Fat elimination in parenterally fed low birth weight infants during the first two weeks of life

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.

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.

Beneficial effect of coinfusing a lipid emulsion on venous patency

The hypothesis that infused fat could prolong venous patency was tested in a paired crossover design. Parenterally fed newborn infants received, for a given level of energy, (60 vs 80 kcal/kg/day), two 6-day isocaloric and isonitrogenous (434 +/- 3.4 mg/kg/day, n = 32) regimens differing only by the fat intake (LF: 1.03 +/- 0.02, HF: 2.78 +/- 0.05 g/kg/day). Paired comparisons of osmolarities within isocaloric (60 or 80 kcal/kg/day) infusions showed that high fat regimens were associated with significantly lower osmolarities. A paired comparison of patency times showed that the drop in osmolarity produced by the high fat regimen at 60 kcal/kg/day led to a significantly longer venous patency time. The comparison of patency times between regimens (LF, 60 kcal/kg/day) and HF, 80 kcal/kg/day) with same osmolarities (702 mOsm/liter) and glucose intakes (11 g/kg/day) documented that the fat emulsion per se had a vascular protective effect. This observation demonstrates that the coinfusion of a lipid emulsion exerts a beneficial effect, whether biochemical or biophysical, on the vascular endothelium of peripheral veins.

Lipid tolerance in the very low birth weight infant on intravenous and enteral feedings

Nutrition is of critical importance to very low birth weight (VLBW) survival. Intravenous (iv) lipid tolerance has been studied using a soybean or safflower-based lipid emulsion. We studied lipid levels in a group of VLBW infants on both intravenous lipids (soybean-safflower emulsion) and on enteral feedings (24 cal/oz premature formula). Levels were obtained on 1, 2, and 3 g/kg/day of iv lipid and after 3 and 10 days of feeding. Triglyceride (TG) and free fatty acid (FFA) proved the most sensitive indicator of both iv and enteral tolerance. The higher the lipid dose, the more likely there would be elevated lipid levels, especially FFA. Mean lipid levels for the group of enteral-fed infants were normal. Comparison of lipid levels on iv to those on enteral feedings showed significant differences in trough iv levels of TG compared to preprandial TG. FFAs tended to be significantly higher on iv feedings. Monitoring lipid levels on iv and enteral feedings is appropriate to document tolerance.

Impaired fat utilization in parenterally fed low-birth-weight infants suffering from sepsis

Lipid infusion in low-birth-weight infants suffering from sepsis is still controversial. Consequently, we investigated the fat tolerance in six low-birth-weight infants with sepsis and 15 low-birth-weight infants without sepsis. For measurement of fat clearance, we assayed the serum concentrations of triglycerides enzymatically, and of the free fatty acids by colorimetric micromethod. The fatty acid oxidation was analyzed with the [13C]triolein breath test by means of ratio-mass spectrometry. The infants were maintained on continuous parenteral nutrition with various amounts of soybean oil emulsion (1 g, 2 g, and 3 g fat/kg body weight per day). Comparing the lipid infusion of 1 and 2 g fat/kg body weight per day between the two groups, we found triglyceride and free fatty acid values in both groups to be in the normal range. At a dose of 3 g of fat/kg body weight per day, septic low-birth-weight infants showed a significantly higher concentration of triglycerides (2.02 +/- 0.46 mmol/liter) and of free fatty acids (2.06 +/- 0.45 mmol/liter) than the nonseptic low-birth-weight infants (triglycerides: 1.09 +/- 0.43 mmol/liter; free fatty acids: 1.05 +/- 0.41 mmol/liter). The low-birth-weight infants with sepsis showed a reduced fat oxidation rate of 16.0 +/- 1.5% in contrast to that of the low-birth-weight infants without sepsis, whose rate was 38.4 +/- 1.8%. Accordingly, we apply dosages not exceeding 2 g of fat/kg body weight per day to septic low-birth-weight infants.

Plasma amino acids in supplementary parenteral nutrition of preterm infants. Effect of different quantities of amino acid infusion and comparison with enteral feeding

The present investigation aims to determine quantity and quality of the amino acid (AA) solution to be used in supplementary parenteral nutrition (SPN). We established the plasma AA concentrations of preterm infants (birthweight 1160-1940 g, mean 1540; gestational age 29-30 weeks, mean 32) divided into three groups. Group I (n = 11) and group II (n = 12) were put on a standardised SPN regimen starting with an intravenous supply of 2.5 resp. 1.5 g AA/kg/day. Infants of group III were formula-fed, and served as controls. A total of 231 aminograms was obtained during the first two weeks of age. Comparison of groups I and II to group III revealed plasma accumulation of six AA in group I. Supplementation in group II resulted in a normal pattern, except alanine, proline, and methionine. However, only deviations of proline and methionine may be judged as imbalances, and lowering in composition may be considered. We conclude that the low intravenous AA intake employed in group II may be preferred in SPN of preterm infants.

Lipid infusion in premature infants suffering from sepsis

In as much as possible side effects attributing to insufficient fat clearance with hyperlipemia, parenteral lipid administration to septic premature infants is controversial. In this study serum triglyceride and free fatty acid concentrations of nine low birth weight infants with septicemia and 21 low birth weight infants without septicemia were measured. Acidosis, hypoxia, hyperglycemia, and cardiovascular insufficiency were treated before parenteral lipid infusion was started. There was no occurrence of septic shock. In the course of fat infusion with 3 g/kg body weight per day in low birth weight infants without systemic infection we only found triglyceride concentrations of 1.15 mmol/liter and free fatty acid levels of 1.05 mmol/liter. Premature infants with septicemia showed, under fat application of 2 g/kg body weight per day, mean triglyceride levels of 1.67 mmol/liter and free fatty acid values of 1.94 mmol/liter. The highest concentrations occurred at 3 g fat/kg body weight per day with triglycerides of 2.02 mmol/liter and free fatty acids of 2.06 mmol/liter. They indicate a reduced clearance and support earlier findings of reduced utilization of infused fat in premature infants with septicemia. Triglyceride concentrations more than 1.7 mmol/liter probably induce an increase of phagocytosis of the fat particles with the effect of a partial block of the reticuloendothelial system and an impairment of pulmonary diffusion capacity. Therefore, we suggest dosages no higher than 2 g fat/kg body weight per day to low birth weight infants and we advise to check the triglycerides daily. Hypertriglyceridemia implicates an immediate reduction or total interruption of the lipid infusion until normal triglyceride values are regained.