qNOX/qCON EEG monitoring to guide sedation during gastroscopy and colonoscopy

Exploration of the Range of the Quantitative Nociception Index (qNOX) During Gastrointestinal Endoscopy Under Intravenous Sedation: a Multicenter Clinical Study

This trial tests whether qNOX and qCON EEG monitoring can better guide sedation and pain response for adults having propofol or propofol-plus-sufentanil gastroscopy and colonoscopy under IV sedation.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 900 (estimated)
• Ages: 18 Years to 60 Years
• Sex: All
• Sponsor: First Affiliated Hospital of Chongqing Medical University (other)
• Locations: 1 site (Chongqing, Chongqing Municipality)
• Trial ID: NCT06777589 on ClinicalTrials.gov

What this trial studies

This multicenter clinical study will enroll 900 adult outpatients undergoing IV‑sedated gastroscopy or colonoscopy and assign them to propofol alone or propofol plus low‑dose sufentanil groups for each procedure. An Apollo‑9000A monitor will continuously record qCON and qNOX indices while investigators collect blood pressure, heart rate, SpO2, and MOAA/S scores at predefined time points. The study will compare index values, hemodynamic responses, sedation scores, and adverse events to identify a reasonable qNOX range and the optimal timing to perform endoscopy during sedation. The findings aim to define monitoring thresholds that correspond to adequate analgesia and reduced procedural stress.

Who should consider this trial

Good fit: Adults aged 18–60 with ASA I–II, BMI 18–28 kg/m², undergoing diagnostic or therapeutic gastroscopy or colonoscopy under IV sedation who can give informed consent.

Not a fit: Patients who are pregnant or lactating, have severe neurological disease, chronic pain or substance abuse, known difficult airways, require complex endoscopic techniques, or fall outside the age/BMI/ASA criteria are unlikely to benefit from the study results.

Why it matters

Potential benefit: If successful, this could provide clear qNOX thresholds to help clinicians time endoscopic procedures and tailor sedation for safer, more comfortable exams.

How similar studies have performed: Related EEG-based indices such as BIS and emerging qCON/qNOX monitors have shown promise for perioperative sedation and nociception monitoring, but optimal qNOX targets for endoscopy are not yet standardized.

Eligibility criteria

Inclusion Criteria

1. Age between 18 and 60 years old;
2. ASA-PS (American Society of Anesthesiologists Physical Status) classification of I to II;
3. Body Mass Index (BMI): 18 to 28 kg/m²;
4. Patients undergoing diagnostic and therapeutic procedures under sedation for lower gastrointestinal endoscopy;
5. Clear understanding and voluntary participation in this study, with informed consent signed.

Exclusion Criteria

1. Patients requiring complex endoscopic techniques for diagnosis and treatment;
2. Patients who have participated in other clinical trials in the past three months;
3. Pregnant and lactating patients;
4. Patients with allergies to sedatives/anesthetics and other severe anesthesia risks;
5. Patients with preoperative chronic pain or a history of substance abuse;
6. Patients with severe neurological diseases such as stroke, hemiplegia, convulsions, epilepsy, etc.;
7. Patients with known difficult airways such as limited mouth opening, restricted neck and jaw movement, rheumatoid spondylitis, temporomandibular joint arthritis, etc.;
8. Patients with potentially life-threatening circulatory and respiratory diseases that are not adequately controlled, such as uncontrolled severe hypertension, severe arrhythmias, unstable angina pectoris, acute respiratory infections, asthma exacerbations, etc.;
9. Patients with liver dysfunction (Child-Pugh Class C or higher), acute upper gastrointestinal bleeding with shock, severe anemia, gastrointestinal obstruction with gastric retention.

Where this trial is running

Chongqing, Chongqing Municipality

• China,Chongqing The First Affiliated Hospital of Chongqing Medical University — Chongqing, Chongqing Municipality, China (RECRUITING)

Study contacts

• Study coordinator: Qin Liu

Conditions: Nociception, endoscopy, Depth of anesthesia