Executive summary of the workshop "Nutritional Challenges in the High Risk Infant"

High versus standard volume enteral feeds to promote growth in preterm or low birth weight infants

BACKGROUND

Human milk is the best enteral nutrition for preterm infants. However, human milk, given at standard recommended volumes, is not adequate to meet the protein, energy, and other nutrient requirements of preterm or low birth weight infants. One strategy that may be used to address the potential nutrient deficits is to give a higher volume of enteral feeds. High volume feeds may improve nutrient accretion and growth, and in turn may improve neurodevelopmental outcomes. However, there are concerns that high volume feeds may cause feed intolerance, necrotising enterocolitis, or complications related to fluid overload such as patent ductus arteriosus and chronic lung disease. This is an update of a review published in 2017.

OBJECTIVES

To assess the effect on growth and safety of high versus standard volume enteral feeds in preterm or low birth weight infants. In infants who were fed fortified human milk or preterm formula, high and standard volume feeds were defined as > 180 mL/kg/day and ≤ 180 mL/kg/day, respectively. In infants who were fed unfortified human milk or term formula, high and standard volume feeds were defined as > 200 mL/kg/day and ≤ 200 mL/kg/day, respectively.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search Cochrane Central Register of Controlled Trials (CENTRAL; 2020 Issue 6) in the Cochrane Library; Ovid MEDLINE (1946 to June 2020); Embase (1974 to June 2020); and CINAHL (inception to June 2020); Maternity & Infant Care Database (MIDIRS) (1971 to April 2020); as well as previous reviews, and trial registries.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared high versus standard volume enteral feeds for preterm or low birth weight infants.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We analysed treatment effects in individual trials and reported risk ratio (RR) and risk difference for dichotomous data, and mean difference (MD) for continuous data, with respective 95% confidence intervals (CIs). We used the GRADE approach to assess the certainty of evidence. The primary outcomes were weight gain, linear and head growth during hospital stay, and extrauterine growth restriction at discharge.

MAIN RESULTS

We included two new RCTs (283 infants) in this update. In total, we included three trials (347 infants) in this updated review. High versus standard volume feeds with fortified human milk or preterm formula Two trials (283 infants) met the inclusion criteria for this comparison. Both were of good methodological quality, except for lack of masking. Both trials were performed in infants born at < 32 weeks' gestation. Meta-analysis of data from both trials showed high volume feeds probably improves weight gain during hospital stay (MD 2.58 g/kg/day, 95% CI 1.41 to 3.76; participants = 271; moderate-certainty evidence). High volume feeds may have little or no effect on linear growth (MD 0.05 cm/week, 95% CI -0.02 to 0.13; participants = 271; low-certainty evidence), head growth (MD 0.02 cm/week, 95% CI -0.04 to 0.09; participants = 271; low-certainty evidence), and extrauterine growth restriction at discharge (RR 0.71, 95% CI 0.50 to 1.02; participants = 271; low-certainty evidence). We are uncertain of the effect of high volume feeds with fortified human milk or preterm formula on the risk of necrotising enterocolitis (RR 0.74, 95% CI 0.12 to 4.51; participants = 283; very-low certainty evidence). High versus standard volume feeds with unfortified human milk or term formula One trial with 64 very low birth weight infants met the inclusion criteria for this comparison. This trial was unmasked but otherwise of good methodological quality. High volume feeds probably improves weight gain during hospital stay (MD 6.2 g/kg/day, 95% CI 2.71 to 9.69; participants = 61; moderate-certainty evidence). The trial did not provide data on linear and head growth, and extrauterine growth restriction at discharge. We are uncertain as to the effect of high volume feeds with unfortified human milk or term formula on the risk of necrotising enterocolitis (RR 1.03, 95% CI 0.07 to 15.78; participants = 61; very low-certainty evidence).

AUTHORS' CONCLUSIONS

High volume feeds (≥ 180 mL/kg/day of fortified human milk or preterm formula, or ≥ 200 mL/kg/day of unfortified human milk or term formula) probably improves weight gain during hospital stay. The available data is inadequate to draw conclusions on the effect of high volume feeds on other growth and clinical outcomes. A large RCT is needed to provide data of sufficient quality and precision to inform policy and practice.

