Assessment of the Berlin Questionnaire for evaluation of hypoxemia risk in subjects undergoing deep sedation for screening gastrointestinal endoscopy

Place of high-flow nasal oxygen in nonoperating room anesthesia

PURPOSE OF REVIEW

This article aims to assess the utility of high-flow nasal oxygen (HFNO) therapy in nonoperating room anesthesia (NORA) settings.

RECENT FINDINGS

The number of procedural interventions under deep sedation in NORA is still increasing. Administration of oxygen is recommended to prevent hypoxemia and is usually delivered with standard oxygen through nasal cannula or a face mask. HFNO is a simple alternative with a high warmed humidified flow (ranging from 30 to 70 l/min) with a precise fraction inspired of oxygen (ranging from 21 to 100%). Compared to standard oxygen, HFNO has demonstrated efficacy in reducing the incidence of hypoxemia and the need for airway maneuvers. Research on HFNO has primarily focused on its application in gastrointestinal endoscopy procedures. Yet, it has also shown promising results in various other procedural interventions including bronchoscopy, cardiology, and endovascular procedures. However, the adoption of HFNO prompted considerations regarding cost-effectiveness and environmental impact.

SUMMARY

HFNO emerges as a compelling alternative to conventional oxygen delivery methods for preventing hypoxemia during procedural interventions in NORA. However, its utilization should be reserved for patients at moderate-to-high risk to mitigate the impact of cost and environmental factors.

British Society of Gastroenterology guidelines on sedation in gastrointestinal endoscopy

Over 2.5 million gastrointestinal endoscopic procedures are carried out in the United Kingdom (UK) every year. Procedures are carried out with local anaesthetic r with sedation. Sedation is commonly used for gastrointestinal endoscopy, but the type and amount of sedation administered is influenced by the complexity and nature of the procedure and patient factors. The elective and emergency nature of endoscopy procedures and local resources also have a significant impact on the delivery of sedation. In the UK, the vast majority of sedated procedures are carried out using benzodiazepines, with or without opiates, whereas deeper sedation using propofol or general anaesthetic requires the involvement of an anaesthetic team. Patients undergoing gastrointestinal endoscopy need to have good understanding of the options for sedation, including the option for no sedation and alternatives, balancing the intended aims of the procedure and reducing the risk of complications. These guidelines were commissioned by the British Society of Gastroenterology (BSG) Endoscopy Committee with input from major stakeholders, to provide a detailed update, incorporating recent advances in sedation for gastrointestinal endoscopy.This guideline covers aspects from pre-assessment of the elective 'well' patient to patients with significant comorbidity requiring emergency procedures. Types of sedation are discussed, procedure and room requirements and the recovery period, providing guidance to enhance safety and minimise complications. These guidelines are intended to inform practising clinicians and all staff involved in the delivery of gastrointestinal endoscopy with an expectation that this guideline will be revised in 5-years' time.

Machine learning-based risk prediction of hypoxemia for outpatients undergoing sedation colonoscopy: a practical clinical tool

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Safety and efficacy of remimazolam tosilate combined with low-dose fentanyl for procedural sedation in obese patients undergoing gastroscopy: study protocol for a single-centre, double-blind, randomised controlled trial

INTRODUCTION

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.

METHODS AND ANALYSIS

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.

ETHICS AND DISSEMINATION

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.

TRIAL REGISTRATION NUMBER

ChiCTR2200067076.

Dynamic prediction of hypoxemia risk at different time points based on preoperative and intraoperative features: machine learning applications in outpatients undergoing esophagogastroduodenoscopy

BACKGROUND

Hypoxemia often occurs in outpatients undergoing anesthesia-assisted esophagogastroduodenoscopy (EGD). However, there is a scarcity in tools to predict the hypoxemia risk. We aimed to solve this problem by developing and validating machine learning (ML) models based on preoperative and intraoperative features.

