Plasma lipid and plasma lipoprotein concentrations in low birth weight infants given parenteral nutrition with twenty or ten percent lipid emulsion

Reactive Astrocytes and Emerging Roles in Central Nervous System (CNS) Disorders

In addition to their many functions in the healthy central nervous system (CNS), astrocytes respond to CNS damage and disease through a process called "reactivity." Recent evidence reveals that astrocyte reactivity is a heterogeneous spectrum of potential changes that occur in a context-specific manner. These changes are determined by diverse signaling events and vary not only with the nature and severity of different CNS insults but also with location in the CNS, genetic predispositions, age, and potentially also with "molecular memory" of previous reactivity events. Astrocyte reactivity can be associated with both essential beneficial functions as well as with harmful effects. The available information is rapidly expanding and much has been learned about molecular diversity of astrocyte reactivity. Emerging functional associations point toward central roles for astrocyte reactivity in determining the outcome in CNS disorders.

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.

ASPEN lipid injectable emulsion safety recommendations part 2: Neonate and pediatric considerations

Lipid injectable emulsions (ILEs) are complex pharmaceutical formulations intended as a source of energy and fatty acids for parenteral nutrition (PN) therapy. Part 1 of this series addressed issues associated with and safety recommendations pertaining to adult ILE use. Part 2 addresses ILE safety in neonatal and pediatric patients. Considerations for ILE use in the neonatal and pediatric populations differ from those of adults. For example, these patients often require higher doses compared with adult counterparts to support growth, development, and daily metabolic needs. ILE is also frequently administered as a separate infusion as opposed to in a total nutrient admixture owing to compatibility and stability issues and limitations to intravenous access in the neonatal and pediatric populations. ILE is the most frequent PN ingredient associated with PN errors occurring in the administration, prescribing, and transcribing processes. Concerns exist with use of in-line filters and repackaging of commercial products for infusion. ILE use in neonatal and pediatric patients has been associated with both minor and major adverse effects, which most often occur with doses exceeding manufacturer recommendations. Gaps in ILE best practices for neonatal and pediatric patients predispose to errors in the PN use system. This paper describes safe-use considerations for ILE products available in the United States in neonatal and pediatric patients, including indications, prescribing, order review, preparation, administration, and monitoring. This paper has been approved by the American Society for Parenteral and Enteral Nutrition (ASPEN) Board of Directors.

A detailed guide to lipid therapy in intestinal failure

Intravenous lipid emulsions are an integral part of nutrition therapy in the intestinal failure patient. In addition to being a concentrated source of non-protein calories, they provide the essential fatty acids necessary for growth and development. Depending upon the oil source used in these products, complications such as intestinal failure associated liver disease (IFALD) can occur. This review will discuss the risks and benefits associated with these products, especially as they relate to the pediatric intestinal failure patient.

Intravenous Fat Emulsion Formulations for the Adult and Pediatric Patient: Understanding the Differences

Intravenous fat emulsions (IVFEs) provide essential fatty acids (EFAs) and are a dense source of energy in parenteral nutrition (PN). Parenterally administered lipid was introduced in the 17th century but plagued with side effects. The formulation of IVFEs later on made it a relatively safe component for administration to patients. Many ingredients are common to all IVFEs, yet the oil source(s) and its (their) percentage(s) makes them different from each other. The oil used dictates how IVFEs are metabolized and cleared from the body. The fatty acids (FAs) present in each type of oil provide unique beneficial and detrimental properties. This review provides an overview of IVFEs and discusses factors that would help clinicians choose the optimal product for their patients.

ESPGHAN Committee on Nutrition Position Paper. Intravenous Lipid Emulsions and Risk of Hepatotoxicity in Infants and Children: a Systematic Review and Meta-analysis