Role of the Proportional Intake of Fortified Mother's Own Milk in the Weight Gain Pattern of Their Very-Preterm-Born Infants

Breastfeeding has been recommended for preterm infants as the optimal diet from nutritional, gastrointestinal, immunological, and developmental perspectives. However, the relevance of differing intakes of fortified mother’s own milk (MOM) on the growth of their preterm infants is a challenging question because of the potential risk of extrauterine growth impairment, apart from its essential role in the provision of biological and immunological factors, and the reduction of serious morbidities. We aimed to identify the weight gain pattern in very-preterm-born infants with respect to their proportional intake of fortified MOM. The daily and average weight gain, dietary volume, calories, and proportional intake of fortified MOM were studied in a cohort of 84 very-preterm-born infants during the first 2 weeks post initiation of full enteral feeds. Groups 1, 2, and 3 were comprised of infants with a proportional fortified MOM intake of 85% or more, 35% to 84.9%, and 0 to 34.9%, respectively. Data analysis included regression models and a group-based comparison of the number of infants with weight gain that would be considered minimally acceptable for normal intrauterine growth. The infants’ weight gain was not found to be associated with the proportional intake of fortified MOM or other feeding parameters. Overall, the intergroup variability in the proportion of infants with weight gain less than the lower limit of normal fetal growth was insignificant. During the first 2 weeks post initiation of full enteral feeds, the weight gain pattern of the studied very-preterm-born infants was not significantly dependent on the proportional intake of fortified maternal milk.

Early Serum Gut Hormone Concentrations Associated With Time to Full Enteral Feedings in Preterm Infants

OBJECTIVES

The primary objective of this study was to evaluate early postnatal serum gut hormone concentrations in preterm infants as predictors of time to full enteral feedings. The secondary objective was to identify infant characteristics and nutritional factors that modulate serum gut hormone concentrations and time to full enteral feedings.

METHODS

Sixty-four preterm infants less than 30 weeks of gestation were included in this retrospective cohort study. Serum gut hormone concentrations at postnatal days 0 and 7 were measured using enzyme-linked immunosorbent assays. Linear regression and mediation analyses were performed.

RESULTS

Median (interquartile range) serum concentrations of glucose-dependent insulinotropic peptide (GIP) and peptide YY (PYY) on postnatal day 7 were 31.3 pg/mL (18.2, 52.3) and 1181.7 pg/mL (859.0, 1650.2), respectively. GIP and PYY concentrations on day 7 were associated with days to full enteral feedings after adjustment for confounders (β = -1.1, P = 0.03; and β = -0.002, P = 0.02, respectively). Nutritional intake was correlated with serum concentrations of GIP and PYY on postnatal day 7 and time to full enteral feedings. Mediation analysis revealed that the effect of serum gut hormone concentrations on time to full enteral feedings was not fully explained by nutritional intake. Intrauterine growth restriction, mechanical ventilation on postnatal day 7, and patent ductus arteriosus treated with indomethacin were associated with longer time to full enteral feedings.

CONCLUSIONS

Serum concentrations of GIP and PYY on postnatal 7 are independently associated with time to full enteral feedings. The link between serum gut hormone concentrations and time to full enteral feedings is not fully mediated by nutritional factors, suggesting an independent mechanism underlying the influence of gut hormones on feeding tolerance and time to full enteral feedings.

Comparison of volume and frequency advancement feeding protocols in very low birth weight neonates

Objective:

To determine the outcomes in very low birth weight (VLBW) neonates receiving volume advancement versus frequency advancement feeding protocols.

Methods:

This controlled clinical trial was conducted in Children Hospital Multan within duration of 6 months from February 2017 to August 2017. VLBW neonates having weight < 1500 g at the time of birth were included. The protocol for frequency advancement (FA) group was to give 1 ml/kg human or pre-formula milk after every 8 hours and in volume advancement (VA) group after every 3 hours initially. After three days, in FA group duration of feeds was decreased gradually from 8 to 2 hours and feed volume of 10 ml.kg^-1.day^-1 until full-recommended dose of feeding i.e. 150 ml.kg^-1.day^-1 reached. While in VA group, volume of 20 ml.kg^-1.day^-1 was given until full-recommended dose of feeding reached. Days to achieve full feed, weight gain, and length of hospital stay were primary study outcomes.

Results:

Baseline weight of neonates was 1148 (111) grams in VA 1179 (106) grams in FA groups (p-value 0.18). In VA group, full feed was achieved in 11.04 (2.38) days versus 15.76 (2.48) days in FA group (P-value <0.001). Duration of IV fluid therapy were 13.5 (8.4) days in FA group versus 9.4 (7.6) in VA group (p-value <0.001). Moreover weight gain at the end of feeding protocol was significantly higher in VA group 1440 (78) grams versus 1284 (99) grams in FA group (P-value <0.001). Necrotizing entero-colitis occurred in only one neonate that was belonging to volume advancement group.

