Intravenous nutrition and postnatal growth of the micropremie

Macronutrients and Micronutrients in Parenteral Nutrition for Preterm Newborns: A Narrative Review

Preterm neonates display a high risk of postnatal malnutrition, especially at very low gestational ages, because nutritional stores are less in younger preterm infants. For this reason nutrition and growth in early life play a pivotal role in the establishment of the long-term health of premature infants. Nutritional care for preterm neonates remains a challenge in clinical practice. According to the recent and latest recommendations from ESPGHAN, at birth, water intake of 70-80 mL/kg/day is suggested, progressively increasing to 150 mL/kg/day by the end of the first week of life, along with a calorie intake of 120 kcal/kg/day and a minimum protein intake of 2.5-3 g/kg/day. Regarding glucose intake, an infusion rate of 3-5 mg/kg/min is recommended, but VLBW and ELBW preterm neonates may require up to 12 mg/kg/min. In preterm infants, lipid emulsions can be started immediately after birth at a dosage of 0.5-1 g/kg/day. However, some authors have recently shown that it is not always possible to achieve optimal and recommended nutrition, due to the complexity of the daily management of premature infants, especially if extremely preterm. It would be desirable if multicenter randomized controlled trials were designed to explore the effect of early nutrition and growth on long-term health.

Sustaining improved nutritional support for very low birthweight infants

Background

Postnatal growth failure (PGF) in very low birthweight (VLBW) infants is a result of factors such as prematurity, acute illness and suboptimal nutritional support. Before this project began, 84% of appropriately grown VLBW infants in our neonatal intensive care unit experienced PGF. The aims of this quality improvement project were to reduce the percentage of infants discharged with PGF to less than 50% within 2 years and to maintain a rate of PGF under 50%.

Methods

All inborn VLBW infants were eligible for this study. Infants with congenital anomalies were excluded. We determined key drivers for optimal nutrition and identified potentially better practices (process measures) based on a review of the literature, which included more rapid initiation of starter total parenteral nutrition (TPN), aggressive use and advancement of regular TPN, and fortification of human milk when the volume of intake reached 80 mL/kg/day. Three Plan-Do-Study-Act (PDSA) cycles were tested.

Results

Time to initiation of starter TPN was significantly reduced from 5.5 hours to under 3 hours. Regular TPN provided the goals for amino acids and lipids at increased frequency after the first two PDSA cycles. The proportion of infants whose milk was fortified at 80 mL/kg/day increased after the third PDSA cycle.

Conclusions

We found a sustained decrease in the percentage of infants discharged with PGF from 84% at baseline to fewer than 50% beginning in 2010–2011 through 2016, with 23.1% of infants experiencing PGF in 2016. We have achieved improved nutritional support for VLBW infants using the model for improvement.

Early energy and protein intakes and associations with growth, BPD, and ROP in extremely preterm infants

BACKGROUND & AIM

Extremely preterm infants face substantial neonatal morbidity. Nutrition is important to promote optimal growth and organ development in order to reduce late neonatal complications. The aim of this study was to examine the associations of early nutritional intakes on growth and risks of bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) in a high-risk population.

METHODS

This population-based cohort study includes infants born before 27 0/7 weeks of gestational age without severe malformations and surviving ≥10 days. Intake of energy and protein on postnatal days 4-6 and association with weight standard deviation score (WSDS) from birth to day 7, as well as intakes of energy and protein on postnatal days 4-6 and 7 to 27, respectively, and association with composite outcome of death and BPD and separate outcomes of BPD and ROP were examined, and adjusted for potential confounders.

RESULTS

The cohort comprised 296 infants with a median gestational age of 25 3/7 weeks. Expressed as daily intakes, every additional 10 kcal/kg/d of energy during days 4-6 was associated with 0.08 higher WSDS on day 7 (95% CI 0.06-0.11; p < 0.001). Between days 7 and 27, every 10 kcal/kg/d increase in energy intake was associated with a reduced risk of BPD of 9% (95% CI 1-16; p = 0.029) and any grade of ROP with a reduced risk of 6% (95% CI 2-9; p = 0.005) in multivariable models. This association was statistically significant in infants with ≤10 days of mechanical ventilation. In infants with >10 days of mechanical ventilation, a combined higher intake of energy and protein was associated with a reduced risk of BPD.

CONCLUSION

Early provision of energy and protein may reduce postnatal weight loss and risk of morbidity in extremely preterm infants.

