Endoscopic retrograde cholangiopancreatography (ERCP) is performed using anaesthesia or conscious sedation, though the effectiveness, adverse events (AEs), and tolerability of each approach remain unclear. Thus, we compared these approaches prospectively.

We performed a multi-centre prospective cohort study including patients with native papillae undergoing ERCP for biliary indications between 2018 and 2023. The primary outcome was sedation-related AEs, defined as sustained hypoxaemia or hypotension, unplanned mask ventilation or intubation, vasopressor or reversal agent use, cardiorespiratory arrest, or death. Secondary outcomes included other AEs, technical success measures, and patient-reported tolerability using a validated scale. Multivariable logistic regression was performed in addition to propensity score-matched analyses.

At 8 centres, a total of 3174 first-time biliary ERCPs were performed, 433 (13.6%) employing anaesthesia. Nine sedation-related AEs occurred with conscious sedation (0.3%), while 2 (0.5%) occurred with anaesthesia (odds ratio, OR, 0.35, 0.07-2.37). Only 25 (0.9%) conscious sedation-supported ERCPs were aborted due to the inability to appropriately sedate patients. There were no significant differences in other AE rates, cannulation success, time, or attempts, use of pre-cut or needle-knife access methods, or inadvertent pancreatic duct cannulation. Odds of significant patient-reported intra-procedural awareness and discomfort were both higher with conscious sedation (ORs 16.19, 4.81-54.53, and 21.25, 4.44-101.61, respectively). Propensity score-matched analyses yielded no differences in any outcome compared with primary analyses.

Routine biliary ERCP is equally safe and effective with conscious sedation (vs anaesthesia). Given regional resource limitations, conscious sedation is justified as a primary option for routine biliary ERCP.

The safety and effectiveness of propofol in more complex endoscopic procedures, such as endoscopic retrograde cholangiopancreatography, remain unknown. Thus, we aimed to evaluate propofol sedation during endoscopic cholangiopancreatography, ultrasound-guided intervention, and gastroduodenal stenting and examine risk factors for excessive sedation.

We retrospectively analyzed data from 870 patients who underwent endoscopic treatment with propofol sedation for biliary and pancreatic disease between October 2020 and September 2021. Sedation included propofol and fentanyl, with continuous monitoring of vital signs and the bispectral index. The assessed risk factors included age, complications, body mass index, treatment duration, and specialty.

Distal bile duct treatment (n = 367), hilar bile duct treatment (n = 197), post-small-intestinal reconstruction treatment (n = 75), endoscopic ultrasound-guided intervention (n = 140), and gastrointestinal obstruction treatment (n = 91) were performed. The rates of excessive sedation, hypoxemia, and hypotension were 7.8%, 6.0%, and 1.8%, respectively. Post-small-intestinal reconstruction treatment had the highest incidence rate of excessive sedation (16%), whereas endoscopic ultrasound-guided intervention had the lowest incidence rate (4.3%). Multivariate analysis revealed significant associations between excessive sedation and comorbid sleep apnea, obesity, and prolonged procedural time.

Obesity, sleep apnea syndrome, and prolonged procedure time are risk factors for excessive sedation related to propofol use. Thus, sedation techniques should be tailored for these patients.

Understanding the different pharmacodynamic responses to narcotics in patients with or without obesity is particularly important for the safety of gastroscopy sedation. This study aimed to determine the median effective dose (ED50) of ciprofol combined with low-dose sufentanil to inhibit the response to gastroscope insertion in obese or nonobese patients.

A total of 27 obese patients (BMI 30-40 kg/m2) and 25 nonobese patients (BMI 18-25 kg/m2), aged between 18 and 65 years, with ASA physical status of 1-2, were included in this study. All patients underwent painless gastroscopy and received intravenous sufentanil at a dose of 0.1 μg/kg, followed by ciprofol administration. The initial dose of ciprofol for the first patient in both groups was 0.4 mg/kg, the subsequent dose was determined by the response of the previous patient to gastroscope insertion (cough, choking, body movement, etc.) using Dixon's up-and-down method. The dose was increased or decreased by 0.05 mg/kg depending on the observed responses. Data collection continued until 7 crossover points were obtained. Probit regression and bootstrapping methods were employed to calculate the median effective dose (ED50) and 95% confidence intervals (CIs). The ED50 values were then compared between the obese and nonobese patient groups.

The ED50 of ciprofol combined with sufentanil inhibiting response to gastroscope insertion in patients with obesity was 0.186 mg/kg with 95% CI of 0.153∼0.209 mg/kg, was significantly lower than patients with nonobese was 0.237 mg/kg with 95% CI of 0.206∼0.253 mg/kg (p < 0.05).

The ED50 values of ciprofol combined with sufentanil inhibiting response to gastroscope insertion in patients with obesity was lower than in patients with normal weight.

https://www.chictr.org.cn/bin/project/edit?pid=202873, identifier ChiCTR2300074216.

To determine whether high flow nasal cannula (HFNC) oxygenation can reduce the incidence of hypoxia during sedated gastrointestinal endoscopy in patients with obesity.

Multicentre, randomised, parallel group trial.

Three tertiary hospitals in Shanghai, China.

1000 adult patients with obesity (body mass index ≥28) who were scheduled for gastrointestinal endoscopy.

Participants were randomly allocated to receive regular nasal cannula oxygenation or HFNC oxygenation during a sedated procedure with propofol and low dose sufentanil.

The primary outcome was the incidence of hypoxia (75%≤SpO2<90% for <60 s) during the procedure. Secondary outcomes included the incidences of subclinical respiratory depression (90%≤SpO2<95% for any duration) and severe hypoxia (SpO2<75% for any duration or 75%≤SPO2<90% for >60 s) during the procedure.

From 6 May 2021 to 26 May 2023, 984 patients (mean age 49.2 years; 36.9% (n=363) female) completed the study and were analysed. Compared with regular nasal cannula oxygenation, HFNC oxygenation reduced the incidence of hypoxia from 21.2% (103/487) to 2.0% (10/497) (difference -19.14, 95% confidence interval -23.09 to -15.36; P<0.001), subclinical respiratory depression from 36.3% (177/487) to 5.6% (28/497) (difference -30.71, -35.40 to -25.92; P<0.001), and severe hypoxia from 4.1% (20/487) to 0% (0/497) (difference -4.11%, -6.26 to -2.48; P<0.001). Other sedation related adverse events did not differ between the two groups.

