A continuous manometric study of the human pylorus

Previous manometric studies of the pylorus in humans have yielded conflicting data. These interstudy variations may be the result of differences in technique. It is also possible that pyloric pressure shows cyclic variations with the interdigestive motility complex. Pyloric pressure was monitored continuously for 300 min in 6 healthy men by means of a Dent sleeve. Gastroduodenal activity was measured simultaneously by using a perfused catheter system with two antral and two duodenal ports. With this method the pylorus was shown to have no elevation in basal pressure above baseline duodenal pressure during phase III. Basal pyloric pressure varied between subjects in phases I and II, being elevated in some but not in others. Subjects restudied on a separate day often showed a different pattern of activity. Pyloric pressure increased gradually in response to duodenal acidification. This response was blocked by pretreatment with naloxone. The pylorus also showed phasic activity, which was maximal in phase III. This phasic activity could not be distinguished from that of the adjacent antrum and duodenum. In conclusion, pyloric pressure patterns showed marked variation within and between subjects. These variations may explain some of the differences between previous studies.