Decreased lipid intake reduces morbidity in sick premature neonates

Use of Intravenous Soybean and Fish Oil Emulsions in Pediatric Intestinal Failure-Associated Liver Disease: A Multicenter Integrated Analysis Report on Extrahepatic Adverse Events

OBJECTIVE

To compare extrahepatic adverse events during fish oil lipid emulsion (FOLE) or soybean oil lipid emulsion (SOLE) treatment in children with intestinal failure-associated liver disease (IFALD).

STUDY DESIGN

In this multicenter integrated analysis, bleeding, bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), infections, and signs of lipid emulsion intolerance were compared between FOLE recipients (1 g/kg/d) (n = 189) and historical controls who received SOLE (≤3 g/kg/d) (n = 73).

RESULTS

When compared with SOLE recipients, FOLE recipients had a lower gestational age (30.5 vs 33.0 weeks; P = .0350) and higher baseline direct bilirubin (DB) (5.8 vs 3.0 mg/dL; P < .0001). FOLE recipients had a decreased incidence of bleeding (P < .0001), BPD (P < .001), ROP (P < .0156), bacterial and fungal infections (P < .0001), and lipid intolerance signs (P < .02 for all). Patients with bleeding vs patients without bleeding had higher baseline DB; the ORs for baseline DB (by mg/dL) and treatment (FOLE vs SOLE) were 1.20 (95% CI: 1.10, 1.31; P ≤ .0001) and 0.22 (95% CI: 0.11, 0.46; P ≤ .0001), respectively. In preterm infants, a higher BPD (P < .0001) and ROP incidence (P = .0071) was observed in SOLE recipients vs FOLE recipients.

CONCLUSIONS

Children with IFALD who received FOLE had fewer extrahepatic adverse events, including a decreased incidence of bleeding, preterm comorbidities, and lipid intolerance signs compared with children with IFALD who received SOLE. TRIAL REGISTRATION CLINICALTRIALS.GOV: NCT00910104 and NCT00738101.

Safety and Efficacy of Early High Parenteral Lipid Supplementation in Preterm Infants: A Systematic Review and Meta-Analysis

The objective of this systematic review and meta-analysis was to summarize the effects of early initiation and achievement of a high dose of parenteral lipids (≥1.5 g/kg/day reached within the first 24 h of birth) on growth and adverse outcomes in preterm infants. PubMed, EMBASE, and Cochrane databases were utilized to search for publications for this meta-analysis. Randomized controlled trials were eligible if data on growth or clinical outcome was available. The search returned nine studies. The mean proportion of postnatal weight loss (%) was lower (mean difference [MD]: −2.73; 95% confidence interval [CI]: −3.69, −1.78), and the mean head circumference near the term equivalent age (cm) was higher in the early high lipid treatment group (MD: 0.67; 95% CI: 0.25, 1.09). There was a favorable association of early high lipid administration with the incidence of extrauterine growth restriction (relative risk [RR]: 0.27; 95% CI: 0.15, 0.48). Generally, there were no differences in morbidities or adverse outcomes with early high lipid administration. Early initiation of parenteral lipids and high dose achieved within the first 24 h of life appear to be safe and endurable and offer benefits in terms of growth.

Early energy restriction in premature infants and bronchopulmonary dysplasia: a cohort study

Bronchopulmonary dysplasia (BPD) is a multifactor pathology. Animal studies and cohort studies suggest that poor nutrient intake after birth increases the risk of BPD. The objective of the present study was to determine the existence of association between BPD in very low birth weight (VLBW) and energy intake during the first week of life. We recorded in a retrospective cohort study the intake of enteral and parenteral macronutrients during this period by examining the nutritional and clinical history of 450 VLBW newborns admitted to the neonatal intensive care unit. After applying the relevant exclusion criteria, data for 389 VLBW infants were analysed, of whom 159 developed some degree of BPD. Among the newborns with BPD, energy and lipid intake was significantly lower and fluid intake was significantly higher. The energy intake for the 25th percentile in the group without BPD was 1778·2 kJ/kg during the first week of life. An energy intake <1778·2 kJ/kg in this period was associated with a 2-fold increase in the adjusted risk of BPD (OR 2·63, 95 % CI 1·30, 5·34). The early nutrition and the increase of energy intake in the first week of life are associated in our sample with a lower risk of BPD developing.

Emerging Clinical Benefits of New-Generation Fat Emulsions in Preterm Neonates

Soybean oil-based intravenous fat emulsions (IVFEs) have been the predominant parenteral nutrition IVFE used in the United States for neonates over the past 45 years. Even though this emulsion has proven useful in supplying infants with energy for growth and essential fatty acids, there have been concerns over its composition in the development of several morbidities, ranging from sepsis to liver disease, bronchopulmonary dysplasia, and impaired neurodevelopment and growth. The exact mechanisms that drive these morbidities in preterm infants are multifactorial, but potential contributors include high ω-6 (n-6) fatty acid composition, low docosahexaenoic acid and antioxidant supplementation, and the presence of potentially harmful nonnutritive components (eg, phytosterols). To address these issues, new-generation IVFEs with various types and amounts of fat have been developed containing greater amounts of the medium-chain fatty acids, long-chain polyunsaturated fatty acid, docosahexaenoic acid, lower concentrations of ω-6 polyunsaturated fatty acids, supplemental vitamin E, and low or negligible amounts of phytosterols. This review examines the clinical outcomes associated with different morbidities of parenteral nutrition in neonates who have received either soybean oil-based or new-generation IVFEs and addresses whether the proposed benefits of new-generation IVFEs have improved outcomes in the neonatal population.

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.

Review of macronutrients in parenteral nutrition for neonatal intensive care population

Parenteral nutrition (PN) has become essential in the management of sick and growing newborn populations in the NICU. In the past few decades, PN has become fundamental in the nutritional management of the very low birth weight infant (<1,500 g).1 Although the components in PN are commonly determined and ordered by the physician or neonatal nurse practitioner provider, the NICU nurse is responsible for confirming the components in the daily PN prior to infusion and is responsible for maintaining the infusion of PN. Nurses should understand the nutritional components of PN as well as the indications, side effects, and infusion limitations of each component. The purpose of this article is to review the macronutrients in PN, including carbohydrates, protein, and fat. A subsequent article will review the micronutrients in PN, including electrolytes, minerals, and vitamins.

