Practice patterns of sedation for colonoscopy

Remimazolam versus propofol for sedation in gastrointestinal endoscopic procedures: a systematic review and meta-analysis

BACKGROUND

Propofol has a favourable efficacy profile in gastrointestinal endoscopic procedures, however adverse events remain frequent. Emerging evidence supports remimazolam use in gastrointestinal endoscopy. This systematic review and meta-analysis compares remimazolam and propofol, both combined with a short-acting opioid, for sedation of adults in gastrointestinal endoscopy.

METHODS

We searched MEDLINE, Embase, and Cochrane databases for randomised controlled trials comparing efficacy-, safety-, and satisfaction-related outcomes between remimazolam and propofol, both combined with short-acting opioids, for sedation of adults undergoing gastrointestinal endoscopy. We performed sensitivity analyses, subgroup assessments by type of short-acting opioid used and age range, and meta-regression analysis using mean patient age as a covariate. We used R statistical software for statistical analyses.

RESULTS

We included 15 trials (4516 subjects). Remimazolam was associated with a significantly lower sedation success rate (risk ratio [RR] 0.991; 95% confidence interval [CI] 0.984-0.998; high-quality evidence) and a slightly longer induction time (mean difference [MD] 9 s; 95% CI 4-13; moderate-quality evidence), whereas there was no significant difference between the sedatives in other time-related outcomes. Remimazolam was associated with significantly lower rates of respiratory depression (RR 0.41; 95% CI 0.30-0.56; high-quality evidence), hypotension (RR 0.43; 95% CI 0.35-0.51; moderate-quality evidence), hypotension requiring treatment (RR 0.25; 95% CI 0.12-0.52; high-quality evidence), and bradycardia (RR 0.42; 95% CI 0.30-0.58; high-quality evidence). There was no difference in patient (MD 0.41; 95% CI -0.07 to 0.89; moderate-quality evidence) and endoscopist satisfaction (MD -0.31; 95% CI -0.65 to 0.04; high-quality evidence) between both drugs.

CONCLUSIONS

Remimazolam has clinically similar efficacy and greater safety when compared with propofol for sedation in gastrointestinal endoscopies.

Propofol sedation does not improve measures of colonoscopy quality but increase cost - findings from a large population-based cohort study

Background

Propofol is often used for sedation during colonoscopy. We assessed the impact of propofol sedation on colonoscopy related quality metrics and cost in a population-based cohort study.

Methods

All colonoscopies performed at 21 hospitals in the province of Ontario, Canada, during an 18-month period, from April 1, 2017 to October 31, 2018, using either propofol or conscious sedation were evaluated. The primary outcome was adenoma detection rate (ADR) and secondary outcomes were sessile serrated polyp detection rate (ssPDR), polyp detection rate (PDR), cecal intubation rate (CIR), and perforation rate. Binary outcomes were assessed using a modified Poisson regression model adjusted for clustering and potential confounders based on patient, procedure, and physician characteristics.

Findings

A total of 46,634 colonoscopies were performed, of which 16,408 (35.2%) received propofol and 30,226 (64.8%) received conscious sedation. Compared to conscious sedation, the use of propofol was associated with a lower ADR (24.6% vs. 27.0%, p < 0.0001) but not ssPDR (5.0% vs. 4.7%, p = 0.26), PDR (40.5% vs 40.4%, p = 0.79), CIR (97.1% vs. 96.8%, p = 0.15) or perforation rate (0.04% vs. 0.06%, p = 0.45). On multi-variable analysis, propofol sedation was not associated with any differences in ADR (RR = 0.90, 95% CI 0.74-1.10, p = 0.30), ssPDR (RR = 1.20, 95% CI 0.90-1.60, p = 0.22), PDR (RR = 1.00, 95% CI 0.90-1.11, p = 0.99), or CIR (RR = 1.00, 95% CI 0.80-1.26, p = 0.99). The additional cost associated with propofol sedation was $12,730,496 for every 100,000 cases.

Interpretation

The use of propofol sedation was not associated with improved colonoscopy related quality metrics but increased costs. The routine use of propofol for colonoscopy should be reevaluated.

Funding

None.

The role of endoscopist adenoma detection rate in in sex differences in colonoscopy findings: cross-sectional analysis of the SCREESCO randomized controlled trial

BACKGROUND

Fewer adenomas are detected at colonoscopy in women compared to men and failure to detect adenomas and sessile serrated polyps is associated with an increased risk of post-colonoscopy colorectal cancer. The aim of this study was to investigate whether this was in part due to the greater difficulty of conducting colonoscopy in women, with the difference being more apparent in colonoscopies conducted by less skilled endoscopists.

MATERIAL AND METHODS

Cross-sectional exploratory analysis of data on 16,551 individuals undergoing a primary colonoscopy (PCOL group) or colonoscopy after positive faecal immunochemical test (FIT group) within the randomized controlled trial SCREESCO. Endoscopist adenoma detection rate (ADR; low or high) was determined based on each endoscopist's colonoscopies performed in SCREESCO. In each study group, the relationship between the sex difference in colonoscopy outcome and endoscopist ADR was assessed using multiplicative interaction tests.

RESULTS

Endoscopists performed equally many colonoscopies in men and women (median 52% men). There were no signs of effect modification of the risk ratio of any finding (men vs women) by endoscopist ADR in the PCOL group (p = 0.33) or the FIT group (p = 0.30). The proportion of incomplete index colonoscopies was lower in men than in women in both groups and there was no effect modification by endoscopist ADR in either the PCOL group (p = 0.41) or the FIT group (p = 0.96).

CONCLUSIONS

This study provides no evidence that endoscopist skill measured by ADR underlies the sex difference in adenoma detection at colonoscopy. This study has trial number NCT02078804 and is registered with ClinicalTrials.gov.

