Postoperative HypoxemiaNCT07545642
Effect of Lateral Versus Supine Positions on Postoperative Hypoxemia
A study testing Lateral decubitus position group (Group L) and Supine position group (Group S) in people with Postoperative Hypoxemia, run by General Hospital of Ningxia Medical University at 1 site in China.
Trial summary
Using prospective real-world data, this study aims to determine whether the lateral decubitus position reduces the incidence of post-procedure hypoxemia in patients undergoing painless gastroscopy/colonoscopy, thereby providing a simple, non-invasive, and low-cost optimization strategy for clinical practice. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Postoperative Hypoxemia
- What is being tested?
- Lateral decubitus position group (Group L) and Supine position group (Group S)
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 960 participants
- Where
- 1 siteChina
- Study dates
- 22 Apr 2026to 30 Jul 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥ 18 years.
- Both sexes.
- American Society of Anesthesiologists (ASA) physical status classification I-III.
- Scheduled for combined painless esophagogastroduodenoscopy/colonoscopy or either of the two procedures.
- Ability to understand the study protocol and provide written informed consent.
- A broad set of inclusion criteria was adopted to enroll a patient population that better reflects routine clinical practice. The study aimed to enhance the generalizability of the findings by including patients with various comorbidities, such as preprocedural hypoxemia (room-air SpO₂ ≤ 90%), history of pulmonary surgery, obstructive sleep apnea (OSA), and other pulmonary conditions (including asthma, COPD, chronic bronchitis, emphysema, and pulmonary bullae).
Who cannot join
- Severe cardiovascular or cerebrovascular diseases.
- Pregnant patients.
- History of hypersensitivity to ciprofol.
- Withdrawal Criteria:
- Endotracheal intubation required during the procedure.
- Voluntary withdrawal requested by the patient or their legal representative.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site, 1 recruiting
- Recruiting
General hospital of Ningxia medical university, Yinchuan, Ningxia
Yinchuan, Ningxia, 750001
Xiaoyong Wei, Degree, 86-951-674-3252, weixy9912@126.cm
About this study
Official title: Effect of Lateral Versus Supine Positions on Postoperative Hypoxemia in Patients Undergoing Painless Gastroscopy and Colonoscopy: A Prospective Randomized Controlled Study
Using prospective real-world data, this study aims to determine whether the lateral decubitus position reduces the incidence of post-procedure hypoxemia in patients undergoing painless gastroscopy/colonoscopy, thereby providing a simple, non-invasive, and low-cost optimization strategy for clinical practice.
Read the detailed description
Painless gastroscopy and colonoscopy have become essential modalities for the screening and diagnosis of digestive tract diseases, with their utilization increasing annually. However, hypoxemia remains the most common complication during these procedures, with reported incidences ranging widely from 1.8% to 69%. Severe hypoxemia can lead to adverse outcomes, including arrhythmias, hemodynamic decompensation, and hypoxic brain injury. Consequently, developing effective strategies to prevent hypoxemia in patients undergoing sedation for gastrointestinal (GI) endoscopy is of significant clinical value.
Current clinical research has primarily focused on hypoxemia occurring during the endoscopic procedure itself, whereas there is a paucity of high-quality evidence regarding the incidence and preventive measures of hypoxemia during the recovery phase. Specifically, the impact of body positioning on post-procedural hypoxemia remains largely unexplored. Emerging evidence suggests that the lateral decubitus position significantly reduces the incidence of hypoxemia during adult sedation. Anatomically, in the supine position, residual sedative effects combined with gravity cause the tongue and soft palate-structures lacking bony support-to collapse posteriorly, leading to upper airway obstruction. Conversely, the lateral position helps maintain a patent airway by preventing this collapse and optimizing the ventilation-perfusion (V/Q) matching, thereby stabilizing oxygenation.
Despite this theoretical basis, prospective studies investigating the effect of body positioning on recovery-phase hypoxemia in real-world settings are lacking. Therefore, this study hypothesizes that the lateral decubitus position reduces the incidence of recovery-phase hypoxemia compared to the supine position. Using prospective real-world data, we aim to validate this hypothesis and provide a simple, non-invasive, and cost-effective optimization strategy for clinical practice.
