Hypoxia and tachycardia during endoscopic retrograde cholangiopancreatography: detection by pulse oximetry

Development of a predictive model for hypoxia due to sedatives in gastrointestinal endoscopy: a prospective clinical study in Korea

BACKGROUND/AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Korean clinical practice guidelines for diagnostic and procedural sedation

Safe and effective sedation depends on various factors, such as the choice of sedatives, sedation techniques used, experience of the sedation provider, degree of sedation-related education and training, equipment and healthcare worker availability, the patient's underlying diseases, and the procedure being performed. The purpose of these evidence-based multidisciplinary clinical practice guidelines is to ensure the safety and efficacy of sedation, thereby contributing to patient safety and ultimately improving public health. These clinical practice guidelines comprise 15 key questions covering various topics related to the following: the sedation providers; medications and equipment available; appropriate patient selection; anesthesiologist referrals for high-risk patients; pre-sedation fasting; comparison of representative drugs used in adult and pediatric patients; respiratory system, cardiovascular system, and sedation depth monitoring during sedation; management of respiratory complications during pediatric sedation; and discharge criteria. The recommendations in these clinical practice guidelines were systematically developed to assist providers and patients in sedation-related decision making for diagnostic and therapeutic examinations or procedures. Depending on the characteristics of primary, secondary, and tertiary care institutions as well as the clinical needs and limitations, sedation providers at each medical institution may choose to apply the recommendations as they are, modify them appropriately, or reject them completely.

Academy of Medicine, Singapore clinical guideline on the use of sedation by non-anaesthesiologists during gastrointestinal endoscopy in the hospital setting

INTRODUCTION

In Singapore, non-anaesthesiologists generally administer sedation during gastrointestinal endoscopy. The drugs used for sedation in hospital endoscopy centres now include propofol in addition to benzodiazepines and opiates. The requirements for peri-procedural monitoring and discharge protocols have also evolved. There is a need to develop an evidence-based clinical guideline on the safe and effective use of sedation by non-anaesthesiologists during gastrointestinal endoscopy in the hospital setting.

METHODS

The Academy of Medicine, Singapore appointed an expert workgroup comprising 18 gastroenterologists, general surgeons and anaesthesiologists to develop guidelines on the use of sedation during gastrointestinal endoscopy. The workgroup formulated clinical questions related to different aspects of endoscopic sedation, conducted a relevant literature search, adopted Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology and developed recommendations by consensus using a modified Delphi process.

RESULTS

The workgroup made 16 recommendations encompassing 7 areas: (1) purpose of sedation, benefits and disadvantages of sedation during gastrointestinal endoscopy; (2) pre-procedural assessment, preparation and consent taking for sedation; (3) Efficacy and safety of drugs used in sedation; (4) the role of anaesthesiologist administered sedation during gastrointestinal endoscopy; (5) performance of sedation; (6) post-sedation care and discharge after sedation; and (7) training in sedation for gastrointestinal endoscopy for non-anaesthesiologists.

CONCLUSION

These recommendations serve to guide clinical practice during sedation for gastrointestinal endoscopy by non-anaesthesiologists in the hospital setting.

Evaluation of bispectral index monitoring efficacy in endoscopic patients who underwent retrograde cholangiopancreatography and received sedoanalgesia

INTRODUCTION

Bispectral index (BIS) monitoring provides an objective, non-invasive measurement of the level of consciousness in a sedated patient.

AIM

In this prospective study, we aimed to investigate the hypothesis that risk of respiratory depression could be reduced and the desired level of sedation with minimal doses of propofol could be achieved by using BIS monitoring in endoscopic retrograde cholangiopancreatography (ERCP) procedures.

MATERIAL AND METHODS

Sixty patients in the ASA 1-2 category, who were scheduled for an ERCP with sedation, were randomly divided into two groups. The procedure was performed, and sedation was administered so that the patient's Ramsay Sedation Score (RSS) would be 4-5 in the first group (group 1) and the patient's BIS value would be 65-75 in the second group (group 2). Cardiopulmonary complications, the total duration of the procedure, and the total amount of propofol administered were recorded.