Conclusion:

Volume advancement (VA) feeding is better as compared to frequency advancement (FA) feeding in very low birth weight neonates.

Growth and body composition of preterm infants less than or equal to 32 weeks: Cohort study

BACKGROUND

Extremely preterm infants with weights less than the 10th percentile at discharge have a fat-free mass deficit.

AIM

To analyze the relationship of weight Z-scores less than -2SD at term age with fat-free mass and fat mass at term age and at 1 and 3 months of corrected age in very preterm infants.

STUDY DESIGN

COHORT STUDY: Subjects: Sixty-six preterm infants born before or at 32 weeks gestation with birth weight equal or greater than the 10th percentile for age were included at term age. They were classified according to weight Z-score as either: "term (-)" (n = 18) if weight Z-scores were less -2SD or "term (+)" (n = 48) if the weight Z-scores were equal or greater than -2SD at term age.

OUTCOME MEASURES

Growth and body composition by an air displacement plethysmography system and bioimpedance were assessed at term age and 1 and 3 months of corrected age.

RESULTS

Lower fat-free mass persisted up to 3 months in the "term (-)" group [4137 g (645) vs 4592 g (707), p < .01]. Fat mass was lower in the "term (-)" group at term and at 1 month but was similar at 3 months of corrected age [1295 g (774) vs 1477 g (782), p = .109]. Weight, length and head circumference Z-scores were lower in the "term (-)" group compared to those in the "term (+)" group.

CONCLUSIONS

The lean tissue deficits were maintained in the "term (-)" group while the differences in body fat percentage were not.

High versus standard volume enteral feeds to promote growth in preterm or low birth weight infants

BACKGROUND

Breast milk alone, given at standard recommended volumes (150 to 180 mL/kg/d), is not adequate to meet the protein, energy, and other nutrient requirements of growing preterm or low birth weight infants. One strategy that may be used to address these potential nutrient deficits is to give infants enteral feeds in excess of 200 mL/kg/d ('high-volume' feeds). This approach may increase nutrient uptake and growth rates, but concerns include that high-volume enteral feeds may cause feed intolerance, gastro-oesophageal reflux, aspiration pneumonia, necrotising enterocolitis, or complications related to fluid overload, including patent ductus arteriosus and bronchopulmonary dysplasia.

OBJECTIVES

To assess the effect on growth and safety of feeding preterm or low birth weight infants with high (> 200 mL/kg/d) versus standard (≤ 200 mL/kg/d) volume of enteral feeds. Infants in intervention and control groups should have received the same type of milk (breast milk, formula, or both), the same fortification or micronutrient supplements, and the same enteral feeding regimen (bolus, continuous) and rate of feed volume advancement.To conduct subgroup analyses based on type of milk (breast milk vs formula), gestational age or birth weight category of included infants (very preterm or VLBW vs preterm or LBW), presence of intrauterine growth restriction (using birth weight relative to the reference population as a surrogate), and income level of the country in which the trial was conducted (low or middle income vs high income) (see 'Subgroup analysis and investigation of heterogeneity').

SEARCH METHODS

We used the Cochrane Neonatal standard search strategy, which included searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2) in the Cochrane Library; MEDLINE (1946 to November 2016); Embase (1974 to November 2016); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to November 2016), as well as conference proceedings, previous reviews, and trial registries.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared high-volume versus standard-volume enteral feeds for preterm or low birth weight infants.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We analysed treatment effects in individual trials and reported the risk ratio and risk difference for dichotomous data, and the mean difference for continuous data, with respective 95% confidence intervals. . We assessed the quality of evidence at the outcome level via the GRADE approach.

MAIN RESULTS

We found one eligible trial that included 64 infants. This trial was not blinded. Analysis showed a higher rate of weight gain in the high-volume feeds group: mean difference 6.20 g/kg/d (95% confidence interval 2.71 to 9.69). There was no increase in the risk of feed intolerance or necrotising enterocolitis with high-volume feeds, but 95% confidence intervals around these estimates were wide. We assessed the quality of evidence for these outcomes as 'low' or 'very low' because of imprecision of the estimates of effect and concern about risk of bias due to lack of blinding in the included trial. Trial authors provided no data on other outcomes, including gastro-oesophageal reflux, aspiration pneumonia, necrotising enterocolitis, patent ductus arteriosus, bronchopulmonary dysplasia, or long-term growth and neurodevelopment.

