Ambulatory manometric recording of anorectal activity

PURPOSE: Ambulatory anorectal manometry is usually analyzed by computer ana lysis only. An in-depth analysis with visual assessment of the recordings c ombined with computer analysis is presented. METHODS: Recordings of 20 to 2 4 hours in length were performed on ten healthy subjects. Spontaneous anal canal relaxations were analyzed and related to changes in rectal pressure a nd any reported rectal sensation. Pressure variations in the anorectum, inc luding the rectal motor complex, were studied. RESULTS: In the awake subjec t the frequency of anal canal relaxations was 14.5 to 18.7/hour, and the fr equency was 4.3/hour while asleep. They can be divided into two different s ubtypes. The amplitude of the pressure fall was 26 to 29 mmHg, but diminish ed during sleep to 19 mmHg. The duration of each relaxation was 16 to 19 se conds. Passage of flatus and the sensation of flatus in the rectum occurs 1 .5 and 1.2 times per hour, respectively, usually with simultaneous anal can al relaxation. The frequency of rectal motor complexes in the midrectum was 0.4/hour and in the lower rectum was 0.7/hour; the duration was 10.3 and 5 .8 minutes, respectively, with no nocturnal variation. The complexes could not be related to anorectal events. CONCLUSIONS: The study provides supplem entary knowledge of anorectal physiology, particularly of anal canal relaxa tion, and proposes a more detailed method for evaluation of data obtained b y ambulatory anorectal manometry.