Nutrition support intervention varies depending on which phase of illness a patient may be in. Three phases of critical illness are highlighted.1–3
FIRST PHASE OF ILLNESS: ACUTE PHASE
Duration: 6 to 8 hours after onset of illness or trauma
Characteristics: Fever, tachycardia, hypoglycemia
Nutrition intervention: Usually NPO during resuscitation with fluids, inotropes, pressors, and/or blood products
Please note, though, that growth is inhibited at this time. Energy metabolism is diverted toward the stress or injury.
SECOND PHASE OF ILLNESS: EBB PHASE
Weights most likely will reflect increased fluid status due to increased ADH and not reflect the true somatic status of the patient.
THIRD PHASE OF ILLNESS: FLOW PHASE
TWO SUBCATEGORIES: CATABOLIC AND ANABOLIC
Characteristics: Hypermetabolism due to endogenous catabolism of fat, carbohydrate, and protein stores; active inflammatory processes; hyperglycemia; glucose intolerance; lipolysis; and negative nitrogen balance
Nutrition intervention: Until the metabolic and hormonal alterations subside, nutrient provision should remain toward basal metabolic needs with the exception of providing an increased amount of protein as permissible per renal and liver status. Amino acids are pulled from muscle, connective tissue, and the gut (if inactive) to promote gluconeogenesis and production of acute-phase proteins, such as C-reactive protein (CRP).
There will be a decrease in synthesis of visceral protein stores of albumin and prealbumin.
Characteristics: Restoration of tissue composition, depleted energy reserves, and positive nitrogen balance
Nutrition intervention: Nutrient provision should now be increased to promote nutrition repletion. Patient is now approaching convalescence and growth will resume; thus, more calories will be needed.
COMPONENTS OF ENERGY EXPENDITURE
Total energy expenditure = Basal metabolic rate + Energy from thermogenesis + Energy for activity* + Energy for growth* + Energy for healing process4
*Please note patients in the PICU are usually not active nor are they growing, so these components are excluded in determining energy needs.5
CONSIDERATIONS FOR DETERMINING ENERGY NEEDS
Phase of illness
Severity and duration of illness
Respiratory status: intubated vs. O2 (mask ventilation/nasal cannula) vs. room air
Muscle relaxed or pentobarbital coma
Injury or stress factors, such as fever, sepsis, wounds, burns, cardiac failure, status post surgery
Baseline calorie needs (especially if chronically ill)
CALCULATING CALORIE PROVISIONS
There are many predictive equations, of which none are based on the critically ill pediatric population except for the White equation. This equation includes many patient variables (based on age, weight, weight for age Z score, body temperature, number of days after intensive care admission, and primary reason for admission) and is not easy to calculate.6 Table 62-1 provides a basic approach to calculating calorie needs.
Resting Energy Expenditure
||Download (.pdf) TABLE 62-1
Resting Energy Expenditure
|Age ||REE (kcals/kg/d) |
|2–6 mo ||54 |
|7–12 mo ||51 |
|13–35 mo ||56 |
|3 yr (boys/girls) ||57/55 |
|4–8 yr (boys/girls) ||48/45 |
|9–13 yr (boys/girls) ||36/32 |
|14–18 yr (boys/girls) ||28/26 |
|>18 yr (boys/girls) ||28/23 |
The gold standard for determining calorie needs is to measure the patient's calorie needs by indirect calorimetry, otherwise known as a metabolic cart study, which is reviewed in Chapter 9.7 A metabolic cart may be available in the PICU and be conducted by the appropriate trained personnel.
See Table 62-1 for the predictive equation to use to estimate resting energy expenditure (REE = Basal metabolic needs X Factor for thermogenesis) needs during the acute and ebb phases of illness8:
As the patient's acute illness status improves, the energy needs may increase, with the goal of moving toward the patient's usual baseline calorie needs.9
Protein Recommendations During Critical Illness5
||Download (.pdf) TABLE 62-2
Protein Recommendations During Critical Illness5
|Age ||Protein in g/kg/day |
|0–2 yr ||2–3 |
|2–13 yr ||1.5–2 |
|13–18 yr ||1.5 |
Enteral mode: Use of the gut is always preferred.
Contraindications: Gastrointestinal surgery, prolonged ileus, severe emesis, and/or diarrhea.
Formula selection: Formulas available vary per institution. Selection of the type of formula is based on the patient's acute clinical/medical status to discern the use of a standard intact, semi-elemental, or elemental formula.
Please note the use of fiber-containing formula may be prudent, as constipation may be an issue due to use of sedation agents in the PICU (formulas for children >1 year old contain fiber).
Mode of delivery: Continuous versus bolus
Continuous feeds are recommended if the patient is sedated and/or muscle relaxed or if concern for aspiration/reflux.
Bolus feeds can be started if the patient is more alert and concern for reflux/aspiration is absent. Bolus feeds mimic a more physiologic feeding pattern.
