Introduction
Painless gastrointestinal (GI) endoscopy is widely performed using intravenous sedation to improve patient comfort. Commonly used agents such as propofol and opioids, though effective, are associated with respiratory depression and an increased risk of hypoxemia, even under monitoring [1]. Patients with obesity are particularly vulnerable due to upper airway obstruction from tongue displacement and reduced chest wall compliance, leading to transient ventilatory impairment during sedation [2]. Maintaining airway patency while preserving spontaneous ventilation is therefore crucial. The nasopharyngeal airway (NPA) provides a simple and minimally invasive means of bypassing supraglottic obstruction and ensuring adequate ventilation. When combined with a circle system, it allows effective oxygenation while maintaining spontaneous respiration.
This case series is reported to demonstrate the safety and effectiveness of using an NPA with a circle system for spontaneous ventilation during GI endoscopy, especially in patients at increased risk of airway compromise.
Case Report
Case 1
A 32-year-old female scheduled for endoscopic retrograde cholangiopancreatography (ERCP) for common bile duct (CBD) stenting and stone removal had a body mass index (BMI) of 27 kg/m². Airway assessment revealed mouth opening >2 finger breadths, Mallampati grade II, a short neck, and a double chin.
Case 2
A 57-year-old male posted for upper gastrointestinal endoscopy had a BMI of 32 kg/m². Airway examination showed mouth opening >2 finger breadths, thyromental distance >3 finger breadths, and Mallampati grade II.
Case 3
A 52-year-old male planned for ERCP had a BMI of 30 kg/m². Airway assessment demonstrated mouth opening >2 finger breadths, thyromental distance >3 finger breadths, and Mallampati grade III.
Case 4
A 57-year-old male undergoing upper GI endoscopy had a BMI of 30.8 kg/m², with mouth opening >2 finger breadths, thyromental distance >3 finger breadths, and Mallampati grade III.
Case 5
A 46-year-old female scheduled for ERCP had a BMI of 35.6 kg/m². Airway assessment showed mouth opening >2 finger breadths, thyromental distance >3 finger breadths, and Mallampati grade II.
For all patients, standard ASA monitoring including pulse oximetry, non-invasive blood pressure, and ECG was instituted upon arrival in the endoscopy suite. A 20-G intravenous cannula was secured, and baseline oxygen saturation was recorded. Nasal prongs were initially applied, and topical anesthesia was provided using 10% lignocaine spray to the nose and throat. Sedation was achieved with intravenous midazolam 1 mg, fentanyl 50 µg, and titrated doses of propofol, while maintaining spontaneous ventilation.
A lubricated nasopharyngeal airway (RUSCH) of appropriate size was inserted and connected to a circle system using an 8-mm endotracheal tube connector [Fig.1]. Oxygen was delivered at 10 L/min, and anaesthesia was maintained with intermittent propofol boluses. The average procedure duration was 20-30 minutes, with a maximum duration of 60 minutes. All patients remained hemodynamically stable throughout the procedure, with no episodes of hypoxemia [Fig.2], and were comfortable in the post-procedure period.
Discussion
Patients with obesity are particularly prone to hypoxemia during procedural sedation because of anatomical and physiological alterations such as a short neck, reduced functional residual capacity, decreased chest wall compliance, and a narrowed upper airway. In addition, propofol administration in obese patients is dose-dependent and significantly increases the risk of apnea and hypoxemia during anaesthesia. Previous studies have reported that the incidence of hypoxemia in obese patients receiving propofol and opioids during endoscopy may reach up to 32% when oxygen is delivered through an endoscopic respiratory mask [2].
High-flow nasal oxygen techniques, including Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE), are used in some centres during gastrointestinal endoscopy; however, their application may be limited in patients with significant upper airway obstruction or reduced respiratory effort. The NPA serves as an effective artificial airway extending from the nasal cavity to the glottic level, directly relieving obstruction caused by posterior tongue displacement. Its effectiveness in upper airway management is well established, with studies demonstrating successful replacement of laryngeal mask airways by NPAs during plastic surgery performed under general anaesthesia [3].
While both NPA and THRIVE support oxygenation, the NPA offers distinct advantages. It provides immediate airway patency by bypassing soft tissue obstruction, making it particularly useful in patients with partial airway collapse, such as those with obesity, obstructive sleep apnea, or altered consciousness. Unlike THRIVE, which relies on the patient’s spontaneous respiratory effort, the NPA maintains airflow even in the presence of reduced respiratory drive and is compatible with both spontaneous and assisted ventilation. Furthermore, the NPA can be safely used when oropharyngeal airways are contraindicated, such as in trismus or facial trauma (in the absence of basal skull fracture).
In addition to its clinical effectiveness, the NPA is a simple, cost-effective device requiring minimal equipment and no separate oxygen delivery port, making it suitable for use in diverse clinical settings, including endoscopy suites and resource-limited environments. These advantages emphasize the role of the NPA connected to a circle system as a practical and reliable airway management strategy during gastrointestinal endoscopy under sedation.
Conclusion
The nasopharyngeal airway is a simple, cost-effective airway adjunct that functions as an artificial conduit from the nasal cavity to the glottis, facilitating airway patency during procedural sedation. When used in conjunction with a circle system, it allows effective oxygen delivery while preserving spontaneous ventilation. Owing to its ease of insertion and minimal equipment requirement, this technique can be readily adopted by anaesthesiologists and endoscopists to enhance airway safety during gastrointestinal endoscopy.
Contributors: MS: Conceptualization, study design, data collection, manuscript drafting; SB: Data analysis, literature review, manuscript editing, clinical supervision, case selection. MS will act as a study guarantor. Both authors approved the final version of this manuscript and are responsible for all aspects of this study.
Funding: None; Competing interests: None stated.
References
- Xiao Q, Yang Y, Zhou Y, Guo Y, Ao X, Han R, et al. Comparison of nasopharyngeal airway device and nasal oxygen tube in obese patients undergoing intravenous anesthesia for gastroscopy: A prospective and randomized study. Gastroenterol Res Pract. 2016;2016:2641257.
- Xiang D, Deng L, Zhou R, Zhang X, Tian L, Jiang W, et al. Comparison of nasopharyngeal airway with endoscopic respiratory mask for hypoxemia in painless gastrointestinal endoscopy in obese outpatients: Study protocol for a randomized controlled trial. Med Devices (Auckl). 2025;18:97-106.
- El-Ozairy HSE, Abd-Elmaksoud AM, El-Hennawy AM. Comparison between nasopharyngeal airway and laryngeal mask airway in blepharoplasty under general anaesthesia. A randomized controlled trial. Anaesthesiol Intensive Ther. 2020;52(5):389-394.