Does nasal oxygen reduce the cardiorespiratory problems experienced by elderly patients undergoing endoscopic retrograde cholangiopancreatography?

Preprocedural Oxygenation and Procedural Oxygenation During Pediatric Procedural Sedation: Patterns of Use and Association With Interventions

STUDY OBJECTIVE

Preprocedural oxygenation (pre-emptive oxygenation started during presedation and/or induction) and procedural oxygenation (pre-emptive oxygenation started during any phase of sedation) are easy-to-use strategies with potential to decrease adverse events. Here, we describe practice patterns of preprocedural oxygenation and procedural oxygenation. We hypothesized that patients who received preprocedural oxygenation or procedural oxygenation would have a lower risk of airway/breathing/circulation interventions during sedation compared with patients without procedural oxygenation.

METHODS

We performed a retrospective, multicenter, cross-sectional study of pediatric sedations from April 2020 to July 2023 using the Pediatric Sedation Research Consortium multicenter database. The patient-level and sedation-level characteristics were described using frequencies and proportions, stratified by preprocedural oxygenation and procedural oxygenation status. We determined the site-level frequency of preprocedural oxygenation and procedural oxygenation use. We used inverse probability of treatment weighting to calculate the risk difference for interventions associated with preprocedural oxygenation and procedural oxygenation.

RESULTS

This study included a total of 85,599 pediatric sedations; 43,242 (50.5%) patients received preprocedural oxygenation (used oxygen before sedation and/or at induction) and a total of 52,219 (61.0%) received procedural oxygenation pre-emptively at any time during the sedation. There was no statistical difference in overall interventions with either preprocedural oxygenation (risk difference -0.06%; 95% confidence interval -4.26% to 4.14%) or procedural oxygenation (risk difference -1.07%; 95% confidence interval -6.44% to 4.30%).

CONCLUSION

Pre-emptive preprocedural oxygenation and procedural oxygenation were not associated with a difference in the use of airway/breathing/circulation interventions in pediatric sedations.

Efficact of Supplemental Oxygen During Procedural Sedation and Analgesia in Elderly Patients in the Emergency Department

BACKGROUND

The use of supplemental oxygen (SO) for procedural sedation and analgesia (PSA) is recommended in many guidelines, but the evidence of SO for the elderly is limited.

OBJECTIVES

This study aimed to compare the incidence of hypoxia with or without SO in PSA for the elderly patients.

METHODS

We prospectively collected data on all patients undergoing PSA in the emergency department (ED) from May 2017 through December 2021. These data are from the Japanese Procedural SedaTion and Analgesia Registry. We included all elderly patients (65 years and older) who received PSA in the ED. We performed propensity score analysis for inverse probability of treatment weighting (IPTW) to balance the baseline characteristics. The primary outcome was the incidence of hypoxia (SpO2 < 90%), and the secondary outcome was the incidence of bag-valve mask ventilation.

RESULTS

Among 1465 patients in the registry, we included 816 (55.7%) patients in the analysis. After propensity score method for IPTW, the distributions of confounders were closely balanced between the two groups. The incidence of hypoxia was significantly lower in the SO group compared with the non-SO group (6.2% vs. 19.3%; difference -13.1%; 95% confidence interval [CI] -9.8 to -16.4; p < 0.001). SO was also associated with a lower incidence of bag-valve mask ventilation (5.2% vs. 15.4%; difference -10.2%; 95% CI -7.1 to -13.2; p < 0.001).

CONCLUSIONS

In a propensity-matched analysis, SO was associated with a lower incidence of hypoxia in elderly patients during ED PSA.

Intravenous Lidocaine Significantly Reduces the Propofol Dose in Elderly Patients Undergoing Gastroscopy: A Randomized Controlled Trial

Objective

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.

Methods

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.

Results

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.

Conclusion

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.

2021 Korean Society of Gastrointestinal Endoscopy Clinical Practice Guidelines for Endoscopic Sedation

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.

[2021 Korean Society of Gastrointestinal Endoscopy Clinical Practice Guidelines for Endoscopic Sedation]

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.

2021 Korean Society of Gastrointestinal Endoscopy Clinical Practice Guidelines for Endoscopic Sedation

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.

Comparison of a Nasal Mask and Traditional Nasal Cannula During Intravenous Anesthesia for Gastroscopy Procedures: A Randomized Controlled Trial

BACKGROUND:

Hypoxemia can occur during gastroscopy under intravenous anesthesia. The aim of this randomized controlled trial was to evaluate whether oxygenation using a nasal mask can reduce the incidence of hypoxemia during gastroscopy under intravenous anesthesia compared with a traditional nasal cannula.