METHODS

All data were retrospectively collected from June 2021 to February 2022. The most appropriate predictive features were selected by the least absolute shrinkage and selection operator, which were incorporated and modelled by 4 ML algorithms. The area under the precision-recall curve (AUPRC) was used as the main evaluation metric to select the best models, and the selected models were compared with the STOP-BANG score. Their predictive performance was visually interpreted by SHapley Additive exPlanations. The primary endpoint of this study was hypoxemia during the procedure, defined as at least one reading of pulse oximetry < 90% without probes misplacement from the anesthesia induction beginning to the end of EGD, while the secondary endpoint was hypoxemia during induction, from the induction beginning to the start of endoscopic intubation.

RESULTS

Of 1160 patients in the derivation cohort, 112 patients (9.6%) developed intraoperative hypoxemia, of which 102 (8.8%) occurred during the induction period. In temporal and external validation, no matter whether based on preoperative variables or still based on preoperative plus intraoperative variables, our models showed excellent predictive performance for the two endpoints, significantly better than STOP-BANG score. In the model interpretation section, preoperative variables (airway assessment indicators, pulse oximeter oxygen saturation and BMI) and intraoperative variables (the induced propofol dose) made the highest contribution to the predictions.

To our knowledge, our ML models were the first to predict hypoxemia risk, which achieved excellent overall predictive ability integrating various clinical indicators. These models have the potential to become an effective tool for adjusting sedation strategies flexibly and reducing the workload of anesthesiologists.KEY MESSAGESThis study is the first model employing ML methods based on preoperative and preoperative plus intraoperative variables for predicting the risk of hypoxemia during induction and the whole EGD procedure respectively.Our four models achieved satisfactory predictive performance and outperformed STOP-BANG score in terms of AUPRC in the temporal and external validation cohorts respectively.We found that the relevant variables of airway assessment should be fully taken into account when analyzing the risk factor of hypoxemia, and the effect of patients' age on their hypoxemia risk should be considered in conjunction with the propofol dose.

An interpretable artificial neural network model for predicting hypoxemia via an online tool in adult (18-64) patients during esophagogastroduodenoscopy

Background

The hypoxemia risk in adult (18-64) patients treated with esophagogastroduodenoscopy (EGD) under sedation often poses a dilemma for anesthesiologists. We aimed to establish an artificial neural network (ANN) model to solve this problem, and introduce the Shapley additive explanations (SHAP) algorithm to further improve the interpretability.

Methods

The relevant data of patients underwent routine anesthesia-assisted EGD were collected. Elastic network was used to filter the optimal features. Airway-ANN and Basic-ANN models were established based on all collected indicators and remaining variables excluding airway assessment indicators, respectively. The performance of Basic-ANN, Airway-ANN and STOP-BANG was evaluated by the area under the precision-recall curve (AUPRC) on temporal validation set. The SHAP was used for revealing the predictive behavior of our best model.

Results

999 patients were eventually included. The AUPRC value of Airway-ANN model was significantly higher than Basic-ANN model in the temporal validation set (0.532 vs 0.429, P < 0.05). And the performance of both two ANN models was significantly better than that of STOP-BANG score (both P < 0.05). The Airway-ANN model was deployed to the cloud (http://njfh-yxb.com.cn:2022/airway_ann).

Conclusion

Our online interpretable Airway-ANN model achieved satisfying ability in identifying the hypoxemia risk in adult (18-64) patients undergoing EGD.

Validity Analysis of Neck Circumference as a Screening Test for Hypoxia Occurrence in Patients Undergoing Sedative Endoscopy

This study was performed to check the validity of and propose a cutoff point for measuring the neck circumference for screening hypoxia occurrence in patients undergoing sedative endoscopy. Data were collected from 168 patients who visited the Endoscopy Center of G University Hospital between 27 April 2020 and 12 June 2020 to undergo sedative endoscopy. Hypoxia occurrences were measured using sleep questionnaires (STOP-BANG and Berlin questionnaires), and the neck circumference measurements of the patients were compared. Neck circumference as a predictor of hypoxia and its sensitivity and specificity according to the cutoff values were high; thus, it is a valid screening test for hypoxia in patients undergoing sedative endoscopy. The most appropriate cutoff values for sitting neck circumference and lying neck circumference in men were 40.5 and 40.3, respectively, and those for women were 35.3 and 35.8, respectively. Hypoxia can be predicted in patients undergoing sedative endoscopy by measuring their neck circumference.