The effect of parenteral lipid emulsions on pulmonary hemodynamics and eicosanoid metabolites in preterm infants: a pilot study

BACKGROUND

Soy-based intravenous fat emulsion (IVFE) is known to cause a rise in pulmonary artery pressure in the preterm infant, thought to be mediated through eicosanoid metabolites of linoleic acid. We compared the effect of soy-based IVFE and an olive-oil-based IVFE containing less than half the content of linoleic acid on pulmonary artery pressure and eicosanoid metabolites in preterm infants receiving parenteral nutrition.

METHODS

In this pilot study at a regional neonatal intensive care unit (ICU), infants received either a soy-based or olive-oil-based IVFE as part of an otherwise identical feeding protocol. Pulmonary artery pressure and urinary thromboxane B2 and prostaglandin F1 alpha were measured at baseline and maximum lipid infusion.

RESULTS

There was a greater fall in pulmonary artery pressure in the olive-oil-based IVFE group compared with the soy-based IVFE group. A decrease in urine thromboxane/prostaglandin F1 alpha ratio was seen only in the olive-oil-based IVFE group.

CONCLUSIONS

In the parenterally fed preterm infant, an olive-oil-based IVFE may have a beneficial effect on pulmonary artery pressure when compared with soy-based IVFE. Effects on pulmonary vascular tone are likely to be mediated through alterations in eicosanoid metabolism. A randomized trial is warranted to compare the effects of different lipid emulsions.

Parenteral lipid administration to very-low-birth-weight infants--early introduction of lipids and use of new lipid emulsions: a systematic review and meta-analysis

BACKGROUND

The use of intravenous lipid emulsions in preterm infants has been limited by concerns regarding impaired lipid tolerance. As a result, the time of initiation of parenteral lipid infusion to very-low-birth-weight (VLBW) infants varies widely among different neonatal intensive care units. However, lipids provide energy for protein synthesis and supply essential fatty acids that are necessary for central nervous system development.

OBJECTIVE

The objective was to summarize the effects of initiation of lipids within the first 2 d of life and the effects of different lipid compositions on growth and morbidities in VLBW infants.

DESIGN

A systematic review and meta-analysis of publications identified in a search of PubMed, EMBASE, and Cochrane databases was undertaken. Randomized controlled studies were eligible if information on growth was available.

RESULTS

The search yielded 14 studies. No differences were observed in growth or morbidity with early lipid initiation. We found a weak favorable association of non-purely soybean-based emulsions with the incidence of sepsis (RR: 0.75; 95% CI: 0.56, 1.00).

CONCLUSIONS

The initiation of lipids within the first 2 d of life in VLBW infants appears to be safe and well tolerated; however, beneficial effects on growth could not be shown for this treatment nor for the type of lipid emulsion. Emulsions that are not purely soybean oil-based might be associated with a lower incidence of sepsis. Large-scale randomized controlled trials in preterm infants are warranted to determine whether early initiation of lipids and lipid emulsions that are not purely soybean oil-based results in improved long-term outcomes.

Interventions for prevention of neonatal hyperglycemia in very low birth weight infants

BACKGROUND

Among very low birth weight (VLBW) infants, early neonatal hyperglycemia is common and is associated with increased risks for death and major morbidities. It is uncertain whether hyperglycemia per se is a cause of adverse clinical outcomes or whether outcomes can be improved by preventing hyperglycemia.

OBJECTIVES

To assess effects on clinical outcomes of interventions for preventing hyperglycemia in VLBW neonates receiving full or partial parenteral nutrition.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, issue 4 of 12, 2011; MEDLINE (1966 to April 2011); EMBASE (1980 to April 2011); CINAHL (1982 to Nov 2008); abstracts of Pediatric Academic Societies 2000 to 2011 and European Society for Pediatric Research 2005 to 2010.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of interventions for prevention of hyperglycemia in neonates with birth weight < 1500 g or gestational age < 32 wk.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for eligibility and extracted data on study design, methods, clinical features, and treatment outcomes. Included trials were assessed for blinding of randomization, intervention and outcome measurement, and completeness of follow-up. Treatment effect measures for categorical outcomes were relative risk and risk difference, and for continuous outcomes, mean difference, each with their 95% confidence intervals.

MAIN RESULTS

We detected four eligible trials. Two trials compared lower versus higher rates of glucose infusion in the early postnatal period. These trials were too small to assess effects on mortality or major morbidities. Two trials, one a moderately large multicentre trial (NIRTURE, Beardsall 2008), compared insulin infusion with standard care. Insulin infusion reduced hyperglycemia but increased death before 28 days and hypoglycemia. Reduction in hyperglycemia was not accompanied by significant effects on major morbidities; effects on neurodevelopment are awaited.

AUTHORS' CONCLUSIONS

Glucose infusion rate: There is insufficient evidence from trials comparing lower with higher glucose infusion rates to inform clinical practice. Large randomized trials are needed, powered on clinical outcomes including death, major morbidities and adverse neurodevelopment.Insulin infusion: The evidence reviewed does not support the routine use of insulin infusions to prevent hyperglycemia in VLBW neonates. Further randomized trials of insulin infusion may be justified. They should enrol extremely low birth weight neonates at very high risk for hyperglycemia and neonatal death. They might use real time glucose monitors if these are validated for clinical use. Refinement of algorithms to guide insulin infusion is needed to enable tight control of glucose concentrations within the target range.

Feeding very-low-birth-weight infants: our aspirations versus the reality in practice

Recently, new guidelines for enteral feedings in premature infants were issued by the European Society of Pediatric Gastroenterology, Hepatology, and Nutrition Committee on Nutrition. Nevertheless, practice proves difficult to attain suggested intakes at all times, and occurrence of significant potential cumulative nutritional deficits 'lies in wait' in the neonatal intensive care unit. This review describes several aspects that are mandatory for optimizing nutritional intake in these vulnerable infants. These aspects range from optimal infrastructure to the initiation of parenteral nutrition with proper transition to enteral breast or formula feedings. Proper monitoring of nutritional tolerance includes serum biochemistry although proper specific markers are unknown and safety reference values are lacking. Although a lot of progress has been made through research during the last few decades, numerous questions still remain unanswered as to what would be the optimal quantity and quality of the various macronutrients. The inevitable suboptimal intake may, however, contribute significantly to the incidence of neonatal diseases, including impaired neurodevelopment. Therefore, it is pivotal that all hospital staff acknowledges that preterm birth is a nutritional emergency and that all must be done, both in clinical practice as well as in research, to reduce nutritional deficits.

