Trajectory of Metabolic Derangement in Infants with Necrotizing Enterocolitis Should Drive Timing and Technique of Surgical Intervention

BACKGROUND: Seven clinical metrics of metabolic derangement (MD7) have improved the timing of surgical intervention in infants with necrotizing enterocolitis (NEC). We compared surgical NEC outcomes based on MD7 at our center (unit S) with a similar center (unit B) that based its intervention on abdominal radiograph. STUDY DESIGN: Premature infants undergoing surgical care for NEC were evaluated. MD7 included positive blood culture, acidosis, bandemia, hyponatremia, thrombocytopenia, hypotension, and neutropenia. Surgical recommendations were stratified as observation or intervention. Good outcomes included full enteric feeding by discharge and poor outcomes were death or dependence on parenteral nutrition. For unit S and unit B, the frequency, median, and mode of MD7 component per case were determined for observation and intervention. Mann-Whitney U test and Wilcoxon matched pairs were used to compare positive MD7 frequency for observation with intervention. Institutional mortality was compared and metabolic severity of unit cohorts was evaluated by incidence of MD7 in each. RESULTS: From March 2005 to July 2008, forty-one infants at unit S underwent 62 surgical evaluations. Observation was elected in 38 (median 1 MD7 per case, mode 0). Operative intervention occurred in 24 (median 4 MD7 per case, mode 4). Proportional MD7 difference between observation and intervention was significant (p = 0.018, U = 6). From February 2007 to December 2008, sixty-five unit B infants received 81 evaluations, recommending 37 observations (median 2 MD7 per case, mode 2), and 44 interventions (median 3 MD7 per case, mode 3). MD7 proportions between observation and intervention were not significant (p = 0.318, U = 16). Poor outcomes rates for unit S and unit B infants were 24% and 66%, respectively (p = 0.0001). Severity of MD7 did not differ between institutions (p = 0.53, U = 19). CONCLUSIONS: These data demonstrate variability in surgical approach to NEC. The MD7 panel describes the trajectory of metabolic derangement, defines more timely surgical intervention, and demonstrates that waiting for free air is too late. (J Am Coll SLIT 2010;210:847-854. (C) 2010 by the American College of Surgeons)