Baseline Cannabinoid Use Is Associated with Increased Sedation Requirements for Outpatient Endoscopy

Background and Aims: Given the underlying properties of cannabinoids, we aimed to assess associations between cannabinoid use and sedation requirements for esophagogastroduodenoscopy (EGD) and colonoscopy. Methods: A prospective cohort study was conducted at three endoscopy units. Adult outpatients undergoing EGD or colonoscopy with endoscopist-directed conscious sedation (EDCS) were given questionnaires on cannabinoid use and relevant parameters. Outcomes included intraprocedural midazolam, fentanyl, and diphenhydramine use, procedural tolerability, and adverse events. Multivariable logistic regression was performed to yield adjusted odds ratios (AORs) of outcomes. Results: A total of 419 patients were included. Baseline cannabinoid use was associated with high midazolam use, defined as ≥5 mg, during EGD (AOR 2.89, 95% confidence interval, CI: 1.19-7.50), but not during colonoscopy (AOR 0.89, 95% CI 0.41-1.91). Baseline cannabinoid use was associated with the administration of any diphenhydramine during EGD (AOR 3.04, 95% CI: 1.29-7.30) with a similar nonsignificant trend for colonoscopy (AOR 2.36, 95% CI: 0.81-7.04). Baseline cannabinoid use was associated with increased odds of requiring high total sedation, defined as any of midazolam ≥5 mg, fentanyl ≥100 mcg, or any diphenhydramine during EGD (AOR 3.72, 95% CI: 1.35-11.68). Cannabinoid use was not independently associated with fentanyl use, intraprocedural awareness, discomfort, or adverse events. Conclusions: Baseline cannabinoid use was associated with higher sedation use during endoscopy with EDCS, particularly with midazolam and diphenhydramine. Given increasingly widespread cannabinoid use, endoscopists should be equipped with optimal sedation strategies for this population. As part of the informed consent process, cannabis users should be counseled that they may require higher sedation doses to achieve the same effect.

The Efficacy and Safety of Remimazolam Besylate Combined with Esketamine for Outpatient Colonoscopy: A Prospective, Randomized, Controlled Clinical Trial

Purpose

Evaluate the efficacy and safety of remimazolam besylate combined with esketamine for outpatient colonoscopy.

Patients and methods

A total of 150 outpatients undergoing colonoscopy were randomized into two groups. A MOAA/S score ≤3 was maintained. The primary outcome was the rate of successful colonoscopy completion. Time indicators, hemodynamic parameters, the consumption of lidocaine, esketamine, propofol and remimazolam besylate, MOAA/S scores and bispectral index (BIS) values, the lowest SpO2, body movement, the use of rescue medication, endoscopist and patient satisfaction, recall of the procedure, mini-mental state examination (MMSE), fatigue level and adverse events were recorded.

Results

Procedure completion was equivalent between groups (P > 0.05). Both induction and awakening times were significantly shorter in the P group (P < 0.05). There were no significant differences in colonoscopy time and discharge time (P > 0.05). The lowest SpO2 was significantly lower in the P group, while the level of fatigue was higher (P < 0.05). Patient satisfaction was significantly higher in the R group (P < 0.05). Endoscopist satisfaction was significantly higher in the P group (P < 0.05). There were no significant differences in both systolic and diastolic blood pressure between groups except at T5 and T6 (P > 0.05). Both HR and RR were significantly lower in the P group from T3 to T5 (P < 0.05). BIS values were significantly lower in the P group from T3 to T5, while MOAA/S was significantly lower in the P group at T3 and T4 (P < 0.05). Pain on injection was significantly higher in the P group (P < 0.05).

Conclusion

Remimazolam besylate has a similar efficacy to propofol when combined with subanesthetic doses of esketamine during outpatient colonoscopy. Remimazolam besylate combined with esketamine resulted in less injection pain and more stable hemodynamics, although it prolonged induction and awakening time.

Advances in Analgosedation and Periprocedural Care for Gastrointestinal Endoscopy

The number and complexity of endoscopic gastrointestinal diagnostic and therapeutic procedures is globally increasing. Procedural analgosedation during gastrointestinal endoscopic procedures has become the gold standard of gastrointestinal endoscopies. Patient satisfaction and safety are important for the quality of the technique. Currently there are no uniform sedation guidelines and protocols for specific gastrointestinal endoscopic procedures, and there are several challenges surrounding the choice of an appropriate analgosedation technique. These include categories of patients, choice of drug, appropriate monitoring, and medical staff providing the service. The ideal analgosedation technique should enable the satisfaction of the patient, their maximum safety and, at the same time, cost-effectiveness. Although propofol is the gold standard and the most used general anesthetic for endoscopies, its use is not without risks such as pain at the injection site, respiratory depression, and hypotension. New studies are looking for alternatives to propofol, and drugs like remimazolam and ciprofol are in the focus of researchers' interest. New monitoring techniques are also associated with them. The optimal technique of analgosedation should provide good analgesia and sedation, fast recovery, comfort for the endoscopist, patients' safety, and will have financial benefits. The future will show whether these new drugs have succeeded in these goals.

Effect of visual distraction on pain in adults undergoing colonoscopy: a meta-analysis

BACKGROUND

Pain is a contributing factor to the low compliance rate for performing a colonoscopy on screening for colorectal cancer.

PURPOSE

This meta-analysis aimed to evaluate the effect of visual distraction on adults undergoing colonoscopy.

METHODS

We searched PubMed, EMBASE, Web of Science, and Cochrane Library Database from their inception to February 2022. Randomized controlled trials comparing visual distraction with non-visual distraction were considered for inclusion. The fixed-effects and random-effects models were used to pool the data from individual studies and the Cochrane risk of bias assessment tool was used to determine the methodology quality.

RESULTS

This meta-analysis included four studies (N = 301) for pain level and total procedure time, three studies (N = 181) for satisfaction score, three studies (N = 196) for anxiety level, and four studie (N = 402) for willingness to repeat the procedure. The pooled analysis shown that significantly lower pain levels (SMD, - 0.25; 95% CI - 0.47 to - 0.02; P = 0.03), higher satisfaction score with the procedure (SMD, 0.63; 95% CI, 0.33 to 0.93; P < 0.0001), and higher willingness to repeat the procedure (OR, 2.66; 95% CI 1.70 to 4.17; P < 0.0001) in the visual distraction group than those in the non-visual distraction group, with no significant differences in total procedure time (SMD,- 0.07; 95% CI - 0.30 to 0.15; P = 0.53) or anxiety level (SMD,- 0.27; 95% CI - 0.55 to 0.01; P = 0.06).

CONCLUSIONS

Visual distraction improved the patient's pain, satisfaction, and willingness to repeat the procedure. Thus, visual stimulation is an effective way to reduce pain during colonoscopy and should be recommended.