Nutrition of preterm infants in relation to bronchopulmonary dysplasia

BACKGROUND

The pathogenesis of bronchopulmonary dysplasia (BPD) is multifactorial. In addition to prenatal inflammation, postnatal malnutrition also affects lung development.

METHODS

A retrospective study was performed to analyse during the first two weeks of life the total, enteral and parenteral nutrition of premature infants (<31 weeks, birth weight ≤1500 g) born between 08/04 and 12/06.

RESULTS

Ninety-five premature infants were analysed: 26 with BPD (27 ± 1 weeks) and 69 without BPD (28 ± 1 weeks). There was no statistical significant difference in the total intake of fluids, calories, glucose or protein and weight gain per day in both groups. The risk of developing BPD was slightly increased in infants with cumulative caloric intake below the minimal requirement of 1230 kcal/kg and a cumulative protein intake below 43.5 g/kg. Furthermore, the risk of developing BPD was significantly higher when infants had a cumulative fluid intake above the recommended 1840 ml/kg. In infants who developed BPD, the enteral nutrition was significantly lower than in non-BPD infants [456 ml/kg (IQR 744, 235) vs. 685 (IQR 987, 511)]. Infants who did not develop BPD reached 50% of total enteral feeding significantly faster [9.6 days vs. 11.5].

CONCLUSIONS

Preterm infants developing BPD received less enteral feeding, even though it was well compensated by the parenteral nutrient supply. Data suggest that a critical minimal amount of enteral feeding is required to prevent development of BPD; however, a large prospective clinical study is needed to prove this assumption.

Intestinal absorption of lipid emulsion in premature infants: a pilot study

BACKGROUND

Adequate nutritional intake is essential in the very-low-birth-weight infant, but difficult to achieve in the first few postnatal days. Can lipids be given enterally in the first few days of life in sick preterm infants?

OBJECTIVE

To determine tolerance and absorption of lipid emulsion when fed enterally to very-low-birth-weight infants.

DESIGN/METHODS

Infants had a birth weight <1,500 g, an appropriate weight for gestational age, and were receiving parenteral nutrition. We performed a progressive series of studies, enrolling 5 infants in each group. Group 1 infants were fed enteral lipid emulsion at 1 g/kg/day for 4 days, starting when 60 ml/kg/day of breast milk was tolerated enterally. Simultaneously, a matched control group which received no oral lipid emulsion was enrolled. We then enrolled group 2 infants who were fed 3 g/kg/day with the same protocol as group 1. Group 3 infants were fed enteral lipid emulsion starting in the first 72 h of life. The infants were fed 1, 2 and 3 g/kg/day subsequently for 48 h each. Fat absorption was measured.

RESULTS

Gestational age was 24.6-30.8 weeks and birth weight was 620-1,400 g. One infant (group 1) developed necrotizing enterocolitis 1 week after the study. There were no other adverse clinical findings. On average, enteral lipid emulsion was started on day 8 of life in groups 1 and 2, and on day 2 in group 3. The intestinal lipid absorption was 93.6% (min. = 76%). There was no difference in fat absorption between the 4 groups (p > 0.05).

CONCLUSIONS

Lipid emulsions are an isotonic high-calorie source which can be given safely enterally instead of intravenously in the immediate neonatal period of very-low-birth-weight infants without clinical adverse effects and with almost complete absorption. There are potential advantages to oral administration of a lipid emulsion starting in early life which require further investigation.

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.

Interventions for prevention of neonatal hyperglycemia in very low birth weight infants

BACKGROUND

Among very low birth weight (VLBW) infants, early neonatal hyperglycemia is common and is associated with increased risks for death and major morbidities. It is uncertain whether hyperglycemia per se is a cause of adverse clinical outcomes or whether outcomes can be improved by preventing hyperglycemia.

OBJECTIVES

To assess effects on clinical outcomes of interventions for preventing hyperglycemia in VLBW neonates receiving full or partial parenteral nutrition.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, issue 4 2008; MEDLINE (1966 - Nov 2008); EMBASE (1980 - Nov 2008); CINAHL (1982 - Nov 2008); abstracts of Pediatric Academic Societies 2000 - 2008 and European Society for Paediatric Research 2005 - 2008.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of interventions for prevention of hyperglycemia in neonates with birth weight < 1500 g or gestational age < 32 wk

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for eligibility and extracted data on study design, methods, clinical features, and treatment outcomes. Included trials were assessed for blinding of randomization, intervention and outcome measurement, and completeness of follow-up. Treatment effect measures for categorical outcomes were relative risk and risk difference, and for continuous outcomes, mean difference, each with their 95% confidence intervals.

MAIN RESULTS

We detected four eligible trials. Two trials compared lower vs. higher rates of glucose infusion in the early postnatal period. These trials were too small to assess effects on mortality or major morbidities. Two trials, one a moderately large multicentre trial (NIRTURE, Beardsall 2008), compared insulin infusion with standard care. Insulin infusion reduced hyperglycemia but increased death before 28 days and hypoglycemia. Reduction in hyperglycemia was not accompanied by significant effects on major morbidities; effects on neurodevelopment are awaited.

AUTHORS' CONCLUSIONS

Glucose infusion rate: There is insufficient evidence from trials comparing lower with higher glucose infusion rates to inform clinical practice. Large randomized trials are needed, powered on clinical outcomes including death, major morbidities and adverse neurodevelopment.Insulin infusion: The evidence reviewed does not support the routine use of insulin infusions to prevent hyperglycemia in VLBW neonates. Further randomized trials of insulin infusion may be justified. They should enrol extremely low birth weight neonates at very high risk for hyperglycemia and neonatal death. They might use real time glucose monitors if these are validated for clinical use. Refinement of algorithms to guide insulin infusion is needed to enable tight control of glucose concentrations within the target range.

A randomized controlled trial on parenteral nutrition, oxidative stress, and chronic lung diseases in preterm infants

OBJECTIVES

To evaluate the effect of trace elements (TEs), when added to total parenteral nutrition (TPN) solutions, on peroxides load, and to test the hypothesis that protection of TPN from light can decrease peroxides load and is associated with improvement in oxidant-related clinical outcomes in preterm infants.

