Guidelines for Pediatric Parenteral Nutrition

INDICATIONS: If the GI tract works, use it; partial/trophic GI feeds as possible . Parenteral nutrition should only be used when there is a clear indication.

Energy & nutrient requirements & delivery

ENERGY:

True/False: Patients on TPN usually need higher caloric intakes (relative to body weight).

This is FALSE. Patient on TPN frequently have several factors contributing to lower calorie needs. First, there is usually decreased energy expenditure from activity compared to healthy peers. Second, there may be additional limitations on activity such as is seen with sedation and mechanical ventilation. And third, with the infusion of nutrients directly into the veins, the energy expenditure related to the thermic effect of food is eliminated. The thermogenic effect of feeding can contribute to 7 – 10% of energy expenditure. So, even though patients on parenteral nutrition are often critically ill, their energy needs will not necessarily be higher.

Intravenous Energy Needs in Kcal/kg/day:	Factors that may increase energy needs	Factors that may decrease energy needs
0-1 mo. = 100 – 110	Fever Sepsis Burns Trauma Cardiac or Pulmonary Dz. “Catch up” Growth Major surgery	Sedation Pentobarbital Coma Mechanical Ventilation Starvation Paralysis
2-4 mo. = 90 – 100
5 – 60 mo. = 70 – 90
> 5 years = 1500 kcal for the first 20 kg, + 25 kcals for each additional kg

Potential complications of overfeeding	Potential complications of underfeeding
Hypercapnia and respiratory distress Hepatic lipogenesis Hyperglycemia Electrolyte abnormalities Impaired phagocytosis Increased metabolic rate	Respiratory dysfunction Poor wound healing Increased infection risk Poor prognosis

AVOID OVERFEEDING!!

Sources of Energy in parenteral solutions:

Carbohydrate (dextrose): 3.4 kcal/g

Lipids ( 20%): 10 kcal/g or 2 kcal/cc

Protein (amino acids): 4 kcal/g       (g N = protein g/6.25)

CARBOHYDRATE:

True or False: Dextrose should provide the main exogenous energy source during TPN.

This is TRUE. Intravenous dextrose suppresses the endogenous breakdown of protein for energy, provides an easily oxidized substrate, and provides the primary fuel for the brain, red and white bloods cells, and for wounds.

• IV dextrose should be the main source of exogenous energy: it suppresses gluconeogenesis and provides easily oxidized substrate;
• Start at D10-12.5%; ­ by 2.5% per day (2.5 g/kg/d) until reach goal of ~ 50-60% of total kcal
• Glucose load is dependent on concentration & rate (g/kg/d or mg/kg/min); max hepatic oxidation rates are highest in young infant (18 g/kg/d » 12.5 mg/kg/min), lowest in adults (4.3 g/kg/d » 3.0 mg/kg/min); exceeding these may result in complications (see below) (Max [dextrose] per peripheral vein = 10 – 12.5%)

What is the impact of abruptly consolidating TPN from 24 hr to 12 hr (i.e., cyclic) TPN?

This significantly increases the carbohydrate load during infusion by giving the same amount of carbohydrate in half the time.

Why should you gradually (2.5-5%/day) advance dextrose?

1. Allow veins to accommodate (IV dextrose is hypertonic);
2. Allow pancreas to adjust;
3. Allow liver to adjust

Complications of IV dextrose administration:

• Hyperglycemia
• Hypoglycemia
• Hypertriglyceridemia
• Fatty liver (hepatic lipogenesis)
• Excessive CO ₂ production/retention

PROTEIN:

True/False: It is impossible to achieve positive Nitrogen balance with TPN if you can’t provide adequate energy intake.

This is True. In the absence of adequate substrate to meet energy needs, protein will be catabolized for energy (gluconeogenesis). Achieving positive Nitrogen balance requires a balance between meeting energy demands and providing adequate protein.

• Goal is to provide Nitrogen & EAA needs; “requirements” are age dependent (~ 1 – 3 g/kg/d) & increased in certain conditions (e.g., prematurity, hypermetabolism)
• Percent amino acids ordered in TPN is dependent on both requirement (g) & volume of TPN delivered ( \ 5% of 100 cc = 5g = 2.5% of 200 cc, etc); typically amino acids provide ~ 8-10% of total energy intake. [Max via peripheral vein = 2%]
• Amino acid solutions: standard (Novamine) vs. Trophamine vs. other (Hepatamine, Nephramine); Trophamine w/ Cysteine added: provides source for taurine ; esp. important for neonates + protective for long term TPN; cysteine is also a component of glutathione.
• Albumin: use prudently as clinically necessary for oncotic pressure; do not consider as source of nutritional value.

LIPIDS:

True/False: Intravenous fat emulsions have a high osmotic load & thus can’t be used in peripheral intravenous catheters.
This is FALSE. Intravenous lipid emulsions have a low osmolality (280 mOsm/kg H20), and provide an extremely important source of energy in peripheral parenteral nutrition where the concentrations of dextrose and amino acids must be limited due to osmolality concerns.

