Validation of ultrasound methods to monitor gastric volume changes in preterm infants.

OBJECTIVES

The aim of this study was to validate 4 sonographic methods of estimating stomach volume for the purpose of monitoring changes in gastric volume over time and to describe the echogenic characteristics of milk feeds.

METHODS

Twenty-four infants were monitored during a single intragastric tube feed, with 2 ultrasound images of the entire stomach and an image of the antral cross-sectional area (ACSA) before, during, and after the feed. Raw measurements, 3 stomach volume calculations, and ACSA were tested for intra- and interrater agreement. Calculated stomach volumes and ACSA were compared with delivered feed volumes, and characteristics of stomach image echogenicity graded at each time point.

RESULTS

Spheroid calculation of stomach volume was the most reliable and valid measure of stomach volume. Fortified breast milk feeds were more echogenic than unfortified breast milk feeds. Residual stomach volumes (median 2.12 mL, range 0.59-9.27 mL) were identified in 18 of 24 infants.

CONCLUSIONS

Direct ultrasound stomach measurement (spheroid) will provide a useful research tool and a potential clinical tool for assessing gastric emptying and feeding intolerance in preterm infants.