Efficacy and safety of midazolam combined with dezocine for sedation and analgesia in digestive endoscopy: A prospective open single-center study

Objective: Digestive endoscopy is an important means of diagnosing and treating gastrointestinal diseases and a tool for screening and monitoring early gastrointestinal tumors. Digestive endoscopy can be performed using midazolam combined with dezocine for sedation and analgesia. This study explored the efficacy and safety of midazolam combined with dezocine. Methods: A total of 135 patients undergoing digestive endoscopy in the Department of Gastrointestinal Endoscopy of the Sixth Affiliated Hospital, Sun Yat-sen University, from June 2021 to September 2021, were enrolled and non-blindly and non-randomly divided into a sedation-endoscopy-group (SEG, n = 45), anesthesia-endoscopy-group (AEG, n = 44), and ordinary-endoscopy-group (OEG, n = 46). Vital signs, levels of sedation and analgesia, the degree of pain during colonoscopy, satisfaction, and the incidence of complications were compared among the three groups. Results: There were no statistically significant differences in vital signs (blood pressure, pulse, respiration, and blood oxygen saturation) among the three groups before endoscopy (p > 0.05). The AEG reported no pain during colonoscopy, and the pain score during colonoscopy for the SEG was lower than that for the OEG (1.11 ± 1.21 vs. 3.00 ± 1.16, p < 0.001). The scores for satisfaction were 8.84 ± 1.30 points in the SEG, 8.95 ± 1.10 points in the AEG, and 6.37 ± 0.90 points in the OEG; the differences were statistically significant (p < 0.001). The total incidence of complications in the AEG was 38.64% (17/44), which was significantly higher than that in the SEG [13.33% (6/45)] and OEG [13.04% (6/46)] (p < 0.001). In the SEG, the overall incidence of complications in women was significantly higher than that in men (p = 0.027). Conclusion: Digestive endoscopy using midazolam combined with dezocine for sedation makes patients more comfortable, more satisfied and more compliant than the ordinary endoscopy. Additionally, it is comparable to endoscopy under general anesthesia with propofol with regard to comfort, satisfaction, and patient compliance and comparable to the ordinary endoscopy with regard to safety. Considering the shortage of anesthesiologists, the application of midazolam combined with dezocine in digestive endoscopy is worthy of clinical popularization. This study has been registered in the Hospital Ethics Committee of the Sun Yat-sen University Sixth Affiliated Hospital (Ethical Number: 2021ZSLYEC-182).

Sedative effect of remimazolam combined with alfentanil in colonoscopic polypectomy: a prospective, randomized, controlled clinical trial

Background

Remimazolam is a newer benzodiazepine with properties of rapid onset, short duration of action, and fast recovery. Our study was to evaluate the effects of different doses of remimazolam combined with alfentanil in colonoscopic polypectomy.

Methods

One hundred twenty patients were randomly divided into four groups: alfentanil and propofol (AP) group, alfentanil and remimazolam 0.1 mg/kg (AR1 group), 0.15 mg/kg (AR2 group), or 0.2 mg/kg (AR3 group). Patients in the four groups received alfentanil 10 μg/kg, followed by propofol 2 mg/kg and three dosages of remimazolam. Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scale, heart rate (HR), oxygen saturation (SpO₂), respiratory rate (RR), bispectral index (BIS) values and mean arterial pressure (MAP) were collected at intervals of 5 min and analyzed at different time points: before anesthesia (T0), 5 min (T1), 10 min (T2), 15 min after anesthesia (T3) and at the end of surgery (T4). The average MAP was calculated utilizing the average of all MAP values. The primary outcome was the success rate of sedation. Secondary outcomes included time to full alert and adverse events.

Results

The success rate of sedation was 100% among the four groups. The incidence of hypotension was significantly decreased (all P < 0.05) and the average MAP was higher in AR1-AR3 groups than AP group (all P < 0.001). None of the patients developed bradycardia or hypertension during surgery in all study groups. BIS values were higher (all P < 0.001) and the time to full alert was statistically shorter in AR1-AR3 groups (all P < 0.05) compared with the AP group. The MOAA/S score in AR1 was higher than AR2 (P < 0.05) and the AR3 group (P < 0.05) at T1 and BIS values in the AR1 group were significantly higher than AR3 group (P < 0.05) at T4.

Conclusions

Remimazolam combined with alfentanil have a non-inferior sedative effect than propofol during the colonoscopic polypectomy. Moreover, this combination of two short-acting drugs might be a safer alternative.

Trial registration

The clinical trial was registered on (16/05/2021, ChiCTR2100046492).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01805-3.

Pre-procedural Preparation and Sedation for Gastrointestinal Endoscopy in Patients with Advanced Liver Disease

Gastrointestinal endoscopy in patients with advanced liver disease poses various challenges, a major one being procedural sedation and its associated considerations. While sedation during endoscopy can improve patient comfort, decrease anxiety, and facilitate procedural completion, in patients with advanced liver disease, it is also associated with substantial and unique risks due to alterations in drug metabolism and other factors. As such, the choice of sedative agent(s) and related logistics may require careful inter-disciplinary planning and individualized considerations. Furthermore, a large proportion of agents require dose reductions and particular monitoring of the vital signs, level of consciousness, and other indices. In the present review, we provide a contemporary overview of procedural sedation considerations, commonly used intravenous sedatives, and second-line as well as novel sedatives for gastrointestinal endoscopy in patients with advanced liver disease.

Comparison of ciprofol (HSK3486) versus propofol for the induction of deep sedation during gastroscopy and colonoscopy procedures: A multi-centre, non-inferiority, randomized, controlled phase 3 clinical trial

Ciprofol is a propofol analogue with improved pharmacokinetic properties. A multi‐centre, non‐inferiority trial was conducted to compare the deep sedation properties of ciprofol and propofol with a non‐inferiority margin of 8% in patients undergoing gastroscopy and colonoscopy. In total, 289 patients were randomly allocated for surgery (259 colonoscopy and 30 gastroscopy) at a 1:1 ratio to be given intravenous injections of ciprofol (0.4 mg/kg) or propofol (1.5 mg/kg). The primary outcome was the success rate of colonoscopy defined as colonoscopy completion with no need for an alternative sedative or >5 ciprofol or propofol top up doses within any 15‐min time period. The success rate of colonoscopy was 100% in the ciprofol group vs. 99.2% in the propofol group (mean difference 0.8%, 95% CI: −2.2% to 4.2%). Except for the gastrointestinal lesions found during the gastroscopy and colonoscopy procedures, the occurrence rates of adverse drug reactions in the ciprofol and propofol groups were 31.3% and 62.8%, respectively (P < 0.001). Pain on injection was less common in the ciprofol group (4.9% vs. 52.4%, P < 0.001). The outcomes demonstrated that ciprofol was non‐inferior to propofol with regard to successful sedation for gastroscopy or colonoscopy procedures and no obvious important adverse events occurred.

