quantitative consciousness index monitoring of sedation during endoscopy：a prospective observational preliminary study

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This study aimed to investigate the application of novel electroencephalography-derived indices, the quantitative consciousness index (qCON) and the quantitative nociception index (qNOX), for monitoring sedation and analgesia, and to determine the optimal qCON range associated with stable procedural conditions. Methods: This prospective observational preliminary study enrolled 220 patients undergoing elective gastroscopy or colonoscopy. All patients received propofol and sufentanil for anesthesia. Depth of anesthesia and nociception were continuously monitored using qCON and qNOX. Hemodynamic parameters, body movements, and cough reflexes were recorded at predefined time points. The primary outcome was optimal sedation quality, defined as hemodynamic fluctuations within 10% of baseline and the absence of body movement or coughing. Results: The optimal qCON range associated with stable hemodynamics and absence of noxious responses was 55～63 (95% CI: 55.25–62.62 for gastroscopy; 55.25–62.52 for colonoscopy). Strong correlations were observed between qCON and qNOX (gastroscopy: qNOX = 0.78 × qCON + 26.1, R² = 0.714; colonoscopy: qNOX = 0.83 × qCON + 22.47, R² = 0.716; p < 0.001). The qNOX index demonstrated a faster response to noxious stimuli compared to qCON during both induction and recovery phases. Conclusion: The qCON index provides an objective guidance for sedation depth during painless gastrointestinal endoscopy. Maintaining qCON within the range of 55 to 63 is associated with optimal procedural conditions. The combined use of qCON and qNOX monitoring can help optimize the balance between sedation and analgesia, potentially improving the safety and quality of endoscopic sedation. Trial registration Trial registration: This study was registered at ClinicalTrials.gov (Registration Number: NCT06604156). The registration was completed on April 11, 2024. qCON qNOX Sedation monitoring Gastrointestinal endoscopy Nociception Anesthesia depth Figures Figure 1 Figure 2 Figure 3 1. Introduction Gastrointestinal endoscopy is the primary method for examining gastrointestinal diseases [1-3] . With the advancement of comfortable healthcare and the improvement of public health awareness, most patients opt for painless diagnostic and therapeutic procedures [4-7] . Currently, the assessment of sedation depth duringgastrointestinal endoscopy primarily relies on the clinical experience and judgment of the anesthesiologist, as there is no universally accepted objective monitoring standard [8, 9] . Consequently, clinical parameters such as blood pressure, heart rate, and responses to nociceptive stimuli are commonly utilized to titrate analgesicand sedative agents. However, it remains challenging to attribute changes in theseparameters specifically to either analgesic or sedative effects. Anesthesiologists rarely utilize monitoring devices such as Bispectral Index (BIS) or Narcotrend to assess the sedation depth during gastrointestinal endoscopy [10-13] . However, these indices primarily reflect the level of sedation and hypnoticeffect rather than the response to nociceptive stimulation [14, 15] . The quantitative consciousness (qCON) index and quantitative nociception (qNOX) index are novel monitoring methods based on dynamic electroencephalography, which generate values ranging from 0 to 99 through an adaptive neuro-fuzzy inference system and nonlinear analysis. The qCON index measures the depth of sedation and hypnosis, whereas the qNOX index reflects the intensity of the response to nociceptive stimuli [16-19] . During general anesthesia, maintaining qCON values between 40～60 and qNOX values within 30～50 indicates an appropriate state of sedation and analgesia [17, 20, 21] . Nevertheless, no studies have yet investigated the trends of qCON values during painless gastrointestinal endoscopy. Safe and effective sedation monitoring includes direct visual monitoring and physiological monitoring, which involve assessing the patient's hemodynamics and depth of sedation [22-24] . Direct visual monitoring involves closely observing respiratory patterns, chest wall movement, changes in skin color, and involuntary movements or facial expressions as indicators of painful stimuli. Physiological monitoring can be categorized into several types: hemodynamic monitoring (e.g., heart rate, blood pressure, and electrocardiogram), oxygenation monitoring (e.g., pulse oximetry), ventilation monitoring (e.g., pulse oximetry, end-tidal carbon dioxide monitoring), and depth of sedation monitoring [23] . Therefore, this study utilized qCON and qNOX monitoring to evaluate the sedation and analgesia status of patients undergoing painless gastrointestinal endoscopy, combined with visual assessment (cough reflex, respiratory depression, and body movement) and clinical physiological monitoring (vital signs and pulse oximetry). The study amis to explore the optimal sedation range for digestive endoscopy under sedation. 2. Materials and Methods Study Population: This study was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (Approval No.: 2024-109-01), and was registered at ClinicalTrials.gov (NCT06604156) on April 11, 2024. Written informed consent was obtained from all participants prior to their inclusion in the study, and Written informed consent for publication was obtained from all participants. We enrolled patients aged 18～60 years, with BMI 18～28 kg/m² and ASA physical status I or II, who underwent sedated digestive endoscopy at the outpatient department of our hospital between September 1, 2024, and November 30, 2024. Patients were excluded if they met any of the following criteria: pregnancy or lactation; allergy or contraindication to opioids or propofol; severe neurological disorders (e.g., stroke, hemiplegia, convulsion, epilepsy); anticipated difficult airway (e.g., cervical spine fixation, limited mouth opening); Respiratory diseases potentially increasing airway sensitivity, including tracheitis, bronchitis, asthma, chronic obstructive pulmonary disease, or acute respiratory infection; conditions impairing pharyngolaryngeal function (e.g., chronic pharyngitis, laryngitis, laryngeal edema, recurrent laryngeal nerve paralysis); esophageal disorders potentially causing dysphagia or reflux (e.g., esophagitis, esophageal stenosis, esophageal dysmotility); Life-threatening uncontrolled cardiovascular diseases (e.g., severe uncontrolled hypertension, severe arrhythmia, unstable angina). study design: Patients were divided into two groups based on endoscopic modality: the gastroscopy group ( n =110) and the colonoscopy group ( n =110). All patients received intravenous anesthesia induction with propofol combined with low-dose sufentanil. Anesthesia Protocol: All patients were instructed to fast for 6 hours and abstain from clear fluids for 2 hours preoperatively. For patients undergoing gastroscopy, 10 mL of lidocaine mucilage was administered orally for topical pharyngeal anesthesia before induction. For those scheduled for colonoscopy, lidocaine mucilage was applied to the anal surface and the colonoscope shaft. Patients were placed in the left lateral position and received nasal oxygen at 5 L/min. Standard monitoring included non-invasive blood pressure, heart rate, and pulse oximetry. Anesthesia depth was monitored using the qCON/qNOX indices (Apollo-9000A, Chongqing Xider Medical Instrument Co., China), with three forehead electrodes capturing raw EEG signals. Parameters recorded included the qCON index (reflecting hypnosis), qNOX index (reflecting nociception), burst suppression