Abstract
Background
Respiratory depression and airway obstruction are the most common respiratory adverse reactions in elderly patients undergoing gastroenteroscopy under sedation. Additionally, sharing the airway with endoscopists can complicate airway management. Here, we plan to apply COMBO (Capnography Monitoring Bite Block Oxygenation) endoscopy of the oropharyngeal airway, a novel airway management device with integrated capnography monitoring and dual oxygenation support, to investigate the incidence of adverse events such as hypoxaemia and airway obstruction in elderly patients during anaesthesia, providing a reference for airway management in clinical practice.
Methods and findings
This will be a prospective, randomized, controlled clinical study. We will enrol 164 elderly patients (aged 65–80 years) scheduled for painless gastroenteroscopy. The participants will be randomly assigned to two groups. In the experimental group, an oropharyngeal airway designed for gastroscopy will be used. The control group will receive an ordinary endoscopic bite block. The primary outcome measure will be the incidence of hypoxia (75% ≤ SpO2 < 90%, ≤ 60 s), and the secondary outcome measures will be the incidence of severe hypoxia (SpO2 < 75% or 75% ≤SpO2 < 90%, ≥ 60 s); incidence of circulatory fluctuations [severe bradycardia (< 50 beats/min), a mean arterial pressure (MAP) fluctuation greater than 30% of the baseline value or an MAP < 60 mmHg]; incidence of airway intervention; dose of additional drugs administered during the procedure; endoscopist satisfaction; and incidence of various adverse events.
Results
This clinical study aims to evaluate whether an oropharyngeal airway dedicated to gastroscopy can effectively maintain airway patency and alleviate retrolingual collapse, thereby preventing hypoxaemia. It also aims to determine whether it can reduce the incidence of respiratory-related adverse events.
Trial Registration
This clinical trial protocol was formally registered at ClinicalTrials.gov (Registration Number: NCT06711328) on November 26, 2024.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12871-025-03311-8.
Keywords: Elderly patients, Endoscopic oropharyngeal airway, Gastroenteroscopy
Introduction
For digestive system diseases with a high incidence, timely prevention, treatment, and endoscopic examination of the digestive system are essential for detecting early lesions [1]. Some studies have shown that a single colonoscopy screening can reduce the incidence and mortality of colorectal cancer within 20 years [2]. Wendy Atkin et al.. reported that a single colonoscopy can provide effective protection against colorectal cancer and death for up to 17 years [3].
During endoscopy, the gastroscope enters the gastrointestinal tract through the oropharynx. Owing to the high sensitivity of the pharynx, gastroscope placement commonly causes pain, nausea, and vomiting and may even cause suffocation. Severe discomfort, such as vomiting, coughing or pain during physical movement, may worsen the original disease or interrupt the examination or treatment [4]. Conversely, painless gastroenteroscopy significantly alleviates patients’ anxiety, fear, pain, and other adverse emotions [5]; in addition, it creates an optimal environment for examination. Sedation enables patients to cooperate better with the examination, thus increasing the detection of early cancer (EC) and precancerous lesions (including high-grade intraepithelial neoplasia (HGIN)) in the upper digestive tract (UGI) and promoting the implementation of a painless diagnosis and treatment. This gives patients greater satisfaction during gastroenteroscopy and a higher detection rate of early digestive system lesions [6, 7].
With the increasing ageing of the global population, a growing proportion of elderly patients are undergoing gastrointestinal endoscopy procedures. This demographic shift has led to an increased incidence of anaesthesia-related adverse events, particularly hypoxaemia, airway obstruction, and haemodynamic instability, which predominantly affect the respiratory and cardiovascular systems [8]. Advanced age is an independent risk factor for hypoxaemia in patients undergoing painless gastroenteroscopy [9, 10]. Owing to the combined effects of physiological and pathological characteristics, such as reduced lung compliance, reduced alveolar active substances, reduced lung parenchymal function, and decreased respiratory reserve capacity, as well as many chronic diseases [11], elderly patients undergoing gastroenteroscopy are more prone to varying degrees of airway obstruction or hypoxaemia caused by respiratory depression during anaesthesia [12, 13]. The intense stimulation of the pharynx by gastroscopy is likely to cause coughing, reflux aspiration, body movement, and other adverse reactions, requiring more drugs to deepen anaesthesia. Propofol is the most commonly used anaesthetic drug during gastroenteroscopy. It can inhibit the circulation and respiration of patients to varying degrees, resulting in an increased incidence of intraoperative hypoxaemia and hypotension [14, 15]. Anaesthetic drugs can also weaken the protective reflex of the digestive tract, resulting in a higher incidence of reflux, cough and aspiration during gastroenteroscopy under sedation [16].
