Intraluminal pressures during perfusion of the human colon in situ

Nine healthy human volunteers underwent colonic perfusion and recording of the intraluminal pressure simultaneously in the right, transverse, and left colon. Isotonic saline was infused into the caecum at various flow rates from 10 to 30 ml per min. During colonic perfusions, pressure waves were simple and distorted only by respiratory artifacts. Their amplitude was large (10 to 44 cm of H2O), of long duration (8 to 68 sec), and of low frequency (0.2 to 1.8 wave per min). The frequency of the waves was very stable and this stability was uninfluenced by the site of recording and the rate of perfusion. A pressure wave in the right colon was always followed within 3 sec by a wave in the transverse and left colon. The frequency and amplitude of the waves increased in all subjects and at all rates of perfusion from right to left colon (P less than 0.001). The wave frequency increased with the perfusion flow rate (P less than 0.001). The relationship between the perfusion flow rate and the waves amplitude was curvilinear (P less than 0.01). It is concluded that in the human colon perfused in situ there is a gradient of motility preventing aboral propulsion. This study suggests that during perfusion, liquids are trapped in the right colon. Data on transport of water and electrolytes, obtained from whole colon perfusion, may in fact reflect events occurring in the proximal part of the large bowel.