Gastric emptying patterns of a liquid meal in newborn infants measured by epigastric impedance

Epigastric impedance was used to measure the gastric emptying patterns of a liquid non-caloric meal (5 mL water kg⁻¹) in 30 healthy newborn infants. Twenty-six mature infants were examined in the first eight days of life, and four preterm infants were examined within 6 weeks after birth. The recordings consisted of two components: the emptying signal (the DC component), and a phasic 3 cycles per minutes (CPM) signal (the AC component). In some of the infants the phasic 3 CPM signal was also seen during the fasting state.
For mature infants the median half emptying time (T₅₀) was 6.9 min. For a second meal given within one hour after the first meal the half emptying time was 5.5 min ( P  < 0.01). In preterm infants the emptying times were not significantly different from mature infants.
Day-to-day variation was low with a coefficient of variation of 17% in nine infants.
A periodic change of the impedance signal, the phasic 3 CPM signal, was observed after a meal in 24 of the infants. The median frequency was 3.0 CPM in 20 mature and 2.9 CPM in four preterm infants. In nine infants a phasic 3 CPM signal was also observed during the fasting state, with a median frequency of 2.9 CPM.
Measurement of gastric emptying pattern with epigastric impedance is a simple investigation for the evaluation of gastric emptying time and phasic activity in mature and preterm infants. However, the method is sensitive to spontaneous movements of the children, resulting in non-valid measurements in around one fourth of the infants.