METHODS:

A total of 574 patients scheduled for gastroscopy under intravenous anesthesia were enrolled and randomly assigned to receive either a nasal mask or a traditional nasal cannula for oxygenation. The primary outcome was the incidence of hypoxemia. The secondary outcomes included the incidence of severe hypoxemia, duration of hypoxemia, minimum oxygen saturation, the proportion of emergency airway management, length of procedure, recovery time, and the satisfaction of the anesthetist and gastroenterologists as well as other adverse events (including cough, hiccups, nausea and vomiting, reflux, aspiration, and laryngospasm).

RESULTS:

A total of 565 patients were included in the analysis: 282 patients in the nasal cannula group and 283 patients in the nasal mask group. The incidence of hypoxemia was lower in the nasal mask group (18.0%) than in the nasal cannula group (27.7%; relative risk [RR] = 0.65; 95% confidence interval [CI], 0.48–0.89; P = .006), and the hypoxemia lasted a median of 18.0 seconds (interquartile range, 10.0–38.8) in the nasal mask group and 32.5 seconds (20.0–53.5) in the nasal cannula group (median difference –14.50; 95% CI, −22.82 to −1.34; P = .047). The proportion of patients requiring emergency airway management was significantly lower in the nasal mask group (8.8%) than in the nasal cannula group (19.1%; RR, 0.46; 95% CI, 0.30–0.73; P < .001). No difference was found in the overall incidence of other adverse events between the 2 groups (nasal mask 20.8%; nasal cannula 17.0%; RR, 1.23; 95% CI, 0.87–1.73; P = .25). Satisfaction was higher with the nasal mask than with the nasal cannula from the perspective of anesthetists (96.1% for nasal mask versus 84.4% for nasal cannula; RR, 1.14; 95% CI, 1.08–1.20; P < .001) and gastroenterologists (95.4% for mask versus 81.9% for cannula; RR, 1.17; 95% CI, 1.10–1.24; P < .001). There were no significant differences in the incidence of severe hypoxemia, minimum oxygen saturation, length of procedure, or recovery time between the 2 groups.

CONCLUSIONS:

Nasal mask oxygenation reduced the incidence of hypoxemia during anesthesia for gastroscopy under intravenous anesthesia.

Oxygenation before Endoscopic Sedation Reduces the Hypoxic Event during Endoscopy in Elderly Patients: A Randomized Controlled Trial

Background: Sedation endoscopy increases patient and examiner satisfaction but involves complications. The most serious complication is hypoxia, the risk factors for which are old age, obesity, and American Society of Anesthesiologists physical status of 3 or greater. However, clear evidence of oxygenation during sedation endoscopy for elderly people is lacking in US, European, and Korean guidelines. Method: This study was conducted for 1 year starting in August 2018 to evaluate whether pre-oxygenation use 1 min before sedation endoscopy could reduce the incidence of hypoxia in patients older than 65 years of age. A total of 70 patients were divided into the non-oxygenated group (n = 35; control group) and oxygen-treated group (n = 35; experimental group) during endoscopy. Result: The incidence of hypoxia was 28 (80%) in the control group versus 0 (0%) in the pre-oxygenated group. Factors related to hypoxia in the non-oxygenated group were a relatively high dose of midazolam and concomitant injection with narcotic analgesics such as pethidine. Conclusion: The incidence of hypoxia during sedation endoscopy is high in patients over 65 years, but oxygenation during endoscopic sedation in elderly people can significantly reduce the incidence of intraprocedural hypoxic events.

Comparison of two supplement oxygen methods during gastroscopy with intravenous propofol anesthesia in obese patients: study protocol for a randomized controlled trial

BACKGROUND

Hypoxemia is a major complication in obese patients undergoing gastrointestinal endoscopy under intravenous anesthesia or sedation due to altered airway anatomy. We design this randomized controlled trial (RCT) to compare efficacy and safety of the Wei nasal jet tube (WNJT) and nasal prongs for supplement oxygen during gastroscopy with intravenous propofol anesthesia in obese patients.

METHODS

The study will be a single-center, prospective RCT. A total of 308 obese patients will be recruited and randomly assigned to receive either the WNJT (group A) or nasal prongs (group B). During gastroscopy with intravenous propofol anesthesia, 5 L/min of oxygen will be delivered through the jet port of the WNJT in the group A and via the nasal prongs in the group B. The primary outcome is the incidence of hypoxemia and severe hypoxemia. The secondary outcomes are adverse events during the gastroscopy, postoperative complications, and satisfaction of the anesthetist, physician, and patient.

