Discharge Readiness After Propofol With or Without Dexmedetomidine for Colonoscopy

A Randomized Controlled Trial

Leonard U. Edokpolo, M.D.; Daniel J. Mastriano, M.D.; Joanna Serafin, Ph.D.; Jeremy C. Weedon, Ph.D.; Maryam T. Siddiqui, M.D.; Dennis P. Dimaculangan, M.D.


Anesthesiology. 2019;131(2):279-286. 

In This Article

Abstract and Introduction


Background: Enhanced recovery protocols employ various approaches to minimize detrimental side effects of anesthetizing agents. The authors tested the hypothesis that adding low-dose dexmedetomidine to propofol for anesthesia in ambulatory colonoscopies, compared with propofol alone, would lower the propofol requirement, improve the intra-procedure hemodynamic state, and not increase time-to-discharge.

Methods: In this noninferiority, double-blind, randomized controlled trial, patients having colonoscopies received total IV anesthesia either with propofol and placebo (n = 50), or propofol and a bolus dose of dexmedetomidine, 0.3 μg/kg (n = 51). Additional propofol was administered to maintain a Bispectral Index score of 60. Following the procedure, readiness for discharge was assessed regularly using the Modified Post Anesthetic Discharge Scoring System until discharge criteria were met. The primary outcome was the percentage of patients meeting discharge criteria within 30 min from procedure end-time.

Results: Twenty-six of 51 (51%) patients receiving propofol-dexmedetomidine were ready for discharge by 30 min from procedure end time, compared with 44 of 50 (88%) receiving propofol (P < 0.001). Propofol consumption was lower in subjects receiving propofol–dexmedetomidine (140 μg · kg−1 · min−1) compared to those receiving propofol (180 μg · kg−1 · min−1) with P = 0.011. The lowest mean arterial pressure decreased further from baseline in those receiving propofol–dexmedetomidine (−30%; mean decrease −30 ±10.5 mmHg) compared to propofol (−21%; mean decrease, −22 ± 14.2 mmHg) with P = 0.003. There was no difference in incidence of bradycardia, with sustained bradycardia occurring in 3 of 51 (6%) patients receiving propofol–dexmedetomidine compared to 1 of 50 (2%) patients receiving propofol (P = 0.62). No apnea episodes requiring positive-pressure ventilation occurred in either group.

Conclusions: For anesthesia in ambulatory colonoscopy, combining low-dose dexmedetomidine with propofol delayed discharge readiness and provoked hypotension compared to propofol alone.


Approximately 15 million colonoscopy procedures are performed annually in the United States,[1] usually in the ambulatory setting. Propofol is commonly the sole agent for anesthesia due to its rapid onset and the rapid offset that allows for a timely recovery.[2] However, significant hypotension, tachycardia, and apnea, which may not be well tolerated, can occur when large doses are required to complete a procedure.[3,4] Decreasing the anesthetic level in such situations may lead to inadequate sedation, resulting in patient body movement disruptive to the procedure.

Enhanced recovery protocols employ one or more approaches to improve a procedure's clinical outcome. For colonoscopies, this might involve combining several agents with different mechanisms of action to achieve the desired level of anesthesia.[5,6] This approach should theoretically decrease the dose of each drug and minimize individual adverse side effects. Dexmedetomidine is a highly selective, α2-adrenoceptor agonist with anxiolytic, analgesic, and sedative properties.[7,8] It can be safely combined with propofol since it has minimal respiratory depressive effects and has been shown to decrease physiologic stress-response to surgical stimulation.[9–11] Several studies have also shown that it decreases the amount of other anesthetic agents required for sedation.[10,12,13]

When used alone for sedation, dexmedetomidine is known to delay both time to recover from anesthesia and discharge readiness.[14,15] In contrast, several studies have reported that the duration of postoperative recovery was decreased when a low dose of dexmedetomidine was used, as an adjunct with other sedatives and analgesics.[10,12]

With respect to the setting of outpatient colonoscopy, no reports have applied validated discharge criteria to assess whether combining a low dose of dexmedetomidine with propofol affected discharge readiness. For example, Ji et al.[12] compared the effects of dexmedetomidine combined with propofol, versus propofol only, in 90 patients having colonoscopies for polyp resection. They reported that the recovery time was shorter in patients receiving propofol–dexmedetomidine. However, recovery was defined as "patient alert and oriented to name, age and time." This definition does not mean that the patient status is appropriate for discharge to home in the ambulatory setting. A validated criteria for "home-readiness" is defined by a score greater than or equal to 9 on the Modified Post Anesthetic Discharge Scoring System scale.[16,17]

We tested the hypothesis that for patients having ambulatory colonoscopies, anesthesia with a combination of propofol and low-dose dexmedetomidine, compared with propofol alone, would decrease the propofol requirement and improve intraprocedure hemodynamic response, without delaying the time to attain discharge readiness.