Rapid Enteral Feed Volume Advancement’s Effect on Necrotizing Enterocolitis in Very Low Birthweight Preterm Infants

Background: Necrotizing enterocolitis (NEC) is a life-threatening disease of the gastrointestinal tract associated with prematurity and low birthweight in infants. Etiology is likely multifactorial, though perhaps the most indicative risk factor is an immature immune system related to preterm birth. Also, while the role of low birthweight in NEC development is not currently understood, there appears to be a strong correlation between the two. It is estimated that infants with a birthweight of ≤ 1500g, otherwise known as very low birthweight infants or VLBW, account for 12% of NEC morbidity with an associated 30% mortality. Poor swallowing coordination in these infants necessitates enteral feeding until they can safely feed orally without aspirating. However, the introduction of a nasogastric or orogastric tube provides pathogens with a portal of entry to the neonatal gut as well as serving as a reservoir, further increasing the risk for infection. This review aimed to evaluate the effect of rapid enteral feeding volume advancement on NEC incidence in very low birthweight (VLBW) preterm infants compared to slow enteral feeding volume advancement

Methods: After a literature search of CINAHL, PubMed, and Web of Science, two randomized controlled trials and one retrospective cohort study were selected. Key search terms included “preterm” or “premature”, “infant” or “neonate”, “enteral nutrition” or “enteral feed”, “necrotizing enterocolitis” or “NEC”, “neonatal intensive care unit” or “NICU”, and “very low birthweight” or “VLBW”. Inclusion criteria consisted of studies published within 10 years, studies written in English, and studies designed as either experimental or quasi-experimental studies. In total, 9 studies fit the inclusion criteria. The selection was further narrowed based on the similarity of target populations, interventions, and measurement of outcomes.

Results: Study sample sizes ranged from 100 participants to 224 participants and included infants in both the very low birthweight and extremely low birthweight (≤ 1000g) classes. Rapid enteral feed volume advancement rates ranged from advancing by 25 - 36 ml/kg/day while slow enteral feed volume advancement rates ranged from advancing by 15 - 24 ml/kg/day. All four studies found that the rate of enteral feeding volume advancement had no significant effect on NEC incidence. Maas et al. (2013) found NEC incidence was 3.2% in the rapid group versus 2.7% in the control group (no p-value) and Krishnamurthy, Gupta, Debnath and Gomber (2010) found NEC occured in 4% of the rapid advancement group versus 2% of the slow advancement group (p=1). Raban et al. (2016) concluded that that rapid feed volume advancement did not significantly increase the risk of developing NEC compared to slow feed volume advancement (OR = 1.00, 95% CI = 0.51-3.57, p = 0.54). Karagol, Zenciroglu, Okumus, & Polin (2013) found 9% of participants in the rapid advancement group developed NEC versus 11% of participants in the slow advancement group (p = 0.42). Additionally, Raban et al. (2016), Krishnamurthy, Gupta, Debnath and Gomber (2010), and Karagol, Zenciroglu, Okumus, & Polin (2013) found that rapid feeding volume advancement significantly reduced the time to regain birthweight. Maas et al. (2013), Krishnamurthy, Gupta, Debnath and Gomber (2010), and Karagol, Zenciroglu, Okumus, & Polin (2013) found that rapid enteral feeding volume advancement significantly reduced the time to reach full enteral feeds. Krishnamurthy, Gupta, Debnath and Gomber (2010) and Karagol, Zenciroglu, Okumus, and Polin (2013) found that rapid feeding volume advancement significantly reduced length of stay while Maas et al (2013) found that it did not significantly reduce the length of stay. Raban et al. (2016) found that infant who received rapid enteral feeding volume advancement with a high initial feed volume were significantly more likely to have a shorter length of stay, but also found that this effect did not extend beyond 58 days.

Conclusion: The preliminary findings of this review indicate that rapid enteral feed volume advancement presents multiple benefits without increasing the risk of developing NEC in stable preterm neonates. As clinicians trained to deliver feeds, evaluate feeding tolerance, and identify and report early signs of NEC, nurses are uniquely positioned to advocate for the revision of hospital feeding practices to produce better outcomes for their patients. However, the generalization of the findings is limited due to the inclusion of extremely low birthweight (birthweight ≤ 1000g) and exclusion of medically unstable neonates, and single-center design. Future research should focus on evaluating other subclasses of low birthweight infants and expanding to multi-center studies.