ratio (BSR), and signal quality index (SQI). Anesthesia induction consisted of intravenous sufentanil (5㎍; Yichang Renfu Pharmaceutical, China), followed 1 minute later by propofol (1.5～2.5 mg/kg; Chenxin Pharmaceutical, China) injected at 1 mL/3s. The Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale was assessed immediately after propofol administration. Endoscope insertion commenced when the MOAA/S score was ≤1. Anesthesia maintenance was achieved with propofol infusion at 4～6 mg/kg/h, discontinued upon initiation of endoscope withdrawal. Intraoperative events such as coughing or body movement were managed with rescue propofol (0.5 mg/kg). Observation Indices: The following parameters—qCON, qNOX, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (SpO₂), and MOAA/S scores—were recorded at predefined time points. For gastroscopy, time points included baseline value (T 0 ), loss of consciousness (T 1 ), pre-insertion of the gastroscope (T 2 ), passage through the pharynx (T 3 ), 1 minute after intragastric placement (T 4 ), procedure completion (T 5 ), eye opening upon verbal stimulation (T 6 ), and room discharge (T 7 ). For colonoscopy, time points included baseline value (T 0 ), loss of consciousness (T 1 ), pre-insertion of the colonoscope (T 2 ), post-anal insertion (T 3 ), upon reaching the sigmoid colon (T 4 ), splenic flexure (T 5 ), hepatic flexure (T 6 ), procedure completion (T 7 ), eye opening upon verbal stimulation (T 8 ), and room discharge (T 9 ). Additional recordings were obtained during events such as coughing, body movement, biopsy, or polypectomy. Adverse events including hypoxemia, respiratory depression, bradycardia, hypotension, injection pain, coughing, and body movement were documented, along with recovery time and post-procedure complications such as dizziness, blurred vision, nausea, vomiting, abdominal pain, and distension. Statistical Analysis The primary outcome of this study was the quality of anesthesia sedation during gastroscopy (when the endoscope passed the pharynx) or colonoscopy (when the endoscope passed the splenic flexure), defined as follows: fluctuations in HR and SBP within 10% of baseline values, and no body movement or coughing. Previous studies have shown that the incidence of hemodynamic instability during painless gastrointestinal endoscopy is 22.39% [25] . Based on preliminary data from prior experiment, we assumed a hemodynamic instability rate of 30% under the current study conditions. With the application of sedation monitoring, this rate was expected to decrease to 10%. With a significance level (α) set at 0.05 and a power (1–β) of 0.90, and accounting for a 10% dropout rate, the sample size was calculated using PASS 15.0 software. The final estimated sample size was 220 cases, with 110 assigned to the gastroscopy group and 110 to the colonoscopy group. Statistical analyses were performed using SPSS 26.0. All statistical tests were two-sided, and a P-value ≤ 0.05 was considered statistically significant. Normally distributed data are presented as mean ± standard deviation (Mean ± SD) and compared between groups using the t-test, with 95% confidence intervals (CIs) calculated accordingly. Non-normally distributed data are presented as median and interquartile range [Median (IQR)] and compared using the Mann–Whitney test; the 95% CIs were estimated via the Hodges–Lehmann two-sample estimator. 3. Results General Situation: This study included 220 patients, 114 for gastroscopy and 116 for colonoscopy. In the gastroscopy group, 2 patients had missing data, one patient experienced reflux aspiration, and 1 patient was excluded due to incomplete examination; in the colonoscopy group, 1 patient had missing data, and 2 patients were excluded due to incomplete examination. The flowchart in Figure 1 outlines the number of patients at each stage of the study and includes the reasons for exclusion at each stage. The characteristics of the patients who were included in the study are presented in Table 1. Trends in qCON and qNOX Changes: The baseline values of qCON and qNOX were defined as the indices recorded during the 1-minute period prior to anesthesia induction, with the loss of consciousness (LOC) determined by the disappearance of the eyelash reflex during the transition from the awake to anesthetized state. The mean LOC values during gastroscopy and colonoscopy were 69 and 67, respectively. qCON values were elevated during induction and emergence phases but remained between 40 and 60 at all other time points (Figure 2). Similarly, qNOX showed higher values during induction and extubation, ranging between 60 and 80 during other phases (Figure 2). During induction, qCON decreased more rapidly than qNOX, whereas during recovery, qNOX increased faster than qCON (Figure 2). Based on sedation quality criteria (HR and SBP fluctuations within 10% of baseline, and absence of body movement or coughing), patients were categorized into stable and suboptimal sedation groups during gastroscopy (pharyngeal passage) or colonoscopy (splenic flexure passage). In the gastroscopy group, 30 patients achieved stable sedation, with a qCON 95% confidence interval of (55.25, 62.62); in the colonoscopy group, 34 patients had stable sedation, with a qCON 95% confidence interval of (55.25, 62.52) (Table 2). These results indicate that the optimal qCON range for stablesedation during digestive endoscopy is 55～63. A strong correlation was observed between qCON and qNOX: the linear model for gastroscopy was qNOX = 0.78 × qCON + 26.1 (p < 0.001; R² = 0.714), and for colonoscopy, qNOX = 0.83 × qCON + 22.47 (p < 0.001; R² = 0.716) (Figure 3). 4. Discussion The optimal sedation monitoring recommendations should aim to prevent sedation-related adverse events and early detection of oversedation. Close patient monitoring via visual assessment (e.g., coughing, cyanosis, and limb movements) and physiological parameters (e.g., vital signs and oxygenation measured by pulse oximetry) represents the most crucial and reliable approach to avoiding sedation-related complications [7, 26, 27] . This study is the first to apply qCON and qNOX monitoring during digestive endoscopy under sedation, establishing that maintaining qCON values within the range of 55～63 correlates with stable vital signs and the absence of body movement or coughing responses, thereby providing an actionable reference range for sedation depth in clinical anesthesia practice. Monitoring anesthetic depth is critical to avoid intraoperative awareness under general anesthesia while preventing adverse reactions caused by anesthetic overdose. Currently, there is no consensus standard for evaluating anesthetic depth during sedated digestive endoscopy, and clinical practice relies heavily on anesthesiologists’ experience. Previous studies attempted to combine the Bispectral Index (BIS) with the MOAA/S scale to identify an optimal anesthetic depth range for endoscopic procedures [28, 29] . However, the MOAA/S scale is subjective, particularly under deep sedation, limiting its accuracy and correlation with objective measures like BIS [30, 31] . Given the preference for deep sedation among Chinese patients, who generally desire no consciousness during endoscopy, this study used objective vital signs and depth of sedation monitoring to comprehensively assess the level of sedation. The results showed hemodynamic instability (defined as MAP or HR fluctuations >20%) in 34% and 47% of patients undergoing gastroscopy and colonoscopy. As the proportion of elderly patients undergoing sedated endoscopy increases, this study defined ideal sedation quality as hemodynamic fluctuations within 10% and absence of body movement or coughing. The findings indicate