Nutrition Support Team Guide to Maternal Diet for the Human-Milk-Fed Infant

BACKGROUND

Human milk feeding is encouraged for all infants; however, the mammary gland depends on maternal dietary intake of vitamins A, B1, B2, B6, B12, D, docosahexaenoic acid (DHA), choline, and iodine. Nutrition support team knowledge of maternal feeding guidelines for these nutrient sources can therefore impact infant intake. We hypothesized that these key nutrients for lactation in the mother's diet would be less than the dietary guidelines in the United States.

METHODS

This was a secondary analysis of nutrition data collected during a randomized, controlled trial. Dietary records were analyzed from 16 mothers (13 with singleton and 3 with multiple births) completing the study. Mean dietary intakes of selected nutrients were calculated and compared with the current dietary reference intakes.

RESULTS

Mean maternal dietary intake for singletons was significantly (P < .05) lower than the dietary reference intakes for (vitamin A (58%), vitamin D (44%), and choline (58%);) DHA comprised only 5% of the current expert recommendation. Based on singleton recommendations, mothers to twins consumed an adequate intake except for DHA.

CONCLUSIONS

Women providing breast milk for singleton preterm infants did not consume dietary reference intakes for key nutrients. Twin mothers' diets were adequate except for DHA, but these guidelines are based on singleton pregnancies and remain poorly understood for twin needs. The nutrition support team can have a unique role in maternal dietary education to impact human milk nutrient delivery to the infant.

First week weight dip and reaching growth targets in early life in preterm infants

BACKGROUND & AIMS

Aggressive parenteral nutritional practices were implemented in clinical practice over a decade ago to prevent early growth retardation in preterm infants. We aimed to study adherence to current nutritional recommendations in a population of very preterm infants, and to evaluate growth in early life.

METHODS

Preterm infants (gestational age <30 weeks and birth weight <1500 g) were included in a prospective observational cohort study. Data on parenteral and enteral intake were collected on days 1-7, 14, 21 and 28 (d28) of life. Growth data were collected at birth, at moment of maximal weight loss (dip), and either at discharge from the neonatal intensive care unit or at d28, whichever came first. Nutritional intakes were compared to recommendations of current guidelines. The target growth rate was 15-20 g/kg/d.

RESULTS

Fifty-nine infants (63% male) were included. Median gestational age was 27 3/7 (interquartile range 25 6/7;28 4/7), and birth weight was 920 g (720;1200). Median macronutrient intakes were within or above the targets on all study days, but energy targets were not met before day 5. Median growth rates were 9.5 and 18.1 g/kg/d, when calculated from respectively birth and dip to discharge/d28. Eight (14%) versus 46 (78%) infants met the growth targets, when evaluated from respectively birth and dip to discharge/d28.

CONCLUSIONS

In this cohort, only energy intake up to day 5 was lower than recommended. Growth targets were achieved in the majority of the infants, but only when evaluated from dip onward, not from birth.

Examining the side effects of sucrose for pain relief in preterm infants: a case-control study

Sucrose solution is recommended as relevant pain relief management in neonates during acute painful procedures; however, only a few studies have analyzed the potentially adverse effects of sucrose administration to preterm neonates. The goal of this study was to examine the potential side effects of sucrose for pain relief in preterm infants, assessing feeding and weight gain during hospitalization and their feeding patterns postdischarge. The study sample consisted of 43 preterm neonates divided into two groups: a sucrose group (SG, n=18) and a control group (CG, n=25) in which no sucrose was administered. The SG received 0.5 mL/kg 25% oral sucrose for 2 min prior to all acute painful procedures during three consecutive days. A prospective review of medical charts was performed for all samples. The study was done prior to implementation of the institutional sucrose guidelines as a routine service, and followed all ethical requirements. There were no statistically significant differences between groups in terms of weight gain, length of stay with orogastric tubes, and parenteral feeding. Postdischarge, infant nutritional intake included feeding human milk to 67% of the SG and 74% of the CG. There were no statistically significant differences between groups regarding human milk feeding patterns postdischarge. Neonate feeding patterns and weight gain were unaffected following the short-term use of sucrose for pain relief.