RESULTS

The mean SpO2 measurements at the third minute, fifth minute, and 10th minute were higher in the BIS group (p < 0.001) (p < 0.05). The mean number of respirations during the third, fifth, 10th, and 15th minute of sedation was significantly higher in the RSS group than in the BIS group (p < 0.05). There was no difference between the groups in terms of recovery time, total propofol amount, and additional doses of bolus propofol.

CONCLUSIONS

BIS monitoring during sedation with propofol for ERCP did not reduce total propofol use, but it may be an efficient guide for the timing of additional dose administration, which could reduce the risk of respiratory depression, and it could be used safely as an objective method in the follow-up of level of sedation.

Practice Guidelines for Moderate Procedural Sedation and Analgesia 2018

Supplemental Digital Content is available in the text.

Usefulness of Acoustic Monitoring of Respiratory Rate in Patients Undergoing Endoscopic Submucosal Dissection

Aim. The study assessed the usefulness of a recently developed method for respiratory rate (RR) monitoring in patients undergoing endoscopic submucosal dissection (ESD) under deep sedation. Methods. Study subjects comprised 182 consecutive patients with esophageal cancer or gastric cancer undergoing ESD. The usefulness of acoustic RR monitoring was assessed by retrospectively reviewing the patients' records for age, gender, height, weight, past history, serum creatinine, RR before ESD, and total dose of sedative. Results. Respiratory suppression was present in 37.9% of (69/182) patients. Continuous monitoring of RR led to detection of respiratory suppression in all these patients. RR alone was decreased in 24 patients, whereas both RR and blood oxygen saturation were decreased in 45 patients. Univariate analysis showed female gender, height, weight, and RR before treatment to be significantly associated with respiratory suppression. Multivariate analysis showed RR before treatment to be the only significant independent predictor [odds ratio (OR) 0.83, 95% confidence interval (CI) 0.73–0.95, and P = 0.006] of respiratory suppression. Conclusion. In this study, the difference in RR before treatment between patients with and without respiratory suppression was subtle. Therefore, we suggest that acoustic RR monitoring should be considered in patients undergoing ESD under sedation to prevent serious respiratory complications.

Sedation-related complications in gastrointestinal endoscopy

Defining the risk of procedural sedation for gastrointestinal endoscopic procedures remains a vexing challenge. The definitions as to what constitutes a cardiopulmonary unplanned event are beginning to take focus but the existing literature is an amalgam of various definitions and subjective outcomes, providing a challenge to patient, practitioner, and researcher. Gastrointestinal endoscopy when undertaken by trained personnel after the appropriate preprocedural evaluation and in the right setting is a safe experience. However, significant challenges exist in further quantifying the sedation risks to patients, optimizing physiologic monitoring, and sublimating the pharmacoeconomic and regulatory embroglios that limit the scope of practice and the quality of services delivered to patients.

Risk of sedation for diagnostic esophagogastroduodenoscopy in obstructive sleep apnea patients

AIM

To investigate whether patients with obstructive sleep apnea (OSA) are at risk of sedation-related complications during diagnostic esophagogastroduodenoscopy (EGD).

METHODS

A prospective study was performed in consecutive patients with OSA, who were confirmed with full-night polysomnography between July 2010 and April 2011. The occurrence of cardiopulmonary complications related to sedation during diagnostic EGD was compared between OSA and control groups.

RESULTS

During the study period, 31 patients with OSA and 65 controls were enrolled. Compared with the control group, a higher dosage of midazolam was administered (P = 0.000) and a higher proportion of deep sedation was performed (P = 0.024) in the OSA group. However, all adverse events, including sedation failure, paradoxical responses, snoring or apnea, hypoxia, hypotension, oxygen or flumazenil administration, and other adverse events were not different between the two groups (all P > 0.1). Patients with OSA were not predisposed to hypoxia with multivariate logistic regression analysis (P = 0.068).