that maintaining a qCON index between 55 and 63 during intravenous sedation for digestive endoscopy effectively controls MAP and HR within the target range without adverse reactions. The qNOX index reflects the level of nociceptive response and can effectively predict the body's reaction to harmful stimuli such as laryngoscopy, tracheal intubation, and laryngeal mask insertion [32] . A strong correlation was observed between qCON and qNOX. During the induction period, qCON decreased more rapidly than qNOX, whereas during anesthesia recovery, qNOX increased faster than qCON. Additionally, qNOX responded more quickly to nociceptive stimuli, which is consistent with previous findings [20, 33] .Therefore, the qNOX index can be used to determine the critical qCON values at which patients lose and regain consciousness. Our study found that a qNOX value above 70 indicates insufficient analgesia, necessitating additional analgesic drugs; a qNOX value above 80 suggests potential recovery of consciousness, requiring supplemental sedatives; and a qNOX value exceeding 90 may lead to patient arousal even when qCON remains around 60. Contrary to the conventional view that gastroscopy induces stronger nociceptive stimulation than colonoscopy, our findings revealed that colonoscopy is not less stimulating. Both gastroscopy and colonoscopy resulted in qCON indices within the range of 55～63. The strongest stimulation during gastroscopy occurred when the endoscope passed through the pharynx, triggering intense coughing and body movement. In contrast, during colonoscopy, the most significant stimulation arose from visceral pain caused by stretching and distension of the intestine when the endoscope navigated the splenic and hepatic flexures . This perspective differs from that of endoscopists, who often consider the sigmoid colon—with its acute angles—to be the most challenging and stimulating segment. The heightened pain or discomfort experienced at the splenic and hepatic flexures may require increased sedation depth.We also observed that when patients are exposed to intensified harmful stimuli such as insufflation, sharp turns, or traction—even under deep sedation—the cerebral cortex may still respond to these stimuli. This response manifests as enhanced electroencephalographic activity, leading to an elevated qNOX value while the qCON index remains relatively unchanged. This further underscores the importance of closely monitoring procedure-related nociceptive stimulation. Limitations of this study: This is a single-center, prospective, observational study with a relatively small sample size. The results of this study are exploratory in nature and therefore require further validation through multi-center, large-sample studies. Next, we will conduct a multi-center, large-sample interventional clinical study to further validate the range of the qCON index and explore the optimal range of qNOX for gastrointestinal endoscopy. Declarations Ethics Approval and Consent to Participate This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (Approval No.: 2024-109-01).Written informed consent was obtained from all participants. onsent for Publication Written consent for publication was obtained from all individuals (or their guardians) whose data or images appear in this manuscript. "Written informed consent for publication was obtained from all participants." Availability of Data and Materials All data generated or analysed during this study are included in this published article [and its supplementary information files]. Competing Interests The authors declare no competing interests, whether financial or non-financial, relevant to this work. Funding This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Authors' Contributions We have updated the “Author Contributions” section to include all authors, as per the CRediT taxonomy: QinLiu: wrote the main manuscript text; SuMin : Conceptualization, Supervision, Writing, review, editing; Da-Yuan Wei: Data analysis Wen-Jie Cheng: Project administration；Xuan-Qi Yang: Validation. All authors reviewed the manuscript. Each author’s role now reflects their substantive contributions to the study. Acknowledgements Not applicable. References YOUNG E, PHILPOTT H, SINGH R. Endoscopic diagnosis and treatment of gastric dysplasia and early cancer: Current evidence and what the future may hold [J]. World J Gastroenterol, 2021, 27(31): 5126-51. SUH Y S, LEE J, WOO H, et al. 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Tables Table 1 Patient and intervention characteristics Characteristics gastroscopy Colonoscopy Age (yrs) 49（38，56） 49（38，56） Gender (M/F) 33/73 48/59 Weight, kg 57(52.8,65.0) 60(53.0,67.5) Height, cm 160.6±7.7 161.2±7.5 ASA classification score (I/II) 13/93 12/95 Propofol induction dose, mg (IQR) induction dose, Total dose 130.0(120.0,150.0) 125.0(120.0,150.0) Total dose,Total dose 150.0(130.0,180.0) 190.0(150.0,220.0) Duration of procedures (min) 5.0(3.0,6.0) 9.0(6.0,13.0) Anesthesia emergence time (min) 5.0(3.0,7.0) 4.0(2.0,7.0) Duration of stay in PACU (min) 18.0(15.0,18.0) 17.0(15.0,20.0) Data are expressed as mean ± SD or median [Q1–Q3] . ASA=American Society of Anesthesiologists, PACU= postanesthetic care unit. Table 2. qCON levels at the time for inadequate/adequate sedation( Hemodynamic fluctuations within ±10%, without coughing and body movement ).The critical time points for sedation were evaluated during passage of the gastroscope through the pharynx and colonoscopy into the splenic flexure, as this may cause a strong physiological response. Variable No. Mean Median Minimum Maximum 95% CI gastroscopy Adequate sedation 30 58.93 61.00 41.00 72.00 55.25,62.62 inadequate sedation 76 50.97 49.00 39.00 73.00 47.73,54.21 colonoscopy Adequate sedation 34 58.88 62.50 41.00 73.00 55.25,62.52 inadequate sedation 73 53.94 52.50 40.00 80.00 50.49,57.39 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7879324","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":557751703,"identity":"e0d0643c-75da-4c09-b5b5-cd6411b3b297","order_by":0,"name":"Qin Liu","email":"","orcid":"","institution":"The First Clinical College of Chongqing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Qin","middleName":"","lastName":"Liu","suffix":""},{"id":557751706,"identity":"d9d6b9ce-17ea-4b3c-b068-f103d714fe79","order_by":1,"name":"Su Min","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0klEQVRIiWNgGAWjYFAC5oMPEgwkePjZmw8c+PCDKC1syQYfCizkJHuOJR6c2UOUFh4zyRkfKowNbvgYH+ZgI0KDbv+xNGkeA4nEmTN4Phxm4GGQ5xc7gF+L2Y3kw9YgLf3SvRsOF1gwGM6cnUBIC1vibbAtc85uODyDhyHB4DYhLefPGIAdtuFGzoPDPGzEaDmQYyQ5w0AC6P0cBiK13EgDBrKBBCiQDYCBLEGEX84fBkblnzpQVD7+8OGHjTy/NAEt6ECCNOWjYBSMglEwCrADALD4S5EKA4NtAAAAAElFTkSuQmCC","orcid":"","institution":"The First Clinical College of Chongqing Medical University","correspondingAuthor":true,"prefix":"","firstName":"Su","middleName":"","lastName":"Min","suffix":""},{"id":557751712,"identity":"3a6928e1-92a6-4822-a66c-7ba934a8a0bf","order_by":2,"name":"Da-Yuan Wei","email":"","orcid":"","institution":"The First Clinical College of Chongqing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Da-Yuan","middleName":"","lastName":"Wei","suffix":""},{"id":557751719,"identity":"e0145c8b-0459-494a-b4af-865d3c6b8c64","order_by":3,"name":"Wen-Jie Cheng","email":"","orcid":"","institution":"The First Clinical College of Chongqing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Wen-Jie","middleName":"","lastName":"Cheng","suffix":""},{"id":557751721,"identity":"c5e32352-cd40-4073-8b7f-cba127c41c87","order_by":4,"name":"Xuan-Qi Yang","email":"","orcid":"","institution":"The First Clinical College of Chongqing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xuan-Qi","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2025-10-16 