Effect of Preoxygenation Position and Examination Position on Hypoxemia During Painless Gastrointestinal Endoscopy

NCT07673042 | Not Yet Recruiting

• 1 other identifier: dywe0003
• Study Type: interventional
• Target: 208
• Locations: 1 country
• Sites: 1

Brief Summary

To investigate the independent effects and interaction of pre-oxygenation position (left lateral vs left lateral with 30° head-up tilt) and examination position (left lateral vs left lateral with 30° head-up tilt) on hypoxemia during painless gastroscopy and colonoscopy using a 2×2 factorial design.

Conditions

Hypoxemia During Surgery

Outcome Measures

Primary Outcomes (1)

• Incidence of hypoxemia

  Incidence of SpO₂ ≤ 90% for \>10 seconds during the examination.

  During procedure

Secondary Outcomes (12)

• Safe duration of pre-oxygenation

  During procedure

• Incidence of subclinical respiratory depression

  During procedure

• Requirement for jaw thrust

  During procedure

• Requirement for nasal cannula oxygen

  During procedure

• Requirement for increased oxygen flow

  During procedure

Other Outcomes (4)

• Safety outcome endpoints：heart rate

  Baseline and during procedure

• Safety outcome endpoints：blood pressure

  Baseline and during procedure

• Safety outcome endpoints：peripheral oxygen saturation (SpO₂)

  Baseline and during procedure

Study Arms (4)

Group A1B1 (traditional conventional group)

ACTIVE COMPARATOR

Pre-oxygenated left lateral position + examination in left lateral position

Procedure: Pre-oxygenation Position （left lateral position）; Procedure: Examination Position（left lateral position ）

Group A1B2 (improved examination group)

EXPERIMENTAL

Left lateral position with pre-oxygenation + left head elevated 30° during examination

Procedure: Pre-oxygenation Position （left lateral position）; Procedure: Examination Position（left lateral head elevation in a 30-degree position）

Group A2B1 (pre-oxygenation improvement group)

EXPERIMENTAL

Left-sided head position at 30°, pre-oxygenated air administration + examination in left lateral decubitus position

Procedure: Examination Position（left lateral position ）; Procedure: Pre-oxygenation Position（ left lateral head elevation in a 30-degree position）

Group A2B2 (double-position improvement group)

EXPERIMENTAL

Left-sided head height at 30 weeks: pre-oxygenated condition + left-sided head height at 30 weeks examination

Procedure: Pre-oxygenation Position（ left lateral head elevation in a 30-degree position）; Procedure: Examination Position（left lateral head elevation in a 30-degree position）

Interventions

Pre-oxygenation Position （left lateral position） PROCEDURE

An angle measuring device is placed beside the head of the examination bed to enable precise adjustment of the head position. Pre-oxygenation phase: Administer pure oxygen via a standardized mask with tight fit, at a flow rate of 6 L/min; instruct the patient to take deep breaths while receiving continuous oxygen for 3 minutes, maintaining the same body position throughout. If the position is altered during this phase, discontinue the procedure. Left lateral pre-oxygenation: The patient assumes a left lateral position on a horizontal bed surface with the head elevated at 0°, supported by pillows to maintain a neutral spine position and avoid excessive neck extension or flexion.

Also known as: left lateral position

Group A1B1 (traditional conventional group); Group A1B2 (improved examination group)

Examination Position（left lateral position ） PROCEDURE

Examination Phase: From the initiation of anesthesia and endoscope insertion until completion of the procedure, the patient's position and head-of-bed angle must remain fixed throughout; any adjustments are prohibited during this phase. If the position is altered midway through the examination, the patient will be excluded from the study. Left lateral position examination: The patient assumes a 90-degree left lateral position on a horizontal bed surface with the head of the bed elevated to 0°, supported by pillows to maintain a neutral spinal alignment, avoiding excessive neck extension or flexion.

Also known as: Left lateral position

Group A1B1 (traditional conventional group); Group A2B1 (pre-oxygenation improvement group)

Pre-oxygenation Position（ left lateral head elevation in a 30-degree position） PROCEDURE

An angle measuring device is placed beside the head of the examination bed to allow precise adjustment of the head position. Pre-oxygenation phase: The patient receives pure oxygen via a standardized mask with tight fit, at a flow rate of 6 L/min; they are instructed to take deep breaths while receiving continuous oxygen for 3 minutes, maintaining the same body position throughout. If the position is altered during this phase, the procedure is discontinued. Left-sided head elevation (30°): During pre-oxygenation, the patient lies in a left lateral position on a horizontal bed surface with the head elevated by 30°, supported by pillows to maintain a neutral spinal alignment and prevent excessive neck extension or flexion.

Also known as: left lateral head elevation in a 30-degree position

Group A2B1 (pre-oxygenation improvement group); Group A2B2 (double-position improvement group)

Examination Position（left lateral head elevation in a 30-degree position） PROCEDURE

Examination Phase: From the initiation of anesthesia and endoscope insertion until completion of the procedure, the patient's position and head-of-bed angle must remain fixed throughout; any adjustments are prohibited during this phase. If the position is altered midway through the examination, the patient will be excluded from the study. Left lateral decubitus examination: The patient assumes a left lateral position on a horizontal bed surface with the head elevated at 30°, supported by a pillow to maintain a neutral spinal alignment, avoiding excessive neck extension or flexion.

Also known as: left lateral head elevation in a 30-degree position

Group A1B2 (improved examination group); Group A2B2 (double-position improvement group)

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged 18 to 75 years, regardless of gender
• Body mass index (BMI): 18.5 - 35 kg/m²
• ASA physical status class I, II or III
• Scheduled for painless gastroscopy, painless colonoscopy, or combined painless gastroenteroscopy
• Able to understand the study procedure and provide written informed consent

You may not qualify if:

• Severe cardiopulmonary diseases, including severe COPD, heart failure, severe arrhythmia and pulmonary hypertension
• Difficult airway identified before anesthesia
• Severe obstructive sleep apnea (OSA)
• Spinal or thoracic deformity
• Preoperative baseline hypoxemia
• Known allergy to any anesthetic drugs used in this study
• Pregnant females
• Unable to cooperate with required intraoperative body position

Sponsors & Collaborators

• General Hospital of Ningxia Medical University: lead

Study Sites (1)

General hospital of Ningxia medical university

Yinchuan, Ningxia, 750001, China

Location

Study Officials

• Xinli Ni, Doctoral

  General Hospital of Ningxia Medical University

  STUDY CHAIR

Central Study Contacts

xiaoyong wei, Master's degree

CONTACT

86-951-674-3252; weixy9912@126.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Independent statisticians not involved in the study implementation generated random codes via computer and used sequentially numbered, opaque, sealed envelopes to conceal assignment assignments, which were opened immediately prior to intervention administration. Since postural intervention is an operational procedure, blinding could not be implemented for operators (anesthesiologists, endoscopists, or data collectors); subjects were informed of the standard positioning requirements. Data analysts remained completely blinded throughout the process, unaware of patient group assignments, thereby minimizing bias.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 15, 2026
• First Posted: June 29, 2026
• Study Start: June 23, 2026
• Primary Completion: July 31, 2026
• Study Completion (Estimated): August 31, 2026
• Last Updated: June 29, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)