In patients with obesity, oxygenation via HFNC during sedated gastrointestinal endoscopy significantly reduced the incidences of hypoxia, subclinical respiratory depression, and severe hypoxia without increasing other adverse events.

ClinicalTrials.gov NCT04500392.

Adequate oxygenation and airway management during deep sedation can be challenging. We investigated the effect of high-flow nasal cannula (group HF) and conventional nasal cannula (group CO) during sedation for endoscopic submucosal dissection (ESD).

Patients undergoing ESD with deep sedation were enrolled. The primary outcome was difference in lowest oxygen saturation (SpO2) between the groups. Incidence of hypoxia (SpO2 < 90%), patients with SpO2 < 95%, hypercapnia, and airway interventions; operator satisfaction; and adverse events were recorded.

Thirty-two patients in each group completed the study. The mean of minimum SpO2 values was significantly higher in group HF than in group CO (96.8% ± 4.2% vs. 93.3% ± 5.3%, p = 0.005). The incidence of hypoxia was comparable between the groups (4 [12.5%] vs. 6 [18.8%], p = 0.491); however, patients with SpO2 < 95% were significantly less in group HF (5 [15.6%] vs. 18 [56.3%], p = 0.003). Incidence of hypercapnia was higher in group HF than in group CO (14 [46.7%] vs. 5 [16.7%], p = 0.013). Airway rescue interventions were significantly less common in group HF. Satisfaction of operators and post-procedural complications were comparable between the two groups. In multivariable analysis, group CO and higher body mass index were risk factors for airway managements (odds ratio [95% confidence interval]: 6.204 [1.784-21.575], p = 0.004; 1.337 [1.043-1.715], p = 0.022, respectively).

Compared to conventional nasal cannula, high-flow nasal cannula maintained higher minimum SpO2 value during deep sedation with propofol-remifentanil for ESD.

Clinical Trial Registry of the Republic of Korea (KCT0006618, https://cris.nih.go.kr ; registered September 29, 2021; principal investigator: Ji Won Choi).

With the increasing prevalence of obesity and morbid obesity, this subgroup's contribution to patients presenting for elective procedures requiring sedation is significant. Gastrointestinal (GI) procedures clearly form the largest group of such procedures. These procedures may be intended to treat obesity such as the insertion of an intragastric balloon or one or more unrelated procedures such as a screening colonoscopy and (or) diagnostic/therapeutic endoscopy. Regardless of the procedure, these patients pose significant challenges in terms of choice of sedatives, dosing, airway management, ventilation, and oxygenation. An understanding of dissimilarity in the handling of different groups of medications used by an anesthesia provider and alterations in airway anatomy is critical for providing safe sedation. Administration of sedative medications and conduct of anesthesia requires dose modifications and airway adjuncts. In this review, we discuss the above issues in detail, with a particular focus on GI endoscopy.

In recent years, as the number of people with obesity has surged, the number of morbidly obese patients has also grown. The pathophysiological changes in morbid obesity can lead to combined lung diseases, which may result in hypoventilation, hypoxemia, acute upper airway obstruction, acute respiratory distress syndrome, and sleep apnea syndrome, posing serious challenges to anesthesia management. Here, we describe a case of the administration of remimazolam combined with remifentanil in a patient with morbid obesity undergoing gastroscopy. This has rarely been reported in clinical practice, and we present our management experience here with the aim of providing a reference for clinical work.

We report the case of a 32-year-old male hypertensive patient with a height of 180 cm, weight of 145 kg, and body mass index of 44.8 kg/m2. The patient's main complaint was intermittent hunger pain for more than 1 year, and duodenal polyps were found. Considering the patient's morbid obesity and the combination of sleep apnea syndrome and hypertension, we administered remimazolam along with remifentanil to ensure perioperative safety.

The procedure lasted 30 min, and the anesthesia was satisfactory with no complications. Remimazolam combined with remifentanil intravenous anesthesia is safe for short gastroscopy in patients with morbidly obesity. The administration of a small dose of split-titration delivery facilitates the maintenance of stable vital signs.

Sedation has become a standard practice for patients undergoing gastrointestinal (GI) endoscopy. However, considering the serious cardiopulmonary adverse events associated with sedatives, it is important to identify patients at high risk. Machine learning can generate reasonable prediction for a wide range of medical conditions. This study aimed to evaluate the risk factors associated with sedation during GI endoscopy and develop a predictive model for hypoxia during endoscopy under sedation.

This prospective observational study enrolled 446 patients who underwent sedative endoscopy at the Korea University Ansan Hospital. Clinical data were used as predictor variables to construct predictive models using the random forest method that is a machine learning algorithm.

Seventy-two of the 446 patients (16.1%) experienced life-threatening hypoxia requiring immediate medical intervention. Patients who developed hypoxia had higher body weight, body mass index (BMI), neck circumference, and Mallampati scores. Propofol alone and higher initial and total dose of propofol were significantly associated with hypoxia during sedative endoscopy. Among these variables, high BMI, neck circumference, and Mallampati score were independent risk factors for hypoxia. The area under the receiver operating characteristic curve for the random forest-based predictive model for hypoxia during sedative endoscopy was 0.82 (95% confidence interval, 0.79-0.86) and displayed a moderate discriminatory power.

High BMI, neck circumference, and Mallampati score were independently associated with hypoxia during sedative endoscopy. We constructed a model with acceptable performance for predicting hypoxia during sedative endoscopy.

Background: We aimed to compare the prevention of hypoxemia using High-flow nasal oxygen (HFNO) or regular nasal tubing (CNC) in elderly patients undergoing gastroscopy with sedation. Methods: This study was a prospective, randomized, controlled trial conducted at a single center. We included elective patients aged 65 and above who were undergoing gastroscopy with sedation. In the intervention group (HFNO), we set the oxygen flow rate to 60 liters per minute with an oxygen fraction (FiO2) of 0.6, while in the control group (CNC), it was 6 liters per minute. The primary outcome was the occurrence of hypoxemia (defined as Spo2 < 90%). Results: A total of 125 participants were enrolled (HFNO group: n = 63; CNC group: n = 62). The occurrence of hypoxemia was found to be significantly lower in the HFNO group compared to the CNC group (3.2% vs. 22.6%, p = 0.001). Additionally, a significantly shorter duration of low oxygen levels was observed in the HFNO group [0.0 seconds (0.0-13.0)] compared to the CNC group [0.0 seconds (0.0-124.0), p<0.001]. Moreover, a higher minimum Spo2 value was achieved in the HFNO group [99.0% (98.0-100.0) vs. 96.5% (91.0-99.0), p < 0.001], and a shorter recovery time was recorded [0.5 minutes (0.0-0.5) vs. 0.5 minutes (0.0-1.0), p = 0.016] in comparison to the CNC group. There were no differences in terms of comfort level [0 (0-4) vs. 0 (0-5), p = 0.268] between the two groups. Conclusions: The HFNO system was determined to be a safe and highly effective method for oxygen delivery, leading to a reduction in the occurrence of hypoxemia in elderly patients undergoing gastroscopy with sedation. It is recommended that HFNO be considered as the standard approach for management in this population.