The aim of the present article was to perform a systematic review with meta-analysis of available scientific evidence regarding the role of different intravenous lipid emulsions (ILE) in the pathogenesis of cholestasis and parenteral nutrition-associated liver disease. A systematic review of the literature (up to March 2015) identified 23 randomized controlled trials (RCTs). Of these, 17 were performed in preterm infants or critically ill neonates with a short duration of intervention, 2 in older children with short-term use (following surgery or bone marrow transplantation), 1 in neonates with long-term use, and 3 in infants and children receiving long-term parenteral nutrition (PN). Meta-analysis showed no differences in the rate of cholestasis or bilirubin levels associated with short-term use of different ILEs. Because of high heterogeneity of the long-term studies no meta-analysis could be performed. Available studies found that the use of multicomponent fish oil (FO)-containing ILE compared with pure soya bean oil (SO), ILE-reduced liver enzymes, and bilirubin levels in noncholestatic children on long-term PN and one other RCT found that FO-based ILE-reversed cholestasis in a proportion of patients. The ESPGHAN Committee on Nutrition concludes that there is no evidence of a difference in rates of cholestasis or bilirubin levels between different ILE for short-term use in neonates. The use of multicomponent FO-containing ILE may contribute to a decrease in total bilirubin levels in children with IF on prolonged PN. Well-designed RCTs are, however, lacking and long-term effects have not been determined.

Intravenous lipids for preterm infants: a review

Extremely low birth weight infants (ELBW) are born at a time when the fetus is undergoing rapid intrauterine brain and body growth. Continuation of this growth in the first several weeks postnatally during the time these infants are on ventilator support and receiving critical care is often a challenge. These infants are usually highly stressed and at risk for catabolism. Parenteral nutrition is needed in these infants because most cannot meet the majority of their nutritional needs using the enteral route. Despite adoption of a more aggressive approach with amino acid infusions, there still appears to be a reluctance to use early intravenous lipids. This is based on several dogmas that suggest that lipid infusions may be associated with the development or exacerbation of lung disease, displace bilirubin from albumin, exacerbate sepsis, and cause CNS injury and thrombocytopena. Several recent reviews have focused on intravenous nutrition for premature neonate, but very little exists that provides a comprehensive review of intravenous lipid for very low birth and other critically ill neonates. Here, we would like to provide a brief basic overview, of lipid biochemistry and metabolism of lipids, especially as they pertain to the preterm infant, discuss the origin of some of the current clinical practices, and provide a review of the literature, that can be used as a basis for revising clinical care, and provide some clarity in this controversial area, where clinical care is often based more on tradition and dogma than science.

Neonatology/Paediatrics - Guidelines on Parenteral Nutrition, Chapter 13

There are special challenges in implementing parenteral nutrition (PN) in paediatric patients, which arises from the wide range of patients, ranging from extremely premature infants up to teenagers weighing up to and over 100 kg, and their varying substrate requirements. Age and maturity-related changes of the metabolism and fluid and nutrient requirements must be taken into consideration along with the clinical situation during which PN is applied. The indication, the procedure as well as the intake of fluid and substrates are very different to that known in PN-practice in adult patients, e.g. the fluid, nutrient and energy needs of premature infants and newborns per kg body weight are markedly higher than of older paediatric and adult patients. Premature infants <35 weeks of pregnancy and most sick term infants usually require full or partial PN. In neonates the actual amount of PN administered must be calculated (not estimated). Enteral nutrition should be gradually introduced and should replace PN as quickly as possible in order to minimise any side-effects from exposure to PN. Inadequate substrate intake in early infancy can cause long-term detrimental effects in terms of metabolic programming of the risk of illness in later life. If energy and nutrient demands in children and adolescents cannot be met through enteral nutrition, partial or total PN should be considered within 7 days or less depending on the nutritional state and clinical conditions.

Levels of lipids in preterm infants fed breast milk

BACKGROUND

Actual recommendations in preterm infants limit parenteral fat intake to 3-4 g/kg/d. This is based on clinical studies where fat administration was adjusted to achieve levels close to those recommended in adults for atherosclerosis prevention. Data about lipid profiles of breast fed preterm infants who may have fat intakes of up to 7 g/kg/d and could serve as reference are not available.

OBJECTIVE

To establish full lipid profiles in healthy fully breast fed preterm infants and to test the hypothesis that breast milk fat intake leads to serum triglycerides higher than those achieved under full parenteral fat administration.

DESIGN

Serum triglycerides, cholesterol, VLDL, LDL, HDL (all pre- and postprandial), as well as triglycerides in breast milk were measured in 65 healthy, fully breast fed, stable growing preterm infants stratified in 500 g intervals (mean gestational age: 31+/-4 weeks, birth weight: 1500+/-600 g, age at study: 25+/-16 d).