Gender Differences in Colonoscopy: Implications for Clinical Practice and Female Gastroenterologists

BACKGROUND AND AIMS

Performing colonoscopy can be technically challenging in female patients. Female patients may prefer having a female endoscopist. This preference, coupled with the fact that there are fewer female endoscopists, may result in gender differences in colonoscopy practice. We hypothesized that the duration of female colonoscopy is longer and that female endoscopists perform a higher proportion of female colonoscopy than male colleagues. We explored the potential revenue implications of gender differences in screening colonoscopy.

METHODS

We analyzed procedure time and gender differences in 16,573 screening colonoscopies performed by 27 male and 7 female endoscopists over a three-year period in one large academic practice. We modeled the potential revenue impacts of differences in procedure duration, proportion of female colonoscopy and the frequency of detected adenomas.

RESULTS

We found that screening colonoscopy takes 8.8% more time to complete in female patients compared to male patients for all endoscopists (p < 0.001), and that female endoscopists perform an average of 71.2% female exams compared to male endoscopists, who perform an average of 50.8% female exams (p < 0.001). Female patients had a lower detection adenoma rate (ADR), reducing the frequency of polypectomy and reimbursement in an RVU model. The observed gender differences could account for an estimated 9.6% revenue loss per 8-h session for a female gastroenterologist performing screening colonoscopy compared to a male counterpart.

CONCLUSION

Longer colonoscopy duration in females, increased proportion of female colonoscopies for female endoscopists and lower ADR in females may contribute to the gender gap in physician pay in gastroenterology.

Thoughts on factors related to colonoscopy quality

With the increase in health consciousness and the prevalence of early gastrointestinal cancer screening, the number of diagnosed cases of colorectal polyps and adenomas in the Chinese general population has substantially increased. However, the overall adenoma detection rate (ADR) in China remains lower than the global standard of 30%. High quality colonoscopy is pivotal for increasing the ADR and reducing the risk of interval colon cancer. A few factors are related to the quality of colonoscopy, including preoperative evaluation of examinees, bowel preparation, techniques for intubation, use of image enhancement endoscopy, withdraw time, and prevention of adverse events.

Effects of transcutaneous electrical acupuncture point stimulation on peripheral capillary oxygen saturation in elderly patients undergoing colonoscopy with sedation: a prospective randomized controlled trial

INTRODUCTION

This study investigated whether transcutaneous electrical acupuncture point stimulation (TEAS) at PC6 can reduce the proportion of elderly patients experiencing a drop of ⩾4% in peripheral capillary oxygen saturation (SpO₂) while undergoing colonoscopy under sedation.

METHODS

A total of 32 elderly patients (aged ⩾ 65 years) scheduled for colonoscopy were randomly assigned in a 1:1 ratio to receive either real or sham TEAS (treatment or control groups, respectively). Each patient received oxygen (2 L/min) delivered routinely via nasal cannula. The treatment group was given TEAS at PC6 for 20 min at 2 Hz frequency and 6 mA intensity; the control group underwent the same procedures but with zero frequency/intensity. SpO₂ and other physiological parameters were measured prior to sedation and colonoscopy (baseline) and at seven other timepoints through departure from recovery. Depth of anesthesia was measured using a Narcotrend monitor.

RESULTS

Significantly fewer patients in the treatment group experienced a ⩾4% decrease from baseline SpO₂ (2/16) than patients in the control group (10/16; p = 0.004). The two groups were comparable with regard to respiratory rate, systolic and diastolic blood pressures, mean arterial pressure, and heart rate.

CONCLUSION

TEAS applied at PC6 with 2 Hz frequency was feasible and may be helpful in reducing the rate of hypoxia in elderly patients during colonoscopy.Trial registration number: NCT03775122 (ClinicalTrials.gov).

Effect of Midazolam in Addition to Propofol and Opiate Sedation on the Quality of Recovery After Colonoscopy: A Randomized Clinical Trial

BACKGROUND

There is a concern that midazolam, when used as a component of sedation for colonoscopy, may impair cognition and prolong recovery. We aimed to identify whether midazolam produced short- and longer-term effects on multiple dimensions of recovery including cognition.

METHODS

A 2-center double-blinded, placebo-controlled, parallel-group, randomized, phase IV study with a 1:1 allocation ratio was conducted in adults ≥18 years of age undergoing elective outpatient colonoscopy, with sufficient English language proficiency to complete the Postoperative Quality of Recovery Scale (PostopQRS). Participants were administered either midazolam (0.04 mg·kg) or an equivalent volume of 0.9% saline before sedation with propofol with or without an opiate. The primary outcome was incidence of recovery in the cognitive domain of the PostopQRS on day 3 after colonoscopy, which was analyzed using a χ test. Secondary outcomes included recovery in other domains of the PostopQRS over time, time to eye-opening, and hospital stay, and patient and endoscopist satisfaction. All hypotheses were defined before recruitment.

RESULTS

During September 2015 to June 2018, 406 patients were allocated to either midazolam (n = 201) or placebo (n = 205), with one withdrawn before allocation. There was no significant difference in recovery in the cognitive domain of the PostopQRS on day 3 after colonoscopy (midazolam 86.8% vs placebo 88.7%, odds ratio, 0.838; 95% confidence interval [CI], 0.42-1.683; P= .625). Furthermore, there was no difference in recovery over time in the cognitive domain of the PostopQRS (P = .534). Overall recovery of the PostopQRS increased over time but was not different between groups. Furthermore, there were no differences between groups for nociceptive, emotive, activities-of-daily-living domains of the PostopQRS. Patient and endoscopist satisfaction were high and not different. There were no differences in time to eye-opening (midazolam 9.4 ± 12.8 minutes vs placebo 7.3 ± 0.7 minutes; P = .055), or time to hospital discharge (midazolam 103.4 ± 1.4 minutes vs placebo 98.4 ± 37.0 minutes; P = .516).

CONCLUSIONS

The addition of midazolam 0.04 mg·kg as adjunct to propofol and opiate sedation for elective colonoscopy did not show evidence of any significant differences in recovery in the cognitive domain of the PostopQRS, overall quality of recovery as measured by the PostopQRS, or emergence and hospital discharge times. The use of midazolam should be determined by the anesthesiologist.

Comparison of Fentanyl versus Meperidine in Combination with Midazolam for Sedative Colonoscopy in Korea

Background/Aims

Combination of midazolam and opioids is used widely for endoscopic sedation. Compared with meperidine, fentanyl is reportedly associated with rapid recovery, turnover rate of endoscopy room, and quality of endoscopy. We compared fentanyl with meperidine when combined with midazolam for sedative colonoscopy.

