Reduction of conscious sedation requirements by olfactory stimulation: a prospective randomized single-blinded trial

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

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.

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.

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.