RESULTS

Median fat intake was 7.0 g/kg/d (interquartile range: 5.8;8.1) and led to the following serum levels: triglycerides 0.9 (0.6;1.1), cholesterol 3.1 (2.6;3.5), VLDL 0.5 (0.3;0.6), LDL 1.3 (1.1;1.6), HDL 1.1 (0.8;1.4)mmol/L. Small for gestational age infants showed higher triglycerides (p=0.005). Triglycerides (r2=0.08, p=0.023), postprandial triglyceride increase (r2=0.21, p<0.001), cholesterol (r2=0.16, p<0.001) and HDL (r2=0.16, p<0.001) were correlated with weight at study.

CONCLUSION

Though higher by a factor of two, fat intake by breast milk leads to considerably lower lipid levels when compared to published values obtained under parenteral fat intake. Results suggest that either fat absorption is reduced in preterm infants, or the composition of breast milk supports a lower profile of fat levels when compared to commercially available parenteral fat emulsions.

Randomized trial of very low birth weight infants receiving higher rates of infusion of intravenous fat emulsions during the first week of life

OBJECTIVE

The goal was to determine whether very low birth weight infants could tolerate higher rates of infusion of intravenous fat emulsion during the first week of life and maintain their serum triglyceride levels at <or=200 mg/dL.

METHODS

This was a randomized, controlled trial of 110 infants who were classified as appropriate for gestational age and had birth weights between 750 g and 1500 g. The primary clinical outcome was serum triglyceride levels; secondary outcomes also were monitored.

RESULTS

One hundred infants completed the study (experimental group: N = 48; control group: N = 52). Infants in the experimental group had significantly higher energy intake for the entire 7-day study period and achieved 90 kcal/kg per day (1 kcal = 4.184 kJ) significantly sooner (7.38 +/- 3.381 days vs 9.44 +/- 3.578 days). Triglyceride levels for infants in the experimental group remained significantly higher for the first 5 days of life. Fifteen percent of infants in the experimental group but only 4% of infants in the control group developed hypertriglyceridemia. Ten percent of infants in the control group but no infants in the experimental group required insulin therapy. Forty-two percent of infants in the experimental group and 17% of infants in the control group remained at >or=10th percentile for weight for age. Fourteen percent of infants in the control group but no infants in the experimental group developed necrotizing enterocolitis. Twenty-three percent of infants in the control group but only 6% of infants in the experimental group developed retinopathy of prematurity. There were no significant differences in other outcomes.

CONCLUSIONS

Very low birth weight infants can tolerate higher rates of infusion of intravenous fat emulsion solutions during the first week of life without significant adverse events.

The use of IV fat in neonates

IV fat emulsion (IVFE) is an integral part of the parenteral nutrition (PN) regimen in neonates. It provides a concentrated isotonic source of calories and prevents or reverses essential fatty acid deficiency. Continuous administration of IV fat with PN regimens prolongs the viability of peripheral IV lines in infants who might have limited venous access. IVFE must be administered separately from the PN solution in neonates. The acidic pH of a PN solution is necessary for maximum solubility of calcium and phosphorus. If fat emulsion is added to the PN solution, as is done in 3-in-1 (total nutrient admixture) solutions, the high amount of calcium and phosphorus needed by these infants may result in an unseen precipitate with serious consequences. Continuous fat infusion over 24 hours is the preferred method in neonates. The administration rate of 0.15 g/kg/hour for IVFE in the neonate should not be exceeded. Essential fatty acid deficiency can be prevented in neonates by providing IVFE in a dose of 0.5-1.0 g/kg/day. Carnitine is not routinely required to metabolize IVFE in the neonate. Infants should receive 20% lipid emulsion to improve clearance of triglycerides and cholesterol. Serum triglyceride levels should be maintained at <150-200 mg/dL in neonates. There are concerns about potential adverse effects of early administration of IV fat in very-low-birth-weight infants weighing <800 g. We hold the IV fat dose at 1.0-1.5 g/kg/day until the second week of life in infants <30 weeks gestation.

In vivo and in vitro properties of an intravenous lipid emulsion containing only medium chain and fish oil triglycerides

BACKGROUND & AIMS

The triglyceride (TG) fatty acyl composition in lipid emulsions influences their metabolism. Little is known about the effects of long chain omega-3 polyunsaturated fatty acids (PUFA) on lipid emulsion metabolism. We investigated possible differences between omega-3 containing emulsions in their metabolism and tissue-targeting in vivo in a mouse model, and in vitro using lipolysis and cell culture experiments.