AUTHORS' CONCLUSIONS

We found only very limited data from one small unblinded trial on the effects of high-volume feeds on important outcomes for preterm or low birth weight infants. The quality of evidence is low to very low. Hence, available evidence is insufficient to support or refute high-volume enteral feeds in preterm or low birth weight infants. A large, pragmatic randomised controlled trial is needed to provide data of sufficient quality and precision to inform policy and practice.

Protein Intake and Growth in Preterm Infants: A Systematic Review

Objective. This review aimed to investigate the relationship between varying levels of enteral protein intake and growth in preterm infants, regardless of feeding method. Data Sources. Electronic databases were searched for relevant studies, as were review articles, reference lists, and text books. Study Selection. Trials were included if they were randomized or quasirandomized, participants were <37 weeks gestation at birth, and protein intakes were intentionally or statistically different between study groups. Trials reporting weight, length, and head circumference gains in infants fed formula, human milk, or fortified human milk were included. Data Extraction. Studies were categorized by feeding-type and relevant data were extracted into summary tables by one reviewer and cross-checked by a second. Data Synthesis. A meta-analysis could not be conducted due to extensive variability among studies; thus, results were synthesized graphically and narratively. Twenty-four trials met the inclusion criteria and were included in a narrative synthesis and 19 in a graphical synthesis of study results. Conclusions. There was extensive variability in study design, participant characteristics, and study quality. Nonetheless, results are fairly consistent that higher protein intake results in increased growth with graphical representation indicating a potentially linear relationship. Additionally, intakes as high as 4.5 g/kg/day were shown to be safe in infants weighing >1000 g.

Feeding tolerance in preterm infants on noninvasive respiratory support

To evaluate differences in feeding tolerance between infants maintained on continuous positive airway pressure (CPAP) and those receiving high-flow (nasal) cannula (HFC) with or without CPAP. This is a retrospective, cross-sectional study. Two groups of very low-birth-weight infants (750-1500 g) were compared on the basis of respiratory support: (1) infants born between the January 2002 and December 2004 treated with CPAP; and (2) infants born between January 2005 and December 2006 treated with HFC with or without CPAP. The groups were compared to determine which of the two attained full feedings sooner. Successful achievement of full feedings was measured in days from birth and defined by discontinuation of hyperalimentation-supplementation and attainment of 120 mL/kg/d of enteral feedings. A total of 185 infants met inclusion criteria (103 who received CPAP exclusively and 82 who received HFC with or without CPAP). There was no statistical difference in time to full enteral feedings between the 2 groups. There was also no difference in time of initiation of oral feeding or days to full oral feedings between 2 groups. The use of HFC was not associated with changes in feeding tolerance in premature infants. Further studies are needed to investigate efficacy and potential advantages and disadvantages to the use of HFC in the very low-birth-weight infant population.

Freezing and thawing effects on fat, protein, and lactose levels of human natural milk administered by gavage and continuous infusion

OBJECTIVES

to analyze the changes in human milk macronutrients: fat, protein, and lactose in natural human milk (raw), frozen and thawed, after administration simulation by gavage and continuous infusion.

METHOD

an experimental study was performed with 34 human milk samples. The infrared spectrophotometry using the infrared analysis equipment MilkoScan Minor® (Foss, Denmark) equipment was used to analyze the macronutrients in human milk during the study phases. The analyses were performed in natural (raw) samples and after freezing and fast thawing following two steps: gavage and continuous infusion. The non-parametric Wilcoxon test for paired samples was used for the statistical analysis.

RESULTS

the fat content was significantly reduced after administration by continuous infusion (p<0.001) during administration of both raw and thawed samples. No changes in protein and lactose content were observed between the two forms of infusion. However, the thawing process significantly increased the levels of lactose and milk protein.

CONCLUSION

the route of administration by continuous infusion showed the greatest influence on fat loss among all the processes required for human milk administration.

Brief parenteral nutrition accelerates weight gain, head growth even in healthy VLBWs

Introduction

Whether parenteral nutrition benefits growth of very low birth weight (VLBW) preterm infants in the setting of rapid enteral feeding advancement is unclear. Our aim was to examine this issue using data from Japan, where enteral feeding typically advances at a rapid rate.

