Influence of Intravenous Propofol Sedation on Anorectal Manometry in Healthy Adults

Background: We aimed to determine whether conscious sedation by propofol Could affect anorectal manometry. Methods: Eighteen healthy subjects underwent anorectal manometry at baseline and during conscious sedation by propofol. Sedation levels were monitored by auditory-evoked potentials. Results: All subjects showed a normal rectoanal inhibitory reflex (RAIR) before conscious sedation. During conscious sedation, the resting anal sphincter pressure was significantly lower compared with that before conscious sedation (15 +/- 2 versus 42 +/- 4 mm Hg, P < 0.001). RAIR was present in all subjects during conscious sedation. There was no difference in threshold volume inducing RAIR before and during conscious sedation (P = NS). The level of auditory-evoked potentials did not correlate well with any of the anorectal parameters. Conclusions: Propofol significantly reduces the resting anal sphincter pressure without affecting RAIR. The inability to obtain useful data in anorectal sensation and sphincter pressure might limit the utility of propofol as a sedation agent for performing anorectal manometry.