Purpose: Doppler pulsed flow and electronic scanning allow for instantaneous measurement of portal vein flow. This method was used to monitor alterations in splanchnic blood flow during exercise.
Methods: Measurements of portal vein blood flow were performed in eight healthy males at rest and at 10-min intervals during cycle ergometry at 70% of maximal aerobic capacity. Subjects stopped cycling briefly (approximately 30 s) and stopped breathing while measurements were made. Flow was calculated from values obtained for velocity of red blood cell passage and cross-sectional area of the vessel.
Results: Cross-sectional area decreased during exercise, resulting in a significant decrease in flow over time (P = 0.0001 by ANOVA). The flow within the portal vein had decreased by 80% after 60 min of exercise (absolute flow, 0.63 +/- 0.13 L x min(-1) at rest and 0.13 +/- 0.04 L x min(-1) at 60 min).
Conclusion: Electronic Doppler flow measurement of portal vein flow is a viable, noninvasive technique that can be used to measure splanchnic blood flow. Values obtained as a result of intensive exercise are in line with earlier results obtained with other techniques.