Hypoxemia is a common side effect of propofol sedation during endoscopy. Applying mild positive airway pressure (PAP) using a nasal mask may offer a simple way to reduce such events and optimize the conditions for diagnostic and therapeutic upper gastrointestinal endoscopies.

We compared overweight patients (body mass index >25 kg/m2) with a nasal PAP mask or standard nasal cannula undergoing upper gastrointestinal endoscopies by non-anesthesiologists who provided propofol sedation. Outcome parameters included the frequency and severity of hypoxemic episodes.

We analyzed 102 procedures in 51 patients with nasal PAP masks and 51 controls. Episodes of hypoxemia (oxygen saturation [SpO2] <90% at any time during sedation) occurred in 25 (49.0%) controls compared to 8 (15.7%) patients with nasal PAP masks (p<0.001). Severe hypoxemia (SpO2 <80%) occurred in three individuals (5.9%) in both groups. The mean delta between baseline SpO2 and the lowest SpO2 recorded was significantly decreased among patients with nasal PAP mask compared to controls (3.7 and 8.2 percentage points difference, respectively). There were significantly fewer airway interventions performed in the nasal PAP mask group (15.7% vs. 41.2%, p=0.008).

Using a nasal PAP mask may be a simple means of increasing patient safety and ease of examination.

Hypoxemia as a common complication in colonoscopy under sedation and may result in serious consequences. Unfortunately, a hypoxemia prediction model for outpatient colonoscopy has not been developed. Consequently, the objective of our study was to develop a practical and accurate model to predict the risk of hypoxemia in outpatient colonoscopy under sedation.

In this study, we included patients who received colonoscopy with anesthesia in Nanjing First Hospital from July to September 2021. Risk factors were selected through the least absolute shrinkage and selection operator (LASSO). Prediction models based on logistic regression (LR), random forest classifier (RFC), extreme gradient boosting (XGBoost), support vector machine (SVM), and stacking classifier (SCLF) model were implemented and assessed by standard metrics such as the area under the receiver operating characteristic curve (AUROC), sensitivity and specificity. Then choose the best model to develop an online tool for clinical use.

We ultimately included 839 patients. After LASSO, body mass index (BMI) (coefficient = 0.36), obstructive sleep apnea-hypopnea syndrome (OSAHS) (coefficient = 1.32), basal oxygen saturation (coefficient = -0.14), and remifentanil dosage (coefficient = 0.04) were independent risk factors for hypoxemia. The XGBoost model with an AUROC of 0.913 showed the best performance among the five models.

Our study selected the XGBoost as the first model especially for colonoscopy, with over 95% accuracy and excellent specificity. The XGBoost includes four variables that can be quickly obtained. Moreover, an online prediction practical tool has been provided, which helps screen high-risk outpatients with hypoxemia swiftly and conveniently.

Obese patients are susceptible to hypoxaemia during procedural sedation. Propofol combined with low-dose opioids is commonly used as a sedation strategy, but it can exacerbate hypoxaemia by causing cardiopulmonary depression and airway obstruction, especially in obese patients. Remimazolam, a novel ultra-short-acting benzodiazepine, has minimal accumulative effects and less cardiorespiratory depression. This study aims to evaluate the safety and efficacy of combining remimazolam tosilate with low-dose fentanyl as an alternative option for procedural sedation in obese patients undergoing gastroscopy.

This randomised controlled trial (RCT) will be conducted in the Endoscopy Centre of the First Affiliated Hospital of Xiamen University, recruiting 174 participants scheduled for painless gastroscopy with a body mass index of 30-39.9 kg×m-2. All patients will be randomly divided into two groups in a 1:1 ratio. The sedation strategy of the intervention group is remimazolam tosilate combined with fentanyl, while the control group is propofol combined with fentanyl. The primary outcome is the incidence of hypoxaemia and the secondary outcomes include the time to ambulation, need for airway manoeuvres and rescue sedation, sleep quality, the incidence of sedation failure, adverse events and the cost of sedatives. All statistical tests will be performed using IBM SPSS V.20.0 statistical software. A p value<0.05 is considered statistically significant.

This RCT was reviewed and approved by the Ethics Committee of the First Affiliated Hospital of Xiamen University (Scientific Research Ethics Review 2022, No.093). The results will be published in peer-reviewed journals.

ChiCTR2200067076.

The present study was focused on evaluating the clinical predictors of hypoxemia and establishing a multivariable, predictive model for hypoxemia in painless bronchoscopy. A total of 244 patients were enrolled in the study, and data were collected using a self-designed data collection. The retrospective data collected in this study included the relevant data of patients undergoing the painless bronchoscopy, and we used univariate analysis to deal with these influencing factors. Multivariate logistic regression analysis was used to establish the prediction equation, and receiver operating characteristic curve analysis was carried out. Receiver operating characteristic curves and the Hosmer-Lemeshow test were used to evaluate the model performance. P < .05 was considered to indicate statistical significance. Multivariate logistic regression indicated that body mass index (BMI) (odds ratio [OR]: 1.169; 95% confidence interval [CI]: 1.070-1.277), arterial partial pressure of oxygen (PaO2) (OR: 4.279; 95% CI: 2.378-7.699), alcohol consumption (OR: 2.021; 95% CI: 1.063-3.840), and whether the bronchoscope operation time exceeds 30 minutes (OR: 2.486; 95% CI: 1.174-5.267) were closely related to the occurrence of hypoxemia. The prediction model developed by the logistic regression equation was -4.911 + 1.454 (PaO2) + 0.156 (BMI) + 0.703 (Alcohol consumption) + 0.911 (time > 30th minutes). The prediction model showed that the area under the receiver operating characteristic curve was 0.687. The predictive model was well calibrated with a Hosmer-Lemeshow x2 statistic of 4.869 (P = .772), indicating that our prediction model fit well. The accuracy (number of correct predictions divided by the number of total predictions) was 75%. The prediction model, consisting of BMI, PaO2, alcohol consumption, and whether the bronchoscope operation time exceeds 30 minutes. It is an effective predictor of hypoxemia during sedation for painless bronchoscopy.

