Objective: To evaluate local intestinal blood flow and its relationship to fasting gut motility in humans.
Design and methods: Regional laser Doppler flowmetry (LDF) was carried out for 8 h in 14 tasted volunteers. LDF measured as perfusion units (PU) was performed using two single-fibre microprobes attached to a small intestinal manometry tube, which monitored migrating motor complexes (MMCs). Luminal pressures of small intestine were registered in analogue and digital recordings.
Results: During phase 1 of MMC, PU values of 65 (33-95) and 37 (20-100) in proximal and distal duodenum were measured. During phase 2, PU values 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 phase 3 there was aboral propagation of LDF activity. Computerized recordings allowed detailed analysis of relationships between LDF pattern and luminal pressures. At pressures below 48 (42-54) mmHg, individual LDF cycles and contraction cycles were phase displaced at 180 degrees, indicating low perfusion during contractions. When pressures exceeded 48 (42-54) mmHg, a decrease in PU was registered and the cycling pattern of LDF was abolished. Then, as luminal pressure decreased below 33 (25-41) mmHg, PU increased by 246%.
Conclusion: Our findings show a relationship 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.