Slow advancement of enteral feed volumes to prevent necrotising enterocolitis in very low birth weight infants

Background The major modifiable risk factors for necrotising enterocolitis (NEC) in very low birth weight (VLBW) infants relate to enteral feeding practices. Observational studies suggest that conservative feeding regimens that include slowly advancing enteral feed volumes reduce the risk of NEC. However, slow feed advancement may delay establishment of full enteral feeding and so be associated with metabolic and infectious morbidities secondary to prolonged exposure to parenteral nutrition. Objectives To determine the effect of slow rates of enteral feed advancement on the incidence of NEC, mortality and other morbidities in VLBW infants. Search strategy We used the standard search strategy of the Cochrane Neonatal Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2010, Issue 4), MEDLINE (1966 to December 2010), EMBASE (1980 toDecember 2010), CINAHL (1982 to December 2010), conference proceedings, and previous reviews. Selection criteria Randomised or quasi-randomised controlled trials that assessed the effect of slow (up to 24ml/kg/day) versus faster rates of advancement of enteral feed volumes upon the incidence of NEC in VLBW infants. Data collection and analysis Data collection and analysis was performed in accordance with the standard methods of the Cochrane Neonatal Review Group. Main results We identified four randomised controlled trials in which a total of 496 infants participated. Few participants were extremely low birth weight or growth restricted. The trials defined slow advancement as daily increments of 15 to 20 ml/kg and faster advancement as 30 to 35 ml/kg. Meta-analyses did not detect statistically significant effects on the risk of NEC (typical relative risk 0.91, 95% confidence interval 0.47 to 1.75) or all cause mortality (typical relative risk 1.43, 95% confidence interval 0.78 to 2.61). Infants who had slow rates of feed volume advancement took significantly longer to regain birth weight [reported median difference 2 to 6 days] and to establish full enteral feeding [reported median difference 2 to 5 days]. Authors' conclusions Current data do not provide evidence that slow advancement of enteral feed volumes reduces the risk of NEC in VLBW infants. Increasing the volume of enteral feeds at slow rather than faster rates results in several days delay in regaining birth weight and establishing full enteral feeds but the long term clinical importance of these effects is unclear. Further randomised controlled trials are needed to determine how the rate of daily increment in enteral feed volumes affects clinical outcomes in VLBW infants.