BNF for Children 2011-2012

466 9.3 Intravenous nutrition BNFC 2011–20129 Nutrition and bloodVoluven c (Fresenius Kabi) AIntravenous infusion, hydroxyethyl starch (weightaverage molecular weight 130 000) 6% in sodiumchloride intravenous infusion 0.9%, net price 500-mLbag = £12.50Hypertonic solutionHyperHAES c (Fresenius Kabi) AIntravenous infusion, hydroxyethyl starch (weightaverage molecular weight 200 000) 6% in sodiumchloride intravenous infusion 7.2%, net price 250-mLbag = £28.00Cautions see notes above; also diabetes9.3 Intravenous nutritionWhen adequate feeding through the alimentary tract isnot possible, nutrients may be given by intravenousinfusion. This may be in addition to oral or enteraltube feeding—supplemental parenteral nutrition, ormay be the sole source of nutrition—total parenteralnutrition (TPN). Complete enteral starvation is undesirableand total parenteral nutrition is a last resort.Indications for parenteral nutrition include prematurity;severe or prolonged disorders of the gastro-intestinaltract; preparation of undernourished patients for surgery,chemotherapy, or radiation therapy; major surgery,trauma, or burns; prolonged coma or inability to eat;and some patients with renal or hepatic failure. Thecomposition of proprietary preparations used in childrenis given in the table Proprietary Infusion Fluids forParenteral Feeding, p. 467.Parenteral nutrition requires the use of a solution containingamino acids, glucose, lipids, electrolytes, traceelements, and vitamins. This is now commonly providedby the pharmacy in the form of an amino-acid, glucose,electrolyte bag, and a separate lipid infusion or, in olderchildren a single ‘all-in-one’ bag. If the patient is able totake small amounts by mouth, vitamins may be givenorally.The nutrition solution is infused through a centralvenous catheter inserted under full surgical precautions.Alternatively, infusion through a peripheral vein may beused for supplementary as well as total parenteralnutrition, depending on the availability of peripheralveins; factors prolonging cannula life and preventingthrombophlebitis include the use of soft polyurethanepaediatric cannulas and use of nutritional solutions oflow osmolality and neutral pH. Nutritional fluids shouldbe given by a dedicated intravenous line; if not possible,compatibility with any drugs or fluids should be checkedas precipitation of components may occur. Extravasationof parenteral nutrition solution can cause severetissue damage and injury; the infusion site should beregularly monitored.Before starting intravenous nutrition the patient shouldbe clinically stable and renal function and acid-basestatus should be assessed. Appropriate biochemicaltests should have been carried out beforehand andserious deficits corrected. Nutritional and electrolytestatus must be monitored throughout treatment. Thenutritional components of parenteral nutrition regimensare usually increased gradually over a number of days toprevent metabolic complications and to allow metabolicadaptation to the infused nutrients. The solutions areusually infused over 24 hours but this may be graduallyreduced if long-term nutrition is required. Home parenteralnutrition is usually infused over 12 hours overnight.Complications of long-term parenteral nutrition includegall bladder sludging, gall stones, cholestasis and abnormalliver function tests. For details of the prevention andmanagement of parenteral nutrition complications, specialistliterature should be consulted.Protein (nitrogen) is given as mixtures of essential andnon-essential synthetic L-amino acids. Ideally, all essentialamino acids should be included with a wide varietyof non-essential ones to provide sufficient nitrogentogether with electrolytes (see also section 9.2.2). Solutionsvary in their composition of amino acids; theyoften contain an energy source (usually glucose) andelectrolytes. Solutions for use in neonates and childrenunder 1 year of age are based on the amino acid profileof umbilical cord blood (Primene c ) or breast milk(Vaminolact c ) and contain amino acids that areessential in this age group; these amino acids may notbe present in sufficient quantities in preparationsdesigned for older children and adults.Energy requirements must be met if amino acids are tobe utilised for tissue maintenance. An appropriateenergy to protein ratio is essential and requirementswill vary depending on the child’s age and condition. Amixture of carbohydrate and fat energy sources (usually30–50% as fat) gives better utilisation of amino acidsthan glucose alone.Glucose is the preferred source of carbohydrate, butfrequent monitoring of blood glucose is required particularlyduring initiation and build-up of the regimen;insulin may be necessary. Glucose above a concentrationof 12.5% must be infused through a central venouscatheter to avoid thrombosis; the maximum concentrationof glucose that should normally be infused in fluidrestricted children is 20–25%.In parenteral nutrition regimens, it is necessary toprovide adequate phosphate in order to allow phosphorylationof glucose and to prevent hypophosphataemia.Neonates, particularly preterm neonates, andyoung children also require phosphorus and calciumto ensure adequate bone mineralisation. The compatibilityand solubility of calcium and phosphorus salts iscomplex and unpredictable; precipitation is a risk andspecialist pharmacy advice should be sought.Fat (lipid) emulsions have the advantages of a highenergy to fluid volume ratio, neutral pH, and iso-osmolaritywith plasma, and provide essential fatty acids.Several days of adaptation may be required to attainmaximal utilisation. Reactions include occasional febrileepisodes (usually only with 20% emulsions) and rareanaphylactic responses. Interference with biochemicalmeasurements such as those for blood gases and calciummay occur if samples are taken before fat has beencleared. Regular monitoring of plasma cholesterol andtriglyceride is necessary to ensure clearance from theplasma, particularly in conditions where fat metabolismmay be disturbed e.g. infection. Emulsions containing20% or 30% fat should be used in neonates as they arecleared more efficiently. Additives should not bemixed with fat emulsions unless compatibility isknown.