SUBJECTS AND METHODS

A total of 80 preterm infants were randomized to 1 of 4 groups (n=20 each): group 1 received a mixture of dextrose and amino acids; group 2 received a mixture of dextrose, amino acids, and lipid emulsion; group 3 received dextrose, amino acids, lipid emulsion, and multivitamins (MVP); and group 4 received dextrose, amino acids, lipid emulsion, MVP, and TEs. Each group was subdivided into photo-protected and photo-exposed subgroups (n=10 each). Using ferrous oxidation of xylenol orange technique, we measured the baseline level of excreted urinary peroxides before and 48 hours after starting TPN. We examined the association among light protection, urinary peroxides, and clinical outcomes of these infants.

RESULTS

Baseline urinary peroxides ranged between 5.5 and 24.8 micromol/L. A significant increase in urinary peroxides was observed in all groups after receiving TPN. The use of TEs did not affect peroxide production. In regression analysis, the addition of MVP (P<0.0001) and the exposure to light (P=0.02) were significantly associated with increased urinary peroxides. In the overall population, light exposure was associated with a significant increase in the incidence of chronic lung disease (adjusted OR 9.26, confidence interval 1.2-73; P=0.03) but had no effect on mortality, necrotizing enterocolitis, or sepsis.

CONCLUSIONS

TEs in TPN solutions have no effect on the production of urinary peroxides. Addition of MVP and exposure of TPN to light are the 2 major sources of peroxides in TPN. Protection from ambient light is associated with a decrease in chronic lung disease.

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.

Increased energy intake for preterm infants with (or developing) bronchopulmonary dysplasia/ chronic lung disease

BACKGROUND

Preterm infants with bronchopulmonary dysplasia/chronic lung disease have nutritional deficits that may contribute to short and long term morbidity and mortality. Increasing the daily energy intake for these infants may improve their respiratory, growth and neurodevelopmental outcomes.

OBJECTIVES

To assess the effect of increased energy intake on mortality and respiratory, growth and neurodevelopmental outcomes for preterm infants with (or developing) CLD/BPD. Secondarily, the review examines any adverse effects associated with increased energy intake.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006) , MEDLINE (accessed via Ovid), references cited in previous relevant Cochrane reviews and in other relevant studies, review articles, standard textbooks, and manuals of neonatal medicine. Hand search results of the Cochrane Neonatal Review Group were also assessed.

SELECTION CRITERIA

All randomized and quasi-randomized trials comparing the outcomes of preterm infants with (or developing) CLD/BPD who had either increased (> 135 kcal/kg/day) or standard energy intake (98 to 135 kcal/kg/day). Increasing energy intake might be achieved enterally and/or parenterally, enterally by increasing the energy content of the milk, increasing feed volume, or by nutrient supplementation with protein, carbohydrate or fat. The primary outcomes were the development of CLD and neonatal mortality; secondary outcomes included respiratory morbidities, growth, neurodevelopmental status and possible complications with increased energy intake.

DATA COLLECTION AND ANALYSIS

We planned to extract data using the standard methods of the Cochrane Neonatal Review Group. Relevant trials would be scrutinized for methodological quality independently by the reviewers to determine their eligibility for inclusion. Data of the included trials would be expressed as relative risk, risk difference, NNT and weighted mean difference where appropriate, using a fixed effect model.

MAIN RESULTS

No eligible trials were identified. Twelve studies that appeared to be relevant were excluded, as no study directly compared increased versus standard energy intakes in infants with CLD/BPD. However, two excluded trials provided some insights into the topic. One study showed that infants with CLD/BPD who were fed formula enriched with protein and minerals had improved growth parameters up until the cessation of the intervention at three months of corrected age. The other study compared different energy density of formula but identical energy intake by setting different feed volumes for both groups. It showed that both groups were unable to achieve the pre-designated feed volumes, and that there were no differences in growth, respiratory outcomes, oedema and the diuretic requirements.

AUTHORS' CONCLUSIONS

To date, no randomized controlled trials are available that examine the effects of increased versus standard energy intake for preterm infants with (or developing) CLD/BPD. Research should be directed at evaluating the effects of various levels of energy intake on this group of infants on clinically important outcomes like mortality, respiratory status, growth and neurodevelopment. The benefits and harms of various ways of increasing energy intake, including higher energy density of milk feed and/or fluid volume (clinically realistic target volume should be set), parenteral nutrition, and the use of various constituents of energy like carbohydrate, protein and fat for this purpose also need to be assessed.

Early and aggressive nutritional strategy (parenteral and enteral) decreases postnatal growth failure in very low birth weight infants

OBJECTIVE

To compare postnatal growth and nutritional deficits after the implementation of two different nutritional strategies in two consecutives periods of time.

METHODS

An early and aggressive nutritional regimen was used in a cohort of 117 very low birth weight (VLBW) infants. Amino acids were administered at the rate of 1.5 g/kg/day along with 5.6 mg/k/min of glucose flow on day 1 of life, and progressively increased to 4 g/kg/day and 13 mg/kg/min. Intravenous lipids were started at 0.5 g/kg/day at 24 h from birth, and increased to 3.5 g/kg/day; enteral feeding was begun at day 1 of life. Uni- and multivariate analyses were used to compare this group with the conventional group of 65 VLBW infants conservatively fed.

RESULTS

Univariate analysis showed that in the aggressive group there was a 66% reduction in the risk of post natal malnutrition at 40 weeks of postmenstrual age (OR 0.34; 95% CI 0.17-0.67). This difference persisted in the multivariate analysis. Energy and protein deficits were lower in the aggressive group (P < 0.001).

CONCLUSIONS

Early and aggressive introduction of total parenteral nutrition and enteral feeding resulted in better growth in weight, length and head circumference, and a reduction of nutritional deficits at 40 weeks of postmenstrual age.

Early introduction of lipids to parenterally-fed preterm infants

BACKGROUND

Lipids are essential components of parenteral nutrition for preterm infants. Parenteral lipids can be administered through a peripheral vein, and their early introduction offers the potential advantages of increasing energy intake and providing essential fatty acids and fat soluble vitamins. Concerns have been raised about potential adverse effects including chronic lung disease (CLD), increase in pulmonary vascular resistance, impaired pulmonary gas diffusion, bilirubin toxicity, sepsis and free radical stress.

OBJECTIVES

To determine the safety and efficacy of 'early' (</= 5 days after birth) introduction of lipids to parenterally fed preterm infants.

