Objective: We observed two clusters of spontaneous pneumoperitoneums in extremely low birth weight infants during the use of a protocol for early dexamethasone prophylaxis (EDP) for bronchopulmonary dysplasia from 1996 to 1997. During surgery, focal small bowel perforation (FSBP) was found in eight of nine cases. A retrospective study was designed to identify risk factors for FSBP in these extremely low birth weight infants.
Methods: A case-controlled analysis was performed using all infants born weighing < 1001 gm and admitted to the University of Washington Medical Center Neonatal Intensive Care Unit during a 13-month period. A total of 51 infants were identified and divided into groups based on treatment or not with dexamethasone and indomethacin. These cohorts were homogeneous for gestational age, birth weight, and perinatal stability. Relative risk and confidence intervals were calculated for each of the comparisons. Routine pathology was performed on all surgical specimens and additional sections were cut and stained for further study.
Results: Infants who received EDP had a relative risk of perforation that was 12.3 times that of untreated infants. Those treated with indomethacin had a risk that was comparable with that for infants who did not receive indomethacin. Infants who received both EDP and indomethacin tended to have higher rates of pneumoperitoneum than infants who received EDP alone but comprised a cohort too small for valid analysis. The pathology of surgical specimens revealed FSBP with segmental loss of the muscularis externa. There was no evidence of fungal or bacterial infection in any of the surgical specimens.
Conclusion: These findings implicate EDP, but not indomethacin, as a significant risk factor for FSBP.