Obese patients who undergo painless gastroscopy are particularly prone to suffer from upper airway obstruction, respiratory depression, and subsequent hypoxemia. Despite adequate preoxygenation, the incidence of hypoxemia remains high. Recently, inspiratory muscle training (IMT) has been considered to be a promising strategy to increase respiratory muscle strength and endurance with the attendant improvement of pulmonary function. However, it remains unclear whether IMT is associated with a lower rate of hypoxemia in obese patients during this sedative procedure. This study aims to investigate the effectiveness of IMT used in obese patients who are scheduled for selective painless gastroscopy.

This prospective, randomized controlled trial (RCT) will enroll 232 obese patients with a body mass index (BMI) of 35-39.9 kg·m-2 who undergo painless gastroscopy at the First Affiliated Hospital of Xiamen University. Subjects will be randomly assigned to two groups with a 1:1 ratio. Participants in both groups will receive IMT for 4 weeks prior to gastroscopy. The intervention group will receive IMT with a load of 30% of the maximal inspiratory pressure (Pi(max)) in the first week, with an increase of 10% per week since the following week, while the counterparts in the control group will not receive any load during the 4-week IMT. The primary outcome is the incidence of hypoxemia during painless gastroscopy. Secondary outcomes include the need for airway maneuvers, blood pressure changes, sleep quality assessment, pro-inflammatory cytokines levels, and monitoring of adverse events.

The outcomes of this study will offer invaluable guidance for the clinical implementation of IMT as a potential non-invasive preventive measure. Additionally, it stands to enrich our comprehension of anesthesia management and airway-related challenges in obese patients undergoing procedural sedation, which we anticipate will further contribute to addressing the turnaround concerns within high-volume, swiftly paced ambulatory endoscopy centers.

This study has been approved by the Ethics Committee of the First Affiliated Hospital of Xiamen University (2022, No.091). The results will be submitted for publication in peer-reviewed journals.

China Clinical Trial Center (ChiCTR2200067041).

Sedation is common during digestive endoscopy to provide comfort and pain relief for patients. However, the use of sedation in endoscopy also poses potential risks, and recent issues have been raised regarding its safety and administration. This literature review paper will discuss the most recent developments in the field of sedation in digestive endoscopy, including the adverse events that might be associated with sedation and how to manage it, the legal issues associated with administration, the impact of COVID-19 on sedation practices, and sedation in special situations. It will also touch upon the current guidelines and recommendations for sedation, including the importance of patient selection and monitoring and the need for training and certification for endoscopists administering sedation. The review will also analyse studies evaluating the safety and efficacy of various sedation techniques, including propofol, midazolam, and others. It will examine the benefits and drawbacks of these agents.

To prospectively evaluate the safety and efficacy of a "muscle relaxant-free" general anesthesia using a combination of remifentanil and propofol, compared to propofol-based monitored anesthesia care and conventional general anesthesia during therapeutic endoscopic retrograde cholangiopancreatography (ERCP).

From September to December 2019, 360 patients scheduled for elective ERCP at the Endoscopy Center of the First Affiliated Hospital of Nanjing Medical University were randomly assigned to three different groups: Group MAC (propofol-based monitored anesthesia care, n=120), Group GA1 (general anesthesia with neuromuscular blocking agents, n=120), or Group GA2 (remifentanil-propofol combination-based muscle relaxant-free general anesthesia, n=120).

The results showed that there was a significant difference in intraprocedural cardiopulmonary adverse events among the three groups (Group MAC, 37.5%; Group GA1, 19.2%; Group GA2, 17.5%; P < 0.001). Total time (from patient entry into the Endoscopy Center to departure) and room time (from patient entry into the endoscopy suit to departure) were shorter in Group GA2 and Group MAC compared to Group GA1 (P < 0.001). Additionally, endoscopist satisfaction levels were significantly higher in Group GA1 and Group GA2 compared to Group MAC (P < 0.001).

The study found that administering propofol-remifentanil combination for "muscle relaxant-free" general anesthesia during therapeutic ERCP was safe and effective. This approach offered greater safety and endoscopist satisfaction than propofol-based monitored anesthesia care, as well as shorter total time and room time than conventional general anesthesia.

Endoscopic retrograde cholangiopancreatography (ERCP) is a commonly performed procedure for pancreaticobiliary disease. While ERCP is highly effective, it is also associated with the highest adverse event (AE) rates of all commonly performed endoscopic procedures. Thus, it is critical that endoscopists and caregivers of patients undergoing ERCP have clear understandings of ERCP-related AEs.

This narrative review provides a comprehensive overview of the available evidence on ERCP-related AEs. For the purposes of this review, we subdivide the presentation of each ERCP-related AE according to the following clinically relevant domains: definitions and incidence, proposed mechanisms, risk factors, prevention, and recognition and management. The evidence informing this review was derived in part from a search of the electronic databases PubMed, Embase, and Cochrane, performed on 1 May 20231 May 2023.

Knowledge of ERCP-related AEs is critical not only given potential improvements in peri-procedural quality and related care that can ensue but also given the importance of reviewing these considerations with patients during informed consent. The ERCP community and researchers should aim to apply standardized definitions of AEs. Evidence-based knowledge of ERCP risk factors should inform patient care decisions during training and beyond.

By continually monitoring end-tidal carbon dioxide concentrations, capnography can detect abnormal ventilation or apnoea early. This randomized, controlled study explored the effect of early intervention with capnography on the incidence of hypoxia in mildly obese patients undergoing sedation for esophagogastroduodenoscopy (EGD) and colonoscopy.

This is a single-center, randomized, single-blind, parallel-assignment, controlled trial. Mildly obese patients (28 kg/m² ≤ BMI < 40 kg/m²) undergoing sedation for EGD and colonoscopy were randomly assigned to either the standard or capnography group. Standard cardiopulmonary monitoring equipment was used in both groups, and additional capnography was performed in the capnography group. In the event of inadequate alveolar ventilation during sedation, five interventions were administered in sequence (a-e) : a: increasing oxygen flow (5 L/min); b: a chin lift or jaw thrust maneuver; c: placement of the nasopharyngeal airway and chin lift; d: mask positive-pressure ventilation, and e: ventilator-assisted ventilation with tube insertion. The primary outcome was the incidence of hypoxia (SpO₂ < 90%, ≥ 10 s) in each group. The secondary outcomes included the incidence of severe hypoxia (SpO₂ ≤ 85%), subclinical respiratory depression (90% ≤ SpO₂ < 95%), interventions, minimum SpO₂ during operation, patient satisfaction, endoscopist satisfaction, and other adverse events of anesthesia sedation.