Since the airway is shared between the anaesthesiologist and the endoscopist during gastroscopy, airway management during anaesthesia is very challenging. Additionally, most patients undergo gastroenteroscopy in the lateral position, and opening the airway through mandibular lifting is not very effective [17]; measures such as high-flow oxygen inhalation when the airway cannot be fully opened seem unable to achieve positive outcomes [18]. Effective ventilation devices can smooth the airway and reduce the incidence of hypoxaemia and other respiratory-related complications, such as choking and laryngeal spasm. Most nasopharyngeal ventilation devices used in clinical practice are nasopharyngeal channels and nasal high-flow oxygen inhalation devices. Although they provide a good oxygen supply, they cannot directly solve upper respiratory tract obstructions, such as tongue retraction, and nasopharyngeal airways carry a risk of nasal bleeding.
Compared with traditional endoscopic bite blocks, the multifunctional device shown in Fig. 1 integrates a bite block, capnography monitoring, oxygenation support, and an innovative oropharyngeal airway design. An oropharyngeal airway is an open tongue depressor that can effectively press the tongue body without affecting the operating space of endoscopists to prevent airway obstruction caused by tongue retraction, establish an oropharyngeal airway, and provide nasal oxygen simultaneously. Moreover, this device can be used for dual oxygenation and capnography monitoring and is capable of providing supraglottic jet ventilation capability. Researchers have noted that end-expiratory carbon dioxide monitoring under sedation can reduce the incidence of decreased oxygen saturation and hypoxaemia in patients undergoing colonoscopy [19–21].
Fig. 1.
Capnography monitoring of bite block oxygenation
Therefore, this study aims to determine the incidence of hypoxaemia and other respiratory adverse events during gastroenteroscopy in elderly patients under sedation with this novel airway management device, providing an effective reference and guidance for clinical application.
Materials and methods
Research design
This will be a prospective, randomized, controlled and interventional clinical study. One hundred sixty-four elderly patients (aged 65–80 years) scheduled to undergo painless gastroenteroscopy in the Department of Digestive Endoscopy at the First Affiliated Hospital of Shandong First Medical University (Shandong Qianfo Hospital) will be recruited. They will be randomly divided into an experimental group (the gastroscopic oropharyngeal airway group) and a control group (the ordinary endoscope bite block group).
The methods and results of this study will be reported according to the Standard Protocol Items: Recommendations for Interventional Trials 2013 statement (Additional file 1). A flow diagram for the trial is presented in Fig. 2.
Fig. 2.
Clinical Trial Flowchart
Inclusion criteria
Aged 65–80 years.
Written informed consent of the patient or their family member.
Painless gastroenteroscopy + colonoscopy.
American Society of Anesthesiologists (ASA) grade I–II.
Exclusion criteria
A clotting disorder or a tendency towards nose and mouth bleeding, mucosal damage or space occupation, oropharyngeal airway implantation difficulties or the inability to perform oropharyngeal airway ventilation for other reasons.
Severe cardiac insufficiency (≤ 4 MetS).
Severe renal insufficiency (acute kidney injury (AKI) and chronic kidney disease (CKD) stage 4 or higher).
Severe liver insufficiency (Child‒Pugh class C or higher liver function).
Chronic obstructive pulmonary disease (COPD), other current acute or chronic pulmonary diseases, or the need for long-term or intermittent oxygen therapy.
Increased intracranial pressure.
Upper respiratory tract infections such as those of the mouth, nose, or throat.
Fever (core body temperature ≥ 37.5 degrees Celsius).
History of sleep apnoea, limited mandibular extension, or the presence of airway tumours.
Allergy to sedatives such as propofol or devices such as tape.
Emergency procedure.
Multiple trauma.
Preoperative SpO2 < 95%.
For patients with a BMI > 30, patients must have documented that they do not suffer from severe obstructive sleep apnoea (AHI ≥ 30 events/hour).
History of drug and/or alcohol abuse within 2 years before initiation of the screening period (drinking more than three times the standard alcoholic beverages per day, equivalent to approximately 10 g of alcohol or 50 g of Chinese liquor).
Patients with documented diagnosis or treatment records of neuropsychiatric disorders within the past 5 years, including neurological disorders such as neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, etc.), cerebrovascular diseases (stroke sequelae, vascular dementia, etc.), epilepsy or seizure history (with episodes within 5 years), central nervous system infections/trauma with residual dysfunction, psychiatric disorders such as psychotic disorders (schizophrenia, delusional disorder, etc.), moderate-to-severe depression/bipolar disorder (currently or within 2 years requiring medication), substance dependence (history of alcohol, drug, or other addictive substance abuse), and other conditions potentially affecting cognition or compliance (e.g., autism spectrum disorder, attention deficit hyperactivity disorder).
