Parenteral nutrition (PN) is a highly specialized therapy for which the indications are limited and serious com- plications can result in morbidity and mortality.
Therefore, unless one routinely provides this type of nutrition therapy, it is best to consult with a NS team if PN is necessary.
PN is indicated if the gastrointestinal tract cannot be used, or cannot fully support the pediatric patient.6,7 Before initiating PN, a careful assessment of the enteral route for NS should be made and the enteral route used whenever possible (Figure 8–1). The largest group for For children aged 1–6 years, formula choices are
limited. The most desirable formula contains 1.0 Kcal/
mL, and has more iron, zinc, calcium, phosphorus, and vitamin D than formulas prepared for older children and adults. For children older than 6 years, adult formu- las are acceptable.
Formulas can also be grouped according to pro- tein, carbohydrate, or fat content. With respect to pro- tein, there are several types of formulas: cows’ milk, soy, partially or extensively hydrolyzed casein (a cows’ milk protein), and formula composed of single amino acids.
Formulas contain one or more different carbohydrates:
lactose, sucrose, hydrolyzed cornstarch, glucose poly- mers, fi ber, tapioca, and maltodextrins. Fat sources can include medium-chain triglycerides, soybean oil, saf- fl ower oil, sunfl ower oil, canola oil, structured lipids, lecithin, corn oil, and coconut oil.
Complications of enteral feedings include mechani- cal, gastrointestinal, metabolic, and biochemical.
Mechanical complications include tube dislodgement or inappropriate tube positioning, pump failure, and tube occlusions.
Gastrointestinal complications include vomiting, diarrhea, aspiration of gastric contents, and constipa- tion. Vomiting can occur because of poor motility, rapid or excessive administration of feedings, hypoproteine- mia, central nervous system problems, or metabolic abnormalities. The development of diarrhea requires careful assessment. Infection, osmotic load from medi- cations, and errors in formula dilution or in the rate of delivery can cause diarrhea. Constipation may occur in children on long-term feeding. Causes include increased transit time, decreased physical activity, poor abdomi- nal muscle tone, and lack of dietary fi ber.
Metabolic complications occur infrequently with enteral feedings because the formulas are complete foods and the gastrointestinal tract and liver provide a
Formula Schedules
Feeding Schedule Advantages Disadvantages
Continuous feedings over 24 hours
Maximal nutrient absorption and physiologic tolerance, recommended for jejunal feeds
Little mobility, no cycling of hormones, requires pump, bag, and tubes, child is tied to feeding equipment
Nocturnal continuous
Excellent nutrient absorption, free during day to eat with family, etc., does not interfere with normal hunger–satiety cycles
Sleep can be disrupted for family and patient, requires pump, bag, and tubes, child is tied to feeding equipment at night, may wake to void Bolus feeds Convenient, mimics normal feeding, does not require
pump, maximal mobility
Increased risk of aspiration, poor tolerance of volume, may not be recommended if refl ux, vomiting, or delayed gastric emptying, normal social interactions are lost, decreases interest in food Table 8–11.
Pediatric Enteral Formulas
Clinical Condition Formula Description Comments
Premature infant (⬍1800 g) Premature formula—12% protein, contains MCT oil, carbohydrate, lactose/glucose polymers, calcium, and phosphorus
Breast milk must be mixed with a breast milk fortifi er since human milk is inadequate in calories, protein, vitamins, and minerals for preterm infants. Soy formulas are not indicated for premature infants Term infant
Primary (very rare) or secondary lactose intolerance
60:40 whey:casein or casein formula The food of choice is breast milk as the sole food for the fi rst 4–6 months and the sole beverage until 1 year of age. Infants must be supplemented with vitamin D and fl uoride, if indicated. Human milk is low in iron and zinc and supplementation may be needed. First solid food should be meat to prevent defi ciency
Casein sensitivity, vegetarian family Lactose-free cow milk Formulas are complete foods and supplementation is not necessary Organ dysfunction (e.g., renal, cardiac) Soy protein formula
Steatorrhea associated with bile acid defi ciency, ileal resection, or lymphatic anomalies
Low electrolyte/renal solute load
Cow’s milk protein and soy protein sensitivity, abnormal nutrient absorption, digestion, and transport, intractable diarrhea or protein–calorie malnutrition
Infant formula with MCT
Hypoallergenic, hydrolyzed casein, or chemically defi ned protein (elemental), lactose and sucrose free 1–6 years old
Oral supplement Acceptable taste, different fl avors For many disabled children the calorie content of formulas is high relative to requirements. There is no low-calorie formula that is complete in all other nutrients. Careful monitoring and adjusting of nutrients is necessary to prevent obesity
Tube feeding Complete nutrition in 1100 mL,
1.0 Kcal/mL caloric density, gluten free, lactose free, isotonic Protein sensitivity/compromised
GI/pancreatic function
Elemental or chemically defi ned Over 6 years
Normal GI function Hypercaloric (1.0–2.0 Kcal/mL) formula
Abnormal bowel movement Added fi ber
Pulmonary/diabetes High fat
High stress, trauma, sepsis, burns Hypercaloric, high protein
Lactose intolerance Lactose-free formula
Compromised GI/pancreatic function, protein allergy
Elemental formula
Organ failure (renal or liver), pre-dialysis Low protein, essential amino acids, low or no electrolytes, consider formula with increased branched chain amino acids
Table 8–12.
bohydrate is necessary to prevent hypoglycemia. Glucose intolerance develops in critically ill patients and careful monitoring of urine and serum glucose is necessary.