DISCUSSION

This RCT aims to clarify whether the WNJT can result in reduced incidences of hypoxemia and complications and provide improved satisfaction to the anesthetist, physician, and patient. Thus, it can be determined if the WNJT is a useful tool for supplement oxygen in obese patients undergoing gastroscopy with intravenous propofol anesthesia. The results will provide the evidence for anesthesiologists to make a decision regarding the choice of supplementary oxygen methods in this condition.

TRIAL REGISTRATION

Chinese Clinical Trial, ChiCTR-IOR-17013089 . Registered on 23 October 2017.

Practice Guidelines for Moderate Procedural Sedation and Analgesia 2018

Supplemental Digital Content is available in the text.

Endoscopic sedation: from training to performance

Adequate sedation and analgesia are considered essential requirements to relieve patient discomfort and pain and ultimately to improve the outcomes of modern gastrointestinal endoscopic procedures. The willingness of patients to undergo sedation during endoscopy has increased steadily in recent years and standard sedation practices are needed for both patient safety and successful procedural outcomes. Therefore, regular training and education of healthcare providers is warranted. However, training curricula and guidelines for endoscopic sedation may have conflicts according to varying legal frameworks and/or social security systems of each country, and well-recognized endoscopic sedation training systems are not currently available in all endoscopy units. Although European and American curricula for endoscopic sedation have been extensively developed, general curricula and guidelines for each country and institution are also needed. In this review, an overview of recent curricula and guidelines for training and basic performance of endoscopic sedation is presented based on the current literature.

European Society of Gastrointestinal Endoscopy, European Society of Gastroenterology and Endoscopy Nurses and Associates, and the European Society of Anaesthesiology Guideline: Non-anaesthesiologist administration of propofol for GI endoscopy

Propofol sedation by non-anaesthesiologists is an upcoming sedation regimen in several countries throughout Europe. Numerous studies have shown the efficacy and safety of this sedation regimen in gastrointestinal endoscopy. Nevertheless, this issue remains highly controversial. The aim of this evidence- and consensus-based set of guideline is to provide non-anaesthesiologists with a comprehensive framework for propofol sedation during digestive endoscopy. This guideline results from a collaborative effort from representatives of the European Society of Gastrointestinal Endoscopy (ESGE), the European Society of Gastroenterology and Endoscopy Nurses and Associates (ESGENA) and the European Society of Anaesthesiology (ESA). These three societies have endorsed the present guideline.The guideline is published simultaneously in the Journals Endoscopy and European Journal of Anaesthesiology.

Endoscopy in the elderly: a review of the efficacy and safety of colonoscopy, esophagogastroduodenoscopy, and endoscopic retrograde cholangiopancreatography

Gastrointestinal endoscopy including colonoscopy, esophagogastroduodenoscopy, and endoscopic retrograde cholangiopancreatography (ERCP) are safe and efficacious in elderly patients. Screening colonoscopies have little efficacy in patients over 80 years. Colonoscopies performed for bleeding or iron-deficiency anemia have a higher yield in elderly patients. Colonic preparations were well tolerated and colonoscopic success rates are high in elderly patients. However, poor colonic preparation is more likely in these patients. Esophagogastroduodenoscopy is a high-yield procedure with no significant increase in adverse events in patients over 80 years with symptoms including dyspepsia and dysphagia. ERCP in the elderly carries a high degree of success with low complication rates. Elderly patients undergoing ERCP carry similar risks of bleeding and perforation and a lower risk of pancreatitis compared with younger patients. Advanced age should not be regarded as an absolute contraindication to any gastrointestinal endoscopy procedure.

Risk factors for hypoxemia during ambulatory gastrointestinal endoscopy in ASA I-II patients

BACKGROUND

Most studies identify the American Society of Anesthesiology (ASA) classification as the most significant risk factor for hypoxemia. The risk factors operative within ASA I and II patients are not well defined. Therefore, we analyzed prospectively collected data to identify the risk factors of hypoxemia in such patients.

METHODS

A combination of a narcotic and benzodiazepine was used for sedation and oxygen was supplemented if hypoxemia (oxygen saturation <or=90%) developed. Univariate and multivariate analyses were performed and correlations estimated for predetermined clinical variables.