Considered inappropriate for participation in this trial by the researchers.
Sample size calculation
In a preexperimental study of the elderly population, the incidence rates of hypoxia in the experimental group and the control group were 0.15 and 0.4, respectively. The sample size was calculated via PASS software, with a two-sided test level α of 0.05 and a test power of 0.9. On the basis of the incidence of hypoxia, 65 patients need to be included in each group. After considering a 20% dropout rate, 82 patients will be required in each group, for a total of 164 patients.
Blinding and randomization
This open-label study maintained blinding for personnel responsible for data management and statistical analysis, despite the absence of overall participant provider blinding. A computer-generated randomization sequence will randomly assign eligible patients to the control or experimental groups. Randomization will be conducted at a 1:1 ratio.
Device specifications
The COMBO endoscopic oropharyngeal airway is produced by Shanghai ALIFUN Medical Technology Co., Ltd. The COMBO endoscopic oropharyngeal airway is available in three sizes: small (S), medium (M), and large (L). The selection criteria were as follows: height < 155 cm: size S; height 155–175 cm: size M; and height > 175 cm: size L. Additionally, within each height category, a size larger than the height-recommended size must be selected if the BMI ≥ 28 kg/m².
The COMBO endoscopic oropharyngeal airway is primarily constructed from medical-grade polymers, featuring a flexible structure with a hydrophilic coating that facilitates atraumatic insertion and minimizes mucosal injury. During the procedure, adjusting the oxygen flow rate to 5–8 L/min is recommended.
Instructions for use:
Before anaesthesia, the bite block is placed into the patient’s mouth and secured by fastening the elastic strap around the back of the head.
One end of the oxygen supply tube is connected to the central oxygen supply, while the other end has two interfaces: one connects to the oxygen delivery port on the bite block component of the oropharyngeal airway; the other interface is used for nasal oxygen administration before anaesthesia to achieve preoxygenation.
After anaesthesia, the oropharyngeal airway component is inserted, the CO₂ sampling tube for end-tidal CO₂ (EtCO₂) monitoring is attached, and then normal diagnostic or therapeutic procedures are performed.
Intervention
The intervention in this study will be carried out by the relevant staff of the undergraduate department participating in this clinical trial, who plan to use SAS to achieve simple randomization grouping:
COMBO endoscopy oropharyngeal airway group (experimental group): From the time anaesthesia is induced until the end of gastroscopy, a continuous oxygen supply is provided through a catheter connected to the bite portion of the endoscope.
In the regular endoscopic bite group (control group), oxygen is supplied through a regular nasal cannula before anaesthesia is induced and until the end of gastroscopy.
Test process
After the study participants enter the examination room, venous access will be established, and 5 ml of 2% lidocaine gel will be used to rinse their mouths and pharynx. Heart rate (HR), pulse oxygen saturation (SpO2), end expiratory carbon dioxide, electrocardiogram, and noninvasive blood pressure (measured every 2.5 min) will be routinely monitored before anaesthesia induction. The study participants will be instructed to lie in the left lateral position.
The clinical doctors will complete the entire experimental procedure in this clinical study.
Before anaesthesia induction, participants in the experimental group will receive 5–6 L/min of oxygen through an endoscopic bite device for approximately 2 min, whereas participants in the control group will inhale 5–6 L/min of oxygen through a nasal cannula for approximately 2 min. Both anaesthesia induction groups will receive 5 µg of sufentanil, followed by an intravenous injection of 1.5 mg/kg propofol 60 s later. After sufficient sedation is reached (MOAA/S < 2) in the COMBO endoscopy oropharyngeal airway group, gastroscopy will begin after the oropharyngeal airway is inserted through the endoscopic bite block. The endoscopic procedure will begin in the ordinary endoscopic bite group once sufficient sedation is achieved. Both groups will receive Continuous infusions of 4 mg/kg·h propofol for anaesthesia maintenance until the procedure is completed. During the diagnosis and treatment process, if coughing or Limb spasm occurs during the endoscopic process, 5 ml of propofol will be administered to reach the appropriate depth of anaesthesia; if the heart rate (HR) is < 50 beats/min, an intravenous injection of 0.5 mg of atropine will be given; if the mean arterial pressure (MAP) falls below 60 mmHg, norepinephrine should be administered as 4–12 µg intravenous boluses, with the initial dose adjusted according to hypotension severity. If blood pressure remains unresponsive within 1 min of the initial dose, repeat bolus doses may be administered at ≥ 1-minute intervals. In hypotensive patients, hypovolemia should be assessed first. On the basis of clinical parameters, including weight and blood pressure, judicious intravenous fluid resuscitation with balanced crystalloids (e.g., lactated Ringer’s solution) or 5% dextrose should be administered as indicated. When the SpO2 is < 92%, artificial airway interventions, such as chin support, assisted breathing, or a face mask, are provided. After the procedure is complete, the patient will not leave the examination room until a MOAA/S score of 3–4 is obtained. If the discharge rating scale score exceeds 9 points after sedation/anaesthesia, family and friends may accompany the patient to leave the hospital. The timing for intervention is when the end-expiratory carbon dioxide decreases by half or disappears, chest wall undulation disappears and/or when the SpO2 is less than 95%. That is, open airway techniques are used sequentially until an SpO2 ≥ 95% is reached, and the last open airway technique is recorded. The open airway methods used in the two groups will be the same: increasing the oxygen flow rate; lifting the lower jaw; providing mask ventilation (if necessary, removing the gastroscope); and performing tracheal intubation or inserting a laryngeal mask for ventilator-assisted ventilation.
