The administration of intravenous conscious sedation to patients undergoing GI endoscopy carries a risk of cardiopulmonary adverse events. Our study aim was to create a score that stratifies the risk of occurrence of either high-dose conscious sedation requirements or a failed procedure.

Patients receiving endoscopy via endoscopist-directed conscious sedation were included. The primary outcome was occurrence of sedation failure, which was defined as one of the following: (1) high-dose sedation, (2) the need for benzodiazepine/narcotic reversal agents, (3) nurse-documented poor patient tolerance to the procedure, or (4) aborted procedure. High-dose sedation was defined as >10 mg of midazolam and/or >200 μg of fentanyl or the meperidine equivalent. Patients with sedation failure (n = 488) were matched to controls (n = 976) without a sedation failure by endoscopist and endoscopy date.

Significant associations with sedation failure were identified for age, sex, nonclonazepam benzodiazepine use, opioid use, and procedure type (EGD, colonoscopy, or both). Based on these 5 variables, we created the high conscious sedation requirements (HCSR) score, which predicted the risk of sedation failure with an area under the curve of 0.70. Compared with the patients with a risk score of 0, risk of a sedation failure was highest for patients with a score ≥3.5 (odds ratio, 17.31; P = 2 × 10^-14). Estimated area under the curve of the HCSR score was 0.68 (95% confidence interval, 0.63-0.72) in a validation series of 250 cases and 250 controls.

The HCSR risk score, based on 5 key patient and procedure characteristics, can function as a useful tool for physicians when discussing sedation options with patients before endoscopy.

Use of anaesthesia services during endoscopy has increased, increasing cost of endoscopy.

To identify risk factors for and develop a clinical prediction score to predict difficult conscious sedation.

We performed a retrospective cross-sectional study of all patients who underwent oesophagogastroduodenoscopy (OGD) and colonoscopy with endoscopist-administered conscious sedation. The endpoint of difficult sedation was a composite of receipt of high doses (top quintile) of benzodiazepines and opioids, or the documentation of agitation or discomfort. Univariate and multivariate analyses were performed to measure association of the outcome with: age, sex, body mass index (BMI), procedure indication, tobacco use, self-reported psychiatric history, chronic use of benzodiazepines, opioids or other psychoactive medications, admission status and participation of a trainee. A clinical prediction score was constructed using statistically significant variables.

We identified 13,711 OGDs and 21,763 colonoscopies, 1704 (12.4%) and 2299 (10.6%) of which met the primary endpoint, respectively. On multivariate analysis, factors associated with difficulty during OGD were younger age, procedure indication, male sex, presence of a trainee, psychiatric history and benzodiazepine and opioid use. Factors associated with difficulty during colonoscopy were younger age, female sex, BMI <25, procedure indication, tobacco, benzodiazepine, opioid and other psychoactive medication use. A clinical prediction score was developed and validated that may be used to risk-stratify patients undergoing OGD and colonoscopy across five risk classes.

Using the Stratifying Clinical Outcomes Prior to Endoscopy (SCOPE) score, patients may be risk stratified for difficult sedation/high sedation requirement during OGD and colonoscopy.

Diagnostic and therapeutic endoscopy can successfully be performed by applying moderate (conscious) sedation. Moderate sedation, using midazolam and an opioid, is the standard method of sedation, although propofol is increasingly being used in many countries because the satisfaction of endoscopists with propofol sedation is greater compared with their satisfaction with conventional sedation. Moreover, the use of propofol is currently preferred for the endoscopic sedation of patients with advanced liver disease due to its short biologic half-life and, consequently, its low risk of inducing hepatic encephalopathy. In the future, propofol could become the preferred sedation agent, especially for routine colonoscopy. Midazolam is the benzodiazepine of choice because of its shorter duration of action and better pharmacokinetic profile compared with diazepam. Among opioids, pethidine and fentanyl are the most popular. A number of other substances have been tested in several clinical trials with promising results. Among them, newer opioids, such as remifentanil, enable a faster recovery. The controversy regarding the administration of sedation by an endoscopist or an experienced nurse, as well as the optimal staffing of endoscopy units, continues to be a matter of discussion. Safe sedation in special clinical circumstances, such as in the cases of obese, pregnant, and elderly individuals, as well as patients with chronic lung, renal or liver disease, requires modification of the dose of the drugs used for sedation. In the great majority of patients, sedation under the supervision of a properly trained endoscopist remains the standard practice worldwide. In this review, an overview of the current knowledge concerning sedation during digestive endoscopy will be provided based on the data in the current literature.