Standardised neonatal parenteral nutrition formulations - an Australasian group consensus 2012

Standardised parenteral nutrition formulations are routinely used in the neonatal intensive care units in Australia and New Zealand. In 2010, a multidisciplinary group was formed to achieve a consensus on the formulations acceptable to majority of the neonatal intensive care units. Literature review was undertaken for each nutrient and recommendations were developed in a series of meetings held between November 2010 and April 2011. Three standard and 2 optional amino acid/dextrose formulations and one lipid emulsion were agreed by majority participants in the consensus. This has a potential to standardise neonatal parenteral nutrition guidelines, reduce costs and prescription errors.

Adaptive regulation of amino acid metabolism on early parenteral lipid and high-dose amino acid administration in VLBW infants - a randomized, controlled trial

BACKGROUND & AIMS

An anabolic state can be achieved upon intravenous amino acid administration during the immediate postnatal phase despite a low energy intake. The optimal dosing of amino acid and energy intake has yet to be established. The aim was to quantify the efficacy of early initiation of parenteral lipids and increased amounts of amino acids on metabolism and protein accretion in very low birth weight infants.

METHODS

28 very low birth weight infants were randomized to receive parenteral nutrition with glucose and either 2.4 g amino acids/(kg·d) (control group), 2.4 g amino acids/(kg·d) plus 2-3 g lipid/(kg·d) (AA + lipid group), or 3.6 g amino acids/(kg·d) plus 2-3 g lipid/(kg·d) (high AA + lipid group) from birth onward. On postnatal day 2, we performed a stable isotope study with [1-(13)C]phenylalanine, [ring-D4]tyrosine, [U-(13)C6,(15)N]leucine, and [methyl-D3]α-ketoisocaproic acid to quantify intermediate amino acid metabolism.

RESULTS

The addition of lipids only had no effect on phenylalanine metabolism, whereas the addition of both lipids and additional amino acids increased the amount of phenylalanine used for protein synthesis. In addition, high amino acid intake significantly increased the rate of hydroxylation of phenylalanine to tyrosine, increasing the availability of tyrosine for protein synthesis. However, it also increased urea concentrations. Increasing energy intake from 40 to 60 kcal/(kg·d) did not increase protein efficiency as measured by phenylalanine kinetics. The leucine data were difficult to interpret due to the wide range of results and inconsistency in the data between the phenylalanine and leucine models.

CONCLUSIONS

High amino acid and energy intakes from birth onwards result in a more anabolic state in very low birth weight infants, but at the expense of higher urea concentrations, which reflects a higher amino acid oxidation. Long-term outcome data should reveal whether this policy deserves routine implementation. This trial was registered at www.trialregister.nl, trial number NTR1445, name Nutritional Intervention for Preterm Infants-2.

[Neonatal parenteral nutrition prescription practices in Portugal]

INTRODUCTION

The use of guidelines for neonatal parenteral nutrition (PN) improves its clinical efficiency and the safety of prescription.

OBJECTIVE

To evaluate the practices of neonatal parenteral nutrition prescription in Portugal, and the adherence to the National Consensus on neonatal PN (2008).

METHODS

A questionnaire based on a multiple choice response on parenteral nutrition prescription was conducted, and sent to the coordinators of the 50 public and private Portuguese neonatal special care units, 25 being level III and 25 level II.

RESULTS

Parenteral nutrition was prescribed in 32 neonatal units, 23 of which (71.9%) responded to the questionnaire. Of the respondents, 19 (82.6%) refer to follow the National Consensus, the remaining following local guidelines; 17 (73.9%) of units referred to using an electronic based system for prescription. In preterm neonates, most mentioned: administering judiciously the fluid intake during the first post-natal week; starting amino acids from the first post-natal day with 1.5-3g/kg/d, increasing up to 3-4g/kg/d; starting lipids from the first three post-natal days with 1g/kg/d, increasing up to 3g/kg/d; administering 40-70mg/kg/d of calcium and of phosphorus with the fixed calcium:phosphorus ratio of 1.7: 1 (mg:mg); and estimating the osmolality of the solutions, and weekly monitoring of serum triglycerides, blood urea, serum phosphorus and liver function.

CONCLUSIONS

The high response rate is probably representative of the practice of PN prescription in Portugal. Most of the units used the National Consensus on neonatal PN as a reference, thus contributing to better nutritional support for neonates.

Early amino acid administration in very preterm infants: Too little, too late or too much, too soon?