- Conditions
- Postoperative Hypoxemia
- Being tested
- Lateral decubitus position group (Group L), Supine position group (Group S)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Lateral decubitus position group (Group L)Procedure or surgery
Upon admission to the Post-Anesthesia Care Unit (PACU), an independent researcher (attending anesthesiologist) assessed the patient using the Ramsay Sedation Scale (1: anxious and agitated; 2: awake, calm, and cooperative; 3: drowsy but responsive to verbal commands; 4: asleep but responsive to tactile stimulation or pain; 5: asleep with a sluggish response to stimulation; 6: deep sleep with no response). Patients in the Lateral Group (Group L) were maintained in the predetermined left lateral position. Standard monitoring was applied, and nasal cannula oxygen was administered at 2 L/min. If SpO₂ remained >95% for at least 5 minutes, oxygen was discontinued for observation. To ensure strict adherence to the protocol, an independent researcher continuously monitored and verified patient positioning (corrections were made only if the patient rolled unconsciously). Patients were evaluated using the Aldrete discharge scoring system; discharge from the PACU occurred when a score of >9 was a
Supine position group (Group S)Procedure or surgery
Upon admission to the Post-Anesthesia Care Unit (PACU), an independent researcher (attending anesthesiologist) assessed the patient using the Ramsay Sedation Scale (1: anxious and agitated; 2: awake, calm, and cooperative; 3: drowsy but responsive to verbal commands; 4: asleep but responsive to tactile stimulation or pain; 5: asleep with a sluggish response to stimulation; 6: deep sleep with no response). Patients in the Supine Group (Group S) were turned from the predetermined lateral position to the supine position without a head pillow (head-of-bed elevation at 0 degrees). Standard monitoring was applied, and nasal cannula oxygen was administered at 2 L/min. If SpO₂ remained >95% for at least 5 minutes, oxygen was discontinued for observation. To ensure strict adherence to the protocol, an independent researcher continuously monitored and verified patient positioning (corrections were made only if the patient rolled unconsciously). Patients were evaluated using the Aldrete discharge
| Study group | Role | What they receive |
|---|---|---|
| Supine position group (Group S) | Experimental | The patient was turned from the predetermined left lateral position to the supine position without a head pillow (head-of-bed elevation at 0 degrees） Receives: Procedure: Supine position group (Group S) |
| Lateral decubitus position group (Group L) | Experimental | Upon arrival in the post-anesthesia care unit (PACU), the patient was kept in the left lateral decubitus position Receives: Procedure: Lateral decubitus position group (Group L) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of recovery-phase hypoxemia,
Proportion of participants experiencing hypoxemia (SpO₂ ≤ 90% lasting >10 seconds) during the post-procedure recovery period.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Secondary outcomes (12)
Incidence of Severe Hypoxemia During Recovery
Proportion of participants experiencing severe hypoxemia, defined as pulse oxygen saturation (SpO₂) < 85% lasting >10 seconds during the post-procedure recovery period.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Subclinical Respiratory Depression during Recovery
Proportion of participants experiencing subclinical respiratory depression, defined as any episode of pulse oxygen saturation (SpO₂) in the range of 90% to <95% (inclusive of 90%, exclusive of 95%) during the post-procedure recovery period.
Measured: From PACU admission until discharge, assessed up to 30 minutes.
Overall Incidence of Airway Intervention During Recovery
Proportion of participants requiring any grade of airway intervention (increase oxygen flow, chin lift, mask ventilation, or reintubation) during recovery.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Cough Severity Grade During Recovery
Severity of cough assessed during the recovery period, graded as:
Grade I: No cough, smooth breathing; Grade II: Single mild cough; Grade III: Multiple coughs lasting <15 seconds; Grade IV: Continuous coughing lasting ≥15 seconds. Reported as the proportion of participants reaching each grade (I-IV).
Measured: From PACU admission until discharge, assessed up to 30 minutes
Length of Stay in Post-Anesthesia Care Unit (PACU)
Time from admission to the post-anesthesia care unit (PACU) until discharge criteria are met (modified Aldrete score ≥9 on three consecutive assessments), recorded in minutes.
