Lipid parenteral nutrition

Essential fatty acid deficiency is rare but can occur with prolonged lipid-free parenteral nutrition, very low fat enteral formulas, severe fat malabsorption, or severe malnutrition. The body can synthesize all fatty acids except for linoleic and linolenic acid, which should constitute approximately 2% to 4% of total calorie intake. 

Long-term parenteral nutrition withont lipid Cystic fibrosis ... 

Lipid emulsions are essential components of parenteral nutrition. However, due to the amount of polyunsaturated fatty acids (PUFA), it is possible that chemical degradation occurs, forming hydroperoxides. 

Lipid peroxides are also able to react with other components of parenteral nutrition admixtures (trace elements), causing a drop in pH with the subsequent potential for physical-chemical instability [29]. Table 11 shows the peroxide value and the pH drop in a pure lipid emulsion and a lipid-containing AlO admixture stored in EVA bags under different conditions of temperature and light exposure in the presence and absence of trace elements. 

FIGURE 7 Influence of a lipid emulsion and daylight on peroxide levels in freshly prepared solutions of parenteral nutrition containing multivitamins (PN + MVI and PN + Lipid + MVI). (PN = parenteral nutrition MVI = multi vitamin preparation.) The data represent the mean SEM,n = 3 the variations are not depicted because of their small size relative to the symbols. The peroxide content rose significantly over time (P < 0.001), and exposure to daylight had a significant effect on peroxide generation (P < 0.001) [33]. 

Picaud, J. C., Steghens, J. P., Auxenfans, C., Barbieux, A., Laborie, S., and Claris, O. (2004), Lipid peroxidation assessment by malondialdehyde measurement in parenteral nutrition solutions for newborn infants A pilot study, Acta Paediatr., 93, 241-245. 

Steger, P. J. K., and Mtihlebach, S. F. (2000), Lipid peroxidatoin of intravenous lipid emulsions and all-in-one admixtures in total parenteral nutrition bags The influence of trace elements, J. Parenteral Enteral Nutr., 24, 37M1. 

Popinska, K., Kierkus, I, Lyszkowska, M., Socha, I, Pietraszek, E., Kmiotek, W., and Ksiazky, J. (1999), Aluminum contamination of parenteral nutrition additives, amino acid solutions, and lipid emulsions, Nutrition, 15, 683-686. 

Injectable lipid emulsions are used to provide parenteral nutrition and their use can be traced back to the 1920s. However, because they are particulate systems by their very nature, administration of emulsions into the blood system must be viewed with care, requiring precautions and special requirements. Indeed, until the 1950s it was not realized that one essential requirement for injectable emulsions was that the droplet diameter must be below 1 pm in diameter. Otherwise there is always a finite risk of blocking the smaller blood vessels. 

Linoleic acid and alpha-linoleic acid are essential fatty acids that are provided in any long-term parenteral nutrition by administering fat emulsions at least twice a week. Fatty acid deficiency is a common complication of severe end-stage liver disease. The ability of short-term intravenous lipid supplementation to reverse fatty acid deficiencies has been studied in patients with chronic liver disease and low plasma concentrations of fatty acids (914). Shortterm supplementation failed to normalize triglycerides. 

Nnssbanm, M.S., Li, S, Bower, R.H., McFadden, D.W., Dayal, R., Fischer, J.E. Addition of lipid to total parenteral nutrition prevents hepatic steatosis in rats by lowering the portal venous insulin/glucagon ratio. J. Parent. Ent. Nutr. 1992 16 106-109... 

Persons at risk for EFA deficiency tend to be the same as those at risk for vitamin E deficiency. Some signs are shared by both defidencies. Premature infants may be at risk for EFA deficiency because of their low stores of lipids and their rapid growth, especially when they are fed diets that do not contain EFAs. For example, fats have been omitted from diets used to feed preterm infants (to avoid a variety of complications). EFA deficiency may develop later in life with fat malabsorption syndromes, EFA deficiency has presented in adults fed by total parenteral nutrition for longer periods, where EFAs had not been included in the liquid diet. 

Martinez, M., and Ballabriga, A. (1987). Effects of parenteral nutrition with high doses of linoleaie on the developing human liver and brain. Lipids 22,133-138. 

Table 1 Some commercial lipid emulsions for parenteral nutrition...

Typical solid lipids used are glycerides and/or fatty acids, and may constitute 30% of the formulation. These are from the same family of lipids found in parenteral nutrition emulsions, such as Intralipid, which have been successfully administered intravenously for several decades. Typical excipients are Dynasan 112, composed of short chain fatty acids, Compritol, lecithin, used as an emulsifier, and surfactants such as polysorbate 80, polaxamer 188, PVP, bile salts such as sodium glycocholate, and Span 85. Water can be replaced with oils or PEG 600 to yield dispersions which can be filled into soft gelatin capsules. 

Two children developed neurological complications of fat emulsion therapy, including focal and generalized seizures, weakness, and altered mental status, before any systemic findings were in evidence (15). Biopsy and autopsy findings included cerebral endothehal and intravascular lipid deposition. These complications are potentially reversible with alteration of the parenteral nutrition content, highlighting the importance of their early recognition. 

In a prospective prevalence study of liver disease in 90 patients with permanent intestinal failure receiving parenteral nutrition hver biopsy was performed in 57 (95). Chronic cholestasis developed in 58 patients after a median of 6 (range 3-132) months, and 37 developed comphcated liver disease after a median of 17 (range 2-155) months. Chronic cholestasis was significantly associated with a risk of liver disease independent of parenteral nutrition, a bowel remnant shorter than 50 cm, and a lipid intake of 1 g/kg/day or more hver disease related to parenteral nutrition was significantly associated with chronic cholestasis and a parenteral hpid intake of 1 g/kg/day or more. The authors concluded that the prevalence of hver disease increased with the duration of parenteral nutrition and was one of the main causes of death in patients with permanent intestinal failure. Parenteral intake of long-chain hpid emulsion should be restricted to less than 1 g/kg/day. 

The role of lipid emulsions in cholestasis associated with long-term parenteral nutrition has been investigated retrospectively in 10 children with a total of 23 episodes of cholestasis, associated with thrombocytopenia in 13 cases (104). Changes in lipid delivery, associated with increased daily amounts, preceded complications in more than half the cases, while temporary reduction in lipid administration led to normalization of bilirubin in 17 episodes. The authors concluded that lipid supply is one of the risk factors for cholestasis associated with parenteral nutrition. They recommended that when cholestasis occurs, lipid should be temporarily withdrawn, especially if there is associated thrombocytopenia. 

---