METHODS

Soy oil (LCT), MCT/LCT/omega-3 (5:4:1, wt/wt/wt), and MCT/omega-3 (8:2, wt/wt) emulsions were radiolabeled with nondegradable 1alpha,2alpha (n)-[3H] cholesteryl oleoyl ether to trace core particle metabolism in C57BL/6J mice following a bolus injection. Blood samples obtained over 25 min and extracted organs were used to measure the tissue distribution of lipid emulsion particles. Lipoprotein lipase (LpL)-mediated hydrolysis experiments and cell uptake studies in cultured J774 murine macrophages were also performed.

RESULTS

Blood clearance of 8:2 was 13.4% and 29.8% faster compared to 5:4:1 and LCT, respectively. LCT had greatest liver uptake. LpL-mediated hydrolysis was greatest in 8:2 and lowest in LCT. Overall, cell TG accumulation in the presence of apolipoprotein E was least with 8:2.

CONCLUSIONS

Our data shows that 8:2 had the most efficient blood clearance but less hepatic uptake in vivo. In vitro, 8:2 had both highest hydrolysis by LpL and intracellular TG utilization in the presence of apoE. Thus, an 8:2 lipid emulsion undergoes efficient blood clearance and may direct omega-3 PUFA more towards extrahepatic tissues.

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.

Early feeding strategies in preterm and critically ill neonates

This two-part article presents feeding strategies for the NICU population over the first several weeks of life. It focuses primarily on the theory and approach to feeding extremely low birth weight (ELBW) infants, but also addresses some issues pertinent to larger, ill infants. The premise for these recommendations is that avoiding early malnutrition in ELBW and ill infants has both short- and long-term benefits. Many practitioners may consider our approach to be somewhat aggressive. In this strategy, total parenteral nutrition (TPN) is initiated in the first hours after birth and is given together with initially small, and then increasing, enteral feedings beginning on the first or second day of life. The role of the TPN is to provide rapid, maximal nutrition and that of the early enteral feedings is to "prime" the gut and stimulate normal gastrointestinal tract activity.

Utilization of docosahexaenoic acid from intravenous egg yolk phospholipid

Docosahexaenoic acid (DHA, 22:6n-3) is provided directly to human premature infants during parenteral nutrition from the egg yolk fraction of an intravenous fat emulsion. This study aimed to determine whether the high egg yolk phospholipid content of Intralipid 10% (IL 10%, Pharmacia, Uppsala, Sweden) relative to the standard emulsion Intralipid 20% (IL 20%, Pharmacia) could be a strategy to increase the delivery of DHA to the developing brain. Male, Large White piglets were randomly selected from sows 3 d after birth. Piglets were assigned to receive a 9-d continuous intravenous infusion commencing 5 d after birth of either Intralipid (IL) 10%, IL 20%, or Lipofundin S 20% (LFS; B. Braun, Melsungen, Germany). There were four piglets in each treatment group. IL 10% provides twice as much DHA as IL 20%, while LFS provides no DHA. Protein and other nutrients were provided enterally using a low-fat milk formula. After 9 d, animals were killed, and the fatty acid compositions of blood, liver, and cerebral cortex were analyzed. IL 10% infusion approximately doubled the amount of plasma phospholipid DHA (microg/mL of plasma) in comparison to IL 20%. However, red blood cells, liver, and cerebral cortex phospholipid DHA levels were indistinguishable between these two groups. LFS was associated with reduced levels of DHA in plasma, red blood cell and liver phospholipids in comparison to IL 20%. We conclude that infusion of additional phospholipid is an ineffective strategy for increasing DHA delivery to piglet tissues. This may be due to the formation of inert phospholipid particles in plasma. The data do not support the concept of using IL 10% as a means of providing additional DHA to premature human infants.

Lipid metabolism of the micropremie

Intravenous lipid emulsions often provide substance for the very low-birth weight or extremely low-birth weight infant that need total parenteral nutrition. The process used in this type of treatment as well as the effects of such treatment are discussed at length in this article. Some of the main compounds of representative lipid emulsions are listed and evaluated and the benefits and consequences of their use are presented.

Intravenous nutrition and postnatal growth of the micropremie

There is a growing body of evidence that early nutritional practices may affect short-term growth and developmental outcome. In addition, they may play a role in determining adult health and disease. There is much that needs to be learned about safe and efficacious nutrient administration in the ELBW population; about techniques to assess the effect of different nutritional strategies; and about the long-term effects of these regimen or development outcome, growth, and disease.

