NEC Screening Abdominal Radiograph vs Bowel Ultrasound in Preemies

Pilot Randomized Control Trial of Necrotizing Enterocolitis Screening Abdominal Radiograph Versus Bowel Ultrasound Plus Abdominal Radiograph in Premature Neonates

The overall primary objective is to establish the feasibility and pilot the design and delivery of a diagnostic randomized controlled trial (RCT) of BUS (bowel ultrasound) for NEC evaluation which will lead to a successful application for a larger, multi-center clinical trial in the future. This program of research is anticipated to have a significant positive impact in the timely and accurate diagnosis of NEC in preterm infants.

Necrotizing enterocolitis (NEC) is the most common bowel disease in premature and low birth weight neonates. NEC is defined by the loss of mucosal integrity of the bowel wall enabling bacteria and other toxins to permeate into the bowel causing ischemia and necrosis which can lead to bowel perforation and sepsis. NEC can result in substantial morbidity and mortality and prolonged hospital stay. In the past, abdominal radiography has been scored on a standard scale that correlated with outcomes. Duke University Medical Center developed a standardized ten-point radiographic scale, the Duke Abdominal Assessment Scale (DAAS) (Appendix B) and was proven to be directly proportional to the severity of NEC on patients that underwent surgery. Abdominal radiographs are assessed for gas pattern, bowel distention, location and features, pneumatosis (gas in bowel wall), portal venous gas, and pneumoperitoneum (free air in peritoneal cavity) to indicate the level of suspicion of NEC. The use of abdominal radiographs is the most common assessment for suspected NEC in infants, however, there have been recent studies done on the utility of bowel ultrasound to aid in early diagnosis of NEC due to the ability to evaluate peristalsis, echogenicity and thickness of bowel wall, pneumatosis and the capability of doing color Doppler to evaluate blood perfusion. A University of Toronto study used ultrasound to assess bowel perfusion with color Doppler in neonates and found a correlation between absence of bowel wall perfusion and the increased severity of NEC on surgical pathology. Although there are similar signs found between abdominal radiography and bowel ultrasound, some of the more severe features such as, pneumoperitoneum, were found to be more sensitive on bowel ultrasound, thus potentially leading to more definitive treatment. Currently, there is no good study evaluating whether the use of bowel ultrasound affects clinical outcomes in VLBW patients over the use of abdominal radiography alone. The use bowel ultrasound has yet to be adopted in the setting of suspicion for NEC at our institution. This is primarily due to the lack of expertise of the ultrasound technologists, radiologists and clinicians. With literature dating back to 2005 supporting the use of bowel ultrasound in diagnosis of severity of NEC, we would like to see if a regimen involving combined ultrasound and radiograph screening for NEC would make a difference in clinical outcomes (morbidity, mortality, and length of stay (LOS)) compared with radiograph screening alone. Calprotectin is a protein found in the stool that, at elevated levels, indicates gastrointestinal inflammation. The addition of fecal biomarkers to the diagnostic work up for NEC also has promising impact. It has been suggested that fecal calprotectin levels obtained at the time of suspicion of NEC may be a useful noninvasive indicator to determine the severity of inflammation in the intestine and whether it is related to NEC or other forms of inflammation. Correlation of the fecal biomarkers with findings on BUS may be helpful to more definitively diagnose NEC.

Infants randomized to the AXR only arm will obtain an AXR as per standard of care. Repeat AXR, if any, will be left to the discretion of the treating neonatologist. In this arm, no BUS study will be performed unless the attending neonatologist decides it is clinically indicated. This situation is expected to be exceedingly rare, as BUS is not part of the standard of care for NEC evaluation. Infants randomized to the AXR and BUS arm will also get an AXR, with repeat AXR left to the discretion of the treating neonatologist. In addition to this standard of care, infants randomized to this arm will receive a BUS as the intervention. This BUS will be ordered at the same time as the initial AXR and will be performed within six hours of the order being placed.

Infants randomized to Arm B will obtain an abdominal x-ray (AXR) as per standard of care and a bowel ultrasound (BUS) as the intervention

Evaluate the difference between medical and surgical management between study arms. Medical management is defined as subjects whom did not undergo surgery for their NEC diagnosis. Surgical management is defined as subjects that had a surgical intervention for the NEC diagnosis. Please note that the study was terminated due to low enrollment numbers, thus statistically relevant and applicable numbers cannot be generated from this small study sample.

The number of days between NEC diagnosis and surgical intervention for those that need it. Days were continuously counted until subject was discharged from the hospital. Please note that the study was terminated due to low enrollment numbers, thus statistically relevant and applicable numbers cannot be generated from this small study sample.

Number of nothing by mouth (NPO) days between subject diagnosis of NEC to when subject was placed back on continuous feeds. Please note that the study was terminated due to low enrollment numbers, thus statistically relevant and applicable numbers cannot be generated from this small study sample.

Inclusion Criteria: • Neonates born prior to or at 28 weeks gestation admitted to NICU at CMH Exclusion Criteria: Infants with chromosomal or multiple congenital anomalies Unable to ultrasound the bowel (e.g. gut in silo, omphalocele, gastroschisis) Infants who are greater than 36 corrected weeks upon admission

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