Methods

A retrospective, cross-sectional, 1:2 matching study was conducted. Induction and recovery time were compared as the primary outcomes. Moreover, cecal intubation time, withdrawal time, total procedure time of colonoscopy, paradoxical reaction, adenoma detection rate, and adverse effect of midazolam or opioids were assessed as the secondary outcomes.

Results

A total of 129 subjects (43 fentanyl vs. 86 meperidine) were included in the analysis. The fentanyl group showed significantly more rapid induction time (4.5±2.7 min vs. 7.5±4.7 min, p<0.001), but longer recovery time (59.5±25.6 min vs. 50.3±10.9 min, p=0.030) than the meperidine group. In multivariate analysis, the induction time of the fentanyl group was 3.40 min faster (p<0.001), but the recovery time was 6.38 min longer (p=0.046) than that of the meperidine group. There was no difference in withdrawal time and adenoma detection rate between the two groups.

Conclusions

The fentanyl group had more rapid sedation induction time but longer recovery time than the meperidine group.

Propofol versus midazolam with or without short-acting opioids for sedation in colonoscopy: a systematic review and meta-analysis of safety, satisfaction, and efficiency outcomes

BACKGROUND AND AIMS

Propofol is increasingly being used for sedation in colonoscopy; however, its benefits over midazolam (± short-acting opioids) are not well quantified. The objective of this study was to compare safety, satisfaction, and efficiency outcomes of propofol versus midazolam (± short-acting opioids) in patients undergoing colonoscopy.

METHODS

We systematically searched Medline, Embase, and the Cochrane library (to July 30, 2018) for randomized controlled trials of colonoscopies performed with propofol versus midazolam (± short-acting opioids). We pooled odds ratios for cardiorespiratory outcomes using mixed-effects conditional logistic models. We pooled standardized mean differences (SMDs) for patient and endoscopist satisfaction and efficiency outcomes using random-effects models.

RESULTS

Nine studies of 1427 patients met the inclusion criteria. There were no significant differences in cardiorespiratory outcomes (hypotension, hypoxia, bradycardia) between sedative groups. Patient satisfaction was high in both groups, with most patients reporting willingness to undergo a future colonoscopy with the same sedative regimen. In the meta-analysis, patients sedated with propofol had greater satisfaction than those sedated with midazolam (± short-acting opioids) (SMD, .54; 95% confidence interval [CI], .30-.79); however, there was considerable heterogeneity. Procedure time was similar between groups (SMD, .15; 95% CI, .04-.27), but recovery time was shorter in the propofol group (SMD, .41; 95% CI, .08-.74). The median difference in recovery time was 3 minutes, 6 seconds shorter in patients sedated with propofol.

CONCLUSIONS

Both propofol and midazolam (± short-acting opioids) result in high patient satisfaction and appear to be safe for use in colonoscopy. The marginal benefits to propofol are small improvements in satisfaction and recovery time.

Predictors of Failed Conscious Sedation in Patients Undergoing an Outpatient Colonoscopy and Implications for the Adenoma Detection Rate

Guidelines to triage patients to conscious sedation (CS) or monitored anaesthesia care (MAC) for colonoscopy do not exist. We aimed to identify the CS failure rate, predictors of failure, and its impact on the adenoma detection rate (ADR). Strict (based on patient experience) and expanded (based on doses of sedative medications) definitions of CS failure were used. Patient and procedure-related variables were extracted. Multivariable logistic regression identified predictors for CS failure and the ADR. Among 766 patients, 29 (3.8%) and 175 (22.8%) patients failed CS by strict and expanded definitions, respectively. Female gender (OR 3.50; 95% CI: 1.37–8.94) and fellow involvement (OR 4.15; 95% CI: 1.79–9.58) were associated with failed CS by the strict definition. Younger age (OR 1.27, 95% CI: 1.07–1.49), outpatient opiate use (OR 1.71; 95% CI 1.03–2.84), use of an adjunct medication (OR 3.34; 95% CI: 1.94–5.73), and fellow involvement (OR 2.20; 95% CI: 1.31–3.71) were associated with failed CS by the expanded definition. Patients meeting strict failure criteria had a lower ADR (OR 0.30; 95% CI: 0.12–0.77). Several clinical factors may be useful for triaging to MAC. The ADR is lower in patients meeting strict criteria for failed CS.

Feasibility of sedation on demand in Taiwan using water exchange and air insufflation: A randomized controlled trial

BACKGROUND AND AIM

Completion of colonoscopy without sedation eliminates sedation cost and complications. Reported in the United States and Europe, on-demand sedation is not routine practice in Taiwan. Water exchange (WE), characterized by infusion and nearly complete removal of infused water during insertion, reduces insertion pain compared to air insufflation (AI) during colonoscopy. We evaluated the feasibility of on-demand sedation in Taiwan. In a randomized controlled trial of WE vs AI colonoscopy, we also aimed to determine if WE augmented the implementation by reducing insertion pain and decreasing sedation requirement.

METHODS

This prospective patient-blinded study randomized patients to AI or WE (75 patients/group) to aid insertion. The primary outcome was the proportion of patients completing without sedation.

RESULTS

In the AI and WE groups, 76.0% and 93.3% (P = 0.006) completed without need for sedation, respectively. The WE group had lower insertion pain score (mean [SD]) (4.0 [2.9] vs 2.1 [2.6], P < 0.001), lower doses of propofol (25.7 [52.7] mg vs 9.1 [35.6] mg, P = 0.012), and less time in the recovery room (3.4 [7.4] vs 1.5 [5.5], P = 0.027) than the AI group. Patient satisfaction scores and willingness to repeat if needed in the future were similar.

CONCLUSION

On-demand sedation was feasible in Taiwan. The completion rate without sedation was high in patients (76.0% with standard AI) open to the option (no prior intent to receive the standard of full or minimal sedation). WE augmented the implementation by reducing insertion pain and decreasing sedation requirement without adversely affecting patient satisfaction or willingness to repeat.

Factors Affecting Recovery Time after Sedation for Upper Gastrointestinal Endoscopy

The purpose of this study was to investigate factors affecting recovery time after sedation for upper gastrointestinal endoscopy. The study population included 1310 patients in the national gastric cancer screening program who received sedation for upper gastrointestinal endoscopy from April 15, 2015 to December 31, 2018. Multivariate regression analysis was performed to identify factors related to recovery time. The mean recovery time after examination was 51.2 minutes (SD=13.3). Patients with a history of hypertension had a recovery time 2.59 minutes shorter than that of patients without hypertension (p=0.006, Bonferroni-corrected p=0.108). Patients with a history of stroke had a recovery time 9.41 minutes longer than that of patients without stroke (p=0.007, Bonferroni-corrected p=0.124). Patients who received 3 mg midazolam had a recovery time 2.99 minutes longer than that of patients received 2 mg (p=0.001, Bonferroni-corrected p=0.010), and patients who received less than 6 cc of propofol had a recovery time 2.90 minutes longer than those that of patients received 7-12 cc of propofol (p<0.001, Bonferroni-corrected p=0.005). These results suggest that receiving high doses of midazolam and having a history of stroke are associated with longer recovery times. Patients meeting these criteria should be managed carefully after sedation for upper gastrointestinal endoscopy.