228 patients were included (capnography group = 112; standard group = 113; three patients were excluded) in this study. The incidence of hypoxia was significantly lower in the capnography group than in the standard group (13.4% vs. 30.1%, P = 0.002). Subclinical respiratory depression in the capnography group was higher than that of the standard group (30.4% vs. 17.7%, P = 0.026). There was only a 5.4% incidence of severe hypoxia in the capnography group compared with 14.2% in the standard group (P = 0.026). During sedation, 96 and 34 individuals in the capnography and standard groups, respectively, underwent the intervention. There was a statistically significant difference (P < 0.0001) in the number of the last intraoperative intervention between the two groups ( a:47 vs. 1, b:46 vs. 26, c:2 vs. 5, d:1 vs. 2, e:0 vs. 0 ). No significant differences were found between the two groups in terms of minimum SpO₂ during operation, patient satisfaction, or endoscopist satisfaction rating. There was no statistically significant difference in adverse events of anesthesia sedation between the two groups.

Capnography during sedation for EGD and colonoscopy allows for the detection of apnea and altered breathing patterns in mildly obese patients before SpO₂ is reduced. Effective intervention measures are given to patients within this time frame, which reduces the incidence of hypoxia and severe hypoxia in patients.

Ethical approval was granted by the Medical Ethics Committee (Chairperson Professor Tian Hui) of Qilu Hospital, Shandong University ((Ke) Lun Audit 2021 (186)) on 15/07/2021. The study was registered ( https://www.chictr.org.cn ) on 23/10/2021(ChiCTR2100052234). Designed and reported using CONSORT statements.

Hypoxaemia is a significant adverse event during endoscopic retrograde cholangiopancreatography (ERCP) under monitored anaesthesia care (MAC); however, no model has been developed to predict hypoxaemia. We aimed to develop and compare logistic regression (LR) and machine learning (ML) models to predict hypoxaemia during ERCP under MAC.

We collected patient data from our institutional ERCP database. The study population was randomly divided into training and test sets (7:3). Models were fit to training data and evaluated on unseen test data. The training set was further split into k-fold (k=5) for tuning hyperparameters, such as feature selection and early stopping. Models were trained over k loops; the i-th fold was set aside as a validation set in the i-th loop. Model performance was measured using area under the curve (AUC).

We identified 6114 cases of ERCP under MAC, with a total hypoxaemia rate of 5.9%. The LR model was established by combining eight variables and had a test AUC of 0.693. The ML and LR models were evaluated on 30 independent data splits. The average test AUC for LR was 0.7230, which improved to 0.7336 by adding eight more variables with an l₁ regularisation-based selection technique and ensembling the LRs and gradient boosting algorithm (GBM). The high-risk group was discriminated using the GBM ensemble model, with a sensitivity and specificity of 63.6% and 72.2%, respectively.

We established GBM ensemble model and LR model for risk prediction, which demonstrated good potential for preventing hypoxaemia during ERCP under MAC.

Background Propofol is the most common sedative for endoscopies. Propofol alone may require larger doses for adequate level of sedation. Lignocaine is known for its anesthetic-sparing effect. We tested whether the addition of intravenous lignocaine to propofol-based sedation reduces its dose. Methods This prospective, randomized study was performed on 90 patients of 18 to 60 years of age, of either sex of the American Society of Anesthesiologists (ASA) Grade-I & II, and was divided into two groups. Group L + P received IV bolus of 1.5 mg/kg 2% lignocaine over 10 minutes followed by 1.5 mg/ kg/ h infusion and group NS + P- received the equivalent volumes of normal saline in bolus and infusion. Patients were induced with fentanyl (2 µg/kg) and propofol (1 mg/kg). To maintain an adequate sedation level, a supplemental bolus of 0.5 mg /kg propofol was administered. The outcomes recorded were the total and supplemental amount of propofol administered, as well as recovery time. Results The mean supplemental propofol for group L + P and group NS + P- 37.00 ± 29.93 and 58.67 ± 19.49 mg, respectively and mean total propofol consumption was 98.22 ± 34.00 mg and 131.11 ± 23.18 mg, respectively, (p < 0.001). Mean recovery time in group L + P was also shorter (5.22 ± 2.14 versus 9.96 ± 2.14). The incidence of adverse events like gag reflux, upper airway obstruction, pain on injection, and hypotension was significantly lower in group L + P (p < 0.05). Conclusion The addition of lignocaine to propofol-based sedation reduced the overall propofol requirement at the same time maintaining hemodynamic stability, spontaneous respiration, and early recovery.

Despite evidence that high-flow nasal cannula oxygen therapy (HFNC) promotes oxygenation, its application in sedated gastroscopy in elderly patients has received little attention. This study investigated the effect of different inhaled oxygen concentrations (FiO₂) of HFNC during sedated gastroscopy in elderly patients.

In a prospective randomized single-blinded study, 369 outpatients undergoing regular gastroscopy with propofol sedation delivered by an anesthesiologist were randomly divided into three groups (n = 123): nasal cannula oxygen group (Group C), 100% FiO₂ of HFNC group (Group H100), and 50% FiO₂ of HFNC (Group H50). The primary endpoint in this study was the incidence of hypoxia events with pulse oxygen saturation (SpO₂) ≤ 92%. The secondary endpoints included the incidence of other varying degrees of hypoxia and adverse events associated with ventilation and hypoxia.

The incidence of hypoxia, paradoxical response, choking, jaw lift, and mask ventilation was lower in both Group H100 and Group H50 than in Group C (P < 0.05). Compared with Group H100, Group H50 showed no significant differences in the incidence of hypoxia, jaw lift and mask ventilation, paradoxical response, or choking (P > 0.05). No patients were mechanically ventilated with endotracheal intubation or found to have complications from HFNC.

HFNC prevented hypoxia during gastroscopy with propofol in elderly patients, and there was no significant difference in the incidence of hypoxia when FiO₂ was 50% or 100%.

This single-blind, prospective, randomized controlled trial was approved by the Ethics Committee of Nanjing First Hospital (KY20201102-04) and registered in the China Clinical Trial Center (20/10/2021, ChiCTR2100052144) before patients enrollment. All patients signed an informed consent form.