SEARCH STRATEGY

Eligible studies were identified by searching MEDLINE (December 2004), EMBASE 1980 - 2004, Oxford Database of Perinatal Trials, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2004) and CINAHL (December 1982 - December 2004). Abstracts of the Society for Pediatric Research were hand searched from 1980 to 2004 inclusive. No language restrictions were applied.

SELECTION CRITERIA

All randomised or quasi randomised controlled trials comparing 'early' versus 'no early' introduction of lipids to preterm infants.

DATA COLLECTION AND ANALYSIS

Data were sought regarding effects on growth and risk of CLD or death, other respiratory morbidities including duration of respiratory support, duration of supplemental oxygen, the need for home oxygen, pneumothorax (PTX), pulmonary haemorrhage and pulmonary interstitial emphysema (PIE), >/= stage 2 necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), patent ductus arteriosus (PDA), sepsis, intraventricular haemorrhage (IVH), clinically significant thrombocytopenia and significant jaundice. Methodological quality of eligible studies was assessed according to allocation concealment, blinding of intervention, blinding of outcome assessment and completeness of follow up. When appropriate, meta-analysis was conducted to provide a pooled estimate of effect. For categorical data the Typical relative risk (RR), Typical risk difference (RD) and number needed to treat (NNT) with 95% confidence intervals (CI) were calculated. Continuous data were analysed using weighted mean difference (WMD).

MAIN RESULTS

Five studies (n = 397) were included in the review. All studies compared the effectiveness and safety of 'early' introduction versus 'no early' introduction of lipids in preterm infants. The timing of introduction of 'early lipids' ranged from < 12 hours after birth to day five of life. The timing of introduction of lipids in the 'no early' lipid group ranged from day six after birth to day 14 after birth. The initial dose ranged from 0.5 - 1 g/kg/day with gradual daily increments up to a maximum of 2.5 - 3.5 g/kg/day. For the primary outcomes (growth, death and CLD), there was no statistically significant difference between the 'early' lipid and 'no early' lipid groups. Days to regain birth weight: [WMD 0.59 (95% CI -2.41, 3.58); two trials; N = 71]. Rate of weight gain (g/day) during period of hospital stay: [MD -2.40 (95% CI -5.30, 0.50); one trial; N = 129]Death (irrespective of time): [Typical RR 1.04 (95% CI 0.69, 1.56); Typical RD 0.01 (95% CI -0.07, 0.08); five trials; N = 397]Neonatal deaths: [Typical RR 1.35 (95% CI 0.78, 2.34); Typical RD 0.05 (95% CI -0.04, 0.13); four trials; N = 268].CLD: [Typical RR 1.10 (95% CI 0.81, 1.49); Typical RD 0.04 (95% CI -0.09, 0.17); two trials; N = 193]. For the secondary outcomes of other respiratory morbidities including duration of respiratory support, duration of supplemental oxygen, PTX, pulmonary haemorrhage, PIE, NEC, ROP, PDA, sepsis, IVH and significant jaundice, there were no statistically significant differences between 'early' and 'no early' lipid groups.

AUTHORS' CONCLUSIONS

No statistically significant effects of 'early introduction' of lipids on short term nutritional or other clinical outcomes, either benefits or adverse effects, were demonstrated in the studies reviewed. Based on the currently available evidence, 'early' initiation of lipids (</= 5 days after birth) can not be recommended for short term growth or to prevent morbidity and mortality in preterm infants.

Can an alternative umbilical arterial catheter solution and flush regimen decrease iatrogenic hemolysis while enhancing nutrition? A double-blind, randomized, clinical trial comparing an isotonic amino acid with a hypotonic salt infusion

OBJECTIVE

In the process of sampling blood through an umbilical arterial catheter (UAC), infant blood comes into stagnant contact with infusion solution in the "waste syringe" before being reinfused. We have previously demonstrated in vitro that this process is associated with less hemolysis of red blood cells (RBCs) with use of an isotonic solution compared with a hypotonic 0.25 normal saline (NS) solution. The objective of this study was to compare the in vivo effect on hemolysis of 2 UAC infusion/flush regimens (an isotonic regimen vs a hypotonic regimen) and to assess the early nutritional benefit of an amino acid solution as the isotonic UAC infusion solution.

METHODS

Infants who had a birth weight of < or =1.5 kg and were expected to have a UAC for > or =3 days were enrolled within 24 hours of life into this prospective, double-blind, randomized, clinical trial of 2 UAC infusion solution/flush regimens. Power analysis demonstrated that 40 infants were needed to determine differences in hemolysis quantified by plasma-free hemoglobin (PFH) level. Nutrition from glucose was evaluated by measurement of daily dextrose calories. C-peptide was measured to evaluate endogenous insulin production. Adverse events and protein tolerance were tracked.

RESULTS

Twenty-two infants (mean gestational age: 27 weeks; 945 g birth weight) were enrolled in each group, for an average of 4.2 days (range: 2.5-8 days). There were no group differences in demographics. PFH levels were lower for infants who received isotonic amino acid (IAA) in comparison with 0.25 NS (33 +/- 14 mg/dL vs 62 +/- 27 mg/dL, respectively). C-peptide was higher in those who received IAA, as were nonprotein calories received on days 4 to 6 of the study (51 +/- 11 kcal/kg/day vs 44 +/- 12 kcal/kg/day, IAA vs 0.25 NS, respectively).

CONCLUSIONS

Lower PFH levels in IAA versus 0.25 NS group were consistent with our hypothesis of decreased hemolysis with an isotonic infusion/flush regimen. IAA use may also allow greater early glucose nutrition, as indicated by the higher level of endogenous insulin production and improved glucose tolerance. IAA seems to be a superior UAC solution to 0.25 NS in that it is associated with less hemolysis and improved nutrition.

Oxidative stress in childhood—in health and disease states

The accumulated information concerning the involvement of reactive oxygen species in many clinical disorders and disease states has led to the potential for intervention with antioxidants in these cases. There are currently numerous clinical trials involving administration of antioxidants in a variety of conditions such as coronary heart disease, cataract, cancer and neurodegenerative diseases. At the same time therapeutic trials aimed at preventing and delaying the aging process are also under investigation. Numerous disorders, in childhood, have also been linked to oxidative damage. The aim of this review is to provide an overview of oxidative stress, its mechanisms, targets and damage incurred, as pertaining specifically to clinical disorders during childhood. The defense mechanisms against oxidation; the enzymatic antioxidants and low molecular weight antioxidants are defined and a number of methods commonly used for evaluation of oxidative stress (methods for measurement of lipid and protein oxidation end products and methods for measurement of antioxidant defense capacity) described. Specific diseases related to oxidative stress in infancy and childhood are reviewed and the possible effect of nutritional intake on oxidative stress in the healthy child discussed. Other issues addressed include the ability of oxidative stress, as measured in plasma to reflect intratissue oxidation, the need for a simple laboratory method for characterization of an oxidative stress 'profile', the proposed role of oxidative stress in biological processes pertaining to growth and maturation and possible implications of unrestricted antioxidant supplementation.

