Reduction of Conscious Sedation Requirements by Olfactory Stimulation: a Prospective Randomized Single-blinded Trial

Objectives: This study investigated the possibility that olfactory stimulation would decrease sedation needed for colonoscopy and therefore decrease the recovery time needed after conscious sedation.

Materials And Methods: Patients were randomized to receive a cherry-flavoredscent in oxygen flowing at a 4 L per minute rate via nasal cannula or oxygen alone. The scent was provided in a cherry-flavored oil. A Bispectral Index (BIS) monitor (Aspect Medical Systems, Newton, MA) was placed and scores were recorded every 5 minutes during the procedure to control for different sedation patterns between different endoscopists. The recovery area nurse was unaware of whether a given patient was in the aroma or plain oxygen group, and based each patient's discharge on preexisting standardized criteria.

Results: Two hundred and eighty-four (284) patients completed the study. Both the procedure times and the recovery times were not statistically significant between the two groups. The doses of sedatives used, BIS scores at 5 minute intervals, and rate of change in BIS scores were also not statistically significant between the two groups.

Conclusions: Overall, there is no difference between olfactory stimulation and inhaled oxygen with regard to amount of sedation used and recovery times for colonoscopy. An inhaled cherry- scent may not have as great a calming effect as other scents that have been studied.