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.

Inclusion criteria

• Age 18-80 years;
• BMI: 18-30 kg/m²;
• ASA class I-II;
• Scheduled to undergo elective sedated gastrointestinal endoscopy;
• Willing to participate in this study and able to provide written informed consent.

Exclusion criteria

• Diagnosed respiratory diseases, including asthma, bronchitis, chronic obstructive pulmonary disease (COPD), emphysema, moderate or severe obstructive sleep apnea (OSA), pulmonary embolism, pulmonary edema, lung cancer, or upper respiratory tract infection, etc.;
• Coagulation disorders, tendency for oral/nasal bleeding, mucosal injury, or space-occupying lesions;
• Severe cardiac insufficiency (≤4 MetS);
• Severe renal insufficiency (acute kidney injury [AKI] or chronic kidney disease [CKD] stage 4 or higher);
• Severe hepatic insufficiency (Child-Pugh class C or worse);
• Planned therapeutic endoscopy (e.g., polypectomy, endoscopic mucosal resection [EMR], or other therapeutic procedures);
• Pregnancy or breastfeeding;
• Allergy to the study drugs;
• Emergency surgery;
• Daily alcohol intake ≥60 grams;
• History of psychiatric disorders: e.g., depression, severe central nervous system depression, Parkinson's disease, basal ganglia lesions, schizophrenia, epilepsy, Alzheimer's disease;
• Myasthenia gravis;
• Participation in other related clinical trials within the past 3 months;
• Refusal to participate.