766 - Longitudinal Characterization of Preterm Neonatal Intestinal Function Using Bedside Abdominal Ultrasonography

Poster Number: 766
Publication Number: 766.247

Tamara Arnautovic, The Warren Alpert Medical School of Brown University, Rumford, RI, United States; Carl-Christian Jackson, Hasbro Children's Hospital at Rhode Island Hospital, Providence, RI, United States; Terri Williams-Weekes, Tufts Childrens Hospital, Boston, MA, United States; Rodica Turcu, Harvard Medical School, Boston, MA, United States

Background:
Abdominal-related pathology is a common morbidity in the neonatal intensive care unit (NICU). Abdominal radiography (AXR) is the current standard of care imaging modality to assess abdominal pathology. However, there exist several limitations: AXR can be challenging to interpret, has a limited ability to characterize disease progression, relies on late radiographic findings, and is associated with radiation exposure. The benefits of neonatal abdominal ultrasound (AUS) include higher resolution images compared to AXR, dynamic images that allow for better interpretation of bowel viability, lack of radiation exposure, and ease of obtaining images at the bedside.


Objective: AUS can identify changes that occur in the bowel of preterm infants.

Design/Methods: This was a prospective observational cohort study that enrolled infants 26-34 weeks’ gestation within 48 hours of admission to the NICU, who were expected to stay in the NICU for more than 10 days. Infants had an AUS done by a pediatric ultrasonographer once per week. The AUS focused on identifying bowel wall thickness, echotexture, presence of peristalsis, intra-abdominal fluid, bowel perfusion, portal venous gas, and abdominal free air. If an infant developed abdominal symptom defined by modified Bell staging criteria, they underwent twice per week AUS until symptom resolution. All images were reviewed by a pediatric radiologist. Incidental findings of clinical significance were disclosed to the primary clinical team.

Results: Seven infants were enrolled in the study and thirty-five ultrasounds were performed. All infants demonstrated normal bowel peristalsis and perfusion. Trace intra-abdominal fluid was identified in all study patients. No portal venous gas or abdominal free air was identified. One infant had abnormal bowel wall thickness without associated pathology. One infant developed stage 3A necrotizing enterocolitis which was preceded by bowel distention on two AUS, as well as echogenic mesenteric and retroperitoneal fat. An additional infant had an incidental finding of echogenic mesenteric and retroperitoneal perinephric fat. Significant mobile debris was seen in the bladder of one infant on two AUS. All study patients tolerated the AUS exams.

Conclusion(s):
AUS is a feasible bedside tool that can assess peristalsis, blood flow, bowel wall thickness, and presence of free fluid in preterm infants in a real-time longitudinal manner. A novel AUS protocol can be successfully integrated into an US-naïve NICU. A larger-scale study is needed to determine the diagnostic utility of AUS in preterm infants.


Fig 1 Transverse view of dilated bowel.jpeg

Fig 2 Echogenic mesenteric and retroperitoneal perinephric fat.jpeg