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16:32:29","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":32132,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7879324/v1/f828dce4db605f639ef861cb.png"},{"id":97965593,"identity":"2836d195-17bf-481f-b730-6fafe6b97357","added_by":"auto","created_at":"2025-12-11 09:49:39","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":271472,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7879324/v1/ce9b25542a89b99e6d5ca53f.png"},{"id":97965582,"identity":"3ee432bd-4121-403e-9510-c16eb5679a65","added_by":"auto","created_at":"2025-12-11 09:49:38","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":91993,"visible":true,"origin":"","legend":"\u003cp\u003eStudy Flow Diagram\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7879324/v1/2507fd646501d3808ec6a811.jpg"},{"id":97965581,"identity":"8b6c32d0-b0b2-4f20-86aa-da2b81f91e71","added_by":"auto","created_at":"2025-12-11 09:49:38","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":49152,"visible":true,"origin":"","legend":"\u003cp\u003eVariations of qNOX and qCON in gastroscopy (A) at the different time-points (T\u003csub\u003e0 \u003c/sub\u003e=baseline value, T\u003csub\u003e1\u003c/sub\u003e = Loss of Consciousness, T\u003csub\u003e2\u003c/sub\u003e = pre-insertion of the gastroscope, T\u003csub\u003e3\u003c/sub\u003e = As Gastroscopy Passes Through the Pharynx, T\u003csub\u003e4\u003c/sub\u003e = 1 minute after intragastric placement, T\u003csub\u003e5\u003c/sub\u003e = procedure completion, T\u003csub\u003e6\u003c/sub\u003e = eye opening upon verbal stimulation, T\u003csub\u003e7\u003c/sub\u003e = room discharge and Variations of qNOX and qCON in colonoscopy (B) at the different time-points (T\u003csub\u003e0\u003c/sub\u003e = Baseline\u0026nbsp;value, T\u003csub\u003e1\u003c/sub\u003e = Loss of Consciousness, T\u003csub\u003e2\u003c/sub\u003e = pre-insertion of the colonoscope, T\u003csub\u003e3\u003c/sub\u003e = post-anal insertion\u0026nbsp;, T\u003csub\u003e4\u003c/sub\u003e = at the sigmoid colon, T\u003csub\u003e5\u003c/sub\u003e = At the Splenic Flexure, T\u003csub\u003e6 \u003c/sub\u003e= At the Hepatic Flexure, T\u003csub\u003e7 \u003c/sub\u003e= procedure completion, T\u003csub\u003e8\u003c/sub\u003e = eye opening upon verbal stimulation, T\u003csub\u003e9\u003c/sub\u003e = room discharge. Plain circles represent mean val-ues. Error bars represent standard deviations.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7879324/v1/bb0a4aa8bfa83600fd7a3482.jpg"},{"id":97965665,"identity":"d19b1514-8fe9-42eb-8f40-96a364738c67","added_by":"auto","created_at":"2025-12-11 09:50:08","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":106221,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between A qCON and qNOX from T\u003csub\u003e0\u003c/sub\u003e to T\u003csub\u003e7\u003c/sub\u003e in gastroscopy, B qCON and qNOX from T\u003csub\u003e0\u003c/sub\u003e to T\u003csub\u003e9\u003c/sub\u003e in colonoscopy.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7879324/v1/459652d0bda9159ea929ac5a.jpg"},{"id":99774932,"identity":"298e59a3-cb12-4fd4-83d3-f1b292d2144e","added_by":"auto","created_at":"2026-01-08 09:39:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":993844,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7879324/v1/b2d9ace2-c8ce-4b7b-b53b-a86e50c2e7c6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"quantitative consciousness index monitoring of sedation during endoscopy：a prospective observational preliminary study","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eGastrointestinal endoscopy is the primary method for examining gastrointestinal diseases\u003csup\u003e[1-3]\u003c/sup\u003e. With the advancement\u0026nbsp;of comfortable healthcare and the improvement of public health awareness, most patients opt for painless diagnostic and therapeutic procedures\u003csup\u003e[4-7]\u003c/sup\u003e. Currently, the assessment of sedation depth duringgastrointestinal endoscopy primarily relies on the clinical experience and judgment of the anesthesiologist, as there is no universally accepted objective monitoring standard\u003csup\u003e[8, 9]\u003c/sup\u003e. Consequently, clinical parameters such as blood pressure, heart rate, and responses to nociceptive stimuli are commonly utilized to titrate analgesicand sedative agents. However, it remains challenging to attribute changes in theseparameters specifically to either analgesic or sedative effects.\u003c/p\u003e\n\u003cp\u003eAnesthesiologists rarely utilize monitoring devices such as Bispectral Index (BIS) or Narcotrend to assess the sedation depth during gastrointestinal endoscopy\u003csup\u003e[10-13]\u003c/sup\u003e. However, these indices primarily reflect the level of sedation and hypnoticeffect rather than the response to nociceptive stimulation\u003csup\u003e[14, 15]\u003c/sup\u003e. The quantitative consciousness (qCON) index and quantitative nociception (qNOX) index are novel monitoring methods based on dynamic electroencephalography, which generate values ranging from 0 to 99 through an adaptive neuro-fuzzy inference system and nonlinear analysis. The qCON index measures the depth of sedation and hypnosis, whereas the qNOX index reflects the intensity of the response to nociceptive stimuli\u003csup\u003e[16-19]\u003c/sup\u003e. During general anesthesia, maintaining qCON values between 40～60 and qNOX values within 30～50 indicates an appropriate state of sedation and analgesia\u003csup\u003e[17, 20, 21]\u003c/sup\u003e. Nevertheless, no studies have yet investigated the trends of qCON values during painless gastrointestinal endoscopy.\u003c/p\u003e\n\u003cp\u003eSafe and effective sedation monitoring includes direct visual monitoring and physiological monitoring, which involve assessing the patient\u0026apos;s hemodynamics and depth of sedation\u003csup\u003e[22-24]\u003c/sup\u003e. Direct visual monitoring involves closely observing respiratory patterns, chest wall movement, changes in skin color, and involuntary movements or facial expressions as indicators of painful stimuli. Physiological monitoring can be categorized into several types: hemodynamic monitoring (e.g., heart rate, blood pressure, and electrocardiogram), oxygenation monitoring (e.g., pulse oximetry), ventilation monitoring (e.g., pulse oximetry, end-tidal carbon dioxide monitoring), and depth of sedation monitoring\u003csup\u003e[23]\u003c/sup\u003e. Therefore, this study utilized qCON and qNOX monitoring to evaluate the sedation and analgesia status of patients undergoing painless gastrointestinal endoscopy, combined with visual assessment (cough reflex, respiratory depression, and body movement) and clinical physiological monitoring (vital signs and pulse oximetry). The study amis to explore the optimal sedation range for digestive endoscopy under sedation.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003eStudy Population:\u0026nbsp;This study was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (Approval No.: 2024-109-01),\u0026nbsp;\u003cstrong\u003eand was registered at ClinicalTrials.gov (NCT06604156) on April 11, 2024.\u0026nbsp;\u003c/strong\u003eWritten informed consent was obtained from all participants\u0026nbsp;\u003cstrong\u003eprior to their inclusion in the study, and Written informed consent for publication was obtained from all participants.