Measured: From PACU admission until discharge
Respiratory Comfort Score During Recovery
Patient-reported respiratory comfort assessed using a Numerical Rating Scale (NRS) ranging from 0 (worst discomfort) to 10 (greatest comfort)
Measured: From PACU admission until discharge, assessed up to 30 minutes
PACU Nurse Satisfaction Score
Nurse-assessed satisfaction with patient respiratory stability and overall recovery management, rated using a Numerical Rating Scale (NRS) ranging from 0 (lowest satisfaction) to 10 (highest satisfaction), recorded at patient discharge from the post-anesthesia care unit.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Tachycardia During Recovery
Proportion of participants experiencing tachycardia (heart rate >100 beats/min) during the post-procedure recovery period.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Bradycardia During Recovery
Proportion of participants experiencing bradycardia (heart rate <50 beats/min) during recovery.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Hypotension During Recovery
Proportion of participants experiencing hypotension (systolic blood pressure <80 mmHg) during recovery.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Nausea or Vomiting During Recovery
Proportion of participants experiencing nausea (subjective complaint) or vomiting (objective expulsion of gastric contents) during recovery.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Laryngospasm During Recovery
Proportion of participants experiencing laryngospasm (acute upper airway obstruction with stridor/inability to ventilate, resolving with intervention) during recovery.
Measured: From PACU admission until discharge, assessed up to 30 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Apr 2026
- Study start22 Apr 2026
- Primary completion18 Jun 2026
- Study completion30 Jul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Postoperative HypoxemiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 960 participants (estimated)
Sponsor and investigators
- Lead sponsor
- General Hospital of Ningxia Medical University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Xinli Ni, Doctoral, Study chair, 86-951-674-3252
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07545642
- Sponsor's protocol ID
- dywe0001
- Status last verified
- Apr 2026
- First submitted
- 7 Apr 2026
- Last updated
- 24 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Lateral Versus Supine Positions on Postoperative Hypoxemia in Patients Undergoing Painless Gastroscopy and Colonoscopy: A Prospective Randomized Controlled Study
- ClinicalTrials.gov ID
- NCT07545642
- Acronym / sponsor ID
- dywe0001
- Conditions
- Postoperative Hypoxemia
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 960 participants (estimated)
- Lead sponsor
- General Hospital of Ningxia Medical UniversityUniversity, hospital or other
- Study start
- 22 Apr 2026 (actual)
- Primary completion
- 18 Jun 2026 (actual)
- Study completion
- 30 Jul 2026 (estimated)
- First posted
- 22 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Using prospective real-world data, this study aims to determine whether the lateral decubitus position reduces the incidence of post-procedure hypoxemia in patients undergoing painless gastroscopy/colonoscopy, thereby providing a simple, non-invasive, and low-cost optimization strategy for clinical practice.
Detailed description
Painless gastroscopy and colonoscopy have become essential modalities for the screening and diagnosis of digestive tract diseases, with their utilization increasing annually. However, hypoxemia remains the most common complication during these procedures, with reported incidences ranging widely from 1.8% to 69%. Severe hypoxemia can lead to adverse outcomes, including arrhythmias, hemodynamic decompensation, and hypoxic brain injury. Consequently, developing effective strategies to prevent hypoxemia in patients undergoing sedation for gastrointestinal (GI) endoscopy is of significant clinical value.
Current clinical research has primarily focused on hypoxemia occurring during the endoscopic procedure itself, whereas there is a paucity of high-quality evidence regarding the incidence and preventive measures of hypoxemia during the recovery phase. Specifically, the impact of body positioning on post-procedural hypoxemia remains largely unexplored. Emerging evidence suggests that the lateral decubitus position significantly reduces the incidence of hypoxemia during adult sedation. Anatomically, in the supine position, residual sedative effects combined with gravity cause the tongue and soft palate-structures lacking bony support-to collapse posteriorly, leading to upper airway obstruction. Conversely, the lateral position helps maintain a patent airway by preventing this collapse and optimizing the ventilation-perfusion (V/Q) matching, thereby stabilizing oxygenation.