Maternal loading with very low-density lipoproteins stimulates fetal surfactant synthesis

We examined whether administration of very low-density lipoproteins (VLDL) to pregnant rats increases surfactant phosphatidylcholine (PtdCho) content in fetal pre-type II alveolar epithelial cells. VLDL-triglycerides are hydrolyzed to fatty acids by lipoprotein lipase (LPL), an enzyme activated by heparin. Fatty acids released by LPL can incorporate into the PtdCho molecule or activate the key biosynthetic enzyme cytidylyltransferase (CCT). Dams were given BSA, heparin, VLDL, or VLDL with heparin intravenously. Radiolabeled VLDL given to the pregnant rat crossed the placenta and was distributed systemically in the fetus and incorporated into disaturated PtdCho (DSPtdCho) in pre-type II cells. Maternal administration of VLDL with heparin increased DSPtdCho content in cells by 45% compared with control (P < 0.05). VLDL produced a dose-dependent, saturable, and selective increase in CCT activity. VLDL did not significantly alter immunoreactive CCT content but increased palmitic, stearic, and oleic acids in pre-type II cells. Furthermore, hypertriglyceridemic apolipoprotein E knockout mice contained significantly greater levels of DSPtdCho content in alveolar lavage and CCT activity compared with either LDL receptor knockout mice or wild-type controls that have normal serum triglycerides. Thus the nutritional or genetic modulation of serum VLDL-triglycerides provides specific fatty acids that stimulate PtdCho synthesis and CCT activity thereby increasing surfactant content.

Metabolism and nutritional support in the surgical neonate

Various factors can influence the metabolism of surgical neonates. These include prematurity, operative stress, critical illness, and sepsis. The nutritional management of surgical infants with congenital or acquired intestinal abnormalities has improved after the introduction of parenteral nutrition. This article is focused on the energy and protein metabolism of surgical neonates with particular reference to the metabolic response to operative trauma and sepsis. The metabolic utilization of intravenous nutrients also is discussed. The metabolic response to operative trauma is different between neonates and adults. Infants have high rates of protein turnover and are avid retainers of nitrogen. Energy expenditure increases only transiently (4 to 6 hours) after major surgery in neonates. Protein turnover and catabolism seems not to be affected by major operative procedures in neonates. In neonates on parenteral nutrition, carbohydrate and fat have an equivalent effect on protein metabolism. The main determinants of fat utilization are carbohydrate intake and resting energy expenditure. Parenteral nutrition in surgical neonates is associated with increased production of oxygen-free radicals. This seems to be related to intravenous fat administration. Promoting fat utilization by reducing the carbohydrate to fat ratio in the intravenous diet reduces free radical activity to a similar extent as fat exclusion. Glutamine appears to be safe for use in neonates and infants and is "conditionally essential" in very-low birth weight infants and in septic neonates. Enteral glutamine supplementation in very-low birth weight infants reduces the risk of sepsis. The metabolism of surgical neonates is affected by operative trauma, critical illness, and sepsis. Nutritional support in surgical neonates has a profound impact on outcome. Exogenous glutamine can modulate immune, metabolic, and inflammatory responses. Further investigations are needed to clarify the clinical benefit of parenteral or enteral glutamine administration in surgical neonates.

Intravenous lipid composition affects hypoxic pulmonary vasoconstriction in the newborn piglet

To examine the effects of altering the fatty acid (FA) composition of intravenous (IV) lipid emulsions on pulmonary vascular resistance (PVR) and thromboxane production, we studied three groups of newborn piglets after three days of either sow's milk (milk), or total parenteral nutrition (TPN) with either iv soy bean oil (SBO, 52% n-6 and 8% n-3 FA) or fish oil (FO, 5% n-6 and 51% n-3 FA) emulsions. At baseline, and during hypoxia at 20 min and 2 h, cardiac output (Q) was measured, PVR calculated and plasma levels of a prostacyclin metabolite (6-keto-PgF1α) and thromboxane B2 (TxB2) were measured. Fatty acid composition of the lung phospholipids was analyzed. There was an exaggerated increase in PVR and decrease in Q during prolonged hypoxia in the TPN-SBO group as compared with the other two groups. There was no difference in PVR and Q between the milk and TPN-FO groups. FA of lung phospholipids reflected the high dietary level of long chain n-3 FA in the TPN-FO group. However, no differences in plasma levels of 6-keto-PgF1α or TxB2 were found. Intravenous emulsions made from SBO reduced cardiac output and increased pulmonary vascular resistance in the hypoxic newborn piglet, whereas iv FO emulsions did not. When subjects with pulmonary hypertension are receiving TPN iv SBO may be detrimental; iv FO may be beneficial, giving similar responses as in a milk-fed subject.Key words: total parenteral nutrition, fish oil, pulmonary hypertension, lipid emulsion, fatty acids.Key words: total parenteral nutrition, fish oil, pulmonary hypertension, lipid emulsion, fatty acids.

Effects of various arterial infusion solutions on red blood cells in the newborn

AIM

To examine in vitro the effects of brief contact with various infusion solutions on red blood cells from newborn infants, as occurs in the "waste" syringe during routine blood sampling from umbilical artery catheters. The mixture of blood and solution in the "waste" syringe is usually reinfused into the baby. Reinfused red blood cells may be damaged by the infusion solution. It is hypothesised that an isotonic amino acid solution would cause no red blood cell agglutination and no more haemolysis than many commonly used solutions.

METHODS

Blood was obtained from the placentas of 15 normal term babies. Haemolysis was estimated by measuring plasma (free) haemoglobin after mock blood sampling. Agglutination was measured semiquantitatively by direct observation.