Primary outcome measure
The main outcome measure will be the incidence of hypoxia during anaesthesia in patients undergoing painless gastroscopy (75% ≤ SpO2 < 90% ≤ 60 s).
Secondary outcome measures
The secondary outcome measures will be as follows: (1) the incidence of severe hypoxia (SpO2 < 75% or 75% ≤ SpO2 < 90%); (2) the incidence of respiratory intervention procedures (measured every 60 s); (3) circulation fluctuations [severe bradycardia (< 50 beats/minute), MAP fluctuations with an amplitude exceeding 30% of the baseline value or an MAP < 60 mmHg]; (4) the incidence of coughing, laryngeal spasm, reflux aspiration, anaesthetic dosage, diagnosis and treatment time, and awakening time (the time from the end of diagnosis and treatment to the time the patient provides an accurate answer for their name and age after awakening); and (5) the satisfaction of postoperative patients and endoscopists (0 is very dissatisfied, 10 is very satisfied).
Remedial and supportive treatment
If severe airway spasms, ventilation disorders, and ineffective airway improvement occur during the procedure, measures such as mask pressure oxygen supply, emergency endotracheal intubation, or cricothyroid puncture will be taken. When emergencies and accidents occur during the procedure, the patient will be treated as the primary focus, and their safety is the top priority. Participants should be rescued and treated according to clinical routines.
Safety evaluation procedure
In the present study, the risks of bleeding, such as bleeding caused by oral and pharyngeal tumours, inflammation, infection, and ulcers will be evaluated. It is not advisable to use an airway in these patients.
Termination and exit procedures
Participants in the study who experience severe airway spasms, ventilation disorders, and ineffective improvement in the airway requiring emergency endotracheal intubation or cricothyroid puncture will receive life-saving measures immediately and will automatically be excluded from the trial.
Statistical analysis
The statistical analysis plan will be developed before the end of the experiment and finalized before the database is locked. All the statistical tests, including descriptive statistics and analysis methods, will be conducted via two-sided tests, and SPSS 22 will be used for statistical analysis. For patient information, the mean ± standard deviation will be reported for continuous variables that follow a normal distribution, and a t test will be used to compare differences between groups. Variables that do not follow a normal distribution will be represented by the median (upper and lower quartiles), and a nonparametric rank sum test (Mann‒Whitney U test) will be used to compare differences between groups. For categorical variables such as the incidence of hypoxia, the frequency and rate (or composition ratio) will be reported, and the chi-square test or Fisher's exact test will be used to compare differences between groups.
The main indicators will be as follows: 1) The occurrence of intraoperative hypoxia will be described in terms of frequency (incidence), and the chi-square test or Fisher’s exact test will be used to determine if there is a difference in the incidence of hypoxia between the two groups. A P value of <0.05 will indicate statistical significance, with a 95% confidence interval. 2) The following methods for handling missing data will be used: patients with missing values will be excluded, or missing value imputation methods (such as the mean imputation, maximum likelihood estimation, or multiple imputation) will be applied for missing or illogical data.
For continuous variables with low missing rates and stable distributions, mean imputation is employed. For indicators with missing values caused by incomplete records or other random factors, multiple imputation is preferred because it is more suitable for handling missing-at-random scenarios and generates multiple datasets for consolidated results. With respect to indicators that exhibit nonlinear relationships with other variables—which may correlate with patient age, sex, disease severity, etc.—machine learning algorithms such as regression or random forest will be considered for missing value prediction. For continuous dynamic data metrics such as the circulatory heart rate, which may demonstrate trends, periodicity, or autocorrelation, time series methods (e.g., ARIMA) or machine learning approaches (e.g., LSTM neural networks) will be adopted to predict missing values by leveraging adjacent data points.
Other analytical methods
There are no further planned analyses in this study.
