Reliability of the serial sampling technique for determination of gastric emptying.

The purpose of this study was to determine if gastric emptying data obtained in one trial (using the intubation and aspiration method) is representative of that obtained in subsequent trials or on repeated days. Nine healthy adults consumed a volume of water (5.5 ml/kg body weight) which contained a nonabsorbable marker. Following a fifteen-minute rest period, the stomach contents were aspirated using a 50 ml syringe. This procedure was repeated three additional times on the same day with a fifteen minute interval separating each trial. On two other days the identical procedures were performed. A significant daily variation was found for residue volume, gastric secretion, and percent of original drink emptied. However, no significant difference between trials within a day was found for the residue volume, gastric secretion, and percent of original drink emptied. Generalizability coefficients, which are "reliability-like" coefficients, were also calculated. These coefficients indicate that a combination of at least 2 days with at least 2 trials/day should be used in order to obtain reliable gastric emptying data.