CONCLUSION

In patients with OSA, this limited sized study did not disclose an increased risk of cardiopulmonary complications during diagnostic EGD under sedation.

Pre-existing diseases of patients increase susceptibility to hypoxemia during gastrointestinal endoscopy

Hypoxemia is the most common adverse event that happened during gastrointestinal endoscopy. To estimate risk of hypoxemia prior to endoscopy, American Society of Anesthesiology (ASA) classification scores were used as a major predictive factor. But the accuracy of ASA scores for predicting hypoxemia incidence was doubted here, considering that the classification system ignores much information about general health status and fitness of patient that may contribute to hypoxemia. In this retrospective review of clinical data collected prospectively, the data on 4904 procedures were analyzed. The Pearson’s chi-square test or the Fisher exact test was employed to analyze variance of categorical factors. Continuous variables were statistically evaluated using t-tests or Analysis of variance (ANOVA). As a result, only 245 (5.0%) of the enrolled 4904 patients were found to present hypoxemia during endoscopy. Multivariable logistic regressions revealed that independent risk factors for hypoxemia include high BMI (BMI 30 versus 20, Odd ratio: 1.52, 95% CI: 1.13–2.05; P = 0.0098), hypertension (Odd ratio: 2.28, 95% CI: 1.44–3.60; P = 0.0004), diabetes (Odd ratio: 2.37, 95% CI: 1.30–4.34; P = 0.005), gastrointestinal diseases (Odd ratio: 1.77, 95% CI: 1.21–2.60; P = 0.0033), heart diseases (Odd ratio: 1.97, 95% CI: 1.06–3.68; P = 0.0325) and the procedures that combined esophagogastroduodenoscopy (EGD) and colonoscopy (Odd ratio: 4.84, 95% CI: 1.61–15.51; P = 0.0292; EGD as reference). It is noteworthy that ASA classification scores were not included as an independent predictive factor, and susceptibility of youth to hypoxemia during endoscopy was as high as old subjects. In conclusion, some certain pre-existing diseases of patients were newly identified as independent risk factors for hypoxemia during GI endoscopy. High ASA scores are a confounding predictive factor of pre-existing diseases. We thus recommend that youth (≤18 yrs), obese patients and those patients with hypertension, diabetes, heart diseases, or GI diseases should be monitored closely during sedation endoscopy.

Safety and efficacy of ERCP after recent myocardial infarction or unstable angina

BACKGROUND

ERCP after myocardial infarction (MI) or unstable angina (UnA) can potentially entail significant cardiovascular risks.

OBJECTIVE

To analyze the safety of ERCP after MI or UnA.

DESIGN

Retrospective study.

PATIENTS

Adult patients less than 30 days after MI or UnA.

SETTING

Three hospitals from 1985 to 2010, encompassing 7600 ERCPs.

INTERVENTIONS

ERCP.

MAIN OUTCOME MEASUREMENTS

ERCP diagnosis, therapy, efficacy, and complications.

RESULTS

Thirteen patients (mean age 77.9 ± 11.4 years) underwent ERCP on average 6.9 ± 7.7 days after MI. ERCP indications were suspected choledocholithiasis/gallstone pancreatitis (n = 10); cholangitis (n = 7); obstructive jaundice with suspected pancreatic mass (n = 1); and biliary stent removal/replacement (n = 2). ERCP revealed choledocholithiasis (n = 8); previous stent (n = 2); and nonpathologic findings (n = 3). Therapies included balloon sweep (n = 11), sphincterotomy (n = 8), visible stones extracted by balloon sweep (n = 8), and biliary stent placement/replacement/removal (n = 3). Two mild complications occurred: hypotension during ERCP successfully treated with ephedrine and obstructing periampullary clot successfully removed at repeat ERCP. Eleven patients subsequently did well (mean hospital discharge 6.5 days after ERCP); 1 patient with metastatic ovarian cancer remained ventilator dependent, and another patient with multiple comorbidities had a fatal pulmonary embolus 10 days after ERCP. Six patients underwent ERCP 7.5 ± 5.2 days after UnA for suspected choledocholithiasis (n = 5) and bile duct injury (n = 1). ERCP findings included choledocholithiasis (n = 3), cystic duct leak (n = 1), ampullary stenosis (n = 1), and nonpathologic findings (n = 1). Sphincterotomy was performed in 5 patients, visible stones were extracted by balloon sweep in 3, and a biliary stent was inserted in 1. One mild complication occurred: hypotension during ERCP which was successfully treated with ephedrine. All 6 patients were discharged (mean 8.0 days after ERCP).