Data management
Analytical methods for dealing with protocol noncompliance and any statistical methods for dealing with missing data
In the recruitment stage, we will provide a detailed explanation of the research plan and the risks and complications that may be encountered during the trial to the study participants, obtain informed consent, minimize the withdrawal of study participants and noncompliance with the plan, and avoid data loss as much as possible. Regarding missing or illogical data, we will delete cases with missing values or use data imputation methods (e.g., mean interpolation, maximum likelihood estimation, or multiple interpolation).
The plan is to provide access to the full protocol, participant-level data, and statistical code
Upon reasonable request, the PI will provide interested researchers with statistical codes for analysis. In addition, in accordance with the data retention policy, all completed data will be retained for 10 years after the completion of the study. All the data will be securely stored and maintained in accordance with relevant data protection laws and regulations.
Oversight and supervision of the coordination centre and the formation of the trial steering committee
The Data Monitoring Committee (DMC) team is composed of clinical trial leaders, statisticians, and ethics experts. The DMC's main functions are to monitor the safety of study participants, protect the science and data integrity of the study, and make recommendations on the continuation, adjustment, or termination of the trial.
Internal analysis plan for data
Data entry and management will be the responsibility of the designated data manager. To ensure the accuracy of the data, two data managers will independently make two copies of the input and proofread. If problems are encountered in one of the case reports, the data manager will produce a question-and-answer sheet and send an inquiry to the investigator through the clinical ombudsman, who is expected to complete the document and return it as soon as possible. The data manager will modify, confirm and enter the data according to the researcher's answers.
Adverse event reporting
Any serious adverse events that occur during the research process, in addition to being managed promptly and effectively, will be reported to the ethics committee of the research unit by the researcher within 24 hours of becoming aware of such events. A serious adverse event form must also be completed to document the occurrence time, severity, duration, actions taken, and event outcome.
Communication with the ethics committee
This clinical trial will be conducted in accordance with ethical approval requirements. The ethics committee will be promptly informed when problems arise or if modifications to the trial protocol are necessary during the trial process. Consent is required for any changes to the experimental plan.
Ethical review and communication
The implementation of this study will adhere to the research protocol outlined in"Ethical Review Measures for Life Science and Medical Research Involving Human Subjects" (2023), the "Ethical Review Measures for Biomedical Research Involving Human Subjects" (2016), the WMA "Helsinki Declaration" (2013), the CIOMS "International Ethical Guidelines for Biomedical Research Involving Human Subjects" (2002), the "Management Measures for Investigator-Initiated Clinical Research in Medical and Health Institutions (Trial)", and all applicable laws and regulations of the country implementing the GCP ethical principles research. The research will proceed only after written approval and consent are obtained from the Ethics Committee (IRB/IEC) regarding the protocol, informed consent form, and recruitment materials/procedures for the study participants. Any modifications to the plan will also require IRB/IEC approval. The results of this study will be published in peer-reviewed journals and presented at relevant academic conferences or on research platforms.
Discussion
The World Health Organization predicts that the proportion of the global population aged 60 years and older will increase from 12% in 2015 to 22% in 2050 [22]. Given the ageing population, it is crucial to focus on the physical health of elderly individuals and thoroughly assess their perioperative safety concerns. The incidence of related complications, such as cardiovascular adverse events, is relatively high in elderly patients during anaesthesia [23]. Studies have indicated that advanced age is an independent risk factor for hypoxaemia during painless gastroscopy diagnosis and treatment [24]. Currently, propofol is used as the primary anaesthetic for gastrointestinal procedures, but its adverse reactions, such as hypoxaemia, hypotension, and bradycardia [25, 26], may be more pronounced in elderly patients.
During gastroscopy, approximately 1.5–70% of patients experience hypoxaemia, with 36% of these cases related to respiratory pauses and 30% related to abnormal ventilation [27]. Respiratory-related complications are a significant concern. However, sharing the airway with endoscopists focused on operating through a patient’s mouth is a considerable challenge for anaesthesiologists managing the airway. An endoscopic bite block is typically used during gastroscopy to prevent patients from biting the endoscope and their tongue. However, this block cannot maintain an open airway. Under sedation and anaesthesia, the pharynx is the primary site of airway obstruction. This may be because the pharynx is the only area not encased by the hyoid bone structure [28], making it more prone to collapse. In addition, tongue retraction can lead to upper respiratory tract obstruction and hypoxaemia. In severe cases of respiratory obstruction, considerable negative pressure can be generated in the throat [29], increasing oesophageal pressure [30] and increasing the likelihood of reflux aspiration. Studies have shown that the size of the upper airway in both men and women decreases with age [31]. When hypoxaemia occurs during gastroscopy, the lower jaw may need to be lifted to clear the airway, or the procedure may need to be terminated by the endoscopist. In such cases, the gastroscope is withdrawn, and oxygen is administered through a mask.
