Purpose or Case Report: Although ultrasound has advantages for bowel assessment in infants, the majority of bowel evaluation still takes place by radiograph. Although radiographic signs of advanced necrotizing enterocolitis (NEC) have been well documented, there is poor understanding of gas patterns in less severe NEC or other causes of feeding intolerance. Progressively abnormal appearance of gas patterns in NEC has been described, but it is unclear what role a gastric sump plays. Because a sump decompresses bowel and changes the gas pattern, its role in the progression of abnormal bowel gas patterns warrants attention.
Methods & Materials: We retrospectively reviewed bowel gas patterns in babies < 1 year old in the neonatal intensive care unit (NICU) over a one-year period. We selected infants whose abdomen or chest/abdomen radiographs were performed for reasons including: NEC, necrotizing, enterocolitis, pneumatosis, distension, or perforation. To assess how the sump affected progression of bowel gas pattern, we randomly selected 11 infants with 5 - 20 radiographs for the above indications performed < 24 hours from each prior. We evaluated supine radiographs using the Duke Abdominal Assessment Score (DAAS) and noted sump presence in the images. Chi-square tests assessed differences in proportions of infants with presence/absence of sump having positive/negative DAAS score.
Results: Our review included 107 exams on 11 patients. DAAS score 4 (Separation or focal thickening of bowel loops) was associated with presence of a sump in 88% of exams (p = 0.01). DAAS scores 0 (Normal gas pattern) and 2 (Moderate distention) were associated with absence of a sump in 62% of exams (p < 0.01) and 78% of exams (p < 0.05), respectively. DAAS score 3 (Focal moderate distention of bowel loops) had a trending significance with a sump present in 77% of exams (p = 0.07). Remainder of the DAAS scores ≤ 7 had no association with sump. No DAAS scores > 7 were recorded in our study.
Conclusions: Presence of a sump was associated with the appearance of separation or focal thickening of bowel loops and may correlate with focal moderate distention in a larger sample. It is therefore worth considering whether these gas patterns truly represent progression of disease or simply bowel decompression with a sump. In such cases, ultrasound may help differentiate fluid-filled bowel from partially decompressed bowel. A better understanding of the pathophysiology underlying these gas patterns may help guide management before the advanced stage of NEC.