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.