Clinical use of lipid emulsions

Substantial progress has been made in the understanding of the metabolism of intravenous lipid emulsions and the delivery of their various components to specific tissues or cells. Lipid emulsions should be considered not only as a means of providing energy substrates but also specific compounds that participate in the regulation of key metabolic functions. Such improved knowledge should find applications in the metabolic care of different types of patients.

Nutritional support of infants and children: supply and metabolism of lipids

The quantity and quality of dietary lipids and their metabolism are of major importance for the growth, body composition, development and long-term health of children, both in health and disease. Lipids are the major source of energy in early childhood and supply essential lipid-soluble vitamins and polyunsaturated fatty acids that are required in relatively high amounts during early growth. Lipids affect the composition of membrane structures, and modulate membrane functions as well as the functional development of the central nervous system. Some long-chain polyunsaturated fatty acids serve as precursors for bioactive lipid mediators, including prostaglandins, thromboxanes and leukotrienes, which are powerful regulators of numerous cell functions such as thrombocyte aggregation, inflammatory reactions and immune functions. Here we review some aspects of the biochemistry and physiology of lipids and their implications for lipoprotein metabolism, energy balance and the lipid supply during early childhood through the placenta, human milk, enteral diets and parenteral lipid emulsions.

Drugs causing dyslipoproteinemia

Diuretics and beta-blockers have a strong tendency to affect serum lipids adversely, whereas the peripherally acting alpha-blocking agents consistently result in beneficial effects. Most of the other antihypertensive agents (calcium channel blockers, ACE inhibitors, angiotensin II receptor antagonists, and drugs that act centrally) are lipid neutral. The effect of steroid hormones varies with the drug, dose, and route of administration. In general, androgens lower HDL-C and have a variable effect on LDL-C. The effects of progestins vary greatly depending on their androgenicity, and estrogens are beneficial except when hypertriglyceridemia occurs with oral estrogens. Glucocorticoids raise HDL-C and may also increase triglycerides and LDL-C. Retinoids increase triglycerides and LDL-C and also reduce HDL-C. Interferons can cause hypertriglyceridemia. Following organ transplantation, a dyslipidemia often ensues. This is caused in part by the medications used to prevent rejection (glucocorticoids, cyclosporine, and FK-506) and requires close attention and, in some patients, drug therapy to prevent coronary artery disease.

Lipid supply and metabolism in infancy

The rapid growth of young infants is supported by a high dietary fat intake close to 50% of the energy intake, resulting in a high dietary energy density. The adequacy of diets with low fat content during the second half year of life with respect to supporting growth has recently been studied. The digestion of dietary lipids is initiated by gastric lipolysis, which may provide an important contribution to total fat digestion in premature infants. The supply, metabolism and biological effects of long-chain polyunsaturated fatty acids during early development has been the subject of intensive research in recent years in view of potential effects on growth and functional development of visual and neural tissues. Intravenous lipid emulsions are an indispensable part of parenteral nutrition of young children, and efforts are being made to improve the parenteral feeding regimens to meet the metabolic needs for this sensitive group of patients.

Comparison between two fat emulsions: Intralipid 30 cent vs intralipid 10 cent in critically ill patients

Fat emulsions, Intralipid 30% and Intralipid 10% were compared in terms of the resulting plasma levels of different lipid components and clinical tolerance in critically-ill patients with multi-injuries. Sixteen critically-ill patients with severe systemic inflammatory response were randomly assigned to two groups, each one comprised of eight patients. Each group was administered the same quantity of fat/Kg/day either Intralipid 30% or Intralipid 10%. The infusion lasted 12|h daily for 6 days. During the infusion of the fat emulsion, a lower median plasma concentration of triglycerides, phospolipids and free cholesterol was observed in patients who received Intralipid 30% compared with those who received Intralipid 10%. The above observations were sustained 4 h after the termination of the infusion. Free fatty acids had a higher mean plasma concentration in the group of patients who received Intralipid 30%. There were no differences between the two groups as far as the median plasma concentration of cholesterol and lipoproteins (LDL, HDL, VLDL) are concerned. On the contrary, there was an increase in LpX in the Intralipid 10% group. From the above findings, we draw the conclusion that Intralipid 30% revealed better profiles of different lipid components than Intralipid 10% in critically-ill patients. The new emulsion of higher concentration in triglyceride was proved clinically safe and its use is suggested for critically-ill patients who require total parenteral nutrition.