\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eWe enrolled patients aged 18～60 years, with BMI 18～28 kg/m\u0026sup2; and ASA physical status I or II, who underwent sedated digestive endoscopy at the outpatient department of our hospital between September 1, 2024, and November 30, 2024. Patients were excluded if they met any of the following criteria: pregnancy or lactation; allergy or contraindication to opioids or propofol; severe neurological disorders (e.g., stroke, hemiplegia, convulsion, epilepsy); anticipated difficult airway (e.g., cervical spine fixation, limited mouth opening); Respiratory diseases potentially increasing airway sensitivity, including tracheitis, bronchitis, asthma, chronic obstructive pulmonary disease, or acute respiratory infection; conditions impairing pharyngolaryngeal function (e.g., chronic pharyngitis, laryngitis, laryngeal edema, recurrent laryngeal nerve paralysis); esophageal disorders potentially causing dysphagia or reflux (e.g., esophagitis, esophageal stenosis, esophageal dysmotility); Life-threatening uncontrolled cardiovascular diseases (e.g., severe uncontrolled hypertension, severe arrhythmia, unstable angina).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003estudy design:\u0026nbsp;\u003c/strong\u003ePatients were divided into two groups based on endoscopic modality: the gastroscopy group (\u003cem\u003en\u003c/em\u003e=110) and the colonoscopy group (\u003cem\u003en\u003c/em\u003e=110). All patients received intravenous anesthesia induction with propofol combined with low-dose sufentanil.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnesthesia Protocol:\u0026nbsp;\u003c/strong\u003eAll patients were instructed to fast for 6 hours and abstain from clear fluids for 2 hours preoperatively.\u0026nbsp;For patients undergoing gastroscopy, 10 mL of lidocaine mucilage was administered orally for topical pharyngeal anesthesia before induction. For those scheduled for colonoscopy, lidocaine mucilage was applied to the anal surface and the colonoscope shaft. Patients were placed in the left lateral position and received nasal oxygen at 5 L/min. Standard monitoring included non-invasive blood pressure, heart rate, and pulse oximetry. Anesthesia depth was monitored using the qCON/qNOX indices (Apollo-9000A, Chongqing Xider Medical Instrument Co., China), with three forehead electrodes capturing raw EEG signals. Parameters recorded included the qCON index (reflecting hypnosis), qNOX index (reflecting nociception), burst suppression ratio (BSR), and signal quality index (SQI). Anesthesia induction\u0026nbsp;consisted of intravenous\u0026nbsp;sufentanil\u0026nbsp;(5㎍; Yichang Renfu Pharmaceutical, China), followed 1 minute later by propofol (1.5～2.5 mg/kg; Chenxin Pharmaceutical, China) injected at 1 mL/3s. The Modified Observer\u0026rsquo;s Assessment of Alertness/Sedation (MOAA/S) scale was assessed immediately after propofol administration. Endoscope insertion commenced when the MOAA/S score was\u0026nbsp;\u0026le;1. Anesthesia maintenance\u0026nbsp;was achieved with propofol infusion at 4～6 mg/kg/h, discontinued upon initiation of endoscope withdrawal. Intraoperative events such as coughing or body movement were managed with rescue propofol (0.5 mg/kg).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObservation Indices:\u003c/strong\u003e The following parameters\u0026mdash;qCON, qNOX, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (SpO₂), and MOAA/S scores\u0026mdash;were recorded at predefined time points. For gastroscopy, time points included baseline value (T\u003csub\u003e0\u003c/sub\u003e), loss of consciousness (T\u003csub\u003e1\u003c/sub\u003e), pre-insertion of the gastroscope (T\u003csub\u003e2\u003c/sub\u003e), passage through the pharynx (T\u003csub\u003e3\u003c/sub\u003e), 1 minute after intragastric placement (T\u003csub\u003e4\u003c/sub\u003e), procedure completion (T\u003csub\u003e5\u003c/sub\u003e), eye opening upon verbal stimulation (T\u003csub\u003e6\u003c/sub\u003e), and room discharge (T\u003csub\u003e7\u003c/sub\u003e). For colonoscopy, time points included baseline value (T\u003csub\u003e0\u003c/sub\u003e), loss of consciousness (T\u003csub\u003e1\u003c/sub\u003e), pre-insertion of the colonoscope (T\u003csub\u003e2\u003c/sub\u003e), post-anal insertion (T\u003csub\u003e3\u003c/sub\u003e), upon reaching the sigmoid colon (T\u003csub\u003e4\u003c/sub\u003e), splenic flexure (T\u003csub\u003e5\u003c/sub\u003e), hepatic flexure (T\u003csub\u003e6\u003c/sub\u003e), procedure completion (T\u003csub\u003e7\u003c/sub\u003e), eye opening upon verbal stimulation (T\u003csub\u003e8\u003c/sub\u003e), and room discharge (T\u003csub\u003e9\u003c/sub\u003e). Additional recordings were obtained during events such as coughing, body movement, biopsy, or polypectomy. Adverse events including hypoxemia, respiratory depression, bradycardia, hypotension, injection pain, coughing, and body movement were documented, along with recovery time and post-procedure complications such as dizziness, blurred vision, nausea, vomiting, abdominal pain, and distension.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary outcome of this study was the quality of anesthesia sedation during gastroscopy (when the endoscope passed the pharynx) or colonoscopy (when the endoscope passed the splenic flexure), defined as follows: fluctuations in HR and SBP within 10% of baseline values, and no body movement or coughing. Previous studies have shown that the incidence of hemodynamic instability during painless gastrointestinal endoscopy is 22.39%\u003csup\u003e[25]\u003c/sup\u003e. Based on preliminary data from prior experiment, we assumed a hemodynamic instability rate of 30% under the current study conditions. With the application of sedation monitoring, this rate was expected to decrease to 10%.\u0026nbsp;With a significance level (\u0026alpha;) set at 0.05 and a power (1\u0026ndash;\u0026beta;) of 0.90, and accounting for a 10% dropout rate, the sample size was calculated using PASS 15.0 software. The final estimated sample size was 220 cases, with 110 assigned to the gastroscopy group and 110 to the colonoscopy group.\u003c/p\u003e\n\u003cp\u003eStatistical analyses were performed using SPSS 26.0. All statistical tests were two-sided, and a P-value \u0026le; 0.05 was considered statistically significant. Normally distributed data are presented as mean \u0026plusmn; standard deviation (Mean \u0026plusmn; SD) and compared between groups using the t-test, with 95% confidence intervals (CIs) calculated accordingly. Non-normally distributed data are presented as median and interquartile range [Median (IQR)] and compared using the Mann\u0026ndash;Whitney test; the 95% CIs were estimated via the Hodges\u0026ndash;Lehmann two-sample estimator.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e\u003cstrong\u003eGeneral Situation:\u003c/strong\u003e This study included 220 patients, 114 for gastroscopy and 116 for colonoscopy. In the gastroscopy group, 2 patients had missing data, one patient experienced reflux aspiration, and 1 patient was excluded due to incomplete examination; in the colonoscopy group, 1 patient had missing data, and 2 patients were excluded due to incomplete examination.\u0026nbsp;\u003cstrong\u003eThe flowchart in Figure 1 outlines the number of patients at each stage of the study and includes the reasons for exclusion at each stage.