LIMITATIONS

Small study size; retrospective study.

CONCLUSIONS

This study suggests that therapeutic ERCP involves acceptable risks when performed soon after MI or UnA for suspected choledocholithiasis or other therapeutic indications and may be performed in such situations when strongly indicated.

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.

The utility of upper endoscopy in patients with concomitant upper gastrointestinal bleeding and acute myocardial infarction

Patients who present with upper gastrointestinal bleeding (UGIB) in the setting of acute myocardial infarction (AMI) may have suffered an UGIB that subsequently led to an AMI or endured an AMI and subsequently suffered a UGIB as a consequence of anticoagulation. We hypothesized that patients in the former group bled from more severe upper tract lesions. The aim of this study was to evaluate predictors for endoscopic therapy in patients who suffer a concomitant UGIB and AMI. Retrospective, single center medical record abstraction of hospital admissions from January 1, 1996-December 31, 2002. During the study period, 183 patients underwent an esophagogastroduodenoscopy (EGD) within 7 days of suffering an AMI and UGIB (AMI group N=105, UGIB group N=78). A higher proportion of patients in the UGIB group (41%) was found to have high-risk UGI lesions requiring endoscopic treatment compared to patients in the AMI group (17%; P < 0.004). UGIB as the inciting event and patients suffering from hematemesis and hemodynamic instability were significantly associated with requiring endoscopic therapy. Although predominantly diagnostic, endoscopic findings in the AMI group did alter the decision to perform cardiac catheterization in 43% of patients. Severe complications occurred in 1% (95% confidence interval, 0%-4%) of patients. We conclude that in patients suffering from concomitant UGIB and AMI, urgent endoscopy was most beneficial in patients with UGIB as the initial event and those presenting with hematemesis and hemodynamic instability. In patients without these clinical features, urgent endoscopy may be delayed, unless cardiac management decisions are dependent on endoscopic findings.

Oxygen desaturation during oesophageal manometry

Eighteen generally fit clinical patients were monitored with pulse oximetry. Mean oxygen saturation levels were lower (P<0.05) during oesophageal manometry (97.7-97.3%) than before it (98.3%). Fourteen out of seventeen (successful) traces had short 4-8% desaturation episodes, and in worst cases there were 8-9 episodes. It seems, therefore, that even patients with no predisposing factors than perhaps smoking and mild bronchial asthma are vulnerable to some oxygen desaturation in oesophageal manometry.

Predictive factors of oxygen desaturation during upper gastrointestinal endoscopy in nonsedated patients

BACKGROUND

Hypoxemia can occur during upper gastrointestinal endoscopy with or without pharmacologic sedation. We investigated possible predictive factors of severe oxygen desaturation (SaO2 < 90%) in nonsedated patients undergoing endoscopy.

METHODS

A total of 481 patients who underwent upper gastrointestinal endoscopy without sedation were monitored with continuous pulse oximetry. Multivariate logistic regression analysis was used to identify factors related to the patient, the examination, and the monitoring data that would predict severe desaturation.

RESULTS

Mild desaturation (SaO2 between 90% and 94%) was found in 23.7% of the patients, and severe desaturation (SaO2 < 90%) was found in 6.4%. The variables found to predict severe desaturation were basal SaO2 < 95% (odds ratio 67.7), respiratory disease (odds ratio 30.5), more than one attempt needed for intubation (odds ratio 39.4), emergency procedure (odds ratio 14.9), and American Society of Anesthesiologists score of III or IV (odds ratio 3.9).