The COMBO endoscopic oropharyngeal airway used for gastroscopy in our study serves as a bite block and can maintain the oropharyngeal airway without hindering the ability of endoscopists. Moreover, the device includes an oxygen supply and end-tidal carbon dioxide (CO₂) sampling channels positioned near the glottis, ensuring efficient oxygen delivery and accurate capnography readings. In addition, the specialized compatibility of the oxygenation channel with high-frequency jet ventilation systems enables effective supraglottic ventilation, serving as a critical safety mechanism for managing difficult airways and respiratory compromise, thereby increasing patient safety during procedural sedation.
This study aims primarily to investigate the incidence of hypoxaemia and observe the frequency of adverse respiratory events such as reflux, aspiration, and laryngeal spasm. The primary purpose of this study is to determine whether this COMBO endoscopy oropharyngeal airway can effectively clear the airway, reduce the incidence of airway-related adverse events, provide a smoother anaesthetic experience, reduce the use of anaesthetic drugs, and thus reduce the incidence of anaesthesia-related complications. A more stable and safe anaesthesia environment can be provided for elderly patients undergoing gastrointestinal endoscopy.
However, a key limitation of this study is its single-centre design. To address this limitation, we plan to conduct a multicentre validation study incorporating the following safeguards: the establishment of detailed standard operating procedures and quality control protocols and the implementation of centralized training for all trial personnel. This standardized framework will facilitate recruitment across geographically diverse hospitals while expanding the sample size and enhancing subpopulation representation (e.g., patients with obesity, BMI ≥ 30 kg/m²). The multicentre validation will rigorously evaluate whether CIMBO reduces hypoxemia incidence during anaesthesia for painless gastrointestinal endoscopy, thereby providing more robust evidence for clinical application.
Through the results of this study, we hope to provide a theoretical foundation and practical insights into airway management in clinical anaesthesia. This approach could be applied for anaesthesia during gastroscopy and airway management during other sedation procedures, such as bronchoscopy, providing new ideas and experiences.
Supplementary Information
Acknowledgements
The COMBO endoscopic oropharyngeal airway was manufactured by Shanghai ALIFUN Medical Technology Co., Ltd. and donated for clinical application under third-party witnessed supervision. We are deeply grateful for the tremendous support this company has provided for this clinical trial.
Disclaimer
The donor of the consumables has no role in the design and implementation of the study or in the decision to write and submit this manuscript.
Patient and public involvement
Patients and/or the public were not involved in the design, conduct, reporting, or dissemination plans of this research.
Abbreviations
- COMBO
Capnography monitoring of bite block oxygenation
- MAP
Mean arterial pressure
- OSA
Obstructive sleep apnoea
- EC
Early cancer
- HGIN
High-grade intraepithelial neoplasia
- UGI
Upper digestive tract
- SpO2
Peripheral oxygen saturation
- ASA
American Society of Anesthesiologists
- MetS
Metabolic equivalents
- COPD
Chronic obstructive pulmonary disease
- BMI
Body mass index
- HR
Heart rate
- MOAA/S
Modified observer alertness/sedation scale
- CKD
Chronic kidney disease
Authors’ contributions
Jianbo Wu is the project leader and is responsible for the quality control of topic selection, design, experimental supervision and paper revision. Qi You is responsible for the design of the entire study and writing the paper. Chuanyu Sun, Xiaojing Liu and Meng Yang will contribute to the implementation and analysis of the program.
Funding
The COMBO endoscopic oropharyngeal airway was manufactured by Shanghai ALIFUN Medical Technology Co., Ltd. and donated for clinical application under third-party witnessed supervision. We are deeply grateful for the tremendous support this company has provided for this clinical trial.
Data availability
No datasets were generated or analysed during the current study.
Declarations
Ethics approval and consent to participate
The Institutional Review Committee of the First Affiliated Hospital of Shandong First Medical University (Shandong Qianfoshan Hospital) approved the experimental protocol and performed the ethics review on August 22, 2024. The ethics approval number is YXLL-KY-2024(083). The results of this study will be reported in peer-reviewed journals and at relevant academic conferences or on related research platforms.
