Necrotizing enterocolitis: risk factor analysis and role of gastric residuals in very low birth weight infants

Necrotizing enterocolitis (NEC) usually occurs in very low birth weight infants and is the most common gastrointestinal emergency in the neonatal intensive care unit. Inasmuch as NEC mortality and morbidity are extremely high, early diagnosis becomes essential. Increased gastric residuals are used to define NEC stage, but studies on qualitative and quantitative residual features as markers of NEC risk are still lacking. The primary goal of this analysis was evaluation of the role of gastric residuals in early identification of patients at risk for NEC. The secondary goal was investigation of NEC risk factors, besides prematurity and birth weight.

In a case-control study, NEC patients were matched with control infants by gestational age and birth weight. Feeding tolerance was assessed by maximum gastric residual volume, maximum residual as percentage of previous feeding, and residual appearance. Mortality and NEC risk factors were also evaluated.

In all, 844 very low birth weight infants were admitted to the neonatal intensive care unit during the study period, with an overall mortality before discharge of 14.6%. NEC frequency was 2%. Patent ductus arteriosus was significantly associated with NEC. Mean maximum residual from birth to NEC onset and maximum residual as percentage of the corresponding feed volume were significantly higher in patients than in control infants, as was the percentage of infants with hemorrhagic residuals.

Gastric residuals are a marker of feeding intolerance, and bloody residuals seem to be the best predictor for NEC. For early detection of very low birth weight infants at risk for NEC, both gastric residual volumes and bloody residuals represent an early relevant marker.