RESULTS

A 0.25% normal saline solution caused 5.4% haemolysis, significantly more than all the other fluids tested. There was less haemolysis with 0. 25% normal saline when there was complete mixing of blood and solution within the "waste" syringe. Normal saline and isotonic sodium acetate solutions caused < 0.1% haemolysis, significantly less than all the other fluids tested. The isotonic amino acid solution caused 0.8% haemolysis, which is similar to that caused by the remaining solutions tested. Agglutination was seen with isotonic dextrose and with the two isotonic amino acid solutions containing cysteine.

CONCLUSIONS

Isotonic amino acid solution (without added cysteine) caused no agglutination and the same or less haemolysis than many commonly used solutions and may offer advantages in nutrition and fluid balance.

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.

Fat emulsion administration in the early postoperative period in patients undergoing esophagectomy for carcinoma depresses arachidonic acid metabolism in neutrophils

The aim of this study was to evaluate the effect of fat emulsion administration on neutrophil arachidonic acid and leukotriene B4 (LTB4) generation in surgically stressed patients. Total parenteral nutrition was administered to 17 patients for 2 wk after esophagectomy for carcinoma. Eight patients received fat with glucose (fat group, 30% of total calories) and 9 patients received glucose (glucose group) as a non-protein calorie source from the day of the operation to the seventh postoperative day (POD), and they gradually were converted to enteral nutrition during the second postoperative week. The arachidonic acid in the fat group decreased in the serum from POD 4 to 14. and in neutrophils from 12 h after the beginning of surgery to POD 14, compared to preoperative levels. LTB4 production by A23187-stimulated neutrophils was highest 6 h after the beginning of surgery, when neutrophil arachidonic acid concentration was decreasing, and then fell below the preoperative value from POD 4 to 14 in both groups. LTB4 production on POD 14 was lower in the fat group than in the glucose group. Biosynthesis of arachidonic acid from linoleic acid is inhibited in surgically stressed patients receiving fat emulsion, resulting in the diminished synthesis of LTB4 by neutrophils. The decrease in LTB4 may diminish chemotactic and chemokinetic signals to other leukocytes.

Lipid peroxidation can be reduced in infants on total parenteral nutrition by promoting fat utilisation

BACKGROUND/PURPOSE

Increased oxygen-derived free radical activity has been reported during total parenteral nutrition (TPN) in infants and has been specifically linked to the fat infusion. The aim of this study was to test the hypothesis that during TPN, oxygen-derived free radical production can be reduced by increasing the utilisation of fat.

METHODS

In experiment A (17 patients) the fat infusion was kept constant (3 g/kg/d) and the carbohydrate infusion was changed from 18 g/kg/d on day 1 to 10 g/kg/d on day 2. In experiment B (six patients) the carbohydrate infusion remained constant and the fat infusion was changed from 3 g/kg/d on day 1 to 0 g/kg/d on day 2. Fat utilisation was measured by indirect calorimetry. Plasma malondialdehyde, an index of lipid peroxidation resulting from increased oxygen-derived free radical activity, was measured by a colorimetric assay.

RESULTS

In both experiments there was no significant change between the two study phases in oxygen consumption, carbon dioxide production, and resting energy expenditure demonstrating that the patients were metabolically stable. In experiment A there was a significant (P = .0005) increase in fat utilisation and a significant (P = .009) decrease in malondialdehyde (MDA) concentration between the two phases. In experiment B there was also a significant (P = .007) decrease in MDA concentration. The decrease in MDA concentration was similar between the two experiments.

CONCLUSIONS

It is not necessary to stop the infusion of fat to reduce free radical production. Promoting fat utilisation by reducing the carbohydrate-fat ratio of the TPN reduces free radical activity to a similar extent as fat exclusion. These findings have important implications for the composition of TPN.

Randomised controlled trial of an aggressive nutritional regimen in sick very low birthweight infants

AIMS

To improve energy intake in sick very low birthweight (VLBW) infants; to decrease growth problems, lessen pulmonary morbidity, shorten hospital stay, and avoid possible feeding related morbidity. Morbidity in VLBW infants thought to be associated with parenteral and enteral feeding includes bronchopulmonary dysplasia, necrotising enterocolitis, septicaemia, cholestasis and osteopenia of prematurity.

METHODS

A prospective randomised controlled trial (RCT) comparing two types of nutritional intervention was performed involving 125 sick VLBW infants in the setting of a regional neonatal intensive care unit. Babies were randomly allocated to either an aggressive nutritional regimen (group A) or a control group (group B). Babies in group B received a conservative nutritional regimen while group A received a package of more aggressive parenteral and enteral nutrition. Statistical analysis was done using Student's t test, the Mann-Whitney U test, the chi 2 test and logistic regression.

RESULTS

There was an excess of sicker babies in group A, as measured by initial disease severity (P < 0.01), but mean total energy intakes were significantly higher (P < 0.001) in group A at days 3 to 42 while receiving total or partial parenteral nutrition. Survival and the incidences of bronchopulmonary dysplasia, septicaemia, cholestasis, osteopenia and necrotising enterocolitis were similar in both groups. Growth in early life and at discharge from hospital was significantly better in babies in group A. There were no decreases in pulmonary morbidity or hospital stay.

CONCLUSION

Nutritional intake in sick VLBW infants can be improved without increasing the risk of adverse clinical or metabolic sequelae. Improved nutritional intake resulted in better growth, both in discharge, but did not decrease pulmonary morbidity or shorten hospital stay.

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.

Randomised trial of effect of delayed intravenous lipid administration on chronic lung disease in preterm neonates

A recent sevenfold increase in the annual incidence of chronic neonatal lung disease (CNLD) on an intensive care unit was attributed to the early administration of intravenous lipid (IVL) in ventilated preterm neonates. When logistic regression was used to eliminate other confounding variables, early delivery of IVL was independently associated with an eight-fold increase in the likelihood of CNLD. Consequently, we designed a prospective study to detect a halving of the incidence of CNLD by delaying IVL administration from 5 days (as is routine practice) to 14 days. Sixty-four parenterally fed preterm neonates weighing < 1,500 g at birth were randomised to receive IVL either on day 5 or day 14. Analysis was by intention to treat, since several infants in the latter group required no parenteral nutrition by day 14. Our results showed that the relative risk (95% confidence interval) of CNLD at 28 postnatal days was 1.15 (0.81-1.62); at 36 weeks postconception, it was 1.08 (0.59-1.99). A study population of > 2,000 would be required to determine whether these relative risks were significantly different from 1.