Cryoballoon (CB) ablation and radiofrequency (RF) ablation are the most common techniques for pulmonary vein isolation (PVI) in patients with symptomatic atrial fibrillation (AF). An increasing number of patients undergoing PVI are obese. To address the paucity of data on outcomes of CB- vs. RF-based PVI in relation to body mass index (BMI) of AF patients.

All patients undergoing de novo PVI between 01/2018 and 08/2019 at University Hospital Cologne were included in this retrospective analysis. Patients of each group (CB-PVI vs. RF-PVI) were analyzed based on their BMI. Hereafter, procedural characteristics and AF recurrence rate were compared regarding different BMI groups.

A total of 526 patients (62% male, 65±11 years) underwent successful de novo PVI (320 CB and 206 RF). In obese patients, two differences in procedural characteristics were noted: A significantly increased contrast medium volume in CB group and a lower fluoroscopy dose in RF group: contrast medium: CB 50 [40-80] vs. RF 20 [20-30], p<0.001; fluoroscopy dose: CB 392.4 [197.9-995.9] vs. RF 282.5 [139.8-507.2], p<0.001. The complication rate was equal throughout all BMI groups, regardless of CB or RF usage. For obese patients, a trend toward a higher AF recurrence rate was revealed after RF-PVI as compared to CB-PVI. In line with previous studies, the overall procedure time was significantly shorter with CB-PVI regardless of BMI.

For obese patients, CB-PVI is similarly safe and effective as RF-PVI. The significantly shorter procedure time for CB-PVI may minimize potential obesity-related complications. However, the lower contrast medium quantity and fluoroscopy dose in RF-PVI must be considered. AF recurrence rates were comparable between CB-PVI and RF-PVI.

To assess which patient factors and procedure-related factors contribute to hypoxemia during esophagogastroduodenoscopy (EGD) and determine whether prophylactic oropharyngeal suctioning reduces the rate of hypoxemia when compared to oropharyngeal suctioning when clinically indicated by patient's coughing or secretions.

This was a single-site study taking place at a private practice, outpatient facility with no anesthesia trainees present. Patients were randomized to one of two groups based on birth month. After the administration of sedating medications but before the insertion of the endoscope, Group A was oropharyngeal suctioned by either the anesthesia provider or the proceduralist. Group B was oropharyngeal suctioned only when clinically indicated by coughing or visible copious secretions.

Data were collected on a variety of patient and procedure-related factors. Associations between these factors and hypoxemia during esophagogastroduodenoscopy were analyzed using the statistical analysis system application JMP. After analysis and literature review, a protocol for prevention and treatment of hypoxemia during EGD was proposed.

This study found that chronic obstructive pulmonary disease increases the risk for hypoxemia during esophagogastroduodenoscopy. There were no other statistically significant associations between other factors and hypoxemia.

This study highlights factors that should be evaluated in the future when considering the risk of hypoxemia during EGD. Although not statistically significant, this study's results indicated that prophylactic oropharyngeal suctioning may reduce rates of hypoxemia, as only 1 of 4 cases of hypoxemia occurred in Group A. Additionally, future studies on hypoxemia during monitored anesthesia care for EGD should include an evaluation of the impact of American Society of Anesthesiologists class, history of chronic obstructive pulmonary disease or asthma, body mass index, obstructive sleep apnea, and opioid administration on hypoxemia risk.

Although conventional oxygen therapy (COT) is widely used, hypoxemia frequently occurs in gastrointestinal endoscopy with conscious sedation and can lead to life-threatening consequences. High flow nasal oxygen (HFNO) has been applied to improve oxygenation in clinical entities. However, its efficacy to prevent hypoxemia in gastrointestinal endoscopy with conscious sedation has not been evaluated.

We searched databases to identify randomized controlled trials that compared the efficacy of HFNO with COT in gastrointestinal endoscopy with conscious sedation. The primary outcome was hypoxemia. Meta-analyses with trial sequential analysis were performed using a random-effects model.

Eight trials with 3212 patients were included. Compared with COT, HFNO significantly reduced the risk of hypoxemia (eight trials; 3212 patients; risk ratio 0.30; 95% confidence interval [CI] 0.13-0.70). Trial sequential analysis showed that the cumulative Z curve did not cross the monitoring or futility boundaries, nor reach the required information size line, indicating that more trials are needed to reach a definitive conclusion. Subgroup analyses indicated the superiority of HFNO over COT with respect to hypoxemia in patients at low risk and high risk. HFNO further improved the lowest oxygen saturation (four trials; 459 patients; mean difference 2.30, 95% CI 0.84-3.77).

Compared with COT, HFNO can reduce the risk of hypoxemia and improve the lowest oxygen saturation in gastrointestinal endoscopy with conscious sedation. However, the results should be interpreted with caution due to substantial heterogeneity and limited evidence. Further studies are needed to verify the preliminary findings.

Propofol-based sedation has been widely used for gastroscopy, but the risk of respiratory suppression in elderly patients should not be overlooked. Intravenous (IV) lidocaine during surgery can reduce the demand for propofol and the incidence of cardiopulmonary complications. We examined whether IV lidocaine reduces the dose of propofol and the occurrence of adverse events during gastroscopy in elderly patients.

We conducted a prospective, single-center, double-blind randomized controlled trial in elderly patients aged ≥65 years with ASA I-II. Subjects were randomly assigned to the lidocaine group (Group L, n=70), who received IV 1.5 mg kg-1 lidocaine followed by a continuous infusion of 4 mg kg-1 h-1 lidocaine, or the normal saline group (Group N, n=70), who received an equal volume of saline in the same way.

IV lidocaine reduced the total and maintenance propofol dose in Group L (p<0.001), with no significant effect on the induction dose. The incidence of intraoperative hypoxia (p=0.035), emergency airway management events (p=0.005), duration of gastroscopy (p<0.05), consciousness recovery time (p<0.001), and postoperative pain (p=0.009) were all reduced in Group L. Patient (p=0.025) and gastroscopist (p=0.031) satisfaction was higher in Group L. Intraoperative hemodynamic parameters, the respiratory rate, the incidence of sedation-related events and anesthesiologist satisfaction were similar between the two groups.

IV lidocaine can significantly reduce the amount of propofol, the incidence of hypoxia and postoperative pain during gastroscopy in elderly patients, with a higher patient and gastroscopist satisfaction.

