Colon cancer : researchers have determined that deep sedation does not improve the colonoscopy quality


Colon cancer is the second leading cause of cancer death in the United States and colonoscopy is the most-used screening tool to detect it.

In a recently published study, researchers from the University of Missouri School of Medicine determined deep sedation does not improve the colonoscopy quality compared to moderate sedation when it comes to the polyp detection rate or adenoma detection rate, the type of polyp that can eventually become cancerous.

“University of Missouri Health Care is always examining ways to improve colonoscopy quality for patients,” said Matthew Bechtold, MD, professor of clinical medicine at the University of Missouri School of Medicine. “

The most important quality measure is the adenoma detection rate and polyp detection rate.”

Researchers conducted a retrospective study of 585 healthy average-risk patients who underwent either a moderate or deep sedation colonoscopy at the same MU Health Care outpatient center in 2015 or 2016.

They found the adenoma and polyp detection rates were not significantly different between the deep sedation and mild sedation groups.

Previous studies have indicated a majority of colonoscopies in the U.S. use moderate sedation instead of deep sedation.

“You usually have 30 minutes to do a colonoscopy,” said Bechtold. “When you sedate with moderate sedation techniques, it takes up to twenty minutes to sedate the patient. Deep sedation with Propofol takes about 15 seconds.

Is the time better spent looking at a patient’s colon or waiting for them to become sedated?

That’s why we thought maybe the deep sedation would yield a better detection rate.”

Deep sedation requires the presence of an anesthesiologist or a certified registered nurse anesthetist, which increases the cost of the procedure.

Bechtold believes that if payment models change, outpatient centers may re-consider moderate sedation if it won’t affect the adenoma detection rate.

But the fast-acting nature of deep sedation combined with the improved patient experience is the reason why it is the preferred choice at MU Health Care.

“If we found a significant improvement in detection with moderate sedation compared to deep sedation, then we may consider going back to moderate sedation,” Bechtold said. “But since we didn’t really find a difference, I think the efficiency factor of deep sedation wins out.”

The study, “Impact of moderate versus deep sedation on adenoma detection rate in index average-risk screening colonoscopies,” was recently published in the Gastrointestinal Endoscopy.

An adequate level of patient sedation allows for thorough and relaxed endoscopic procedures and is desirable for the successful performance of a safe and high-quality colonoscopy.

Historically, sedation was induced and maintained mainly by a combination of a benzodiazepines and opioids (Bdz–O), which ensured a mild–moderate level of sedation; however, more recently propofol-mediated sedation has been introduced as a reasonable alternative for sedation, due to its pharmacokinetic and pharmacodynamic properties, which facilitate rapid onset of action and recovery, as well as its favorable safety profile.1,2

Traditionally, propofol is administered by anesthesiologists, but due to its increasing use within endoscopy units, programs have been developed for nonanesthesia sedationists to use propofol sedation during endoscopy procedures, typically with the sedation being given by trained endoscopists or nurses.

Several studies have demonstrated that propofol-mediated sedation is well tolerated and associated with faster recovery and discharge times compared with Bdz–O sedation, without an increase in adverse events.36 

In addition, patient satisfaction appears to be greater for those undergoing a colonoscopy who receive propofol-mediated sedation,7 and this finding may improve patient compliance and adherence to colorectal cancer-screening and -surveillance programs.

The level of sedation under propofol-mediated sedation increases in a dose-dependent manner, and patients are generally titrated to an adequate level of sedation as required during the procedure,8 which may improve the efficiency and quality of the procedure by providing the endoscopist with optimal conditions for a thorough visualization, while eliminating any distraction due to an uncomfortable patient.

This may be translated into an enhanced adenoma/polyp-detection rate, a premier colonoscopy-quality indicator. Moreover, the more comfortable and sedated a patient is, the higher the likelihood that cecal or terminal ileum intubations can be performed, especially in technically difficult cases.9,10 

An assessment of the effect of propofol-mediated sedation on the outcome of a procedure, namely colonoscopy-quality measures, may be of paramount importance in justifying its widespread use, as controversy remains regarding the limitations concerning the setting and personnel certified to provide propofol-mediated sedation.


We conducted a large retrospective cohort study that examined consecutive patients who had undergone a colonoscopy over a 15-year period within the Gastroenterology Department at the Hillel Yaffe Medical Center, a university-affiliated hospital in Israel.

All patient data were collected from the department’s electronic record system, and only patients who had undergone sedated colonoscopies and had a full data set, including demographic details (age, sex), procedural setting (inpatient/outpatient), indication for exam, type and dose of sedation, quality of bowel preparation, depth of examination, and endoscopic findings, were included in the final analysis.

Patients under the age of 18 years and those who had undergone prior colon resection were excluded. All patients included in the study were unselectively offered propofol-mediated or standard sedation, based mainly on performer or patient preference/experience.

Patients were divided into two groups, with all those who had been sedated using Bdz–O (midazolam/fentanyl) alone or in combination (directed by the endoscopist), representing the control group, and those who underwent propofol-mediated sedation (propofol alone or in combination with Bdz, directed either by the anesthesiologist or the endoscopist) constituting the study (propofol) group.

Polyp-detection rate, cecal intubation rate, and terminal ileum-intubation rate were examined and compared between the sedation groups and also for a subgroup analysis of patients with adequate bowel preparation only.

In the propofol-sedation group, an assessment was made of the correlation between dose and examination outcome.

In the same group, examination outcomes for anesthesiologist-administered propofol-mediated sedated colonoscopies were compared to endoscopist-guided propofol-mediated sedation procedures.

Moreover, we compared examination outcomes for propofol-only sedation with balanced propofol sedation (use of propofol in addition to Bdz–O).

A multivariate analysis was performed to adjust for the potential confounders of age, sex, quality of bowel preparation, procedural setting (outpatient/inpatient), and indications. This study was approved by the Hillel Yaffe Medical Center’s local ethics committee.

More information: Erica P. Turse et al, Impact of moderate versus deep sedation on adenoma detection rate in index average-risk screening colonoscopies, Gastrointestinal Endoscopy (2019). . DOI: 10.1016/j.gie.2019.05.011

Journal information: Gastrointestinal Endoscopy
Provided by University of Missouri-Columbia



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