\u0026nbsp;\u003c/strong\u003eThe characteristics of the patients who were included in the study are presented in Table 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrends in qCON and qNOX Changes:\u0026nbsp;\u003c/strong\u003eThe baseline values of qCON and qNOX were defined as the indices recorded during the 1-minute period prior to anesthesia induction, with the loss of consciousness (LOC) determined by the disappearance of the eyelash reflex during the transition from the awake to anesthetized state. The mean LOC values during gastroscopy and colonoscopy were 69 and 67, respectively. qCON values were elevated during induction and emergence phases but remained between 40 and 60 at all other time points (Figure 2). Similarly, qNOX showed higher values during induction and extubation, ranging between 60 and 80 during other phases (Figure 2). During induction, qCON decreased more rapidly than qNOX, whereas during recovery, qNOX increased faster than qCON (Figure 2). Based on sedation quality criteria (HR and SBP fluctuations within 10% of baseline, and absence of body movement or coughing), patients were categorized into stable and suboptimal sedation groups during gastroscopy (pharyngeal passage) or colonoscopy (splenic flexure passage). In the gastroscopy group, 30 patients achieved stable sedation, with a qCON 95% confidence interval of (55.25, 62.62); in the colonoscopy group, 34 patients had stable sedation, with a qCON 95% confidence interval of (55.25, 62.52) (Table 2). These results indicate that the optimal qCON range for stablesedation during digestive endoscopy is 55～63. A strong correlation was observed between qCON and qNOX: the linear model for gastroscopy was qNOX = 0.78 \u0026times; qCON + 26.1 (p \u0026lt; 0.001; R\u0026sup2; = 0.714), and for colonoscopy, qNOX = 0.83 \u0026times; qCON + 22.47 (p \u0026lt; 0.001; R\u0026sup2; = 0.716) (Figure 3).\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe optimal sedation monitoring recommendations should aim to prevent sedation-related adverse events and early detection of oversedation. Close patient monitoring via visual assessment (e.g., coughing, cyanosis, and limb movements) and physiological parameters (e.g., vital signs and oxygenation measured by pulse oximetry) represents the most crucial and reliable approach to avoiding sedation-related complications\u003csup\u003e[7, 26, 27]\u003c/sup\u003e. This study is the first to apply qCON and qNOX monitoring during digestive endoscopy under sedation, establishing that maintaining qCON values within the range of 55～63 correlates with stable vital signs and the absence of body movement or coughing responses, thereby providing an actionable reference range for sedation depth in clinical anesthesia practice.\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; Monitoring anesthetic depth is critical to avoid intraoperative awareness under general anesthesia while preventing adverse reactions caused by anesthetic overdose. Currently, there is no consensus standard for evaluating anesthetic depth during sedated digestive endoscopy, and clinical practice relies heavily on anesthesiologists\u0026rsquo; experience. Previous studies attempted to combine the Bispectral Index (BIS) with the MOAA/S scale to identify an optimal anesthetic depth range for endoscopic procedures\u003csup\u003e[28, 29]\u003c/sup\u003e. However, the MOAA/S scale is subjective, particularly under deep sedation, limiting its accuracy and correlation with objective measures like BIS\u003csup\u003e[30, 31]\u003c/sup\u003e. Given the preference for deep sedation among Chinese patients, who generally desire no consciousness during endoscopy, this study used objective vital signs and depth of sedation monitoring to comprehensively assess the level of sedation. The results showed hemodynamic instability (defined as MAP or HR fluctuations \u0026gt;20%) in 34% and 47% of patients undergoing gastroscopy and colonoscopy. As the proportion of elderly patients undergoing sedated endoscopy increases, this study defined ideal sedation quality as hemodynamic fluctuations within 10% and absence of body movement or coughing. The findings indicate that maintaining a qCON index between 55 and 63 during intravenous sedation for digestive endoscopy effectively controls MAP and HR within the target range without adverse reactions.\u003c/p\u003e\n\u003cp\u003eThe qNOX index reflects the level of nociceptive response and can effectively predict the body\u0026apos;s reaction to harmful stimuli such as laryngoscopy, tracheal intubation, and laryngeal mask insertion\u003csup\u003e[32]\u003c/sup\u003e. A strong correlation was observed between qCON and qNOX. During the induction period, qCON decreased more rapidly than qNOX, whereas during anesthesia recovery, qNOX increased faster than qCON. Additionally, qNOX responded more quickly to nociceptive stimuli, which is consistent with previous findings\u003csup\u003e[20, 33]\u003c/sup\u003e.Therefore, the qNOX index can be used to determine the critical qCON values at which patients lose and regain consciousness. Our study found that a qNOX value above 70 indicates insufficient analgesia, necessitating additional analgesic drugs; a qNOX value above 80 suggests potential recovery of consciousness, requiring supplemental sedatives; and a qNOX value exceeding 90 may lead to patient arousal even when qCON remains around 60. Contrary to the conventional view that gastroscopy induces stronger nociceptive stimulation than colonoscopy, our findings revealed that colonoscopy is not less stimulating. Both gastroscopy and colonoscopy resulted in qCON indices within the range of 55～63. The strongest stimulation during gastroscopy occurred when the endoscope passed through the pharynx, triggering intense coughing and body movement. In contrast, during colonoscopy, the most significant stimulation arose from visceral pain caused by stretching and distension of the intestine when the endoscope navigated the splenic and hepatic flexures . This perspective differs from that of endoscopists, who often consider the sigmoid colon\u0026mdash;with its acute angles\u0026mdash;to be the most challenging and stimulating segment. The heightened pain or discomfort experienced at the splenic and hepatic flexures may require increased sedation depth.We also observed that when patients are exposed to intensified harmful stimuli such as insufflation, sharp turns, or traction\u0026mdash;even under deep sedation\u0026mdash;the cerebral cortex may still respond to these stimuli. This response manifests as enhanced electroencephalographic activity, leading to an elevated qNOX value while the qCON index remains relatively unchanged. This further underscores the importance of closely monitoring procedure-related nociceptive stimulation.\u003c/p\u003e\n\u003cp\u003eLimitations of this study: This is a single-center, prospective, observational study with a relatively small sample size. The results of this study are exploratory in nature and therefore require further validation through multi-center, large-sample studies. Next, we will conduct a multi-center, large-sample interventional clinical study to further validate the range of the qCON index and explore the optimal range of qNOX for gastrointestinal endoscopy.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics Approval and Consent to Participate\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (Approval No.: 2024-109-01).Written informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003eonsent for Publication\u003c/p\u003e\n\u003cp\u003eWritten consent for publication was obtained from all individuals (or their guardians) whose data or images appear in this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026quot;Written informed consent for publication was obtained from all participants.\u0026quot;\u003c/strong\u003e\u003c/p\u003e\n\u003ch4\u003eAvailability of Data and Materials\u003c/h4\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article [and its supplementary information files].\u003c/p\u003e\n\u003cp\u003eCompeting Interests\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests, whether financial or non-financial, relevant to this work.