RESULTS

40 of 79 patients (51%) developed hypoxemia, which occurred more frequently in the obese (71%; 10/14) than the nonobese (46%; 30/65) group (P=0.08). On multivariate analysis, the odds ratios (OR) and 95% confidence intervals (CI) for developing hypoxemia were age >or= 60 years 4.5 (1.4-14.3) P=0.01, and incremental 25-mg doses of meperidine 2.6 (1.02-6.6) P = 0.04. Body mass index (BMI) significantly correlated with the number of hypoxemic episodes (rho 0.26, 95% CI 0.04-0.48, P=0.02).

CONCLUSION

In ASA I and II patients, BMI significantly correlated with the number of hypoxemic episodes, whereas age >or= 60 years and meperidine dose were significant risk factors for hypoxemia.

Capnographic monitoring of respiratory activity improves safety of sedation for endoscopic cholangiopancreatography and ultrasonography

BACKGROUND & AIMS

The Joint Commission on the Accreditation of Healthcare Organizations recommends ventilation monitoring during procedural sedation for gastrointestinal endoscopy. We sought to determine whether intervention, based on a microstream capnography-based ventilation monitoring system that has been shown to function as an early warning system for hypoxemia, would decrease hypoxemia during endoscopy.

METHODS

Subjects undergoing elective endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography (EUS) under procedural sedation with a combination of opioid and benzodiazepine were randomly assigned to either a study arm in which the endoscopy team was blinded to capnography or an open arm in which the endoscopy team was prompted of capnographic changes. The primary end point was the occurrence of hypoxemia; secondary end points were the occurrences of severe hypoxemia, apnea, and oxygen supplementation.

RESULTS

A total of 263 subjects were enrolled; 247 were analyzed for efficacy. The numbers of hypoxemic events in the blinded and open arms were 132 and 69, respectively (P < .001). Thirty-five percent of all hypoxemic events occurred with completely normal ventilation. Hypoxemia developed in 69% of patients in the blinded arm compared with 46% in the open arm (P < .001). Severe hypoxemia percentages in the blinded and open arms were 31% and 15% (P = .004), for apnea were 63% and 41% (P < .001), for oxygen supplementation were 67% and 52% (P = .02), and for recurrent hypoxemia after oxygen supplementation were 38% and 18% (P = .01), respectively.

CONCLUSIONS

Capnographic monitoring of respiratory activity improves patient safety during procedural sedation for elective ERCP/EUS by reducing the frequency of hypoxemia, severe hypoxemia, and apnea.

Predictive factors of oxygen desaturation of patients submitted to endoscopic retrograde cholangiopancreatography under conscious sedation

BACKGROUND AND AIMS

Hypoxemia can occur during endoscopic retrograde cholangiopancreatography probably induced by the analgesia and sedation done. Moreover the patients prone position difficults the adequate ventilation. The hypoxemia and hypoventilation may not be noticed by nursing staff. A transversal study was used to investigate possible predictive factors of oxygen desaturation in sedated patients with midazolam associated to meperidine undergoing endoscopic retrograde cholangiopancreatography.

PATIENTS AND METHODS

A total of 186 patients were monitored with continuous pulse oximetry. Poisson regression was used to measure the independent effect of each factor adjusted for effects of each of the other factors. The variables studied were: age, gender, hematocrit and hemoglobin levels, scopolamine use, diagnostic or therapeutic exam, American Society of Anesthesiologists Scores (ASA), duration time of exam, sedative used midazolam in the average of 0.07 mg/kg and analgesic drug meperidine in the average of 0.7 mg/kg that was titrated according patients reaction.

RESULTS

No desaturation was found in 113 (60.8%) patients, mild desaturation (SpO2 <92%) in 22 (11.8%) and severe desaturation (SpO2 <90%) in 51 (27.4%). This desaturation was recognized only by the pulse oximeter. There was no need to use any antagonist drug of the sedatives in patients who had severe desaturation, they were just stimulated to deep breaths and oxygen was offered at 2 liters per minute via catheter. The variables found to predict desaturation were age >60 years old and ASA score III. The duration of exam was barely significant for desaturation.

CONCLUSIONS

The variables of age of 60 years old or more, and ASA III score are identified as increased risk for desaturation for patients who undergo endoscopic retrograde cholangiopancreatography under conscious sedation. Long time of exam suggests the patient oxygen desaturate. Such patients require very close monitoring to desaturation and hypoventilation by the assistants and nursing staff alerting to respiratory depression. The use of pulse oximeter and asking for deep breaths during the exam helps to diminish such risks.