Early postnatal growth failure is well described in very preterm infants. It reflects the nutritional deficits in protein and energy intake that accumulate in the first few weeks after birth. This coincides with the period of maximum parenteral nutrition (PN) dependency, so that protein intake is largely determined by intravenous amino acid (AA) administration. The contribution of PN manufacture, supply, formulation, prescribing and administration to the early postnatal nutritional deficit is discussed, focusing on total AA intake. The implications of postnatal deficits in AA and energy intake for growth are reviewed, with particular emphasis on early head/brain growth and long-term neurodevelopmental outcome. The rationale for maximising AA acid intake as soon as possible after birth is explained. This includes the benefits for very early postnatal nutritional intake and metabolic adaptation after birth. These benefits relate to total AA intake and so have to be interpreted with some caution, given the very limited evidence base surrounding the balance of individual AAs in neonatal PN formulations. This work mostly predates current nutritional recommendations and therefore may not provide a true reflection of individual AA utilisation in current clinical practice.

Blood urea nitrogen and serum bicarbonate in extremely low birth weight infants receiving higher protein intake in the first week after birth

OBJECTIVE

To determine correlation between early protein administration and serum blood urea nitrogen (BUN) or bicarbonate (HCO(3)(-)) in extremely low birth weight (ELBW) infants during the first week of life.

STUDY DESIGN

A retrospective review of 154 ELBWs was conducted. Laboratory and nutritional data from postnatal days 1, 4 and 7 were collected. Repeated measures models estimated the relationship of protein intake with BUN and HCO(3)(-) in the first week of life.

RESULT

In total, 359 separate BUN and HCO(3)(-) values were analyzed. Each gram per kilogram of protein administered was associated with an increase in mean BUN of 3.3 mg/dl. This effect decreased daily by 2.1 mg/dl. Each gram per kilogram of protein administered was associated with a decrease in mean HCO(3)(-) by 0.9 mmol/l.

CONCLUSION

The association between protein load and BUN is positive but decreasing over time. Protein is associated with a clinically insignificant decrease in HCO(3)(-). Concerns regarding metabolic derangement from early protein administration in ELBWs are unwarranted.

SCAMP: standardised, concentrated, additional macronutrients, parenteral nutrition in very preterm infants: a phase IV randomised, controlled exploratory study of macronutrient intake, growth and other aspects of neonatal care

Background

Infants born <29 weeks gestation are at high risk of neurocognitive disability. Early postnatal growth failure, particularly head growth, is an important and potentially reversible risk factor for impaired neurodevelopmental outcome. Inadequate nutrition is a major factor in this postnatal growth failure, optimal protein and calorie (macronutrient) intakes are rarely achieved, especially in the first week. Infants <29 weeks are dependent on parenteral nutrition for the bulk of their nutrient needs for the first 2-3 weeks of life to allow gut adaptation to milk digestion. The prescription, formulation and administration of neonatal parenteral nutrition is critical to achieving optimal protein and calorie intake but has received little scientific evaluation. Current neonatal parenteral nutrition regimens often rely on individualised prescription to manage the labile, unpredictable biochemical and metabolic control characteristic of the early neonatal period. Individualised prescription frequently fails to translate into optimal macronutrient delivery. We have previously shown that a standardised, concentrated neonatal parenteral nutrition regimen can optimise macronutrient intake.

Methods

We propose a single centre, randomised controlled exploratory trial of two standardised, concentrated neonatal parenteral nutrition regimens comparing a standard macronutrient content (maximum protein 2.8 g/kg/day; lipid 2.8 g/kg/day, dextrose 10%) with a higher macronutrient content (maximum protein 3.8 g/kg/day; lipid 3.8 g/kg/day, dextrose 12%) over the first 28 days of life. 150 infants 24-28 completed weeks gestation and birthweight <1200 g will be recruited. The primary outcome will be head growth velocity in the first 28 days of life. Secondary outcomes will include a) auxological data between birth and 36 weeks corrected gestational age b) actual macronutrient intake in first 28 days c) biomarkers of biochemical and metabolic tolerance d) infection biomarkers and other intravascular line complications e) incidence of major complications of prematurity including mortality f) neurodevelopmental outcome at 2 years corrected gestational age

Trial registration

Current controlled trials: ISRCTN76597892; EudraCT Number: 2008-008899-14

The effects of early parenteral amino acids on sick premature infants

OBJECTIVES

To study the effects of early parenteral amino acid administration on body weight, fluid compartments and metabolic parameters during the first week of life in sick premature infants.