The effectiveness of high-flow nasal cannula during sedated digestive endoscopy: a systematic review and meta-analysis

BACKGROUND

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.

METHODS

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.

RESULTS

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%).

CONCLUSIONS

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.

Effect of high-flow vs. low-flow nasal plus mouthguard oxygen therapy on hypoxaemia during sedation: a multicentre randomised controlled trial

Whether high-flow vs. low-flow nasal oxygen reduces hypoxaemia for sedation during endoscopic retrograde cholangiopancreatography is currently unknown. In this multicentre trial, 132 patients ASA physical status 3 or higher, BMI > 30 kg.m^-2 or with known or suspected obstructive sleep apnoea were randomly allocated to high-flow nasal oxygen up to 60 l.min^-1 at 100% F_I O₂ or low-flow nasal oxygen at 4 l.min^-1 . The low-flow nasal oxygen group also received oxygen at 4 l.min^-1 through an oxygenating mouthguard, totalling 8 l.min^-1 . Primary outcome was hypoxaemia, defined as S_p O₂ < 90% regardless of duration. Hypoxaemia occurred in 7.7% (5/65) of patients with high-flow and 9.1% (6/66) with low-flow nasal oxygen (percentage point difference -1.4%, 95%CI -10.9 to 8.0; p = 0.77). Between the groups, there were no significant differences in frequency of hypoxaemic episodes; lowest S_p O₂ ; peak transcutaneous carbon dioxide; hypercarbia (transcutaneous carbon dioxide > 2.66 kPa from baseline); requirement of chin lift/jaw thrust; nasopharyngeal airway insertion; bag-mask ventilation; or tracheal intubation. Following adjustment for duration of the procedure, the primary outcome remained non-significant. In high-risk patients undergoing endoscopic retrograde cholangiopancreatography, oxygen therapy with high-flow nasal oxygen did not reduce the rate of hypoxaemia, hypercarbia or the need for airway interventions, compared with combined oral and nasal low-flow oxygen.

High-flow nasal oxygenation or standard oxygenation for gastrointestinal endoscopy with sedation in patients at risk of hypoxaemia: a multicentre randomised controlled trial (ODEPHI trial)

BACKGROUND

We aimed to determine whether high-flow nasal oxygen could reduce the incidence of decreased peripheral oxygen saturation (SpO₂) compared with standard oxygen in patients at risk of hypoxaemia undergoing gastrointestinal endoscopy under deep sedation.

METHODS

This was a multicentre, randomised controlled trial with blinded assessment of the primary outcome evaluating high-flow nasal oxygen (gas flow 70 L min^-1, inspired oxygen fraction 0.50) or standard oxygen delivered via nasal cannula or face mask (6 L min^-1) or nasopharyngeal tube (5 L min^-1) in patients at risk of hypoxaemia (i.e. >60 yr old, or with underlying cardiac or respiratory disease, or with ASA physical status >1, or with obesity or sleep apnoea syndrome) undergoing gastrointestinal endoscopy. The primary endpoint was the incidence of SpO₂ ≤92%. Secondary outcomes included prolonged or severe desaturations, need for manoeuvres to maintain free upper airways, and other adverse events.

RESULTS

In 379 patients, a decrease in SpO₂ ≤92% occurred in 9.4% (18/191) for the high-flow nasal oxygen group, and 33.5% (63/188) for the standard oxygen groups (adjusted absolute risk difference, -23.4% [95% confidence interval (CI), -28.9 to -16.7]; P<0.001). Prolonged desaturation (>1 min) and manoeuvres to maintain free upper airways were less frequent in the high-flow nasal oxygen group than in the standard oxygen group (7.3% vs 14.9%, P=.02, and 11.1% vs 32.4%, P<0.001).

CONCLUSIONS

In patients at risk of hypoxaemia undergoing gastrointestinal endoscopy under deep sedation, use of high-flow nasal oxygen significantly reduced the incidence of peripheral oxygen desaturation.

