HEMODYNAMIC-CHANGES IN THE SMALL-INTESTINE CORRELATE TO MIGRATING MOTOR COMPLEX IN HUMANS

Objective: To evaluate local intestinal blood flow and its relationshi p to fasting gut motility in humans. Design and methods: Regional lase r Doppler flowmetry (LDF) was carried out for 8 h in 14 fasted volunte ers. LDF measured as perfusion units (PU) was performed using two sing le-fibre microprobes attached to a small intestinal manometry tube, wh ich monitored migrating motor complexes (MMCs). Luminal pressures of s mall intestine were registered in analogue and digital recordings. Res ults: During phase 1 of MMC, PU values of 65 (33-95) and 37 (20-100) i n proximal and distal duodenum were measured. During phase 2, PU value s increased by 17% and 38%, respectively (each P<0.001). At phase 3 of MMC, corresponding PU values increased by 363% and 443% (each P<0.001 ) and remained at high levels until termination of phase 3. During pha se 3 there was aboral propagation of LDF activity. Computerized record ings allowed detailed analysis of relationships between LDF pattern an d luminal pressures. At pressures below 48 (42-54) mmHg, individual LD F cycles and contraction cycles were phase displaced at 180 degrees, i ndicating low perfusion during contractions. When pressures exceeded 4 8 (42-54) mmHg, a decrease in PU was registered and the cycling patter n of LDF was abolished. Then, as luminal pressure decreased below 33 ( 25-41) mmHg, PU increased by 246%. Conclusion: Our findings show a rel ationship between fasting motility and blood flow in the human gut, in which the blood flow exhibited a pattern similar to phase 1, 2 and 3 of the MMC.