METHODS

Appropriate for gestational age, sick premature infants were randomized into two groups. Group A infants (n=8, birth weight 1258±339 g) were supplemented with amino acids starting within 24 h of birth and advanced to 2.5 g/kg per day by day 3. Group G infants (n=9, birth weight 1182±214 g) received amino acids starting on day 4 of life. Energy intake was comparable in the 2 groups. Amino acid concentrations and nitrogen balance studies were performed on day 3 of life. Total body water and extracellular water were measured on day 1 and 8 and change in intracellular volume was calculated.

RESULTS

There was no significant difference between the 2 groups in terms of weight, intracellular volume change from day 1 to day 8 of life, despite a significant (P<0.01) difference in protein intake. Plasma ammonia levels were comparable in the 2 groups, but plasma urea levels were significantly higher in group A vs. group G infants (7.2±3.4 mmol/L vs. 3.2±1.2 mmol/L respectively, P<0.01). Nitrogen balance was positive in all group A infants and negative in group G infants. Nitrogen loss was inversely correlated with energy intake in group G infants (P<0.05). The mean plasma amino acid concentrations in group A infants (compared to those of group G) were within previously reported ranges in older premature infants.

CONCLUSIONS

There was no significant effect on body weight and redistribution of body fluid compartments in infants receiving amino acids early during the first week of life. Serum urea concentrations were significantly higher in infants receiving early amino acids. Nitrogen losses in infants who did not receive amino acids were inversely correlated with energy intake during the first 3 days of life.

Nutritional support for extremely low-birth weight infants: abandoning catabolism in the neonatal intensive care unit

PURPOSE OF REVIEW

Obviously, the ultimate goal in neonatology is to achieve a functional outcome in premature infants that is comparable to healthy term-born infants. As nutrition is one of the key factors for normal cell growth, providing the right amount and quality of nutrients could prove pivotal for normal development. However, many premature infants are catabolic during the first week of life, which has directly been linked to growth failure, disease, and suboptimal long-term outcome. This review describes the progress in research on parenteral nutrition for premature infants with a focus on amino acids and the influence of nutrition on later outcome.

RECENT FINDINGS

Although randomized clinical trials on early nutrition for premature infants remain relatively sparse, evidence is accumulating on its beneficial effects both on the short-term and long-term. However, some research also warns for adverse effects.

SUMMARY

Despite the fact that substantially improved nutritional therapies for preterm neonates have been implemented, still, some reluctance exists when it comes to providing high amounts of nutrition to the most immature infants. Pros and cons are outlined, as well as deficits in knowledge, when it comes to providing the optimal nutrient strategy in the first postnatal phase.

Initial nutritional management of the preterm infant

Postnatal nutrition has a large impact on long-term outcome of preterm infants. Evidence is accumulating showing even a relationship between nutrient supply in the first week of life and later cognitive development in extremely low birth weight infants. Since enteral nutrition is often not tolerated following birth, parenteral nutrition is necessary. Yet, optimal parenteral intakes of both energy and amino acids are not well established. Subsequently, many preterm infants fail to grow well, with long-term consequences. Early and high dose amino acid administration has been shown to be effective and safe in very low birth weight infants, but the effect of additional lipid administration needs to be defined.

Early amino acids and the metabolic response of ELBW infants (< or = 1000 g) in three time periods

OBJECTIVE

To evaluate early amino-acid (AA) administration in extremely low birth weight (ELBW) infants over three time periods, beginning with the initiation of this strategy.

STUDY DESIGN

This was a retrospective study of ELBW infants between 2000 and 2007. Nutritional intake and laboratory results were monitored during the first 5 days of life. Growth rates and complications were followed until discharge.

RESULT

Infants were similar in birth weight (BW), gestational age (GA) and severity of illness. The age at initiation of AA decreased significantly over time. Age at weight nadir, return to BW and percent postnatal weight loss decreased in epoch 3. There were modest increases in blood urea nitrogen (BUN), but no significant metabolic disturbances were observed. Cholestasis was more prevalent in epoch 2.

CONCLUSION

AA administration within the first hours of life appears to be safe and beneficial for ELBW infants. Absent signs of renal dysfunction, a modest rise in BUN is consistent with the neonate's utilization of AAs for energy.

Nutritional practices in the neonatal intensive care unit: analysis of a 2006 neonatal nutrition survey

OBJECTIVE

The goal of this investigation was to determine how current parenteral nutrition and enteral nutrition practice intentions for preterm infants compare with published recommendations and previous feeding practices.

