Relationships between spatial patterns of colonic pressure and individual movements of content

The aim of this study was to examine the relationship between colonic press ure waves and movement of content. In 11 healthy subjects, pressures were r ecorded at 10-cm intervals from cecum to rectum for 32 h. In six subjects, transit was simultaneously measured for 8 h after direct cecal instillation of 1.5 mCi of Tc-99m sulfur colloid. Thirty-two percent of isotope movemen ts were related to nonpropagating activity and twenty-eight percent to prop agating sequences. The extent of isotope movement related to propagating se quences (25.1 +/- 2.1 cm) was greater than that due to nonpropagating activ ity (12.8 +/- 0.7 cm; P = 0.0001). Propagating sequences originated signifi cantly more frequently (P = 0.004) and propagated further (P = 0.0006) in t he proximal compared with the distal colon. Only 36% of propagating sequenc es were propulsive of content, and compared with nonpropulsive sequences, t hese propagated further (41 +/- 6 vs. 27 +/- 2 cm; P < 0.05) and had a high er probability of originating proximally (P = 0.0003), a higher pressure wa ve amplitude (50 +/- 5 vs. 34 +/- 4 mmHg; P = 0.0001), and slower velocity (2.2 +/- 0.3 vs. 3.6 +/- 0.47 cm/s; P = 0.02). We conclude that most moveme nts of colonic content are related to pressure waves. There is marked regio nal variation in the prevalence, velocity, and extent of propagation of pro pagating pressure wave sequences, which are an important mechanism for tran sporting content over long distances. The effectiveness of transport by a p ropagating sequence is influenced by its site of origin, amplitude, and vel ocity.