Evaluation of the marker technique for measurement of exocrine pancreatic secretion rate

A secretin-cholecystokinin test was performed in 103 patients, representing both normal and reduced exocrine pancreatic function. The duodenum was intubated with a triple-lumen tube. The gastric and duodenal contents were aspirated separately and sampled in 10-min periods. An inert, water-soluble marker (58Co-vitamin B12 dissolved in isotonic saline) was infused at a constant rate into the duodenum. Exocrine pancreatic secretion was stimulated by continuous intravenous infusion of secretin for 60 min and a combination of secretin and cholecystokinin for another 60 min. The total recovery of the infused marker was 80%. The concentration of marker in the aspirate did not vary significantly between consecutive 10-min periods during the last 20 min of the secretin stimulation period or during the last 50 min of the combined secretin-cholecystokinin stimulation period, indicating a steady secretion rate into the duodenum. By means of the marker concentrations in the aspirate, the duodenal volumes were calculated and found to vary significantly less than the aspirated volumes. This finding demonstrates that the duodenal volume calculated from the recovery of an inert marker is a closer estimate of the true volume than that obtained by the usual aspiration technique without a volume indicator.