Radioactive dilution indicator. I. Measurement of residual fluid in the fasting stomach.

Summary A new procedure employing radioactive zirconium 95 -niobium 95 as a dilution indicator permitted the measurement of any fluid left in the stomach after it was presumably emptied completely by the usual method of blind aspiration. Though the rapid introduction and withdrawal of 100 cc. of fluid into the stomach might act as a stimulus to gastric secretion, it is doubtful that enough secretion would be produced during the 1 min. required for mixing to give a falsely high gastric residuum. A significant residuum of gastric juice was found in over 75 per cent of the patients. This might provide a source of error where volume and acid output are measured by conventional aspiration.