Intravenous lipids are a necessary calorie source and prevent and treat essential fatty acid (EFA) defi ciency. To prevent EFA defi ciency, 2–4% of non-protein calories (0.5–1.0 g/kg/day) must be provided. In balanced PN solutions, 30–40% (3–4 g/kg/day), but not more than 60%, of non-protein calories is provided as lipid.
Intravenous lipids currently available are an emulsion of soy bean oil and egg phospholipids. In a few anecdotal studies in children, a new lipid composed of fi sh oils shows promise in preventing PN-induced cholestasis, but is not readily available in the United States. Lipid should be infused over 24 hours. Lipid solutions are available as 10% or 20% emulsions and in general should be pro- vided as 20%. The 20% emulsion has a slightly higher ratio of phospholipid to triglyceride. This may increase lipoprotein lipase activity, so serum triglycerides and whom PN is indicated is premature infants. The gastro-
intestinal tract development of these infants may not be suffi cient to allow for full enteral nutrition. PN is gener- ally not necessary for children with cancer or pancreati- tis, as preparation for surgery, or for rehabilitating mal- nourished children. However, PN is indicated if hypoproteinemia is present and suffi cient enteral nutri- tion to meet all requirements is not tolerated. Gastroin- testinal tract dysfunction, whether caused by anatomic abnormalities, absorptive inadequacies, or motility dis- orders, can be an indication for PN. For children with short bowel that have not adapted suffi ciently to main- tain nutrition, consideration should be given to a small bowel transplant, because the likelihood of developing cholestasis and eventual liver failure is high.
PN can be administrated through a peripheral or a central vein. If PN is required for less than 7 days and the child is not malnourished, peripheral support can be used. If the child is malnourished, or it is anticipated that PN will be required longer than 7 days, the PN must be administered into a central vein because adequate nutri- ents to rehabilitate a malnourished child or support growth cannot be sustainably delivered through a periph- eral vein. Unless it is anticipated that PN will be needed for more than 3–5 days, little benefi t derives from its use.
Protein sparing can be accomplished in both malnour- ished and fully nourished individuals with the adminis- tration of a 10% dextrose solution. The administration of 10% dextrose may offer protein sparing while a deter- mination of the necessity for PN is made. Caution, how- ever, must be exercised because use of a protein-defi cient diet for longer than 5–7 days in well-nourished children or 3–5 days in malnourished children can lead to the development of kwashiorkor, further impairing the rehabilitation of malnourished children.
PN solutions are necessarily nutritionally com- plete, containing water, calories, protein, electrolytes, minerals, vitamins, and trace elements. In general, PN solutions should be used only to consistently deliver estimated requirements. When changes in solution con- tent are required over a short period of time, such as to correct an electrolyte imbalance, a separate solution designed to correct the problem can be run concur- rently with the pre-mixed solution, rather than discard- ing and remixing an expensive preparation.
Estimation of fl uid requirements can be made on a volume/weight, volume/surface area, or volume/
calorie basis (Table 8–13). Table 8–14 lists recommended daily parenteral requirements for electrolytes.
Glucose is the only clinically available carbohydrate source for PN in children. Table 8–15 lists guidelines for glucose delivery in PN. To prevent hyperosmolality and hyperinsulinemia, glucose infusions are initiated in a stepwise manner. Similarly, when cycling, discontinuing, or interrupting PN solutions, a stepwise decrease in car-
Fluid Requirements
Method Body Weight (kg)
Amount/Day
Volume/weight 0–10 100 mL/kg
10–20 1000⫹ 50 mL/kg
for weight
⬎10 kg
⬎20 kg 1500 ⫹ 20 mL/kg for weight
⬎20 kg Volume/surface
area
0–70 1500–1700 mL/m2
Volume/
kilocalorie
0–70 100 mL/100 kcal
metabolized Baker RD, Baker SS, Davis AM: Pediatric Parenteral Nutrition. New York, Chapman and Hall, 1997. With kind permission of Springer Science and Business Media.
Table 8–13.
Intravenous Requirements for Electrolytes and Minerals
Nutrient Daily Requirement
Sodium 2–4 mEq/kg
Potassium 2–3 mEq/kg
Chloride 2–3 mEq/kg
Calcium 0.5–2.5 mEq/kg
Phosphorus 1–2 mM/kg
Magnesium 0.25–0.5 mEq/kg
Table 8–14.
dependent on PN, iron and carnitine must also be added. Some medications are compatible with PN. The dietitian and pharmacist members of the NS team can help with decisions about which products to choose.
Complications of PN include infections, mechani- cal problems with lines, and metabolic abnormalities.
Some of the complications, such as air embolus, lipid thrombus, catheter perforation of the heart, etc., can be life threatening. Hence, it is important for a NS team including physicians, dietitians, and pharmacists trained and experienced in NS to oversee the patient receiving PN.
The goal of NS is to replete malnourished children, sustain children through a metabolic stress (burns, trauma, and surgery), provide the extra nutrition demanded by a chronic disease (liver, infl ammatory bowel disease, cystic fi brosis, and cancer), and ensure normal growth. The best outcome measure is sustained normal growth.