Serum lipids during parenteral nutrition with a 10% lipid emulsion with reduced phopholipid emulsifier content in premature infants

Fourteen premature infants (range 26 + 0 to 32 + 3), all but two appropriate for gestational age with a mean body weight of 1196 g (range 860 to 2770 g) received a 10% lipid emulsion. This lipid emulsion contained half of the formerly used phospholipid emulsifier concentration reducing the phospholipid/triglyceride ratio to the ratio used for the 20% lipid emulsion (0.06 instead of 0.12). Lipid emulsion was given over a 10 day period commencing at the third day of life with 0.5 g/kg/24 h which was increased daily up to a dose of 2.0-2.5 g/kg/24 h which was reached in all patients at the seventh day of the observation period. During this time mean serum concentrations of cholesterol increased non-significantly from 76.1 mg/dl (SD 33.7) before lipid emulsion to 86.1 mg/dl (SD 36.4) on day seven of the observation period. 13 of the 14 patients (97%) showed no pathological increase of their serum triglyceride concentration during lipid infusion. Mean serum triglyceride concentration increased from 65.3 mg/dl (SD 32.0 mg/dl) before the start of lipid emulsion to 102.6 mg/dl (SD 76.5) on day four (p < 0.05) but with no further significant increase. Lipid emulsions with 10% triglyceride but lower phospholipid content are tolerated without pathological increase in triglyceride or cholesterol serum concentration in the vast majority of premature newborns.

Serum triglycerides of breast milk-fed very-low-birth-weight infants

Normative triglyceride levels were obtained from eighty-five infants weighing < 1500 g. At least 80% of their nutritional intake was their own mother's breast milk. Triglyceride levels did not correlate with birth weight, gestational age, volume of milk fed, age in days, or use of milk fortifier. The 95th percentile triglyceride value was 2.5 mmol/L. Assuming that breast milk-fed infants have triglyceride in the normal range, the acceptable limit of triglyceride values in very-low-birth-weight infants receiving i.v. lipids could be revised upward to 2.5 mmol/L.

Assessing the effect of disease on nutrition of the preterm infant

OBJECTIVE

To review existing data on nutritional requirements of extremely low birth weight (ELBW) and very low birth weight (VLBW) preterm infants (those who weigh < 1000 g and 1000-1500 g at birth, respectively), and the effects of diseases on these nutritional requirements.

DATA SOURCES

A literature search was conducted on applicable articles related to nutritional requirements of preterm ELBW and VLBW infants and the effects of diseases in these infants on their nutritional and metabolic requirements.

DATA SYNTHESIS

The literature was analyzed to determine nutritional requirements of preterm ELBW and VLBW infants, to select the most common diseases that have significant and important effects on nutrition and metabolism in these infants, and to make recommendations about diagnostic and therapeutic approaches to nutritional problems as affected by diseases in ELBW and VLBW infants.

CONCLUSIONS

Many diseases unique to preterm infants, either directly or by enhancing the effects of stress on the metabolism of such infants, provide important changes in the nutrient requirements. The overriding observation from all studies, however, is that ELBW and VLBW preterm infants are underfed during the early postnatal period and that this condition, combined with additional stresses from various diseases, increases the risk of long-term neurological sequelae. The value of achieving a specific body composition and growth weight is less certain. There remains a critical need for determining the right quality as well as quantity of nutrients for these infants.

Tolerance of mixed lipid emulsion in neonates: effect of concentration

AIMS

To compare the effect of concentration of a mixed lipid emulsion (50:50 medium chain triglyceride/long chain triglyceride) (MCT/LCT) on lipid tolerance in neonates.

METHODS

A prospective randomised controlled trial of 75 neonates requiring prolonged parenteral nutrition was conducted in the neonatal intensive care units of the Royal Maternity Hospital, Belfast, and the Waveney Hospital, Ballymena. Thirty eight infants received 10% and 37 20% lipid emulsion. Infants were randomly assigned to groups at the start of parenteral nutrition and studied if they required seven or more days of this. Lipid tolerance was assessed by twice weekly measurements of plasma triglyceride and cholesterol concentrations and weekly measurement of non-esterified fatty acids and beta hydroxy butyrate. Anthropometry was carried out weekly.