Pulmonary vascular resistance during lipid infusion in neonates

Using two-dimensional echocardiography, pulmonary vascular resistance was estimated from right ventricular pre-ejection period to ejection time (RVPEP/ET) in 11 preterm infants with respiratory distress, to test the effect of different doses of continuous lipid infusion. Echocardiography was performed at baseline with no lipid infusing 2 and 24 hours after 1.5 and 3 g/kg/day of intravenous lipid, 24 hours after discontinuing intravenous lipid emulsion, and 2 hours after restarting intravenous lipid. After 24 hours of intravenous lipid at 1.5 g/kg/day the RVPEP/ET rose to mean (SD) 0.287 (0.03) from a baseline value of 0.225 (0.02) and to 0.326 (0.05) after 24 hours of intravenous lipid at 3 g/kg/day. Pulmonary arterial pressure returned to baseline 24 hours after the intravenous lipid had been discontinued. Continuous 24 hour infusion of lipid caused significant dose and time-dependent increases in pulmonary vascular resistance. Intravenous lipid may aggravate pulmonary hypertension.

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.

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.

Fatty acids in pediatric nutrition

The past 20 years have shown that dietary FA molecules are able to mediate and condition biologic functions in an increasing number of biochemical contexts. Different diet interventions can induce measurable alterations at the ultrastructural level of lipid moieties and circulating FAs. This has many consequences for prevention, for therapy, and, in particular, for the management of chronic degenerative disease. From the earliest stages of life, an adequate availability of the n-6 and n-3 series LCP seems essential to ensure the adequate structural and functional development of the various tissues, especially the central nervous system tissues. Recognition of the numerous steps involved in intermediate FA metabolism should induce us to further our understanding of the manifold possibilities open for intervention on FA profile and balance and stress the need for an interdisciplinary approach.

Influence of energy substrates on respiratory gas exchange during conventional mechanical ventilation of preterm infants

OBJECTIVE

The purpose of this study was to determine the optimal parenteral feeding regimen for infants with compromised respiratory function.

METHODS

We studied the influence of varying the source of energy on respiratory gas exchange in 10 infants who were supported by mechanical ventilation and who received intravenous feedings. Two isoenergetic parenteral regimens were infused consecutively; the level of fat intake was varied inversely with that of glucose. Under similar ventilator settings, transcutaneous partial pressures of oxygen and carbon dioxide, as well as indirect calorimetry were measured during each regimen.

RESULTS

Despite the higher carbon dioxide production during the glucose-rich regimen (8.9 +/- 0.7 vs 7.9 +/- 0.4 ml/kg per minute, p < 0.05 by analysis of variance), transcutaneous partial pressure of carbon dioxide remained unaffected, suggesting ventilatory compensation as documented by the increased (p < 0.002) alveolar ventilation. This was not associated with a detectable rise in oxygen consumption, but with a significant change in partial pressure of oxygen (77 +/- 5 vs 66 +/- 3 mm Hg, p < 0.05).

CONCLUSIONS

Ventilator-dependent infants with early and mild bronchopulmonary dysplasia, who receive intravenous feedings of a moderate load of glucose-based energy, can compensate for enhanced carbon dioxide production by increasing their respiratory drive, with a beneficial effect on oxygenation compared with that observed when energy is derived from lipid-based solutions.

Appropriate fluid regimens to prevent bronchopulmonary dysplasia

Pulmonary oedema is an important problem in premature neonates with surfactant deficiency because of fluid accumulation in the lung interstitium and reduced urine output. Some retrospective reports suggest that excessive early hydration might increase the risk of bronchopulmonary dysplasia (BPD). Only three prospective studies evaluating low or conventional fluid administration regimens to very low birth weight infants have been published. According to their results no significant differences in the incidence of BPD have been shown. However, fluid restriction seems to improve the outcome of the infants because of decreased incidence of haemodynamically significant patent ductus arteriosus, necrotizing enterocolitis, pulmonary air leaks and decreased mortality. The appropriate amount of sodium in the intravenous fluids during the first days of life needs further evaluation. In tiny infants with birth weights from 500 to 800g intensive monitoring of fluid balance is essential to control the extremely high fluid losses due to evaporation. Undernutrition is a risk factor of BPD and therefore it is important to start parenteral nutrition early. The benefit of the use of colloids as volume expanders is controversial. According to some retrospective reports there might be an association with increased use of colloidal fluids during the first days of life and the development of BPD. Early excessive fluid administration might constitute a potential risk for low birth weight infants with hyaline membrane disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Feeding the preterm infant

The sick preterm infant has special nutritional needs, and the provision of appropriate nutrition is now recognised as an important part of the increasingly intensive management of this population. "Optimal" nutrition is difficult to define for an individual infant, but prospective randomised studies have shown that the early diet given to preterm infants can have a major impact on their neurological development and growth, with the best outcomes for those receiving either a preterm formula or maternal milk fortified with a range of nutrients. In contrast, diets suitable for term infants do not meet the needs of small preterm infants, either in the short or longer term, and should not be used. This article reviews the nutritional needs of the preterm infant and outlines the strategies commonly used in this area of neonatal intensive care.

The increase in vasomotor tone induced by a parenteral lipid emulsion is linked to an inhibition of prostacyclin production

The aim of the study was to verify whether the infusion of a lipid emulsion causes a rise in vascular pressure related to an imbalance in the production of vasoconstricting and vasodilatating eicosanoids. Segments of umbilical veins were perfused with and without 1.5 microM indomethacin (cyclooxygenase inhibitor) in solutions differing only in their lipid content (control vs. lipid). The lipid-induced higher pressure (p < 0.05) was associated with an inhibition (p < 0.05) in the output of the vasodilatator PGI2, and an increase (p < 0.01) in the production of the vasoconstrictor PGF2 alpha. Indomethacin abolished differences in pressure, but produced a rise (p < 0.01) in vascular tone of both the control and lipid-containing solutions by inhibiting PGI2 synthesis. Prostacyclin was the only eicosanoid significantly correlated (p < 0.01) to vascular tone. The lipid emulsion was therefore linked to the inhibition of the conversion of PGH2 to PGI2. The ensuing greater PGH2 availability would result in vivo, in the increased synthesis of vasoconstricting eicosanoids. The lipid-containing solution produced vasoactive responses similar to those reported with tert-butyl hydroperoxide, suggesting that hydroperoxides contaminating commonly used lipid emulsions could be causing a prostanoid-dependent vasoconstriction.