Despite this theoretical basis, prospective studies investigating the effect of body positioning on recovery-phase hypoxemia in real-world settings are lacking. Therefore, this study hypothesizes that the lateral decubitus position reduces the incidence of recovery-phase hypoxemia compared to the supine position. Using prospective real-world data, we aim to validate this hypothesis and provide a simple, non-invasive, and cost-effective optimization strategy for clinical practice.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Supine position group (Group S) | Experimental | Procedure: Supine position group (Group S)The patient was turned from the predetermined left lateral position to the supine position without a head pillow (head-of-bed elevation at 0 degrees） |
| Lateral decubitus position group (Group L) | Experimental | Procedure: Lateral decubitus position group (Group L)Upon arrival in the post-anesthesia care unit (PACU), the patient was kept in the left lateral decubitus position |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age ≥ 18 years.
- Both sexes.
- American Society of Anesthesiologists (ASA) physical status classification I-III.
- Scheduled for combined painless esophagogastroduodenoscopy/colonoscopy or either of the two procedures.
- Ability to understand the study protocol and provide written informed consent.
Key exclusion criteria (6 listed)
- Severe cardiovascular or cerebrovascular diseases.
- Pregnant patients.
- History of hypersensitivity to ciprofol.
- Endotracheal intubation required during the procedure.
- Voluntary withdrawal requested by the patient or their legal representative.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Lateral decubitus position group (Group L)Upon admission to the Post-Anesthesia Care Unit (PACU), an independent researcher (attending anesthesiologist) assessed the patient using the Ramsay Sedation Scale (1: anxious and agitated; 2: awake, calm, and cooperative; 3: drowsy but responsive to verbal commands; 4: asleep but responsive to tactile stimulation or pain; 5: asleep with a sluggish response to stimulation; 6: deep sleep with no response). Patients in the Lateral Group (Group L) were maintained in the predetermined left lateral position. Standard monitoring was applied, and nasal cannula oxygen was administered at 2 L/min. If SpO₂ remained >95% for at least 5 minutes, oxygen was discontinued for observation. To ensure strict adherence to the protocol, an independent researcher continuously monitored and verified patient positioning (corrections were made only if the patient rolled unconsciously). Patients were evaluated using the Aldrete discharge scoring system; discharge from the PACU occurred when a score of >9 was a | Procedure or surgery | Lateral decubitus position group (Group L) |
| Supine position group (Group S)Upon admission to the Post-Anesthesia Care Unit (PACU), an independent researcher (attending anesthesiologist) assessed the patient using the Ramsay Sedation Scale (1: anxious and agitated; 2: awake, calm, and cooperative; 3: drowsy but responsive to verbal commands; 4: asleep but responsive to tactile stimulation or pain; 5: asleep with a sluggish response to stimulation; 6: deep sleep with no response). Patients in the Supine Group (Group S) were turned from the predetermined lateral position to the supine position without a head pillow (head-of-bed elevation at 0 degrees). Standard monitoring was applied, and nasal cannula oxygen was administered at 2 L/min. If SpO₂ remained >95% for at least 5 minutes, oxygen was discontinued for observation. To ensure strict adherence to the protocol, an independent researcher continuously monitored and verified patient positioning (corrections were made only if the patient rolled unconsciously). Patients were evaluated using the Aldrete discharge | Procedure or surgery | Supine position group (Group S) |
Primary outcome
Incidence of recovery-phase hypoxemia,
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Proportion of participants experiencing hypoxemia (SpO₂ ≤ 90% lasting >10 seconds) during the post-procedure recovery period.
12 secondary outcomes
Incidence of Severe Hypoxemia During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Subclinical Respiratory Depression during Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes.
Overall Incidence of Airway Intervention During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Cough Severity Grade During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Length of Stay in Post-Anesthesia Care Unit (PACU)
Time frame: From PACU admission until discharge
Respiratory Comfort Score During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
PACU Nurse Satisfaction Score
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Tachycardia During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Bradycardia During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Hypotension During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Nausea or Vomiting During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Incidence of Laryngospasm During Recovery
Time frame: From PACU admission until discharge, assessed up to 30 minutes
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Xinli Ni, Doctoral study chair
86-951-674-3252
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Lateral decubitus position group (Group L) and Supine position group (Group S) in people with Postoperative Hypoxemia, run by General Hospital of Ningxia Medical University at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Xiaoyong Wei, Degree (86-951-674-3252, weixy9912@126.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of recovery-phase hypoxemia, (time frame: From PACU admission until discharge, assessed up to 30 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jun 2026.