METHODS

A survey of feeding strategies for 3 preterm infant weight groups was sent to NICU directors, neonatal fellowship directors, neonatologists, neonatal nurse practitioners, and neonatal dieticians. A total of 775 surveys were distributed by both electronic and standard mail services.

RESULTS

There were 176 survey responses (23%). The majority of practitioners initiated parenteral nutrition for very preterm infants in the first day of life. Ninety-one percent of respondents increased protein delivery daily. Most respondents increased lipid delivery at a fixed rate, rather than on the basis of triglyceride levels. Insulin was used in 98% of units, but only 12% of the time as a nutritional adjuvant to increase weight gain. Across all birth weight categories, breast milk was prescribed most commonly for the first enteral feeding. Enteral feedings were started earlier and increased faster than in the past, especially for extremely low birth weight infants (<1000 g). The majority of respondents prescribed enteral feedings for infants with indwelling umbilical arterial (75%) and umbilical venous (93%) catheters. Despite data that more rapid feeding advancement is safe, >80% of respondents increased feedings at rates of 10 to 20 mL/kg per day across all weight categories.

CONCLUSIONS

Clinicians reported that they are initiating parenteral and enteral nutrition earlier and in larger volumes than in the past, reflecting increased knowledge about best nutritional practices in very preterm neonates. The data suggest that the persistent extrauterine growth failure of preterm infants is not attributable to a lack of best nutritional practice knowledge and intention.

Insulin infusion for the treatment of hyperglycemia in low birth weight infants: examining the evidence

FORTY TO 80 PERCENT OF VERY LOW birth weight (VLBW) (infants <1,500 g) and extremely low birth weight (ELBW) (infants <1,000 g) infants will develop hyperglycemia when provided with glucose infusions adequate to meet basal metabolic needs.1,2 Avoiding hyperglycemia while providing adequate nutrition to promote growth and development is a major challenge for health care providers in the NICU. Some health care providers suggest that the judious use of continuous insulin infusion (CII) may provide the opportunity for increasing nutritional support while maintaining euglycemia. A systematic review of the literature is presented to evaluate the evidence supporting this practice.

Improved growth and decreased morbidities in <1000 g neonates after early management changes

OBJECTIVE

To test the hypothesis that three changes in the early management of extremely low birth weight (ELBW) neonates would decrease the incidence of extra-uterine growth restriction (EUGR) by 25%. The three early management practice changes (EMPC) included surfactant at delivery followed by immediate extubation to nasal continuous positive airway pressure (CPAP), decreased oxygen exposure and early parenteral amino acids.

STUDY DESIGN

Historical cohort study of preterm infants<or=1000 g birth weight (BW) born at the University of Texas Medical Branch between January 2001 and June 2002 (pre-EMPC, before changes, n=87) and July 2004 to December 2005 (post-EMPC, after changes, n=76). Outcomes measured included feeding and growth parameters, morbidities and interventions. Statistical analysis included chi2-analysis, Student's t-test, and analysis of variance.

RESULT

Infants in the post-EMPC cohort regained BW more quickly, maintained appropriate size for weight at 36 weeks and had less morbidity associated with poor long-term outcome. Predictors of EUGR included BW<750 g and surgical necrotizing enterocolitis.

CONCLUSION

The introduction of surfactant at delivery followed by immediate extubation to CPAP, decreased oxygen exposure and early parenteral amino acids in ELBW infants is possible, safe and associated with improvements in growth and morbidity.

Parenteral amino acid and metabolic acidosis in premature infants

BACKGROUND

Aggressive parenteral nutrition (PN) including amino acids is recommended for low-birth-weight infants to prevent energy and protein deficit. Their impact on acid-base homeostasis has not been examined.

METHODS

We investigated the impact of dose and duration of parenteral amino acids, with cysteine, on acid-base parameters in 122 low-birth-weight infants. Premature infants <or=32 weeks, <or=1850 g, and receiving parenteral amino acids at 1.5 g/kg/d for an extended period (>24 hours), or 3 g/kg/d for a short (5 hour), extended (24 hour), or prolonged (3-5 days) duration were included in the study. Data were obtained at age 0-3 days (n = 43) or, when clinically stable, age 3-5 days (n = 49). Data from 30 infants, matched for birth weight and gestational age, receiving PN during the first 5 days after birth were also obtained. Acidosis was defined as pH <7.25.

