Real-time bowel ultrasound to characterize intestinal motility in the preterm neonate

To characterize normal patterns of intestinal motility by ultrasound (US) in the preterm neonate during the first 5 days of life.

Bowel US examinations were performed with an US machine (Vivid-i, General Electric) equipped with a 13-MHz linear and 7 MHz sector transducer. Still images and clips were taken from all abdominal quadrants along with Doppler of the superior mesenteric artery. Cumulative motility (CM) was quantified for each patient. Comparisons were made between CM for each day of life. Inter-observer correlations were made using the intra-class correlation coefficient. Notation was made of feeding status, bowel sounds and clinical demographics.

Twenty infants were enrolled in the study. Seventeen infants had 5 days of complete US results available. Mean CM visualized on day of life (DOL) 1 was 28±12. By DOL 4 (38±17, P=0.006) and DOL 5 (41±20, P=0.008) mean CM increased. There was no difference in the resistance index on days imaged. Mean CM correlated with days to reach full feeds and gestational age, but gestational age was a stronger predictor of days to reach full feeds. Intra-observer correlation coefficient was 0.84.

Real-time US provides a quantitative measure of intestinal motility in the preterm infant. Further studies are needed to establish the link between bowel US findings and feeding tolerance.