Effect of Preoxygenation Position and Examination Position on Hypoxemia During Painless Gastrointestinal Endoscopy
24 de junho de 2026 atualizado por: General Hospital of Ningxia Medical University
Effect of Preoxygenation Position and Examination Position on Hypoxemia During Painless Gastrointestinal Endoscopy: A 2×2 Factorial Randomized Controlled Trial
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.
Visão geral do estudo
Status
Ainda não está recrutando
Condições
Intervenção / Tratamento
- Procedimento: Pre-oxygenation Position （left lateral position）
- Procedimento: Examination Position（left lateral position ）
- Procedimento: Examination Position（left lateral head elevation in a 30-degree position）
- Procedimento: Pre-oxygenation Position（ left lateral head elevation in a 30-degree position）
Descrição detalhada
Painless gastroscopy and colonoscopy represent core minimally invasive techniques for colorectal cancer screening and the diagnosis and treatment of gastrointestinal diseases. By utilizing intravenous sedation to ensure a pain-free experience, these procedures are widely adopted in clinical practice. However, perioperative hypoxemia remains the most common and critical safety complication during sedation for endoscopy. It is primarily caused by anesthesia-induced respiratory depression, tongue base collapse, airway obstruction, diaphragmatic compression, and restricted thoracic movement, with significantly elevated risks observed in obese, elderly, snoring, and short-necked patients.
Hypoxemia may trigger bradycardia, arrhythmias, myocardial ischemia, and cerebral hypoxia. In severe cases, it can lead to apnea, laryngospasm, and forced termination of the procedure, making it a key indicator in endoscopic anesthesia quality control.
Pre-oxygenation is a fundamental measure to increase functional residual capacity (FRC) and prolong the safe apneic time prior to induction, thereby preventing hypoxemia. The examination position directly determines airway patency, mandibular relaxation, diaphragmatic position, and thoracic compliance throughout the procedure. Both are critical, controllable factors regulating perioperative oxygenation. Studies have confirmed that the left lateral position reduces the incidence of hypoxemia, while the left lateral position with 30° head elevation effectively relaxes the mandible, alleviates tongue base collapse, reduces abdominal organ pressure on the diaphragm, and improves ventilation and oxygenation by increasing FRC.
Current research largely focuses on either the pre-oxygenation position or the examination position in isolation, presenting notable limitations: first, the interaction between these two positions has not been evaluated, leaving the synergistic or antagonistic effects of combined interventions unclear; second, there is a lack of efficient validation using a factorial design, which is necessary to simultaneously analyze the main effects and interactions of both independent variables.
Addressing these clinical challenges and research gaps, this study employs a 2×2 factorial randomized controlled design. With pre-oxygenation position and examination position serving as the two intervention factors, the study aims to explore the individual and combined effects of both factors on perioperative hypoxemia. The objective is to identify the optimal positional combination, establish standardized and generalizable positioning protocols for painless endoscopy, accurately reduce the incidence of hypoxemia, enhance the precision of anesthesia management, and provide high-level evidence to guide clinical practice.
Tipo de estudo
Intervencional
Inscrição (Estimado)
208
Estágio
- Não aplicável
Contactos e Locais
Esta seção fornece os detalhes de contato para aqueles que conduzem o estudo e informações sobre onde este estudo está sendo realizado.
Contato de estudo
- Nome: xiaoyong wei, Master's degree
- Número de telefone: 86-951-674-3252
- E-mail: weixy9912@126.com
Locais de estudo
-
-
Ningxia
-
Yinchuan, Ningxia, China, 750001
- General Hospital of Ningxia Medical University
-
Contato:
- xiaoyong wei, Master's degree
- Número de telefone: 86-951-674-3252
- E-mail: weixy9912@126.cm
-
-
Critérios de participação
Os pesquisadores procuram pessoas que se encaixem em uma determinada descrição, chamada de critérios de elegibilidade. Alguns exemplos desses critérios são a condição geral de saúde de uma pessoa ou tratamentos anteriores.
Critérios de elegibilidade
Idades elegíveis para estudo
- Adulto
- Adulto mais velho
Aceita Voluntários Saudáveis
Não
Descrição
Inclusion Criteria:
- 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
Exclusion Criteria:
- 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
Plano de estudo
Esta seção fornece detalhes do plano de estudo, incluindo como o estudo é projetado e o que o estudo está medindo.
Como o estudo é projetado?
Detalhes do projeto
- Finalidade Principal: Prevenção
- Alocação: Randomizado
- Modelo Intervencional: Atribuição Paralela
- Mascaramento: Solteiro
Armas e Intervenções
Grupo de Participantes / Braço |
Intervenção / Tratamento |
|---|---|
|
Comparador Ativo: Group A1B1 (traditional conventional group)
Pre-oxygenated left lateral position + examination in left lateral position
|
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.
Outros nomes:
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.
Outros nomes:
|
|
Experimental: Group A1B2 (improved examination group)
Left lateral position with pre-oxygenation + left head elevated 30° during examination
|
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.
Outros nomes:
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.
Outros nomes:
|
|
Experimental: Group A2B1 (pre-oxygenation improvement group)
Left-sided head position at 30°, pre-oxygenated air administration + examination in left lateral decubitus position
|
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.
Outros nomes:
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.
Outros nomes:
|
|
Experimental: Group A2B2 (double-position improvement group)
Left-sided head height at 30 weeks: pre-oxygenated condition + left-sided head height at 30 weeks examination
|
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.
Outros nomes:
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.
Outros nomes:
|
O que o estudo está medindo?