Double blind randomised controlled trial of effect of metoprolol on myocardial ischaemia during endoscopic cholangiopancreatography

OBJECTIVE

To evaluate the effect of metoprolol, a beta adrenergic blocking drug, on the occurrence of myocardial ischaemia during endoscopic cholangiopancreatography.

DESIGN

Double blind, randomised, controlled trial.

SETTING

University Hospital.

SUBJECTS

38 (two groups of 19) patients scheduled for endoscopic cholangiopancreatography.

INTERVENTIONS

Metoprolol 100 mg or placebo as premedication two hours before endoscopy.

MAIN OUTCOME MEASURES

Heart rate, arterial oxygen saturation by continuous pulse oximetry, ST segment changes during endoscopic cholangiopancreatography (an ST segment deviation > 1 mV was defined as myocardial ischaemia), electrocardiogram monitored continuously with a Holter tape recorder.

RESULTS

All patients had increased heart rate during endoscopy compared with rate before endoscopy, but heart rate during endoscopy was significantly lower in the metoprolol group compared with the placebo group (P = 0.0002). Twenty one patients (16 placebo, 5 metoprolol; P = 0.0008) developed tachycardia (heart rate > 100/min) during the procedure, and 11 patients (10 placebo, 1 metoprolol; P = 0.003) developed myocardial ischaemia. One patient in the placebo group had an acute inferolateral myocardial infarction. In the 10 other patients with signs of myocardial ischaemia during endoscopy the ST deviation disappeared when the endoscope was retracted. In all patients myocardial ischaemia was related to increases in heart rate, and 10 of the 11 patients had tachycardia coherent with myocardial ischaemia.

CONCLUSIONS

Metoprolol prevented myocardial ischaemia during endoscopic cholangiopancreatography, probably through lowering the heart rate. Thus, tachycardia seems to be a key pathogenic factor in the development of myocardial ischaemia during endoscopy.

No effect of oxygen therapy on myocardial ischaemia during gastroscopy

BACKGROUND

Myocardial ischaemia (defined as an ST-segment depression on ECG) may occur during upper gastrointestinal endoscopy, but the mechanism is still unknown. The aim of our study was to evaluate the effect of oxygen therapy and tachycardia on the occurrence of ST-segment depression during routine diagnostic esophagogastroduodenoscopy.

METHODS

Eighty-nine consecutive patients were randomized to receive either oxygen (21/min by nasal prongs) or nothing during endoscopy, in which arterial oxygen saturation was measured by continuous pulse oximetry, and ECG was measured continuously with a Holter tape recorder.

RESULTS

A total of 28 patients (12 receiving oxygen) developed ST-segment depression ( > 0.1 mV) during endoscopy. In 22 patients (12 receiving oxygen) ST depression was related to tachycardia, and in 5 of these (none receiving oxygen) simultaneous episodic hypoxaemia was present during the event. Thus, in every case of ST depression related to episodic hypoxaemia there was simultaneous tachycardia. In six patients developing ST depression during endoscopy we did not find preendoscopy levels, and 63 patients (29 receiving oxygen) developed tachycardia during the procedure (rate > 100 min-1_.

CONCLUSIONS

Oxygen therapy had no significant effect on the occurrence of ST-segment depression during upper gastrointestinal endoscopy. The results suggest that tachycardia is more important than hypoxaemia in the pathogenesis of ST depression during gastroscopy.

Oxygen saturation during endoscopic retrograde cholangiopancreatography: a comparison of two protocols of oxygen administration

Patients having endoscopic retrograde cholangiopancreatography (ERCP) are generally elderly and require sedation while in the prone position. These factors may be expected to aggravate any risk of arterial hypoxia. This study evaluated two protocols of oxygen administration, one with and one without pre-oxygenation. In 25 patients in whom pre-oxygenation with 4 litres/minute for five minutes before sedation was used, followed by continuous oxygen administration, arterial oxygen saturation did not fall below 90% at any stage during the procedure. By contrast, in 25 patients who were not pre-oxygenated oxygen saturation fell below 90% in nine (36%). As expected, hypoxia occurred most frequently during the early stages of sedation and endoscope insertion. Hypoxia did not occur in association with operations such as sphincterotomy, stone extraction or stent insertion. This study confirms that arterial hypoxia is a common event during ERCP and can be completely prevented by pre-oxygenation with four litres of oxygen given intranasally for five minutes before sedation.