CLINICAL TRIAL REGISTRATION

NCT03829293.

Predictor of respiratory disturbances during gastric endoscopic submucosal dissection under deep sedation

BACKGROUND

Sedation is commonly performed for the endoscopic submucosal dissection (ESD) of early gastric cancer. Severe hypoxemia occasionally occurs due to the respiratory depression during sedation.

AIM

To establish predictive models for respiratory depression during sedation for ESD.

METHODS

Thirty-five adult patients undergoing sedation using propofol and pentazocine for gastric ESDs participated in this prospective observational study. Preoperatively, a portable sleep monitor and STOP questionnaires, which are the established screening tools for sleep apnea syndrome, were utilized. Respiration during sedation was assessed by a standard polysomnography technique including the pulse oximeter, nasal pressure sensor, nasal thermistor sensor, and chest and abdominal respiratory motion sensors. The apnea-hypopnea index (AHI) was obtained using a preoperative portable sleep monitor and polysomnography during ESD. A predictive model for the AHI during sedation was developed using either the preoperative AHI or STOP questionnaire score.

RESULTS

All ESDs were completed successfully and without complications. Seventeen patients (49%) had a preoperative AHI greater than 5/h. The intraoperative AHI was significantly greater than the preoperative AHI (12.8 ± 7.6 events/h vs 9.35 ± 11.0 events/h, P = 0.049). Among the potential predictive variables, age, body mass index, STOP questionnaire score, and preoperative AHI were significantly correlated with AHI during sedation. Multiple linear regression analysis determined either STOP questionnaire score or preoperative AHI as independent predictors for intraoperative AHI ≥ 30/h (area under the curve [AUC]: 0.707 and 0.833, respectively) and AHI between 15 and 30/h (AUC: 0.761 and 0.778, respectively).

CONCLUSION

The cost-effective STOP questionnaire shows performance for predicting abnormal breathing during sedation for ESD that was equivalent to that of preoperative portable sleep monitoring.

High-flow nasal oxygenation versus standard oxygenation for gastrointestinal endoscopy with sedation. The prospective multicentre randomised controlled ODEPHI study protocol

INTRODUCTION

Hypoxaemia is a major complication during gastrointestinal endoscopy (GIE) procedures (upper/lower) when performed under deep sedation in the procedure room. Standard oxygen therapy (SOT) is used to prevent hypoxaemia. Data suggest that risk factors for hypoxaemia under deep sedation during GIE are obstructive sleep apnoea syndrome, a body mass index above 30 kg/m², high blood pressure, diabetes, heart disease, age over 60 years old, high American Society of Anesthesiologists physical status class and the association of upper and lower GIE. High-flow nasal oxygenation (HFNO) may potentially improve oxygenation during GIE under deep sedation. We hypothesised that HFNO could decrease the incidence of hypoxaemia in comparison with SOT.

METHODS AND ANALYSIS

The ODEPHI (High-flow nasal oxygenation versus standard oxygenation for gastrointestinal endoscopy with sedation. The prospective multicentre randomised controlled) study is a multicentre randomised controlled trial comparing HFNO to SOT during GIE (upper and/or lower) under deep sedation administered by anaesthesiologists in the procedure room. Three hundred and eighty patients will be randomised with a 1:1 ratio in two parallel groups.The primary outcome is the occurrence of hypoxaemia, defined by a pulse oximetry measurement of peripheral capillary oxygen saturation (SpO₂) below or equal to 92% during the GIE procedure. Secondary outcomes include prolonged hypoxaemia, severe hypoxaemia, need for manoeuvres to maintain upper airway patency and other adverse events.

ETHICS AND DISSEMINATION

This study has been approved by the ethics committee (CPP Sud Est Paris V, France), and patients are included after informed consent. The results will be submitted for publication in peer-reviewed journals. As provided for by French law, patients participating in the study are informed that they have the possibility to ask the investigators, once the study is completed, to be informed of the overall results of the study. Thus, a summary of the results will be sent by post to the participants on request.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03829293).