RESULTS

The mean cholesterol in the 10% group was significantly higher within the first seven days of the study compared with the 20% group (3.5 vs 2.87 mmol/l), and continued to rise over the study period in contrast to the 20% group. A similar pattern was observed with the triglyceride concentrations. There was no significant difference in non-esterified fatty acids, beta hydroxy butyrate, or growth between the two groups.

CONCLUSION

Sick neonates show better biochemical tolerance to 20% MCT/LCT emulsion than to 10% emulsion.

Reverse cholesterol transport in the rat following a short-term intravenous infusion of fat emulsion

The effect on cholesterol transport of an intravenous infusion of a fat emulsion (10%) Intralipid or 10% Lipovenös) in vivo was investigated in the rat. Intralipid (1.85 ml/hr/kg body weight in rts for 3 hr) caused a reduction (P < 0.05) in free cholesterol in the aorta (by 25%), in plasma high-density lipoproteins (64%) and in erythrocytes (11%) with a concomitant enrichment of liver free cholesterol (16%), suggesting an enhanced reverse cholesterol transport in this species. Lipovenös under the same conditions gave similar results. Our data support our previous in vivo study in man indicating that infusion of a fat emulsion is able even to remove cholesterol from the arterial wall and thereby possibly be considered as an antiatherosclerotic agent.

Phospholipid-rich particles in commercial parenteral fat emulsions. An overview

In parenteral nutrition, the infusion of a fat EMU supplies both concentrated energy and covers the essential fatty acid requirements, the basic objective being to mimic as well as possible the input of chylomicrons into the blood. This objective is well met by the TAGRP of the EMU, which behave as true chylomicrons. However, commercial EMU also contain an excess of emulsifier in the form of PLRP. The number of these PLRP depends directly on the PL/TAG ratio of the EMU. They differ from the TAGRP by their composition (PL vs TAG and PL), their structure (PL in bilayer versus monolayer), and their granulometry (mean diameter 70-100 nm for PL vs 200-500 nm). The metabolic fate of the PLRP is similar in several ways to that of the TAGRP: exchanges of PL with the PL of the different cellular membranes and of the lipoproteins; captation of free CH from these same structures; and enrichment in apolipoproteins. However, because the TAGRP are the preferred substrates of the lipolytic enzymes, their clearance is much more rapid (half-life < 1 h) than that of the PLRP. As the infusion is continued, the PLRP end up accumulating and being transformed into LP-X (free CH/PL = 1; half-life of several days). As soon as the EMU is infused, the PLRP enter into competition with the TAGRP, in the lipolysis process as well as for sites of binding and for catabolism. The sites for catabolism of the two types of PAR are not the same: adipose tissues and muscles utilize the fatty acids and monoacylglycerols released by the lipolysis of the TAGRP; hepatocytes take up their remnants; the RES and the hepatocytes participate in the catabolism of the PLRP and the LP-X. Thus, prolonged infusion of EMU rich in PLRP leads to a hypercholesterolemia, or at least a dyslipoproteinemia, due to elevated LP-X, associated with a depletion of cells in CH, stimulating thus tissue cholesterogenesis. However, parenteral nutrition has evolved towards the utilization of EMU with a low PL/TAG ratio (availability of 30% formula) and less rapid delivery. For these reasons, the hypercholesterolemias that used to be observed with the 10% EMU have become much less spectacular or have even disappeared. It is interesting to note that patients on prolonged TPN, in particular those with a short small intestine, have weak cholesterolemia, reflecting a lowering of HDL and LDL not masked by elevated LP-X. At present, it seems difficult to produce sufficiently stable parenteral EMU devoid of PLRP. Notwithstanding, all the observations made since the introduction of the EMU in TPN are in favour of the use of PLRP-poor EMU. It is clear that the 10% formulas, and generally those with a PL/TAG ratio of 12/100, are ill-advised, especially in patients with a retarded clearance of circulating lipids.

Effects of administration of different intravenous lipid emulsions on plasma LP-X concentrations in the rat

BACKGROUND

Prolonged parenteral nutrition with lipid emulsions is essential to provide sufficient energy supply and to avoid essential fatty acid deficiency in preterm infants. However, chronic administration of lipid emulsions may lead to the development of pathological plasma lipid and LP-X concentrations. The aim of this study was to evaluate the relative importance of the phospholipid-triglyceride (PL-TG) ratio and the source of phospholipid in lipid emulsions, with respect to plasma lipid and LP-X levels.