CONCLUSIONS

The predictive variables analyzed in this study can be used to identify patients who are at increased risk for desaturation. Such patients require very close monitoring (pulse oximetry at a minimum). Endoscopists and assistants should be especially alert to the possibility of respiratory depression in these patients.

Factors influencing reflectance spectrophotometric measurements of gastrointestinal mucosal blood flow

Although the technique of endoscopic reflectance spectrophotometry has been applied in clinical studies, factors that modify the reproducibility of measurements have not been assessed systematically. To determine the limitations of the technique, measurements were made while endoscopic light intensity, systemic oxygen saturation, and orientation of the measuring probe were varied. The effects of hemorrhagic hypotension and exposure of the mucosa to 10% dextrose were also studied. When a large number (n = 480) of measurements in the human colon were considered, endoscopic light significantly decreased the index of oxygen saturation (ISO2) and increased the index of hemoglobin concentration (IHB). The decrease in ISO2, however, was small and unlikely to be of clinical importance despite being statistically significant. In one subject with chronic lung disease and baseline hypoxemia, administration of supplemental oxygen significantly increased oxygen saturation at the finger tip as measured by an oximeter and ISO2 of the buccal mucosa as measured by reflectance spectrophotometry. Varying the angle between the measuring probe and the gastric mucosa in rats from 90 degrees to 60 degrees did not affect ISO2 or IHB measurements. At 45 degrees, however, IHB but not ISO2 was significantly increased. Ischemia subsequent to induction of hemorrhagic hypotension and hyperemia induced by administration of 10% dextrose could be demonstrated reproducibly. We conclude that by lowering the intensity of endoscopic light and providing supplemental oxygen, errors in the measurement of IHB and ISO2, respectively, can be minimized. Minor deviations from the perpendicular orientation do not significantly affect ISO2 and IHB measurements. Attention to these details enhances the accuracy of endoscopic reflectance spectrophotometric recordings of ISO2 and IHB in clinical studies.

Evaluation of complications during and after conscious sedation for endoscopy using pulse oximetry

All events prolonging an endoscopic procedure or recovery, or requiring a medication or an intervention, were analyzed from a consecutive sample of 508 patients receiving conscious sedation. Although 102 events were identified (20%), 33 of these (7%) were major. These included four episodes of apnea and four patients with a prompt and sustained fall in oxygenation during the procedure; 19 additional patients had a decrease to less than 89% in oxygen saturation in the 30 minutes after the completion of the procedure. The patients with observed events had significantly more major illnesses, a higher fraction older than 70 years, and a higher fraction of endoscopic retrograde cholangiopancreatography than those without events (p < 0.05) but had a similar dose of sedative medications, mean age, and fraction of colonoscopies.

Carbon dioxide retention and oxygen desaturation during gastrointestinal endoscopy

BACKGROUND

Pulse oximetry measures arterial oxygen saturation (SpO2), not hypoventilation, which is directly reflected by increases in carbon dioxide tension.

METHODS

In the present study, transcutaneous carbon dioxide tension (PtcCO2) and SpO2 were measured during 101 endoscopic procedures selected for long duration or comorbid illnesses, and relationships between hypercapnia and hypoxemia were evaluated. Nasal oxygen was administered only for sustained desaturation (SpO2 < 90%).

RESULTS

Mean peak increase in PtcCO2 was significantly higher in patients requiring oxygen for sustained desaturation (16.3 mm Hg; range, 4-52) than in patients breathing room air who had transient or no desaturation (10.2 mm Hg [range, 3-19] and 5.1 mm Hg [range, 0-15]). If nasal oxygen corrected desaturation, even transient recurrence of desaturation indicated worsening CO2 retention, which preceded respiratory arrest in one patient. Independent predictors of hypercapnia were fentanyl and midazolam doses, oxygen requirement, and dementia.