Performing GI endoscopy under sedoanalgesia improves the quality-indices of the examination, in particular for cecal intubation and adenoma detection rates during colonoscopy. The implementation of procedural sedoanalgesia in GI endoscopy is also strongly recommended by the guidelines of the major international scientific societies. Nevertheless, there are regional barriers that prevent the widespread adoption of this good practice. A retrospective monocentric analytic study was performed on a cohort of 529 patients who underwent EGDS/Colonoscopy in sedoanalgesia, with personalized dosage of Fentanyl and Midazolam. ASA class, age and weight were collected for each patient. The vital parameters were recorded during, pre- and post-procedure. The rates of cecal intubation and of procedure-related complications were entered. The VAS scale was used to evaluate the efficacy of sedoanalgesia, and the Aldrete score was used for patient discharge criteria. No clinically significant differences were found between vital signs pre- and post-procedure. Both anesthesia and endoscopic-related complications occurring were few and successfully managed. At the end of examination, both the mean Aldrete score (89.56), and the VAS score (<4 in 99.1%) were suitable for discharge. For the colonoscopies, the cumulative adenoma detection rate (25%) and the cecal intubation rate in the general group (98%) and in the colorectal cancer screening group (100%) were satisfying. Pain control management is an ethical and medical issue aimed at increasing both patient compliance and the quality of the procedures. The findings of this work underscore that in selected patients personalized sedoanalgesia in GI endoscopy can be safely managed by gastroenterologists.

Sedation can resolve anxiety and fear in patients undergoing endoscopy. The use of sedatives has increased in Korea. Appropriate sedation is a state in which the patient feels subjectively comfortable while maintaining the airway reflex for stable spontaneous breathing. The patient should maintain a state of consciousness to the extent that he or she can cooperate with the needs of the medical staff. Despite its benefits, endoscopic sedation has been associated with cardiopulmonary complications. Such cardiopulmonary complications are usually temporary, and most patients recover without sequelae. However, these events may progress to serious complications, such as cardiovascular collapse. Therefore, it is essential to screen high-risk patients before sedation and reduce complications by meticulous monitoring. Additionally, physicians should be familiar with the management of emergencies. The first Korean clinical practice guideline for endoscopic sedation was developed based on previous worldwide guidelines for endoscopic sedation using an adaptation process. The guideline consists of nine recommendations based on a critical review of currently available data and expert consensus when the guideline was drafted. These guidelines should provide clinicians, nurses, medical school students, and policy makers with information on how to perform endoscopic sedation with minimal risk.

Sedation can resolve anxiety and fear in patients undergoing endoscopy. The use of sedatives has increased in Korea. Appropriate sedation is a state in which the patient feels subjectively comfortable while maintaining the airway reflex for stable spontaneous breathing. The patient should maintain a state of consciousness to the extent that he or she can cooperate with the needs of the medical staff. Despite its benefits, endoscopic sedation has been associated with cardiopulmonary complications. Cardiopulmonary complications are usually temporary. Most patients recover without sequelae. However, they may progress to serious complications, such as cardiovascular collapse. Therefore, it is essential to screen high-risk patients before sedation and reduce complications by meticulous monitoring. Additionally, physicians should be familiar with the management of emergencies. The first Korean clinical practice guideline for endoscopic sedation was developed based on previous worldwide guidelines for endoscopic sedation using an adaptation process. The guideline consists of nine recommendations based on a critical review of currently available data and expert consensus when the guideline was drafted. These guidelines should provide clinicians, nurses, medical school students, and policy makers with information on how to perform endoscopic sedation with minimal risk.

Sedation can resolve anxiety and fear in patients undergoing endoscopy. The use of sedatives has increased in Korea. Appropriate sedation is a state in which the patient feels subjectively comfortable while maintaining the airway reflex for stable spontaneous breathing. The patient should maintain a state of consciousness to the extent that he or she can cooperate with the needs of the medical staff. Despite its benefits, endoscopic sedation has been associated with cardiopulmonary complications. Cardiopulmonary complications are usually temporary. Most patients recover without sequelae. However, they may progress to serious complications, such as cardiovascular collapse. Therefore, it is essential to screen high-risk patients before sedation and reduce complications by meticulous monitoring. Additionally, physicians should be familiar with the management of emergencies. The first Korean clinical practice guideline for endoscopic sedation was developed based on previous worldwide guidelines for endoscopic sedation using an adaptation process. The guideline consists of nine recommendations based on a critical review of currently available data and expert consensus when the guideline was drafted. These guidelines should provide clinicians, nurses, medical school students, and policy makers with information on how to perform endoscopic sedation with minimal risk.

Background and study aims  Gastroenterologists are encountering a rising number of obese patients requiring colonoscopy. Existing literature regarding colonoscopy outcomes in this population is scant and conflicting. We analyzed a nationwide cohort of patients to identify the effects of body mass index (BMI) on colonoscopy success, efficacy, and tolerability. Patients and methods  The Clinical Outcomes Research Initiative (CORI) endoscopic database was queried for all colonoscopies in adults between 2008-2014. Patients were stratified into four cohorts based on BMI classification for comparison. Multivariable analysis was performed to identify the effect of BMI on procedure outcome, efficacy and tolerability. Results  Of 41,401 procedures, 27,696 met study inclusion criteria. Of these, 49.4 % were performed for colorectal cancer screening, most commonly under anesthesia directed sedation. Patient discomfort was the reason for an incomplete colonoscopy in 18.7 % of all cases, and more frequent among the overweight and obese cohorts. An inadequate bowel preparation was most common in the class III obesity cohort. Compared to the normal BMI group, a BMI ≥ 30 and < 40 kg/m 2 was associated with an increased odds of an incomplete colonoscopy ( P  = 0.001for overweight, P  = 0.0004 for class I/II obesity), longer procedure ( P  < 0.05 for all) and poorer tolerance ( P  < 0.0001 for class I/II obesity, P  = 0.016 for class III obesity). Anesthesia-administered sedation was more commonly used than endoscopist directed sedation amongst the obese cohort compared with the normal BMI cohort ( P  < 0.0001). Conclusions  Endoscopists should consider the increased odds of incomplete colonoscopy, longer procedures, and poorer tolerance when performing colonoscopy in obese patients to improve clinical management and procedural outcome.

Studies evaluating the role of high-flow nasal cannula (HFNC) in sedated digestive endoscopy have reported conflicting results. This meta-analysis evaluates the effectiveness of HFNC in patients undergoing digestive endoscopy procedures under sedation.

PubMed, Medline, EMBASE, Cochrane Central Register of Controlled Trials and Web of Science, were searched from inception to 31 July 2021. Only randomized clinical trials comparing HFNC with standard nasal cannula oxygen (SNC) during sedated digestive endoscopy were included. The incidence of hypoxemia was the primary outcome, and the secondary outcome was the percentage of patients who needed airway interventions.