Methods

We studied 4005 hospitalized VLBW, very preterm (23–32 weeks' gestation) infants who reached full enteral feeding (100 ml/kg/day) by day 14, from 75 institutions in the Neonatal Research Network Japan (2003–2007). Main outcomes were weight gain, head growth, and extra-uterine growth restriction (EUGR, measurement <10^th percentile for postmenstrual age) at discharge.

Results

40% of infants received parenteral nutrition. Adjusting for maternal, infant, and institutional characteristics, infants who received parenteral nutrition had greater weight gain [0.09 standard deviation (SD), 95% CI: 0.02, 0.16] and head growth (0.16 SD, 95% CI: 0.05, 0.28); lower odds of EUGR by head circumference (OR 0.66, 95% CI: 0.49, 0.88). No statistically significant difference was seen in the proportion of infants with EUGR at discharge. SGA infants and infants who took more than a week until full feeding had larger estimates.

Discussion

Even in infants who are able to establish enteral nutrition within 2 weeks, deprivation of parenteral nutrition in the first weeks of life could lead to under nutrition, but infants who reached full feeding within one week benefit least. It is important to predict which infants are likely or not likely to advance on enteral feedings within a week and balance enteral and parenteral nutrition for these infants.

Aggressive Nutrition of the Preterm Infant

Nutrition of preterm infants should result in growth similar to that of normally growing fetuses of the same gestational age. Unfortunately, most preterm infants are not fed enough to achieve this objective; as a result they are growth restricted by term gestation. Recent studies have demonstrated that early and enhanced "aggressive" nutrition of preterm infants can reduce postnatal growth failure and improve longer-term outcomes, particularly for the brain and its cognitive functions. When preterm infants are fed more aggressively (earlier onset of intravenous and enteral feeding, earlier achievement of full enteral feeding) cumulative energy and protein deficits are reduced and they consistently regain birth weight sooner, the incidence of necrotizing enterocolitis and late-onset sepsis is unchanged or reduced, and they achieve discharge criteria and go home sooner, with overall shorter hospital stays, and have improved anthropometrics by term gestation. More research is needed, however, to determine optimum feeding of preterm infants, particularly during periods of illness and physiological instability.

Effects of human milk fortifier with iron on the bacteriostatic properties of breast milk

OBJECTIVE

To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier (HMF) containing iron.

METHODS

The growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa in 78 samples of pure colostrum or colostrum with added iron-containing HMF was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 10(1) colony forming units (CFUs)/mL of each strain. For quantitative assessment, 1 mL of each strain containing 10(7) CFUs/mL was homogenized with 1 mL of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37°C. Twenty-four hours later, the number of CFUs was counted.

RESULTS

The qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, E. coli growth in the control group was 29.4±9.7×10(6)CFU/mL, while in the HMF group it was 31.2±10.8×10(6)CFU/mL. The difference between the average growth was 1.9±4.9×10(6)CFU/mL (p=0.001). There were no differences in S. aureus and P. aeruginosa growth.

CONCLUSION

Addition of iron at this concentration reduces breast milk bacteriostatic action against E. coli.

Lactation and neonatal nutrition: defining and refining the critical questions

This paper resulted from a conference entitled "Lactation and Milk: Defining and refining the critical questions" held at the University of Colorado School of Medicine from January 18-20, 2012. The mission of the conference was to identify unresolved questions and set future goals for research into human milk composition, mammary development and lactation. We first outline the unanswered questions regarding the composition of human milk (Section I) and the mechanisms by which milk components affect neonatal development, growth and health and recommend models for future research. Emerging questions about how milk components affect cognitive development and behavioral phenotype of the offspring are presented in Section II. In Section III we outline the important unanswered questions about regulation of mammary gland development, the heritability of defects, the effects of maternal nutrition, disease, metabolic status, and therapeutic drugs upon the subsequent lactation. Questions surrounding breastfeeding practice are also highlighted. In Section IV we describe the specific nutritional challenges faced by three different populations, namely preterm infants, infants born to obese mothers who may or may not have gestational diabetes, and infants born to undernourished mothers. The recognition that multidisciplinary training is critical to advancing the field led us to formulate specific training recommendations in Section V. Our recommendations for research emphasis are summarized in Section VI. In sum, we present a roadmap for multidisciplinary research into all aspects of human lactation, milk and its role in infant nutrition for the next decade and beyond.