In this study, participants will be recruited by distributing recruitment materials to potential participants and their family members. The experimental protocol and possible risks will be fully explained to the participants. The study participants and their family members will sign an informed consent form before anaesthesia induction. The participants will take part in this study voluntarily. The participants will not be charged any fees for the oropharyngeal vent, bite block or other consumables used in this study. During the trial, we will strictly implement operating procedures to protect the privacy of the patients and will not disclose the patients’ information, images or personal identities.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Conti CB, Agnesi S, Scaravaglio M, Masseria P, Dinelli ME, Oldani M, Uggeri F. Early gastric cancer: update on prevention, diagnosis and treatment. Int J Environ Res Public Health. 2023;20(3):2149. [DOI] [PMC free article] [PubMed]
- 2.Wooldrage K, Robbins EC, Duffy SW, Cross AJ. Long-term effects of once-only flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: 21-year follow-up of the UK flexible sigmoidoscopy screening randomised controlled trial. Lancet Gastroenterol Hepatol. 2024;9(9):811–24. [DOI] [PubMed] [Google Scholar]
- 3.Atkin W, Wooldrage K, Parkin DM, Kralj-Hans I, MacRae E, Shah U, Duffy S, Cross AJ. Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK flexible sigmoidoscopy screening randomised controlled trial. Lancet. 2017;389(10076):1299–311. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Li XT, Ma CQ, Qi SH, Zhang LM. Combination of propofol and dezocine to improve safety and efficacy of anesthesia for gastroscopy and colonoscopy in adults: a randomized, double-blind, controlled trial. World J Clin Cases. 2019;7(20):3237–46. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Early DS, Lightdale JR, Vargo JJ 2nd, Acosta RD, Chandrasekhara V, Chathadi KV, Evans JA, Fisher DA, Fonkalsrud L, Hwang JH, et al. Guidelines for sedation and anesthesia in GI endoscopy. Gastrointest Endosc. 2018;87(2):327–37. [DOI] [PubMed] [Google Scholar]
- 6.Teh JL, Shabbir A, Yuen S, So JB. Recent advances in diagnostic upper endoscopy. World J Gastroenterol. 2020;26(4):433–47. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Fanti L, Testoni PA. Sedation and analgesia in gastrointestinal endoscopy: what’s new? World J Gastroenterol. 2010;16(20):2451–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Friedrich K, Scholl SG, Beck S, Gotthardt D, Stremmel W, Rex DK, Sieg A. Respiratory complications in outpatient endoscopy with endoscopist-directed sedation. J Gastrointestin Liver Dis. 2014;23(3):255–9. [DOI] [PubMed] [Google Scholar]
- 9.Zevallos-Villegas A, Gonzalez-Rubio J, Neria Serrano F, Gallego-Rodriguez B, Lorente-Gonzalez M, Najera A, Rafael Teran-Tinedo J, Navarro-Lopez JD, Jimenez-Diaz L, Landete P. Factors associated with the effectiveness of high-flow therapy in patients with acute hypoxemic respiratory failure: an observational study. Intensive Crit Care Nurs. 2025;86:103874. [DOI] [PubMed] [Google Scholar]
- 10.Wani S, Azar R, Hovis CE, Hovis RM, Cote GA, Hall M, Waldbaum L, Kushnir V, Early D, Mullady DK, et al. Obesity as a risk factor for sedation-related complications during propofol-mediated sedation for advanced endoscopic procedures. Gastrointest Endosc. 2011;74(6):1238–47. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Yin X, Xu W, Zhang J, Wang M, Chen Z, Liu S, Xu Y, Xu S, Ji D, Wang J, et al. High-flow nasal oxygen versus conventional nasal cannula in preventing hypoxemia in elderly patients undergoing gastroscopy with sedation: a randomized controlled trial. Int J Med Sci. 2024;21(5):914–20. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Lin Y, Zhang X, Li L, Wei M, Zhao B, Wang X, Pan Z, Tian J, Yu W, Su D. High-flow nasal cannula oxygen therapy and hypoxia during gastroscopy with propofol sedation: a randomized multicenter clinical trial. Gastrointest Endosc. 2019;90(4):591–601. [DOI] [PubMed] [Google Scholar]
- 13.Zhang W, Yin H, Xu Y, Fang Z, Wang W, Zhang C, Shi H, Wang X. The effect of varying inhaled oxygen concentrations of high-flow nasal cannula oxygen therapy during gastroscopy with propofol sedation in elderly patients: a randomized controlled study. BMC Anesthesiol. 2022;22(1):335. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Sahinovic MM, Struys M, Absalom AR. Clinical pharmacokinetics and pharmacodynamics of propofol. Clin Pharmacokinet. 2018;57(12):1539–58. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Ding G, Wang L, Zhao W, Diao Y, Song D. Comparison of the efficacy and safety of Ciprofol and Propofol for ERCP anesthesia in older patients: a single-center randomized controlled clinical study. J Clin Anesth. 2024;99: 111609. [DOI] [PubMed] [Google Scholar]