Seven studies that enrolled 2998 patients were included. When compared to SNC, HFNC was associated with a significant reduction in hypoxemia incidence (OR 0.24, 95% CI 0.09 to 0.64) and airway intervention requirements (OR 0.15, 95% CI 0.03 to 0.69), with both high heterogeneity (I² = 81% and 94%). In subgroup analysis, when hypoxemia was defined as pulse oxygen saturation (SpO₂) < 90%, low risk of hypoxemia subjects who received HFNC were associated with a significant reduction in hypoxemia incidence (OR 0.02, 95% CI 0.00 to 0.07; heterogeneity I² = 39%) and airway intervention requirements (OR 0.02, 95% CI 0.01 to 0.04; heterogeneity I² = 15%). However, in the high risk of hypoxemia subjects, there were no significant differences between the two oxygen administration techniques in both primary (OR 0.81, 95% CI 0.36 to 1.78; heterogeneity I² = 0%) and secondary outcomes (OR 0.85, 95% CI 0.46 to 1.59; heterogeneity I² = 0%).

Compared to SNC, HFNC not only reduce the incidence of hypoxemia but also reduce the requirements for airway interventions during sedated digestive endoscopy procedures, especially in patients at low risk for hypoxemia. In high risk of hypoxemia patients, there were no significant differences between the two oxygen administration techniques. Trial registration PROSPERO International prospective register of systematic reviews on 28 July 2021, registration no. CRD42021264556.

The aim of the study is to investigate the influence of endosonographer experience and patient-related factors on the dose of sedation and sedation-related complications during endoscopic ultrasound (EUS).

Our retrospective analysis included EUS investigations performed between 2015 and 2018 at our institution. Sedation-related complications were defined as cardiorespiratory instability with oxygen saturation drop below 90% or prolonged low blood pressure or bradycardia.

In total, 537 EUS examinations were analyzed (37.3% interventional). The median dose of propofol and midazolam were: 140 (30-570) and 3(1-7) mg, respectively. Sedation-related complications were documented in 1.8% of cases. All patients had transient, nonfatal respiratory insufficiency. Totally, 60% of the patients who developed complications were >75 years and 70% were male. The presence of cardiac and/or pulmonary comorbidities was associated with an OR = 8.77 [95% confidence interval (CI), 1.8-41.7] and American Society of Anesthesiologists class III with an OR = 7.64 (95% CI, 1.60-36.3) for the occurrence of sedation-related complications. Endosonographer experience did not influence the rate of sedation-related complications. In both diagnostic and interventional EUS, patients with comorbidities and older age received significantly less sedation. Experienced endosonographers used less sedation than trainees.

Endosonographer experience, patient age and the presence of comorbidities had a significant influence on sedation dose. Sedation-related complications occurred only in 1.8% of cases.

To evaluate the impact of high flow nasal oxygenation (HFNO) on the risk of hypoxemia during gastrointestinal endoscopic procedures (GEPs) under sedation.

Meta-analysis of randomized controlled trials.

Gastrointestinal endoscopy.

HFNO.

Adults patients undergoing GEPs under sedation.

The primary outcome was risk of hypoxemia, while the secondary outcomes included risks of severe hypoxemia, hypercapnia, need for jaw thrust or other airway interventions, and procedural interruption as well as procedure time, minimum SpO₂, and level of carbon dioxide (CO₂). Analyses based on age, gender, flow rate, risk status of patients were performed to investigate subgroup effects.

Medline, Google scholar, Cochrane Library, and EMBASE databases were searched from inception to July 2021. Seven randomized controlled trials (RCTs) involving 2998 patients published from 2019 to 2021 were included. All GEPs were performed under propofol sedation. Pooled results revealed significantly lower risks of hypoxemia [relative risk (RR) = 0.31, 95% CI:0.13-0.75; 2998 patients], severe hypoxemia (RR = 0.38, 95% CI:0.2-0.74; 2766 patients), other airway interventions (RR = 0.34, 95% CI:0.22-0.52; 2736 patients), procedural interruption (RR = 0.12, 95% CI:0.02-0.64, 451 patients) and a lower CO₂ level [standard mean difference (MD) = -0.21, 95% CI: -0.4 to -0.03; 458 patients] in HFNO group compared to control group. Subgroup analysis focusing on risk of hypoxemia showed no significant subgroup effects, indicating consistent benefits of HFNO in different clinical settings. There were no difference in minimum SpO₂ (p = 0.06; 262 patients), risk of hypercapnia (p = 0.09; 393 patients), need for jaw thrust (p = 0.28; 2256 patients), and procedure time (p = 0.41, 1004 patients) between the two groups.

Our results demonstrated the efficacy of high flow nasal oxygenation for reducing the risk of hypoxemia in patients receiving elective gastrointestinal endoscopic procedures under sedation. Further studies are warranted to verify its cost-effectiveness in the gastrointestinal endoscopy setting.

In our preliminary study, there were large individual variations at sedation levels during propofol target-controlled infusion (TCI). The present study aimed to assess the effects of body mass index (BMI) on the pharmacodynamic index of propofol TCI.

This prospective, non-randomized controlled trial evaluated 175 female patients undergoing breast lumpectomy. Anesthesia was induced with propofol using the TCI system embedded Schnider model. The effect compartment concentration was set to 3 μg/ml, and the start time of infusion was recorded. When the target concentration reached 3 μg/ml, the patient could not be awakened (Ramsay sedation score ≥4), and when the Bispectral Index (BIS) was <60, the infusion was discontinued, and the time point was recorded. The observation end-point was set at the Observer's Assessment of Alertness/Sedation (OAA/S) score of <4. The correlation between the BMI and the pharmacodynamic index of propofol was evaluated.

Propofol induction time was significantly correlated with the BMI (p < 0.001). The induction time of the underweight subjects was 10.14 ± 2.19 min, which was remarkably higher than that of normal weight (6.48 ± 3.44 min) and overweight (4.75 ± 2.53 min) individuals (p < 0.001). There were still significant differences after multivariable-adjusted regressions (p < 0.001). There were no significant differences in recovery time and sedative effect indicators, such as Ramsay score, BIS value, and effect compartment concentration, between the three groups (p > 0.05 for all).

These results suggest that the BMI is one of the critical factors affecting the pharmacodynamic index of propofol TCI, and the induction time decreased progressively with increasing BMI. The Schnider model might underpredict doses of propofol for underweight individuals.