NJ versus NG is a debated issue. If there is increased concern for reflux or aspiration post-pylorus (transpyloric tube—ND or NJ), it may help to reduce occurrence of reflux/aspiration.6 Transpyloric tubes need to be placed by a trained health care provider or interventional radiologist.
NG feeds reflect more normal feeding route and are easily placed by bedside nurse.
Note: Cannot provide bolus feeds via an NJ tube.
Total parenteral nutrition (TPN) mode: Less physiologic, more expensive, and increased risk of complications, including infection and line placement problems.10
TPN is individually tailored to the patient by determining the amount of macronutrients and micronutrients to provide.
Dextrose: 3.4 kcals/gm (gm = % dextrose × volume)
Fat (20% IV fat solution): 10 kcals/gm or 2 kcals/mL
Recommended ratio of calories = 50% to 60% carbohydrate, 10% to 20% protein, 30% to 55% fat10
Indications for use are the contraindications for enteral mode.
During critical illness, shifts in fluid and electrolyte status can occur. Monitoring electrolytes (sodium, potassium, chloride, bicarbonate, glucose, blood urea nitrogen [BUN], creatinine, and calcium) is helpful to assess changes and possible need for electrolyte supplementation or adjustments.1–3
TPN labs (electrolytes, ionized calcium, magnesium, phosphorus, and triglyceride) should be checked with every change in TPN concentration.10
C-reactive protein (CRP) levels can help indicate current acute illness status of patient, and obtaining serial measurements can better guide patient's nutrient provision.11
Prealbumin level is a marker of visceral protein stores. During acute illness, prealbumin levels decline. Prealbumin synthesis may resume when the first few phases of illness subside. Serial measurements can indicate the trend of the illness and better guide how much protein to provide (given that CRP levels are within normal limits at the time).11
Premature Infant Formulas
Preterm post-discharge formulas
Full-Term Infant Formulas
Infant standard intact formulas
Infant cow's milk protein–based, lactose-free formulas
Infant soy-based formulas
Infant cow's milk–based with thickening agent formula
Infant cow's milk–based with low mineral content formula
Infant impaired long chain fat digestion/absorption formulas
Infant casein hydrolysate formulas
Infant elemental protein formula
Children formulas (1–10 years of age)
Children standard intact formulas (milk protein based)
Children standard intact formulas (soy protein based)
Children semi-elemental protein formulas
Children elemental protein formulas
Children calorie-dense formulas
Children semi-elemental protein, calorie-dense formulas
Children impaired long chain fat digestion/absorption formulas
Adolescent and Adult Formulas (>10 years old)
Adolescent and adult standard intact formulas
Adolescent and adult calorie-dense formulas
Adolescent and adult semi-elemental protein formulas
Adolescent and adult elemental protein formulas
Adolescent and adult renal formulas
Oral Supplements for Children (1–10 years) and Adolescents/Adults (>10 years)
Kallas HJ, Dimand R. Metabolic and nutritional support of the critically ill child. In: Reifen R, Lerner A, Branski D, et al., eds. Pediatric Nutrition. Pediatric Adolescent Medicine. Vol 8. Basel, Switzerland: Karger; 1998:154–181. doi:10.1159/000061914.
De Carvalho WB, Leite HP. Nutritional support in the critically ill child. In: Nichols DG, ed. Roger's Textbook of Pediatric Intensive Care. 4th ed. Philadelphia, PA: Wolters-Kluwer/Lippincott Williams & Wilkins; 2008:1500–1515.
Chwals RJ. Energy metabolism and appropriate energy repletion in children. In: Baker SS, Baker RD, Davis AM, eds. Pediatric Nutrition Support. Boston, MA: Jones and Bartlett Publishers; 2007:65–82.
Shulman RJ, Phillips S. Parenteral nutrition in infants and children. J Pediatr Gastroenterol Nutr
Mehta NM, Compher C, A.S.P.E.N. Board of Directors,
et al. A.S.P.E.N. Clinical guidelines: Nutrition support of the critically ill child. J Parenter Enteral Nutr. 2009;33(3):260–278.
White MS, Sheperd RW, McEniery JA. Energy expenditure in 100 ventilated, critically ill children: Improving the accuracy of predictive equations. Crit Care Med
Skillman HE, Wischmeyer P. Nutrition therapy in critically ill infants and children. J Parenter Enteral Nutr. 2008;32:520–534. doi:10.1177/0148607108322398.
Bunting KD, Mills J, Ramsey E, et al., eds. Pediatric Nutrition Reference Guide. 10th ed. Houston: Texas Children's Hospital; 2013.
Steinhorn DM, Russo LT. Nutrition issues in critically ill children. In: Fink MP, Abraham E, Vincent JL, et al, eds. Textbook of Critical Care. 5th ed. Philadelphia, PA: Elsevier Saunders, 2005:951–959.
Leonberg B, ed. Pediatric Nutrition Practice Group. Pediatric Nutrition Care Manual. Academy of Nutrition and Dietetics: Chicago; 2012.
Beck FK, Rosenthal TC
. Prealbumin: A marker for nutritional evaluation. Am Fam Physician