RESULTS

Acidosis was evident in all infants between 2 and 5 days after birth. Infants with large patent ductus arteriosus (PDA) exhibited significantly (p < .05) lower pH early, had higher blood urea nitrogen levels (26 +/- 9 vs 18 + 8 mg/dL; p < .05), and had greater weight loss ( approximately 17% of birth weight) when compared with infants without PDA. Gestational age, weight loss, and patent ductus arteriosus accounted for 65% of variance in acidosis.

CONCLUSIONS

Low-birth-weight infants develop metabolic acidosis between 2 and 5 days after birth, irrespective of dose and duration of parenteral amino acid administration. Careful management of parenteral fluids and comorbidities may lower the incidence of acidosis and promote protein accretion.

Postnatal growth failure in preterm infants: ascertainment and relation to long-term outcome

OBJECTIVE

Traditional measure of postnatal growth failure assessment has poor discriminatory power for long-term outcomes. Our objective was to identify measure of postnatal growth failure associated with long-term outcome in preterm infants born at < 28 weeks' gestation.

PATIENTS AND METHODS

Four measures of defining postnatal growth failure at 36 weeks corrected gestational age: (1) weight < 10(th) centile, (2) weight < 3(rd) centile, (3) z score difference from birth > 1 and, (4) z score difference from birth > 2; were compared for their predictive values and strength of association with adverse neurodevelopmental outcomes at 18-24 months.

RESULTS

Postnatal growth failure defined as a decrease in z score of > 2 between birth and 36 weeks corrected gestational age had the best predictive values compared to other postnatal growth failure measures, however, it was significantly associated with psychomotor developmental (P=0.006) but not with mental developmental indices (P=0.379).

CONCLUSION

Postnatal growth failure defined by z score change influenced psychomotor but not mental tasks in this cohort. This method of ascertainment could be useful to identify infants who might benefit from nutritional interventions.

Parenteral amino acid and energy administration to premature infants in early life

After birth, the nutritional supply through the umbilical cord ceases. Premature infants do not immediately tolerate full enteral feedings, yet they retain high nutritional needs for both growth and metabolic maintenance. Parenteral nutrition should therefore be initiated as quickly as possible after premature birth, thereby reducing the dependence on endogenous substrates. Intrauterine studies show very high amino acid uptake, clearly exceeding accretion rates. Studies covering the early neonatal period demonstrate that the initiation of high-dose amino acid administration directly after birth is safe and effective, even at low energy intakes. Future research should reveal whether usage could be improved through better amino acid solutions or by providing more energy via lipids from birth onwards as well.

Safety and efficacy of early amino acids in preterm <28 weeks gestation: prospective observational comparison

OBJECTIVE

To assess the safety and efficacy of early amino acid (AA) administration in preterm neonates <28 weeks gestational age.

STUDY DESIGN

Prospective data collection for 1 year for the late AA group (AA started at 12-30 h) and for another year with practice change to early AA administration (immediately after stabilization).

RESULTS

Time of initiation of AA differed (early group 4+/-3 h vs late group 20+/-6 h; P<0.001). There were no statistically significant differences in the incidence of clinically significant metabolic acidosis. Blood urea at 24 h was higher in the early AA group. No significant differences in growth rate or neonatal outcomes were identified. Days to regain birth weight and sepsis were lower in the early AA group.

CONCLUSIONS

Early AA administration was not associated with any clinically significant adverse effects; it was associated with reduction in the incidence of sepsis and marginally effective in reducing time to regain birth weight.

Glucose intolerance and insulin resistance in extremely premature newborns, and implications for nutritional management

Glucose intolerance and postnatal growth retardation are commonly seen in low-gestation newborns. In contrast to the nutrient compositions of parenteral and enteral nutrition, fetuses at equivalent gestational ages receive much more amino acids (protein) but less glucose and lipids through placental transfer.

CONCLUSION

A nutrition regime that simulates placental nutrient delivery would potentially minimize glucose intolerance and facilitate early attainment of normal growth velocity with normal body composition after preterm birth.