Medidas de resultados primários
Medida de resultado |
Descrição da medida |
Prazo |
|---|---|---|
|
Incidence of hypoxemia
Prazo: During procedure
|
Incidence of SpO₂ ≤ 90% for >10 seconds during the examination.
|
During procedure
|
Medidas de resultados secundários
Medida de resultado |
Descrição da medida |
Prazo |
|---|---|---|
|
Safe duration of pre-oxygenation
Prazo: During procedure
|
Time from cessation of oxygen administration (start of anesthesia induction) to first SpO₂ <92% for ≥3 seconds.
If no desaturation occurs, the value equals the duration from oxygen cessation to end of procedure (right-censored).
|
During procedure
|
|
Incidence of subclinical respiratory depression
Prazo: During procedure
|
Defined as the proportion of participants experiencing SpO₂ between 90% and 95% (inclusive) at any time during the examination.
|
During procedure
|
|
Requirement for jaw thrust
Prazo: During procedure
|
Number of participants requiring manual jaw thrust to relieve airway obstruction during the examination.
|
During procedure
|
|
Requirement for nasal cannula oxygen
Prazo: During procedure
|
Number of participants requiring oxygen supplementation via nasal cannula during the examination.
|
During procedure
|
|
Requirement for increased oxygen flow
Prazo: During procedure
|
Number of participants requiring an increase in oxygen flow rate during the examination.
|
During procedure
|
|
Requirement for mask ventilation
Prazo: During procedure
|
Number of participants requiring bag-mask ventilation during the examination.
|
During procedure
|
|
Requirement for endotracheal intubation
Prazo: During procedure
|
Number of participants requiring endotracheal intubation during the examination.
|
During procedure
|
|
Incidence of airway intervention
Prazo: During procedure
|
Proportion of participants requiring any airway intervention (jaw thrust, nasal cannula, increased flow, mask ventilation, or intubation)
|
During procedure
|
|
Severity of coughing
Prazo: During procedure
|
Assessed using a 4-grade scale: Grade I (none), Grade II (single mild episode), Grade III (multiple episodes <15s), Grade IV (continuous >15s)
|
During procedure
|
|
Length of stay in recovery room
Prazo: Up to 30 minutes post-anesthesia care unit (PACU) admission
|
Time from arrival to discharge from the recovery room (maximum observation 30 minutes)
|
Up to 30 minutes post-anesthesia care unit (PACU) admission
|
|
Endoscopist satisfaction score
Prazo: During procedure
|
Assessed using a Numerical Rating Scale (NRS) ranging from 0 to 10, with higher scores indicating greater satisfaction.
|
During procedure
|
|
Incidence of postoperative nausea, vomiting, headache, and dizziness
Prazo: Up to 30 minutes post-anesthesia care unit (PACU) admission
|
Proportion of participants experiencing nausea, vomiting, headache, or dizziness after awakening in the recovery room.
|
Up to 30 minutes post-anesthesia care unit (PACU) admission
|
Outras medidas de resultado
Medida de resultado |
Descrição da medida |
Prazo |
|---|---|---|
|
Safety outcome endpoints：heart rate
Prazo: Baseline and during procedure
|
Recorded at T0 (before pre-oxygenation), T1 (before induction), T2 (scope insertion), and T3 (scope removal).
|
Baseline and during procedure
|
|
Safety outcome endpoints：blood pressure
Prazo: Baseline and during procedure
|
Recorded at T0 (before pre-oxygenation), T1 (before induction), T2 (scope insertion), and T3 (scope removal)
|
Baseline and during procedure
|
|
Safety outcome endpoints：peripheral oxygen saturation (SpO₂)
Prazo: Baseline and during procedure
|
Recorded at T0 (before pre-oxygenation), T1 (before induction), T2 (scope insertion), and T3 (scope removal).
|
Baseline and during procedure
|
|
Safety outcome endpoints：Incidence of hemodynamic instability in recovery
Prazo: Up to 30 minutes post-anesthesia care unit (PACU) admission
|
Occurrence of tachycardia (>100 bpm), bradycardia (<50 bpm), or hypotension (systolic blood pressure <80 mmHg) during the recovery period.
|
Up to 30 minutes post-anesthesia care unit (PACU) admission
|
Colaboradores e Investigadores
É aqui que você encontrará pessoas e organizações envolvidas com este estudo.
Patrocinador
Investigadores
- Cadeira de estudo: Xinli Ni, Doctoral, General Hospital of Ningxia Medical University
Datas de registro do estudo
Essas datas acompanham o progresso do registro do estudo e os envios de resumo dos resultados para ClinicalTrials.gov. Os registros do estudo e os resultados relatados são revisados pela National Library of Medicine (NLM) para garantir que atendam aos padrões específicos de controle de qualidade antes de serem publicados no site público.
Datas Principais do Estudo
Início do estudo (Estimado)
23 de junho de 2026
Conclusão Primária (Estimado)
31 de julho de 2026
Conclusão do estudo (Estimado)
31 de agosto de 2026
Datas de inscrição no estudo
Enviado pela primeira vez
15 de junho de 2026
Enviado pela primeira vez que atendeu aos critérios de CQ
24 de junho de 2026
Primeira postagem (Real)
29 de junho de 2026
Atualizações de registro de estudo
Última Atualização Postada (Real)
29 de junho de 2026
Última atualização enviada que atendeu aos critérios de controle de qualidade
24 de junho de 2026
Última verificação
1 de junho de 2026
Mais Informações
Termos relacionados a este estudo
Outros números de identificação do estudo
- dywe0003
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