CONCLUSIONS

Severe hypoventilation may occur during endoscopy, undetected by clinical observation or pulse oximetry, but only in sedated patients who require supplemental oxygen to maintain SpO2 above 90%. After oxygen supplementation corrects desaturation, recurrence of desaturation implies severe hypoventilation and warrants limitation of further sedation.

Fentanyl for sedation during upper gastrointestinal endoscopy

The effects of sedation by intravenous fentanyl on the rate-pressure product (pulse rate x systolic blood pressure/100), arterial oxygen saturation, electrocardiographic change, and serum cortisol concentration were studied during gastroduodenoscopy in 84 patients randomized to receive fentanyl or no intravenous sedative (controls). Fentanyl administration increased the tolerance of patients and attenuated the endoscopy-induced rise in rate-pressure product and serum cortisol concentration. Desaturation of arterial oxygen was minimal and there was no difference in arterial oxygen saturation between the fentanyl group and the control group. Therefore, fentanyl appears to be a favorable sedative for upper gastrointestinal endoscopy, since its administration increased the tolerance of patients and decreased cardiac oxygen consumption.

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

Elderly patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) have an increased risk of sedation related complications during the procedure. To determine whether nasal oxygen supplementation (2 l/min) reduces these risks, half of 66 patients aged over 60 undergoing ERCP using minimal midazolam sedation alone were randomised to receive nasal oxygen. The arterial oxygen saturation and pulse rate of all patients were monitored by pulse oximetry before and during the procedure. Only three patients in the oxygen supplemented group (n = 33) required any form of intervention for hypoxia compared with six in the control group (n = 33). Comparison of mean arterial oxygen saturation between the groups showed significantly higher levels in the nasal oxygen group throughout the procedure. Pulse rate comparisons showed no significant difference from control group values, both groups had short periods of significant tachycardia. We conclude that minimal sedation with midazolam alone still produces hypoxia during ERCP in a substantial number of elderly patients. Nasal oxygen supplementation increases the level of patient oxygenation and reduces the need for intervention, but does not reduce tachycardia in the elderly patient. Because hyoscine may be a significant factor contributing to the tachycardia, sparing rather than routine use of this agent is advisable.

Supplemental low flow oxygen prevents hypoxia during endoscopic cholangiopancreatography

Administration of continuous oxygen during ERCP may prevent hypoxia. Oxygen saturation was recorded using pulse oximetry in 50 consecutive patients undergoing ERCP. Patients were randomly allocated to receive no oxygen or low flow oxygen (2 liters/min) via nasal prongs or nasopharyngeal cannula. Oxygen saturation fell below 90% in 47% of patients not receiving oxygen compared with 0% in those administered oxygen (p less than 0.001). No difference existed in oxygen saturations between those groups receiving supplemental oxygen via nasal prongs or nasopharyngeal cannula. Continuous administration of low flow oxygen is recommended during ERCP.

Monitoring and safety in endoscopy

Over 50% of the complications and 60% of the deaths associated with upper GI endoscopy are cardiopulmonary in type. Oxygen desaturation and cardiac arrhythmias at the time of endoscopy are common. Ways of trying to prevent hypoxia occurring are discussed. The most effective of these is the use of supplemental oxygen. Pulse oximeters are being used increasingly frequently by endoscopists. The way in which oximeters work is described in some depth, as are some of the potential errors that may result from their use. The author believes that, as in anaesthetic practice, pulse oximeters will be used ever more frequently by endoscopists and finally become standard equipment in all endoscopy units. The case for using continuous ECG monitoring and blood pressure measurement is briefly discussed. The ASGE have recently published their recommendations on monitoring patients undergoing GI endoscopic procedures. The BSG's own working party on safety and monitoring is in the process of finalizing its recommendations, and the final part of the chapter discusses the views of this working party and gives some insight into what its final recommendations are likely to be.