Assessment of implementation of a standardized parenteral formulation for early nutritional support of very preterm infants

INTRODUCTION

Parenteral nutrition (PN) plays an important role in the nutritional support of very preterm newborns. It has been suggested that a high proportion of PN orders could be standardized. In 2002, we implemented in our unit the preparation of three standardized formulations for PN adapted to the nutritional requirements of premature infants<32 weeks. Following this change of practice, a retrospective observational study was conducted to evaluate the relevance of the implemented standardized PN regime. Twenty premature inborn infants<32 weeks gestation who had received standardized (STD) PN in 2003 were matched for 20 infants who had received individualized (IND) PN in 2001. Adequacy of nutrition was assessed by comparing daily intravenous nutrient intake and biochemical parameters during the first week. Amino-acid intakes on day 3 were higher in the STD group (1.5+/-0.2 g/kg/d vs. 0.9+/-0.5, p<0.001), and the calcium phosphate intakes were better balanced. The cumulated intake of amino acids for the first week was greater in the STD group (+20% ; p=0.0003). Biochemical parameters were similar in both groups. Insulin infusions were less frequent in the STD group (p<0.06).

CONCLUSION

Standardized parenteral formulations provided higher early intakes of amino acid and glucose, a better calcium phosphate ratio, and a greater amount of amino-acid intakes during the first week while maintaining the same biochemical parameters. This strategy forms part of an approach concerning quality control and the respect of good professional practice for the preparation of parenteral nutrition solutions.

Pragmatic approach to in-hospital nutrition in high-risk neonates

Extremely low birth weight infants may experience periods of moderate to severe undernutrition during the acute phase of their respiratory problems. This undernutrition contributes to early growth deficits in these patients and may have long-lasting effects, including poor neurodevelopmental outcome. Early postnatal intravenous amino-acid administration and early enteral feeding strategies will minimize the interruption of nutrient intake that occurs with premature birth. These two strategies will prevent intracellular energy failure, allow the administration of more non-protein energy, as well as enhance overall nutritional health, as evidenced by less postnatal weight loss and earlier return to birth weight, and improved overall postnatal growth and outcome.

Postnatal malnutrition of extremely low birth-weight infants with catch-up growth postdischarge

OBJECTIVE

To assess nutritional intakes and subsequent growth of extremely low birth-weight (BW) infants.

STUDY DESIGN

Chart review of 69 extremely low BW infants stratified into two groups by BW: < or =750 g (group 1; n=27) or 751 to 1000 g (group 2; n=42). Dietary intakes, weights, and head circumferences (HC) were collected through discharge and at 1 month postdischarge. The differences between goals and intakes were calculated weekly during hospitalization. Descriptive comparisons were made between growth parameters at birth, discharge, and follow-up.

RESULTS

Total energy and protein deficits were inversely related to BW. Both groups exhibited extrauterine growth retardation while hospitalized. After discharge, the rates of weight gain and HC growth increased, leading to some growth recovery at follow-up.

CONCLUSIONS

Existing feeding methods resulted in sizeable deficits in energy and protein, particularly for the smallest infants. Changing current practices to limit these deficits is essential to improving postnatal growth.

Aggressive nutrition of the very low birthweight infant

We propose an approach to nutrition of the VLBW infant that aims at minimizing the interruption of nutrient uptake engendered by premature birth. Our approach is aggressive in that it goes beyond current practice in several key aspects. The gap in nutrient intakes between the proposed aggressive approach and current practice will most likely disappear over the next few years as today's aggressive practice becomes tomorrow's standard practice. As the gap diminishes, so will the threat that nutritional deprivation poses to growth and development of VLBW infants.

Growth patterns of extremely low-birth-weight hospitalized preterm infants

OBJECTIVE

To characterize the growth of extremely low-birth-weight (ELBW) infants during hospitalization in terms of weight gain, growth velocity, and relative change in weight.

DESIGN

Retrospective, descriptive design.

SETTING

Two neonatal intensive-care units located in the midwestern United States.

PATIENTS

Thirty-five ELBW infants with a birth weight less than 1,000 g and appropriate for gestational age.

MAIN OUTCOME MEASURES

Clinical data related to the infant's growth and nutrition were obtained from a chart review. Birth weight and discharge weight were compared following conversion of the weights to z scores. The discharge weight was compared to the median weight of a fetus of comparable gestational age based on an intrauterine growth reference. Growth velocity was determined (grams/day).

RESULTS

Weight-for-age z scores decreased significantly between birth and discharge. By discharge, 89% of the infants had discharge weights less than the 10th percentile. The mean discharge weight was significantly less than the median weight of a fetus of comparable gestational age. Days to regain birth weight significantly affected growth outcomes.

CONCLUSION

ELBW infants develop a growth deficit during the first few weeks of life that not only persists but also worsens during hospitalization. Potential causes of this growth deficit include the medical and nutritional management that are part of the usual care of ELBW infants. Because these infants are discharged with this growth deficit, catch-up growth will have to occur at home.