METHODS

Rats were infused for 9 days with IV lipid emulsion containing 10% (IL-10) or 20% (IL-20) egg lecithin or Lipofundin containing 20% soya lecithin (LF), with PL-TG ratios of .12, .06, and 0.75, respectively.

RESULTS

LF significantly increased plasma triglyceride concentration (p < .01), whereas the rise in cholesterol levels observed with all emulsions was primarily caused by the increase in low-density lipoprotein cholesterol concentrations. The plasma phospholipid concentration was increased most by IL-10 (p < .005). There was a strong correlation between the PL-TG ratio of emulsions and the developing plasma phospholipid and LP-X concentrations (r2 = .91 and .96, respectively), despite the different origin of phospholipids in the emulsions, suggesting that it is the PL-TG ratio, rather than the source of phospholipids in lipid emulsions that primarily influences developing plasma lipid and LP-X concentrations.

CONCLUSION

These results indicate that the administration of lipid emulsions with lower PL-TG ratios should be considered, to avoid the development of pathological plasma lipoprotein concentrations.

Plasma lecithin: cholesterol acyltransferase and plasma lipolytic activity in preterm infants given total parenteral nutrition with 10% or 20% Intralipid

The effect of 10% or 20% Intralipid on lipid clearing enzymes, plasma lipids and apoproteins was investigated during the first 5 days after birth in 37 premature infants maintained on total parenteral nutrition; 21 infants received 20% and 16 received 10% Intralipid, respectively. Lipid was infused over a 20-h period at rates of 1, 2 and 3 g/kg/day on consecutive days. Plasma lecithin: cholesterol acyltransferase (LCAT) activity was low and increased significantly (p<0.05) only during infusions of 3 g/kg/day in both groups of infants. Plasma lipolytic activity was generally not affected by the regimen or preparation (10% or 20%) of Intralipid infused, except for higher (p<0.05) levels at 3 g/kg/day of 20% compared with prelipid infusion. Plasma triglyceride concentrations wer similar after 10% or 20% Intralipid, whereas plasma total cholesterol was significantly higher during infusion of 2 and 3 g/kg/day of 10% compared with 20% Intralipid. The efficient clearing of 20% Intralipid might be related to the lower lecithin: triglyceride ration which is compatible with the low LCAT activity of premature infants.

Amino acid and energy needs of pediatric patients receiving parenteral nutrition

The technique of parenteral nutrition has become such an established part of modern pediatric care that it is difficult to imagine how pediatricians, as recently as 25 years ago, managed a large group of very difficult patients; however, despite its obvious nutritional advantages, the technique is not without problems. Many of these can be circumvented or controlled by careful attention to all aspects of the technique. Certainly the incidence of these problems can be maintained at a level sufficiently low that the benefits of the technique far outweigh its risks; however, the technique clearly can be further improved. One requirement for doing so is to recognize that the technique is deceptively simple and that it should not be used indiscriminantly without careful consideration of indications and alternative strategies for nutritional management. Additional research also is required. As discussed earlier, the available parenteral amino acid mixtures and lipid emulsions, although considerably improved over earlier versions, remain far from optimal. Some of the actual and theoretic problems that should be addressed in the near future are discussed in the preceding sections; there also are many others.

Development of pediatric and neonatal parenteral nutrition order forms

The diversity of nutritional needs within the pediatric population makes ordering parenteral nutrition (PN) for infants and children a difficult task for inexperienced clinicians. A well designed PN order form can simplify this task. Standard PN solutions, tables with age-specific nutrient requirements, and guidelines for advancing substrate may improve PN prescriptions and serve as an educational tool. The development of an optimal PN order form for an institution requires consideration of many factors, including the patient population, requirements of the institution, and the needs of the staff and students. One nutrition support team's experience in developing pediatric PN order forms is described.

[Caloric and nitrogen intake during pre- and post-operative periods. method and duration]

Preoperative nutritional support is analysed from 7 prospective studies. Clinical benefits from nutrient intake and duration are not demonstrable. In one study, preoperative long-chain triglycerides infusions are associated with more postoperative complications. Postoperative nutrition is analysed from 20 articles. No one considers the clinical benefit with regard to quantitative and qualitative intakes.