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThis study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; Contributions\u003c/p\u003e\n\u003cp\u003eWe have updated the \u0026ldquo;Author Contributions\u0026rdquo; section to include all authors, as per the CRediT taxonomy: QinLiu: wrote the main manuscript text; SuMin : Conceptualization, Supervision, Writing, review, editing; Da-Yuan Wei: Data analysis\u003c/p\u003e\n\u003cp\u003eWen-Jie Cheng: Project administration；Xuan-Qi Yang: Validation. All authors reviewed the manuscript. Each author\u0026rsquo;s role now reflects their substantive contributions to the study.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eYOUNG E, PHILPOTT H, SINGH R. Endoscopic diagnosis and treatment of gastric dysplasia and early cancer: Current evidence and what the future may hold [J]. World J Gastroenterol, 2021, 27(31): 5126-51.\u003c/li\u003e\n\u003cli\u003eSUH Y S, LEE J, WOO H, et al. National cancer screening program for gastric cancer in Korea: Nationwide treatment benefit and cost [J]. Cancer, 2020, 126(9): 1929-39.\u003c/li\u003e\n\u003cli\u003eSUH Y S, YANG H K. Screening and Early Detection of Gastric Cancer: East Versus West [J]. Surg Clin North Am, 2015, 95(5): 1053-66.\u003c/li\u003e\n\u003cli\u003eXIN L, GAO Y, CHENG Z, et al. 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BMC Anesthesiol, 2025, 25(1): 484.\u003c/li\u003e\n\u003cli\u003eLI J, WANG X, LIU J, et al. Comparison of ciprofol (HSK3486) versus propofol for the induction of deep sedation during gastroscopy and colonoscopy procedures: A multi-centre, non-inferiority, randomized, controlled phase 3 clinical trial [J]. Basic Clin Pharmacol Toxicol, 2022, 131(2): 138-48.\u003c/li\u003e\n\u003cli\u003eSARGIN M, ULUER M S, ŞIMŞEK B. The effect of bispectral index monitoring on cognitive performance following sedation for outpatient colonoscopy: a randomized controlled trial [J]. Sao Paulo Med J, 2019, 137(4): 305-11.\u003c/li\u003e\n\u003cli\u003eYU Y H, HAN D S, KIM H S, et al. Efficacy of bispectral index monitoring during balanced propofol sedation for colonoscopy: a prospective, randomized controlled trial [J]. Dig Dis Sci, 2013, 58(12): 3576-83.\u003c/li\u003e\n\u003cli\u003eGONZ\u0026aacute;LEZ-MENDIBIL I, GARC\u0026iacute;A-PASCUAL E, VILLANUEVA A, et al. Bispectral index monitoring for sedation in scheduled adult colonoscopy: A randomized controlled trial [J]. Rev Esp Anestesiol Reanim (Engl Ed), 2024, 71(9): 633-44.\u003c/li\u003e\n\u003cli\u003eLIN Y J, WANG Y C, HUANG H H, et al. Target-controlled propofol infusion with or without bispectral index monitoring of sedation during advanced gastrointestinal endoscopy [J]. J Gastroenterol Hepatol, 2020, 35(7): 1189-95.\u003c/li\u003e\n\u003cli\u003eLAFERRI\u0026egrave;RE-LANGLOIS P, MORISSON L, JEFFRIES S, et al. Depth of Anesthesia and Nociception Monitoring: Current State and Vision For 2050 [J]. Anesth Analg, 2024, 138(2): 295-307.\u003c/li\u003e\n\u003cli\u003eROGOBETE A F, BEDREAG O H, PAPURICA M, et al. Multiparametric Monitoring of Hypnosis and Nociception-Antinociception Balance during General Anesthesia-A New Era in Patient Safety Standards and Healthcare Management [J]. Medicina (Kaunas), 2021, 57(2).\u003c/li\u003e\n\u003cli\u003eJENSEN E W, VALENCIA J F, LOPEZ A, et al. Monitoring hypnotic effect and nociception with two EEG-derived indices, qCON and qNOX, during general anaesthesia [J]. Acta Anaesthesiologica Scandinavica, 2014, 58(8): 933-41.\u003c/li\u003e\n\u003cli\u003eMELIA U, GABARRON E, AGUST\u0026iacute; M, et al. Comparison of the qCON and qNOX indices for the assessment of unconsciousness level and noxious stimulation response during surgery [J]. J Clin Monit Comput, 2017, 31(6): 1273-81.\u003c/li\u003e\n\u003cli\u003eLINASSI F, VIDE S, FERREIRA A, et al. Relationships between the qNOX, qCON, burst suppression ratio, and muscle activity index of the CONOX monitor during total intravenous anesthesia: a pilot study [J]. J Clin Monit Comput, 2024, 38(6): 1281-90.\u003c/li\u003e\n\u003cli\u003eM\u0026uuml;LLER J N, KREUZER M, GARC\u0026iacute;A P S, et al. Monitoring depth of sedation: evaluating the agreement between the Bispectral Index, qCON and the Entropy Module\u0026apos;s State Entropy during flexible bronchoscopy [J]. Minerva Anestesiol, 2017, 83(6): 563-73.\u003c/li\u003e\n\u003cli\u003eKANG J, FANG C, LI Y, et al. Effects of qCON and qNOX-guided general anaesthesia management on patient opioid use and prognosis: a study protocol [J]. Bmj Open, 2023, 13(5).\u003c/li\u003e\n\u003cli\u003eZHAO B S, DENG B, CHEN Q B, et al. Effect of quantitative consciousness index on seizure parameters during electroconvulsive therapy in patients with major depressive disorder [J]. World J Psychiatry, 2024, 14(9): 1375-85.\u003c/li\u003e\n\u003cli\u003ePARK S W, LEE H, AHN H. Bispectral Index Versus Standard Monitoring in Sedation for Endoscopic Procedures: A Systematic Review and Meta-Analysis [J]. Dig Dis Sci, 2016, 61(3): 814-24.\u003c/li\u003e\n\u003cli\u003ePARK S W. Clinical and economic value of bispectral index monitoring for adequate endoscopic sedation [J]. Clin Endosc, 2022, 55(4): 518-9.\u003c/li\u003e\n\u003cli\u003eOKAMOTO A, KAMATA K, MIYATA T, et al. Bispectral index-guided propofol sedation during endoscopic ultrasonography [J]. Clin Endosc, 2022, 55(4): 558-63.\u003c/li\u003e\n\u003cli\u003eQADEER M A, LOPEZ A R, DUMOT J A, et al. Hypoxemia during moderate sedation for gastrointestinal endoscopy: causes and associations [J]. Digestion, 2011, 84(1): 37-45.\u003c/li\u003e\n\u003cli\u003eSONG N, YANG Y, ZHENG Z, et al. Effect of Esketamine Added to Propofol Sedation on Desaturation and Hypotension in Bidirectional Endoscopy: A Randomized Clinical Trial [J]. JAMA Netw Open, 2023, 6(12): e2347886.\u003c/li\u003e\n\u003cli\u003eDOSSA F, MEGETTO O, YAKUBU M, et al. Sedation practices for routine gastrointestinal endoscopy: a systematic review of recommendations [J]. BMC Gastroenterol, 2021, 21(1): 22.\u003c/li\u003e\n\u003cli\u003eZHANG H, LU Y, WANG L, et al. Bispectral index monitoring of sedation depth during endoscopy: a meta-analysis with trial sequential analysis of randomized controlled trials [J]. Minerva Anestesiol, 2019, 85(4): 412-32.\u003c/li\u003e\n\u003cli\u003ePASTIS N J, YARMUS L B, SCHIPPERS F, et al. Safety and Efficacy of Remimazolam Compared With Placebo and Midazolam for Moderate Sedation During Bronchoscopy [J]. Chest, 2019, 155(1): 137-46.\u003c/li\u003e\n\u003cli\u003ePASTIS N J, HILL N T, YARMUS L B, et al. Correlation of Vital Signs and Depth of Sedation by Modified Observer\u0026apos;s Assessment of Alertness and Sedation (MOAA/S) Scale in Bronchoscopy [J]. J Bronchology Interv Pulmonol, 2022, 29(1): 54-61.\u003c/li\u003e\n\u003cli\u003eKIM T K, NIKLEWSKI P J, MARTIN J F, et al. Enhancing a sedation score to include truly noxious stimulation: the Extended Observer\u0026apos;s Assessment of Alertness and Sedation (EOAA/S) [J]. Br J Anaesth, 2015, 115(4): 569-77.\u003c/li\u003e\n\u003cli\u003eHANNIVOORT L N, VEREECKE H E, PROOST J H, et al. Probability to tolerate laryngoscopy and noxious stimulation response index as general indicators of the anaesthetic potency of sevoflurane, propofol, and remifentanil [J]. Br J Anaesth, 2016, 116(5): 624-31.\u003c/li\u003e\n\u003cli\u003eCHRISTENSON C, MARTINEZ-VAZQUEZ P, BREIDENSTEIN M, et al. Comparison of the Conox (qCON) and Sedline (PSI) depth of anaesthesia indices to predict the hypnotic effect during desflurane general anaesthesia with ketamine [J]. J Clin Monit Comput, 2021, 35(6): 1421-8.