2. Energy - ESPEN

1 2. EnergyMETHODSL iterature SearchMedline search, Pub-Med : publications from 1990 2003, in additionrelevant publications from 1978 were of publications: original papers, meta-analyses,experts recommendations, Words: Energy expenditure, total parenteral nutrition,intensive care, critical care, prematurity, : English, Words: Energy expenditure, resting Energy expenditure,diet induced IN PAEDIATRIC PARENTERALNUTRITION (PN)IntroductionEnergy supply should aim at covering the nutritionalneeds of the patient (basal metabolic rate, physicalactivity, growth and correction of pre-existing malnutri-tion) including the support of anabolic functions (1).

2 Excessive Energy intake may result in hyperglycaemia,increased fat deposition, fatty liver and other complica-tions (2). Underfeeding, on the other hand, may result inmalnutrition, impaired immunologic responses and im-paired growth (3). In general, infants require more calorieswhen fed enterally than when fed parenterally. Energysupply can be divided into protein and non protein(carbohydrate and lipid) calories (see specific chapterson lipids, carbohydrates and amino acids). On a theoreticalbasis, Energy needs can be calculated based on non proteincalories as protein needs are calculated only for new tissuedeposition, as well as for tissue renewal and not as anenergy source.

3 However, since the recommendations forenergy needs in children usually include the proteincontribution to Energy expenditure, most of the statementsin this chapter will include proteins as well as carbohy-drates and lipids for assessment of Energy chapter provides a short overview on Energy , butis not a substitution for a Nutrition Textbook. Sometheoretical issues in Energy supply will be mentioned butthe intention is to provide a practical approach forclinical practice. In general, the total caloric require-ments can either be estimated or directly of Energy expenditure is not routinely doneand different equations were suggested for estimatingenergy needs.

4 These equations (see below) can serve onlyas guidelines when commencing PN. Further aspectsneed to be taken into account according to clinicalparameters:1. Weight gain in regard to the target growth andrequired catch-up growth (see below).2. Recommended intake of the different macronutrients(see specific chapters on lipids, carbohydrates andprotein).3. Tolerance to PN administration hyperglycaemia,hypertriglyceridaemia, liver enzyme abnormalities,cholestasis, tolerance of cyclic administration of Energy NeedsTotal Energy needs of a healthy individual are the sumof different components which can be divided into 4 mainsub-groups: Basal metabolic rate (BMR), diet inducedthermogenesis (DIT), physical activity (PA) and needs may be affected by nutritional status, under-lying diseases, Energy intake, Energy losses, age andgender.

5 No effect of gender on different components ofdaily Energy expenditure was found in free-living prepu-bertal children (4). On the other hand, Goran et al (1991)found that fat free mass, gender and fat mass are importantdeterminants of total Energy expenditure (TEE) inprepubertal children (5). During puberty and adolescence, Energy expenditure is affected by gender, body compo-sition and season, but not by the stage of puberty (6).Basal Metabolic RateBasal metabolic rate (BMR) is the amount of energyneeded for maintaining vital processes of the body notincluding activity and food processing. It is measured ina recumbent position, in a thermo-neutral environmentafter 12 to 18 hours fast, just when the individual hasawakened before starting daily activities.

6 In practice,resting Energy expenditure (REE) is usually measuredinstead of BMR. REE is similarly measured at rest ina thermo-neutral environment, after 8 12 hours fast andnot immediately after awakening. REE doesn t differ bymore than 10% from BMR (7). Sleeping Energy expen-diture, a component of BMR was shown to be equal (8). BMR may be increased in conditions suchas inflammation, fever, chronic disease ( cardiac, pul-monary), or can decrease in response to low of Pediatric Gastroenterology and Nutrition41:S5 S11 November 2005 ESPGHAN. Reprinted with Induced ThermogenesisDiet induced thermogenesis (DIT) reflects the amountof Energy needed for food digestion, absorption and partof synthesis and can, therefore, be affected by the route ofsubstrate administration (oral, enteral or parenteral).

7 DITusually accounts for about 10% of daily Energy needs. Inorally fed healthy adult subjects the time of food con-sumption may affect DIT (9). During PN, DIT and therespiratory quotient are affected by the mode of PNadministration (continuously vs. cyclic) (10 12).ActivityActivity is the amount of Energy spent for daily move-ments and physical activity. In older children, activityaccounts for a large proportion of total Energy expendi-ture. TEE of a hospitalized child lying in bed, on theother hand, is reduced. In contrast to most adults theactivity of children on home parenteral nutrition, whocan attend school, is not reduced (13).To account for Energy needs related to activity, differ-ent metabolic constants were suggested for multiplica-tion of BMR ( EE = BMR3constant).

8 In patients onPN the more applicable constants for sleep-ing, for lying awake and for sitting quietly, for standing quietly or sitting activities (14).Generally or are the constants used for rapid changes in organ maturation and the highergrowth velocity during the first 2 years of life and lateron during adolescence imposes extra caloric needsas compared to adults. The Energy needed to maintainaccelerated growth represents 30 35% of the energyrequirements in term neonates and is greater in preterminfants. Energy cost for 1gr of tissue deposition rangesbetween kcal/g in premature infants and kcal/g inadults recovering from anorexia nervosa (14). In patientsfed parenterally over longer periods of time, growth andbody composition should be assessed on a regular basis,and caloric intake adapted to allow normal GrowthChildren recovering from malnutrition need extracalories to correct their growth deficits (weight, height).

9 In such cases Energy needs may be calculated based onthe 50th percentile of weight and height for the actualage, rather than the present weight. This difference willprovide extra calories (above daily needs) to achievecatch-up growth. Alternatively, calculation may be basedon the actual weight multiplied by , or even by 2 times in severe cases of failure to thrive, to providethe extra calories needed for catch up growth. Furthercaloric needs should be adjusted according to weight andheight ConsiderationsEnergy needs are affected by the underlying diseaseand current nutritional status and should be met accord-ingly (1). Some diseases have been shown to increase orTABLE for calculating REE and BMR (kcal/day) in infantsfrom 0 3 years*SourceGenderEquationWHOmaleREE = = 613Wt251 Schofield (W)maleBMR = = (WH)maleBMR = + = + = + + = + + *Wt = body weight in kilograms; Ht = Length in for calculating REE and BMR (kcal/day) in childrenfrom 3 10 years*SourceGenderEquationWHOmaleREE = + 495femaleREE = + 499 Schofield (W)maleBMR = + 505femaleBMR = + 486 Schofield-(WH)maleBMR = + + = + + = + + = + + ON PAEDIATRIC PARENTERAL NUTRITIONJ Pediatr Gastroenterol Nutr, Vol.

10 41, Suppl. 2, November 2005decrease Energy needs, and some of these situations arediscussed Energy NEEDSE nergy needs can be either measured or calculatedbased on acceptable equations. The best way to assessenergy needs in children is to measure total energyexpenditure or alternatively REE (15). Previous estimationof Energy needs were based mainly on body size ( , height, body surface area) (16), but it has beensuggested that prediction of Energy needs should be basedon fat free mass, to account for differences in body com-position (17) or even on organ tissue mass basis (18).Daily Energy requirements are usually estimated by add-ing the increased Energy expenditure associated with activ-ity, stress, disease state, injury and growth to the calculatedbasal metabolic rate of healthy children (14).