO₂ < 90% lasting < 60 seconds during the procedure.

Secondary Endpoints

Severe hypoxemia (SpO₂ < 75% OR 75% ≤ SpO₂ < 90% lasting ≥ 60 s)

PETCO₂ monitoring success rate (proportion with clear continuous waveform)

Detection rate of hypoventilation events (apnea ≥15-20 s; respiratory rate <8/min for ≥30 s) and early warning time before SpO₂ decline

Incidence of hypercapnia (PETCO₂ >50 mmHg or >45 mmHg for ≥30 s)

Adverse events: airway injury, regurgitation, aspiration, coughing, laryngospasm, post-procedural sore throat, hoarseness, dental/oral soft tissue injury

Airway intervention burden (jaw thrust, increased O₂ flow, procedure pause, face-mask ventilation, laryngeal mask/intubation)

Procedural efficiency (scope insertion-to-withdrawal time, number of interruptions/withdrawals due to respiratory events)

Endoscopist satisfaction (0-10 scale) and patient satisfaction (customized 0-2 per item score)

Safety Outcomes Device-related (mucosal injury, bleeding, sore throat), respiratory events (cough, laryngospasm, aspiration, need for advanced airway), systemic complications (hemodynamic instability, unplanned hospitalization/ICU), serious adverse events (refractory hypoxemia, emergency airway support, arrhythmia, myocardial ischemia, anaphylaxis, stroke).

Statistical Analysis Primary endpoint comparison using chi-square or Fisher's exact test; continuous variables using t-test or Mann-Whitney U test as appropriate. All tests two-sided, significance level α=0.05. Analysis sets: FAS, PP, SS. Missing data handled by multiple imputation where applicable.

Randomization and Blinding Centralized randomization via EDC system using stratified block randomization (block sizes 4,6,8; stratified by center). Patients are blinded to group assignment. Operators are unblinded due to device appearance. Outcome assessors and statisticians are blinded until database lock (two-stage unblinding).

Study Duration Start anticipated June 2026, completion December 2027.

Expected Publications 1-2 SCI-indexed papers reporting the primary and secondary outcomes.