Factors Associated With Adenoma Detection in Propofol-sedated Patients

GOALS

To assess the factors associated with adenoma detection in propofol-sedated patients.

BACKGROUNDS

Low adenoma detection rate (ADR) are linked to increased risk of interval cancer and related deaths. Compared with air insufflation (AI) colonoscopy, the method of water exchange (WE) significantly decreased insertion pain and increased ADR in unsedated patients. Deep sedation with propofol has been increasingly used in colonoscopy. One report suggested that WE significantly increased ADR in propofol-sedated patients, but the factors associated with adenoma detection were not analyzed.

STUDY

Post hoc multiple logistic regression analyses were performed based on pooled data from 2 randomized controlled trials to assess the factors associated with adenoma detection in propofol-sedated patients.

RESULTS

Propofol-sedated patients (n=510) were randomized to AI and WE. The baseline characteristics were comparable. Multiple logistic regression analyses show that age, withdrawal time, indications (screening vs. diagnostic), and WE were significantly and independently associated with higher ADR. WE had fewer patients with inadequate Boston Bowel Preparation Scale score of <6. Despite a significantly shorter inspection time, WE had significantly higher overall ADR than AI, especially in those with adequate Boston Bowel Preparation Scale of ≥6. Right colon ADR (17.5% vs. 10.5%), flat ADR (32.3% vs. 19.4%), combined advanced and sessile serrated ADR (13.1% vs. 7.4%) of WE were significantly higher than those of AI.

CONCLUSIONS

WE enhanced quality of colonoscopy in propofol-sedated patients by significantly improving colon cleanliness and overall ADR. Colonoscopists with patients under propofol sedation might consider evaluating WE method for performance improvement.

Factors associated with polyp detection during colonoscopy: A retrospective observational study

The polyp detection rate (PDR) is an important quality indicator for colonoscopy. Several factors have been shown to be associated with PDR. However, whether the moderate sedation is a factor for polyp detection remains controversial. This study aims to assess factors associated with polyp detection including the moderate sedation factor during colonoscopy. Patients who underwent colonoscopy from June 1, 2014 to May 31, 2015 were enrolled into this retrospective study. Patients with poor colon preparation and failure to reach the cecum were excluded. The clinical factors, including patient's sex, age, midazolam/fentanyl sedation, indications, endoscopist colonoscopy volume, and use of antispasmodic agent were evaluated by multivariate analysis. A total of 3373 patients were included in this study. The mean age was 55.8 years, and 1980 patients (58.7%) were male. Among the 3373 patients, 2513 (74.5%) underwent midazolam/fentanyl-based sedated colonoscopy. The multivariate analysis showed that male sex, age over 50 years old, midazolam/fentanyl sedation and indications of screening and surveillance were significantly associated with polyp detection. Moreover, when stratified by sex and age, the midazolam/fentanyl sedation was associated with polyp detection in male patients and patients over 50 years old. This study has highlighted the role of midazolam/fentanyl sedation administered by colonoscopists as a modifiable factor that may increase polyp detection during colonoscopy.

Effects of Cannabis Use on Sedation Requirements for Endoscopic Procedures

CONTEXT

Cannabis (or marijuana) became legal for recreational use in Colorado in 2012, and this legislation change has created both challenges and opportunities in medicine. More patients are using cannabis, and more patients are now willing to admit cannabis use than in the past, which increases the likelihood that they will be forthcoming about use during medical questioning. Cannabis use may have implications during medical care, including procedural sedation.

OBJECTIVE

To determine whether regular cannabis use had any effect on the dose of medication needed for sedation during endoscopic procedures.

METHODS

A total of 250 medical records were reviewed from 1 endoscopy center and 1 endoscopist to minimize the variability in sedation technique for the study purposes. The cohort was reviewed with regard to age and gender to determine whether differences were present among different groups as to the relative amount of sedation medication required in cannabis users vs nonusers.

RESULTS

Medical records from 250 patients were reviewed, and researchers found that compared with people who did not regularly use cannabis, people who regularly used cannabis required an amount of sedation for endoscopic procedures that was significantly higher (P=.05). The statistical significance persisted when adjusted for age, sex, and use of alcohol, benzodiazepines, and opiates.

CONCLUSION

Determining cannabis use before procedural sedation can be an important tool for planning patient care and assessing both medication needs and possible risks related to increased dosage requirements during endoscopic procedures.

Water Exchange Produces Significantly Higher Adenoma Detection Rate Than Water Immersion: Pooled Data From 2 Multisite Randomized Controlled Trials

GOALS

To test the hypothesis that water exchange (WE) significantly increases adenoma detection rates (ADR) compared with water immersion (WI).

BACKGROUND

Low ADR was linked to increased risk for interval colorectal cancers and related deaths. Two recent randomized controlled trials of head-to-head comparison of WE, WI, and traditional air insufflation (AI) each showed that WE achieved significantly higher ADR than AI, but not WI. The data were pooled from these 2 studies to test the above hypothesis.

STUDY

Two trials (5 sites, 14 colonoscopists) that randomized 1875 patients 1:1:1 to AI, WI, or WE were pooled and analyzed with ADR as the primary outcome.

RESULTS

The ADR of AI (39.5%) and WI (42.4%) were comparable, significantly lower than that of WE (49.6%) (vs. AI P=0.001; vs. WI P=0.033). WE insertion time was 3 minutes longer than that of AI (P<0.001). WE showed significantly higher detection rate (vs. AI) of the >10 mm advanced adenomas. Right colon combined advanced and sessile serrated ADR of AI (3.4%) and WI (5%) were comparable and were significantly lower than that of WE (8.5%) (vs. AI P<0.001; vs. WI P=0.039).

CONCLUSIONS

Compared with AI and WI, the superior ADR of WE offsets the drawback of a significantly longer insertion time. For quality improvement focused on increasing adenoma detection, WE is preferred over WI. The hypothesis that WE could lower the risk of interval colorectal cancers and related deaths should be tested.

