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 in very low birth weight infants relate to enteral feeding regimens. Observational studies suggest that conservative feeding regimens such as delaying the introduction of enteral feeds or slowly advancing feed volumes reduce the risk of necrotising enterocolitis Objectives To determine the effect of slow rates of enteral feed advancement on the incidence of necrotising enterocolitis, mortality and other morbidities in very low birth weight infants. Search strategy The standard search strategy of the Cochrane Neonatal Group was used. Searches were made of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2007), MEDLINE (1966 - December 2007), EMBASE (1980 December 2007), CINAHL (1982- December 2007), 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 necrotising enterocolitis in very low birth weight infants. Data collection and analysis The standard methods of the Cochrane Neonatal Group were used, with separate evaluation of trial quality and data extraction by two authors. Data were synthesised using a fixed effects model and reported using typical relative risk, typical risk difference and weighted mean difference. Main results Three randomised controlled trials in which a total of 396 infants participated were identified. Few participants were extremely low birth weight or growth restricted. The trials were generally of good methodological quality but caregivers and investigators were aware of the allocated interventions. Meta-analyses did not detect statistically significant effects on the risk of necrotising enterocolitis [typical relative risk 0.96 (95% confidence interval 0.48 to 1.92); typical risk difference 0.00 (95% confidence interval -0.05 to 0.05)] or all cause mortality [typical relative risk 1.40 (95% confidence interval 0.71 to 2.80); typical risk difference 0.03 (95% confidence interval -0.03 to 0.10)]. Infants who had slow rates of feed volume advancement took longer to regain birth weight [reported median difference between two and five days] and to establish full enteral feeding [reported median difference between three and five days]. No statistically significant effect on the total duration of hospital stay was detected. Author's conclusions The currently available data do not provide evidence that slow advancement of enteral feed volumes reduces the risk of necrotising enterocolitis in very low birth weight 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 important clinical outcomes in very low birth weight infants, and particularly in extremely low birth weight or growth restricted infants.