SOME PARAMETERS OF LARGE BOWEL MOTILITY IN NORMAL MAN

Abstract

Normal values of bowel habits, colonic transit times of radioopaque markers and anorectal pressures obtained from 114 normal subjects are presented. Their stool frequency ranged from 3-11/7 days; their diet contained an average of 14.4 g of crude fibers. Radioopaque markers progressed regularly among the large bowel and a range of transit times was established for its different segments. Manometric studies included measurements of anal pressure at rest, amplitude and duration of the rectoanal inhibitory reflex, anal inflation reflex and amplitude of rectal contraction in response to rectal distension. Normal ranges were established. Amplitude, duration and magnitude (as measured by planimetry) of anal relaxation elicited by rectal distensions were related to rectal distending volume (P < 0.001). The incidence of spontaneous variations of anal pressure at rest and of overshoot of pressure after the inhibitory reflex was also established. Comparison to patients with constipation to define the symptoms and to understand pathophysiological mechanisms was done in a companion study.