- 16.Vainer I, Allon R, Shapira-Galitz Y, Strinkovsky L, Toh ST, Loh S, Alkan U. Incidence and risk factors of nocturnal penetrations and aspirations in patients with obstructive sleep apnea during drug-induced sedation endoscopy. J Sleep Res. 2024. 10.1111/jsr.14314. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Yin S, Hong J, Sha T, Chen Z, Guo Y, Li C, Liu Y. Efficacy and tolerability of sufentanil, dexmedetomidine, or ketamine added to Propofol-based sedation for gastrointestinal endoscopy in elderly patients: a prospective, randomized, controlled trial. Clin Ther. 2019;41(9):1864-e18771860. [DOI] [PubMed] [Google Scholar]
- 18.Zhang W, Zhu C, Chen X, Tao L, He K, Wu H, Chai X, Wang S, Xia M. Comparison of the innovative endoscopic oropharyngeal airway and the conventional mouthpiece in elderly outpatients undergoing esophagogastroduodenoscopy under sedation: a prospective and randomized study. BMC Gastroenterol. 2022;22(1):8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Beitz A, Riphaus A, Meining A, Kronshage T, Geist C, Wagenpfeil S, Weber A, Jung A, Bajbouj M, Pox C, et al. Capnographic monitoring reduces the incidence of arterial oxygen desaturation and hypoxemia during Propofol sedation for colonoscopy: a randomized, controlled study (ColoCap Study). Am J Gastroenterol. 2012;107(8):1205–12. [DOI] [PubMed] [Google Scholar]
- 20.Klare P, Reiter J, Meining A, Wagenpfeil S, Kronshage T, Geist C, Heringlake S, Schlag C, Bajbouj M, Schneider G, et al. Capnographic monitoring of Midazolam and Propofol sedation during ERCP: a randomized controlled study (EndoBreath Study). Endoscopy. 2016;48(1):42–50. [DOI] [PubMed] [Google Scholar]
- 21.Wang Y, Liu F, Zhang Y, Yang X, Wu J. The effect of capnography on the incidence of hypoxia during sedation for EGD and colonoscopy in mildly obese patients: a randomized, controlled study. BMC Anesthesiol. 2023;23(1):188. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Global burden and strength of evidence for. 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the global burden of disease study 2021. Lancet. 2024;403(10440):2162–203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Causada-Calo N, Bishay K, Albashir S, Al Mazroui A, Armstrong D. Association between age and complications after outpatient colonoscopy. JAMA Netw Open. 2020;3(6):e208958. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Leslie K, Allen ML, Hessian EC, Peyton PJ, Kasza J, Courtney A, Dhar PA, Briedis J, Lee S, Beeton AR, et al. Safety of sedation for gastrointestinal endoscopy in a group of university-affiliated hospitals: a prospective cohort study. Br J Anaesth. 2017;118(1):90–9. [DOI] [PubMed] [Google Scholar]
- 25.García Guzzo ME, Fernandez MS, Sanchez Novas D, Salgado SS, Terrasa SA, Domenech G, Teijido CA. Deep sedation using propofol target-controlled infusion for gastrointestinal endoscopic procedures: a retrospective cohort study. BMC Anesthesiol. 2020;20(1):195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Barends CRM, Driesens MK, van Amsterdam K, Struys M, Absalom AR. Moderate-to-Deep sedation using Target-Controlled infusions of Propofol and remifentanil: adverse events and risk factors: A retrospective cohort study of 2937 procedures. Anesth Analg. 2020;131(4):1173–83. [DOI] [PubMed] [Google Scholar]
- 27.Vargo JJ. 2nd: Sedation-related complications in Gastrointestinal endoscopy. Gastrointest Endosc Clin N Am. 2015;25(1):147–58. [DOI] [PubMed] [Google Scholar]
- 28.Lahav Y, Rosenzweig E, Heyman Z, Doljansky J, Green A, Dagan Y. Tongue base ultrasound: a diagnostic tool for predicting obstructive sleep apnea. Ann Otol Rhinol Laryngol. 2009;118(3):179–84. [DOI] [PubMed] [Google Scholar]
- 29.Stoohs RA, Knaack L, Blum HC, Janicki J, Hohenhorst W. Differences in clinical features of upper airway resistance syndrome, primary snoring, and obstructive sleep apnea/hypopnea syndrome. Sleep Med. 2008;9(2):121–8. [DOI] [PubMed] [Google Scholar]
- 30.Loube DI, Andrada TF. Comparison of respiratory polysomnographic parameters in matched cohorts of upper airway resistance and obstructive sleep apnea syndrome patients. Chest. 1999;115(6):1519–24. [DOI] [PubMed] [Google Scholar]
- 31.Martin SE, Mathur R, Marshall I, Douglas NJ. The effect of age, sex, obesity and posture on upper airway size. Eur Respir J. 1997;10(9):2087–90. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
No datasets were generated or analysed during the current study.