Parenteral and Enteral Nutrition - Lecture 1 Flashcards by Alexa Carnahan

Calculating weights

dry weight = admit weight = actual weight

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IBW formula

male = 50 kg + (2.3 x inches over 60”)
female = 45.5 kg + (2.3 x inches over 60”)

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Dosing body weight (DBW) formula

DBW = IBW + 0.4(wt - IBW)
use if actual body weight is 130% or more of IBW
applies for dosing certain drugs (antibiotics)

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Nutrition body weight (NBW) formula

NBW = IBW + 0.25(wt - IBW)
use if actual body weight is 130% or more of IBW
applies for calculating fluid, electrolyte, and nutrition parameters

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Shift of importance

nutrition support: preserve lean body mass, maintain immune function, avert metabolic complications
now called nutrition therapy

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Alleviate the stress response

provide macro and micronutrient delivery
careful glycemic control
being enteral nutrition early

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Benefits of early initiation

decrease in disease severity
decrease in complications
decrease in ICU length of stay
increase in patient outcomes

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Nutritional assessment

risk factors for malnutrition
history
anthropometrics
classifications of malnutrition
nitrogen balance

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Nutritional assessment - risk factors for malnutrition

UBW (under body weight) = 20% below IBW
involuntary weight loss > 10% within 6 mo: surrogate marker, consider otehr disease states (cancer, TB)
NPO > 10 days (ICU pt): clinically we use inadequate intake > 7 days
gut malfunction (ICU pt)
mechanical ventilation (ICU pt)
increased metabolic needs (ICU pt): trauma/burn pts, high dose steroids
alcohol/substance abuse: decreased functioncal proteins, empty calories
protracted nutrient losses: chronic disease states (HIV/AIDs, cancer)

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Determination of nutrition risk

risk factors for malnutrition
intake anticipated to be insufficient
identify who will benefit most from early nutrition therapy
all hospitalized pts within 48 hrs
many screening and assessment tools exist - NUTRIC and nutritional risk score (NRS-2022)

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NUTRIC

high risk: 6-10 (5-9 w/o IL-6)
low risk: 0-5 (0-4 w/o IL-6)

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Nutritional assessment - history

dietary: diet PTA, intake, swallowing, ulcers, h/o weight loss, anorexia, vomiting, diarrhea
medical: surgical history, PMH
medications: decrease nutrient absorption, alter taste, increase/decrease appetite, N/V

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Nutritional assessment - anthropometrics

science of measuring the human body
somatic (muscle) protein status: weight, triceps skin fold, arm muscle circumference, physical appearance
look at trends

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Visceral protein status

transthyretin (prealbumin): half life (days) - 2-3; normal serum concentration - 15-40 mg/dL

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Visceral protein status may not

accurately represent nutrition status in the ICU setting

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C-reactive protein (CRP)

positive acute phase reactant (increased by at least 25% during inflammation)
normal < 1mg/dL (in clinical practice)
use to assess accuracy of prealbumin (if prealbumin low, check CRP)
prealbumin is falsely decreased in the presence of inflammation: prealbumin decreases as CRP increases –> inflammation; prealbumin decreases as CRP normal –> malnutrition

Nutritional assessment - classifications of malnutrition: protein-calorie malnutrition

marasmus
decrease total intake and/or utilization of food
wasting of skeletal muscle and SQ fat
immunosuppression in severe cases
cachectic appearance

Nutritional assessment - classifications of malnutrition: protein malnutrition

kwashiorkor
adequate caloric intake; relative protein malnutrition
catabolic (breaking down proteins) trauma pts, burn pts

Nutritional assessment - classifications of malnutrition: mixed

chronically ill starved pts who are metabolically stressed
decrease in visceral proteins, poor wound healing, immunocompromised

Marasmus

protein/calorie
sx: peeling and alternatively pigmented skin, hair loss, edema, swelling, skin folds are formed
wasting of muscles: quite evident
treatment: provide a well-balanced substrate, consider addition of vit B

Kwashiorkor

protein only
sx: large belly, diarrhea, change in skin pigment, decreased muscle mass, failure to gain weight, fatigue, hair changes
wasting of muscles: not evident
treatment: provide carbs followed by high protein

Nutritional assessment - nitrogen balance

measure of urinary excretion of nitrogen as urea nitrogen (urinary urea nitrogen; UUN) - measure of substance in vs measure of substance out (how much extra nitrogen is your body excreting in the form of urine)
nitrogen released from protein catabolism –> converted to urea and excreted in the urine
stress increase, protein catabolism increase and UUN increase
measured from 24-hour urine collection
represents 85-90% of total nitrogen excretion

Nitrogen balance - non-urinary sources of nitrogen loss

sweat, feces, respirations, gastrointestinal fistula, wound drainage, skin exfoliation, burns

Nitrogen balance study used to assess

the adequacy of protein repletion
ideal goal: +3 to +5 grams (want positive nitrogen balance)

Nitrogen balance formula

nitrogen balance = (N in) - (N out) N in = 24 hr protein intake (g)/6.25 N out = 24 hr UUN (g) + factor (3-5 g) generally use 4 g as your estimate

Nutritional requirements

caloric requirements protein requirements

Estimating caloric needs

harris-benedict equation: basal energy expenditure (BEE) - bare minimum amount of energy/calories to maintain life OR resting energy expenditure (REE)

Stress or activity factor to use with harris-benedict equation

maintenance: % of REE = 120-130, activity factor = 1.2-1.3 mild, moderate: % of REE = 150, activity factor = 1.5 severe, thermal burn: % of REE = 200+, activity factor = 2 TEE = REE x stress/activity factor(s)

Non-stressed, non-depleted

20-25 kcal/kg/day

Trauma/stress/surgery, critically ill, major burns

25-30 kcal/kg/day basically use for anyone in the hospital

Obesity: BMI 30-50

11-14 kcal/kg/day (actual body weight)

Obesity: BMI > 50

22-25 kcal/kg/day (ideal body weight)

Indirect calorimetry

preferred method for critically ill pts provides energy expenditure (REE, RQ) at that ONE point in time, then extrapolated to 24 hrs abbreviated weir equation: TEE = REE x 1.2 (using activity factor of 1.2) for all energy production, oxygen is consumed and carbon dioxide is produced: RQ = Vco2/Vo2

Respiratory quotient values

overfeeding: lipogenesis - RQ = 1-1.2; carbohydrate oxidation - RQ = 1 normal: mixed substrate - RQ = 0.85-0.95 underfeeding: protein oxidation - RQ = 0.82; fat oxidation - RQ = 0.71; ethanol - RQ = 0.67 goal: 0.85-0.95 (monitor once weekly)

Protein requirements

maintenance: 0.8-1 gm/kg/day mild-moderate stress (floor pts): 1-1.5 gm/kg/day moderate-severe stress (ICU, trauma, surgery, burn): 1.5-2 gm/kg/day obesity (BMI > 30): 2 gm/kg/day (ideal body weight) severe obesity (BMI >/= 40): 2.5 gm/kg/day (ideal body weight)

Additional considerations

adequate calories must be present for appropriate protein utilization: ensure adequate NPC, usually include protein in calculation of total calories protein tolerance may be decreased in some disease states (renal and hepatic failure)

Non-protein calorie (NPC) distribution

standard distribution (70/30): 70-85% dextrose, 15-30% fat adjust based on tolerance: blood sugars, triglycerides, RQ from indirect calorimetry 100/0 may be utilized during sepsis or bloodstream infections (leave out fat)