Providers' Perceptions of Barriers to Optimal Communication With Patients During the Postcolonoscopy Experience

INTRODUCTION

Colonoscopy screening is an effective method of detecting and preventing colorectal cancer. Standard procedure for most colonoscopies (98%) is to use conscious sedation, which can cause short-term cognitive impairment postprocedure, including communication difficulties. In this study, we explored providers' (gastroenterology doctors and nurses) perceptions of the barriers to optimal communication with patients immediately following colonoscopy.

METHODS

We conducted interviews with 61 providers across 5 clinical configurations. Interviews were transcribed and coded with NVivo version 11 software.

RESULTS

Themes emerged regarding barriers to optimal provider-patient communication postcolonoscopy: patient barriers (sedation and patient characteristics), caregiver barriers, and system characteristics.

CONCLUSIONS

Providers' perceived barriers to communication are an important topic to study. They endorsed, in particular, interventions that target the postcolonoscopy time frame when patients may still be sedated, but providers must convey important discharge and follow-up instructions.

Colonoscopy in the very elderly

INTRODUCTION

Colonoscopy is the gold standard test for investigating lower gastrointestinal symptoms and is an important therapeutic tool for colonic polypectomy. This paper is aimed at the general physician and examines the role of colonoscopy in very elderly patients by exploring the particular risks in this population, the yield of colonoscopy and potential alternative investigations.

SOURCES OF DATA

Original research and review articles were identified through selective PubMed searches. Guidelines were identified through interrogation of national and international society websites in addition to PubMed searches.

AREAS OF AGREEMENT

Advanced age alone is not a reason to avoid investigation. The decision to perform colonoscopy in this population must take into account indication and yield, risks of the procedure and bowel preparation, physical fitness of the patient, potential alternative and the ability to consent. As a general rule, the principle of 'first doing no harm' should be applied and requires balancing of the risks of the procedure and preparation with the benefits of doing the test.

AREAS OF CONTROVERSY

There is no defined upper age limit at which colonoscopy is contraindicated, however; the National Health Service Bowel Cancer Screening Programme stops inviting patients for screening and surveillance colonoscopy at age 75.

GROWING POINTS AND AREAS TIMELY FOR DEVELOPING RESEARCH

The concepts of 'first do no harm' and shared decision-making are not new but are increasingly important, particularly in this patient group. It is crucial to provide patients with information about risks, benefits and alternative investigations to empower their decision-making.

Changes in the Pharmacokinetics of Phenytoin in Dextran Sulfate Sodium–Induced Ulcerative Colitis in Mice

We previously demonstrated that the expression levels of drug-metabolizing enzymes, cytochrome P450 (CYP) enzymes, in the liver are significantly decreased in a murine model of ulcerative colitis (UC). In this study, we investigated changes in the pharmacokinetics of phenytoin, a CYP2C substrate drug, in the presence of UC. Colitis was induced by feeding male mice 3.5% dextran sulfate sodium (DSS) dissolved in drinking water for 10 days. The messenger RNA (mRNA) expression of CYP2C29 and CYP2C37 and the protein expression of CYP2C in the liver were evaluated via real-time reverse transcription–polymerase chain reaction and Western blotting, respectively. In DSS-treated animals, both mRNA and protein expression levels of CYP2C in the liver were significantly reduced relative to those in control animals (by 20%-40%). Phenytoin (30 mg/kg) was administered orally in a single dose to mice, and plasma concentrations were measured. Plasma concentrations of phenytoin were higher in the DSS-treated group than in the control group at 12, 24, and 36 hours after administration. Animals given DSS also exhibited a higher area under the plasma concentration–time curve extrapolated to infinity (AUCinf, 315 μg·h/mL), a delayed elimination half-life ( T1/2, 8.1 hours), and a decreased body clearance (CL/F, 3.52 mL/h) compared with that of control animals (AUCinf, 215 μg·h/mL; T1/2, 3.6 h; CL/F, 5.58 mL/h). This study indicated that the presence of UC decreases CYP2C expression levels in the liver, thereby delaying the metabolism of CYP2C substrates, including phenytoin, and increasing blood concentrations of these substrates.

Sedation for routine gastrointestinal endoscopic procedures: a review on efficacy, safety, efficiency, cost and satisfaction

Most gastrointestinal endoscopic procedures are now performed with sedation. Moderate sedation using benzodiazepines and opioids continue to be widely used, but propofol sedation is becoming more popular because its unique pharmacokinetic properties make endoscopy almost painless, with a very predictable and rapid recovery process. There is controversy as to whether propofol should be administered only by anesthesia professionals (monitored anesthesia care) or whether properly trained non-anesthesia personnel can use propofol safely via the modalities of nurse-administered propofol sedation, computer-assisted propofol sedation or nurse-administered continuous propofol sedation. The deployment of non-anesthesia administered propofol sedation for low-risk procedures allows for optimal allocation of scarce anesthesia resources, which can be more appropriately used for more complex cases. This can address some of the current shortages in anesthesia provider supply, and can potentially reduce overall health care costs without sacrificing sedation quality. This review will discuss efficacy, safety, efficiency, cost and satisfaction issues with various modes of sedation for non-advanced, non-emergent endoscopic procedures, mainly esophagogastroduodenoscopy and colonoscopy.

Bolus Administration of Fentanyl and Midazolam for Colonoscopy Increases Endoscopy Unit Efficiency and Safety Compared With Titrated Sedation

BACKGROUND & AIMS

Guidelines recommend slow titration of sedatives for moderate sedation. Bolus sedation, in which a larger weight-based dose of medication is given upfront, has been shown in a single trial to be beneficial. We evaluated the effects of bolus sedation on procedural safety, efficiency, and patient experience.

METHODS

We performed a retrospective analysis of colonoscopies performed between April 2010 and April 2011 at Duke Medical Center. Colonoscopies before October 2010 were performed with nurse-directed titration of sedative (n = 966); colonoscopies performed after October 2010 were performed with physician-directed administration of bolus sedative (n = 699). We compared sedation and recovery times, medication doses, and adverse events between groups. We also compared patient satisfaction in a subset of patients from each group. Data were compared using the chi-square test for categorical variables and Wilcoxon rank sum test for continuous and ordinal categorical variables.

