Ultrasonic assessment of gastric emptying in the preterm infant.

The study of gastric emptying in the preterm infant has been hampered by the absence of a suitable, valid technique. We have evaluated gastric antral clearance using serial ultrasonic measurement of the antral cross sectional area (ACSA). The study was easy to perform, providing successful results in 15 of 17 low birth-weight infants, with feed volumes of 8-31 ml/kg. ACSA was closely related to intragastric volume (mean (range) r = 0.96 (0.89-0.99)). Measurements were reproducible: mean (SE) coefficient of variation was 7.7% (1.1). Gastric antral clearance was observed as a fall in ACSA that began shortly after completion of the feed and returned to prefeed values at a variable rate. The pattern of gastric antral transit was entirely consistent with recognised patterns of gastric emptying and half gastric antral clearance times ranged from 20-63 minutes. Ultrasonic measurement of gastric antral clearance is a new technique allowing the study of gastric emptying in the preterm infant.