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 Patient and intervention characteristics\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003egastroscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eColonoscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eAge (yrs)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e49（38，56）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e49（38，56）\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eGender (M/F)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e33/73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e48/59\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eWeight, kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e57(52.8,65.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e60(53.0,67.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eHeight, cm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e160.6\u0026plusmn;7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e161.2\u0026plusmn;7.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eASA classification score (I/II)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e13/93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e12/95\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003ePropofol induction dose, mg (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003einduction dose, Total dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e130.0(120.0,150.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e125.0(120.0,150.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eTotal dose,Total dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e150.0(130.0,180.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e190.0(150.0,220.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eDuration of procedures (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e5.0(3.0,6.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e9.0(6.0,13.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eAnesthesia emergence time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e5.0(3.0,7.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e4.0(2.0,7.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 215px;\"\u003e\n \u003cp\u003eDuration of stay in PACU (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 164px;\"\u003e\n \u003cp\u003e18.0(15.0,18.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e17.0(15.0,20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eData are expressed as mean \u0026plusmn; SD or median [Q1\u0026ndash;Q3] . ASA=American Society of Anesthesiologists, PACU= postanesthetic care unit.\u003c/p\u003e\n\u003cp\u003eTable 2. qCON levels at the time for inadequate/adequate sedation( Hemodynamic fluctuations within \u0026plusmn;10%, without coughing and body movement ).The critical time points for sedation were evaluated during passage of the gastroscope through the pharynx and colonoscopy into the splenic flexure, as this may cause a strong physiological response.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003eNo.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003eMedian\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003eMinimum\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003eMaximum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003egastroscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003eAdequate sedation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e58.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e61.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e41.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e72.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e55.25,62.62\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003einadequate sedation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e50.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e49.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e39.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e73.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e47.73,54.21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003ecolonoscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003eAdequate sedation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e58.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e62.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e41.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e73.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e55.25,62.52\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003einadequate sedation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e53.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e52.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e40.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e80.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e50.49,57.39\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"qCON, qNOX, Sedation monitoring, Gastrointestinal endoscopy, Nociception, Anesthesia depth","lastPublishedDoi":"10.21203/rs.3.rs-7879324/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7879324/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eThe assessment of sedation depth during painless gastrointestinal endoscopy primarily relies on clinical experience due to the lack of a universally accepted objective standard. This study aimed to investigate the application of novel electroencephalography-derived indices, the quantitative consciousness index (qCON) and the quantitative nociception index (qNOX), for monitoring sedation and analgesia, and to determine the optimal qCON range associated with stable procedural conditions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003eThis prospective observational preliminary study enrolled 220 patients undergoing elective gastroscopy or colonoscopy. All patients received propofol and sufentanil for anesthesia. Depth of anesthesia and nociception were continuously monitored using qCON and qNOX. Hemodynamic parameters, body movements, and cough reflexes were recorded at predefined time points. The primary outcome was optimal sedation quality, defined as hemodynamic fluctuations within 10% of baseline and the absence of body movement or coughing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eThe optimal qCON range associated with stable hemodynamics and absence of noxious responses was 55～63 (95% CI: 55.25–62.62 for gastroscopy; 55.25–62.52 for colonoscopy). Strong correlations were observed between qCON and qNOX (gastroscopy: qNOX = 0.78 × qCON + 26.1, R² = 0.714; colonoscopy: qNOX = 0.83 × qCON + 22.47, R² = 0.716; p \u0026lt; 0.001). The qNOX index demonstrated a faster response to noxious stimuli compared to qCON during both induction and recovery phases.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThe qCON index provides an objective guidance for sedation depth during painless gastrointestinal endoscopy. Maintaining qCON within the range of 55 to 63 is associated with optimal procedural conditions. The combined use of qCON and qNOX monitoring can help optimize the balance between sedation and analgesia, potentially improving the safety and quality of endoscopic sedation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration: This study was registered at ClinicalTrials.gov (Registration Number: NCT06604156). The registration was completed on April 11, 2024.\u003c/strong\u003e\u003c/p\u003e","manuscriptTitle":"quantitative consciousness index monitoring of sedation during endoscopy：a prospective observational preliminary study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-11 09:49:33","doi":"10.21203/rs.3.rs-7879324/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"24301b23-17ba-4fa1-b037-335178688033","owner":[],"postedDate":"December 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-08T09:39:03+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-11 09:49:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7879324","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7879324","identity":"rs-7879324","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}