The variability of the incremental postprandial portal vein flow response is partly caused by a relationship between fasting flow rate and phase activity of the migrating motor complex

Objective Results from studies on portal flow rate (PFR) have demonstrated a considerable intra- as well as interindividual variability of the increme ntal integrated response (IIR). We hypothesized that part of the variation of the IIR might be related to variability of the fasting PFR caused by a r elationship between PFR and characteristics of the migrating motor complex (MMC). Design We examined 12 healthy men and PFR was recorded by using the percuta neous colour Doppler technique. Gastric emptying (GE) was determined by sci ntigraphy and the meal consisted of an omelette of 100 g (1400 kJ; 60% fat, 20% protein, 20% carbohydrates) tagged with Tc-99m sulphur colloids follow ed by 150 ml water mixed with In-111 DTPA. The design included recording of PFR in phase II as well as in phase III of the MMC. Meal ingestion took pl ace in the following duodenal phase I. Postprandial recordings of GE and PF R were performed at 10 min intervals for the following 2 h. Results Median (95% confidence limits) amount of solid emptied at 120 min w as 68% (59-81%). PFR in phase III was significantly higher than in phase II (1.56 l/min (1.35-1.93 l/min) vs 0.96 l/min (0.84-1.12 l/min), P < 0.001). PFR increased after the meal and a peak flow of 2.19 l/min (1.58-2.46 l/mi n) was recorded 10 min after ingestion (P < 0.01 vs phase III). Based on th ese characteristics a difference in IIR is to be expected, and the calculat ions revealed that IIR is considerably higher in the phase II series than i n the phase III series (50 l/min x 120 min (8-90 l/min) vs -26 l/min x 120 min (-55 to 1 l/min), P< 0.001). In both series a weak but significant inve rse relationship was demonstrated between amounts emptied during a 20-min p eriod and the corresponding IIR (n = 72; r = -0.27, P < 0.05 (III); r = -0. 29; P < 0.05 (II)). Conclusion We conclude that fasting PFR is related to phase activity of the MMC and characteristics of the postprandial IIR depend upon MMC activity a t the time of recording of the fasting value. Future studies on PFR need to be performed with phase related recording of fasting flow and meal ingesti on in relation to preselected characteristics of the MMC. (C) 1999 Lippinco tt Williams & Wilkins.