• High energy density (should provide 20 – 40% total energy) + meet Essential Fatty Acid (EFA) needs ( minimum intake to meet EFA: 2 g/kg of lipid emulsion 3x/wk or 2-4% of calories as linoleic acid – 300 mg linoleic acid/100 kcals)>
• Start with 1 g/kg/d over 16 hr – 24 hours; advance by 0.5-1.0 g/kg/d; check triglyceride level; do not increase if serum TG > 150 as trough or > 250 during infusion ; TG’s > 400 may cause pancreatitis.
• Avoid exceeding maximum grams/kg/day of fat based on age: Neonate 2.5 – 3.0 g/kg and < 2.5 g/kg/hour, Infant 3.0 g/kg, toddlers and children 3.0 – 3.5 g/kg, and pre-teens and adolescents 2.0 – 3. 0 g/kg.
• Advantages of IV fat emulsions: low CO ₂ production, low energy cost of storage (vs. CHO ® fat), ¯ stimulation of insulin, ¯ risk of hepatic steatosis;
• Disadvantages: impaired function of lymphocytes, PMN’s, macrophages (due to administering at rates > rate of hydrolysis/clearance); omega 6 series ® may enhance production of inflammatory mediators and possibly ¯ pulmonary O ₂ diffusion (however, there is not yet consensus in this area). There is also potential for displacement of bilirubin and drugs from albumin binding sites by free fatty acids. Caution is needed in giving intravenous lipids with a total bilirubin > 10.

ELECTROLYTES & MICRONUTRIENTS:

True or False: Electrolyte and micronutrient content of TPN isn’t really that important, especially if other I.V. fluid is being provided.

This is FALSE. The electrolyte and micronutrient content of TPN is extremely important, even for relatively short periods of TPN support. Metabolic complications of improper provisions of electrolytes and micronutrients can be severe and life threatening. Common problems seen are hypernatremia, hyponatremia, acidosis, hypophosphatemia, hypokalemia or hyperkalemia, and hyperglycemia. Do not take this portion of TPN ordering for granted.

• For neonates, electrolytes are frequently ordered on a per kilogram basis, whereas for pediatric patients they are often ordered on a per liter basis. Be attentive to how the electrolytes are ordered.
• When electrolytes are ordered per liter, the required concentrations will depend to some extent on the flow rate of the infusate and will have to be modified if flow rates are unusually high or low.
• Administer sodium cautiously for the severely malnourished or hypermetabolic patient because of impaired cellular membrane function and high intracellular sodium levels.
• Replacement electrolytes and fluids should generally be given via separate infusate tailored to the composition of the lost fluid and containing no dextrose.
• Adjust specific nutrients (e.g. Na, K, P, Ca, Zn according to ­ losses/requirements or ¯ in excretion (e.g. Cu, Mn with cholestasis)

ORDERING & MONITORING:

– Determine goals & document

– Monitor whether/when goals reached; adjust as needed! (i.e., don’t over/underfeed)

• Monitor for tolerance, imbalances, complications;

Suggested monitoring:

1. Daily weight, weekly height and head circumference

2. Urine glucose, specific gravity; dipstick once q shift while changing concentrations of dextrose. Check serum glucose if glucosuria is detected.

3. Blood glucose: check 4 hr after starting or changing rate of dextrose concentration of infusate, then daily for two days or until stable;

4. Serum electrolytes, HCO ₃ , BUN daily x 2 days after starting or changing infusion rate or composition; then q 3rd day.

5. Liver function tests, albumin, PO4, magnesium initially, then weekly unless unstable or reason to suspect need to monitor more closely (e.g. with PO4 and Mg in a refeeding syndrome case); taper to q.o. wk or prn if TPN and patient stable; zinc, copper, + manganese every 4-6 weeks on chronic patients;

6. Serum triglyceride (if fat emulsion in use); daily after starting or changing quantity of fat, then weekly. (Draw trough level prior to starting daily infusion, if possible).

COMPLICATIONS:

True or False: TPN complications can be minimized with proper care regarding use and administration.

This is TRUE. Many TPN complications can be prevented with proper care and stringent guidelines regarding use. Proper catheter care and aseptic technique can significantly reduce the incidence of line infections and prolong the life of the line. Careful advancement of fluid, macronutrient, micronutrient, and electrolyte content can prevent metabolic complications along with close monitoring of patient vital signs and labs.

– Mechanical: catheter insertion, catheter care, occlusion (e.g. clot, fat, mineral precipitates)

– Infectious: fever in child with Broviac is line sepsis until proven otherwise!

– Metabolic:

• Includes hyperglycemia, hypoglycemia, nutrient imbalances;
• TPN-Associated Cholestasis = most critical, likely multifactorial;

Patient risk factors : TPN risk factors :

prematurity, nutrient imbalances, esp. amino acid toxicity

sepsis bypass nl. physiologic/hormonal control major surgery (esp. GI) overfeeding

lack of enteral feeds oxidant stress? – Cu, Mn, photo-oxidation

bacterial colonization of small bowel

TPN Associated Cholestasis – Treatments to consider: enteral feeds even if just trophic amounts, ursodeoxycholic acid, antibiotics for small bowel bacterial overgrowth, possible use of cholecystokinin to stimulate bile flow, light protect TPN (reduce photo-oxidation), and cycle TPN if patient is otherwise metabolically stable.