RESULTS

Patients in the bolus group had a shorter sedation time (6.0 min) than patients in the titration group (13.0 min; P < .01) and a slightly longer colonoscopy time (25.0 min vs 24.0 min in the titration group; P < .01). Recovery time did not differ significantly between groups (53.0 min in the bolus group vs 52.1 min in the titration group; P = .07). Patients in the bolus group received lower weight-adjusted doses of fentanyl (1.71 μg/kg vs 1.89 μg/kg in the titration group) and midazolam (0.065 mg/kg vs 0.075 mg/kg in the titration group). A smaller proportion of patients in the bolus sedative group developed hypotension (12.7% vs 17.9% in the titration group; P < .01). These findings persisted even after adjustment for baseline patient age, race, sex, smoking status, alcohol use, body mass index, and American Society of Anesthesiologists' classification.

CONCLUSIONS

In a retrospective study of patients undergoing colonoscopy, we found that compared with titrated administration of sedative, bolus dosing improves endoscopy unit efficiency and safety and decreases the amount of sedative required. This benefit does not come at the expense of the patient experience.

Prospective multicenter randomized controlled trial comparing adenoma detection rate in colonoscopy using water exchange, water immersion, and air insufflation

BACKGROUND AND AIMS

Adenoma detection rate (ADR), defined as the proportion of patients with at least one adenoma of any size, is a quality indicator. We tested the hypothesis that water exchange (WE) improves ADR but water immersion (WI) has no adverse effect on ADR compared with air insufflation (AI).

METHODS

A prospective study was conducted at the Dalin Tzu Chi Hospital in southern Taiwan and the Hualien Tzu Chi Hospital in eastern Taiwan on patients randomly assigned to WE, WI, or AI with stratification by the 3 study colonoscopists. The primary outcome was ADR.

RESULTS

From July 2013 to December 2015, 651 patients were recruited and randomized into 3 groups with a 1:1:1 ratio (217 patients per group). Overall, ADR met quality standards: WE 49.8% (95% CI, 43.2%-56.4%), AI 37.8% (95% CI, 31.6%-44.4%), and WI 40.6% (95% CI, 34.2%-47.2%). Compared with AI, WE significantly increased ADR (P = .016). There was no difference between WI and WE. ADRs of WI and AI were comparable. Compared with AI, WE confirmed a longer insertion time, higher cleanliness score, but similar adenoma per positive colonoscopy (APPC) and withdrawal time with polypectomy. Subgroup analysis found WE significantly increased ADR in propofol-sedated patients. Multivariate generalized linear mixed model analysis revealed that age ≥50 years, WE (vs AI), colonoscopy indication, no previous history of colonoscopy, and withdrawal time >8 minutes were significant predictors of increased ADR.

CONCLUSIONS

Confirmation of prior reports showing WE, but not WI, increased ADR further strengthened the validity of our observations. WE significantly increased ADR in propofol-sedated patients. The outcome differences justify assessment of the role of WE in colorectal cancer prevention. Similar APPC and withdrawal times suggest that adequate inspection was performed on colonoscope withdrawal in each of the study arms. (Clinical trial registration number: NCT01894191.).

Does deep sedation with propofol affect adenoma detection rates in average risk screening colonoscopy exams?

AIM

To determine the effect of sedation with propofol on adenoma detection rate (ADR) and cecal intubation rates (CIR) in average risk screening colonoscopies compared to moderate sedation.

METHODS

We conducted a retrospective chart review of 2604 first-time average risk screening colonoscopies performed at MD Anderson Cancer Center from 2010-2013. ADR and CIR were calculated in each sedation group. Multivariable regression analysis was performed to adjust for potential confounders of age and body mass index (BMI).

RESULTS

One-third of the exams were done with propofol (n = 874). Overall ADR in the propofol group was significantly higher than moderate sedation (46.3% vs 41.2%, P = 0.01). After adjustment for age and BMI differences, ADR was similar between the groups. CIR was 99% for all exams. The mean cecal insertion time was shorter among propofol patients (6.9 min vs 8.2 min; P < 0.0001).

CONCLUSION

Deep sedation with propofol for screening colonoscopy did not significantly improve ADR or CIR in our population of average risk patients. While propofol may allow for safer sedation in certain patients (e.g., with sleep apnea), the overall effect on colonoscopy quality metrics is not significant. Given its increased cost, propofol should be used judiciously and without the implicit expectation of a higher quality screening exam.

How to improve patient satisfaction during midazolam sedation for gastrointestinal endoscopy?

AIM

To determine the procedure-related factors that affect sedation satisfaction and to make a suggestion to improve it.

METHODS

We prospectively enrolled a total of 456 patients who underwent outpatient endoscopy procedures with midazolam sedation between March 2014 and August 2014. All patients completed both pre- and post-endoscopy questionnaires about sedation expectations and satisfaction.

RESULTS

The study cohort included 167 (36.6%) patients who underwent esophagogastroduodenoscopy (EGD), 167 (36.6%) who underwent colonoscopy, and 122 (26.8%) who underwent a combined procedure (EGD and colonoscopy). Over 80% of all patients were satisfied with sedation using midazolam. In univariate and multivariate analyses, total procedure time in the EGD group, younger age (≤ 50 years), and longer colonoscopy withdrawal time in the colonoscopy group were related to decreased satisfaction with sedation. However, in active monitoring and intervention group, there was no decrease in grade of satisfaction despite longer procedure time due to more procedures during colonoscopy. Younger age (≤ 50 years), longer inter-procedure time gap, and colonoscopy withdrawal time were related to decreased satisfaction in the combined EGD and colonoscopy group.

CONCLUSION

Midazolam is still a safe and effective sedative for gastrointestinal endoscopy. Satisfaction with sedation depends on several factors including age (≤ 50 years) and procedure time duration. To improve patient satisfaction with sedation, active monitoring of sedation status by the endoscopist should be considered for patients who require long procedure time.

Autonomous Retroflexion of a Magnetic Flexible Endoscope

Retroflexion during colonoscopy is typically only practiced in the wider proximal and distal ends of the large intestine owing to the stiff nature of the colonoscope. This inability to examine the proximal side of the majority of colon folds contributes to today's suboptimal colorectal cancer detection rates. We have developed an algorithm for autonomous retroflexion of a flexible endoscope that is actuated magnetically from the tip. The magnetic wrench applied on the tip of the endoscope is optimized in real-time with data from pose detection to compute motions of the actuating magnet. This is the first example of a completely autonomous maneuver by a magnetic endoscope for exploration of the gastrointestinal tract. The proposed approach was validated in plastic tubes of various diameters with a success rate of 98.8% for separation distances up to 50 mm. Additionally, a set of trials was conducted in an excised porcine colon observing a success rate of 100% with a mean time of 19.7 s. In terms of clinical safety, the maximum stress that is applied on the colon wall with our methodology is an order of magnitude below what would damage tissue.