Applied potential tomography in the measurement of gastric emptying in infants.

The aim of this study was to investigate the feasibility of using applied potential tomography (APT), a noninvasive and nonradioactive method, to measure the rate of gastric emptying in preterm babies and infants < 3 months old. APT, a form of electrical impedance tomography, creates tomographic images of tissue resistivity to a small electrical current and has been used to study gastric emptying in adults. The rate of gastric emptying of 53 preterm infants and 29 term infants was measured. The test feed was either milk (formula milk or expressed breast milk) or Dioralyte (a commercial rehydration solution). When a nasogastric tube was present, the results obtained by APT were validated by comparing the volume of feed estimated to be present with the volume that could be aspirated. All infants completed the investigation without any problems. APT demonstrated a slower rate of emptying of milk feeds than Dioralyte and showed that milk and Dioralyte feeds in preterm babies emptied at a similar rate to feeds in term infants. In validation studies, gastric emptying has been observed in 44 of 47 studies, and this finding was confirmed by aspiration of the nasogastric tube. Applied potential tomography is a safe, noninvasive method for measuring gastric emptying in small infants.