PPT 2

• Parenteral Nutrition (PN)


  Feeding method where nutrients are administered intravenously, bypassing the digestive system
• Parenteral Nutrition (PN) requirements


  • What is the patient's energy need? (kcal required/day)
  • How much protein/nitrogen does the patient need in a day?
  • How much fluid can the patient tolerate and need?
  • How much fat emulsion can the patient be given/tolerate
  • How much dextrose is needed? The dextrose concentration?
  • Which electrolytes are needed and how much?

  
• Not all the time electrolytes are added
• Total Parenteral Nutrition (TPN)


  • Must be individualized
  • Standard concentrations of protein, carbohydrate, and fat that are available in standard volumes limit the degree of individualization when used
  • Mixing different formulas in calculated amounts can be used in developing feeding solutions for most patients
  • Dextrose solutions and lipid emulsions are common macronutrients used to provide energy in a parenteral solution
  • Nitrogen for protein synthesis is obtained from synthetic crystalline L-amino acid solutions
• Determining Energy Needs


  1. Harris-Benedict Equation

  2. Energy Needs (kcal/kg) based on the following scale

  3. Indirect Calorimetry and Metabolic Cart
• Harris-Benedict Equation


  For men: B.E.E / BMR = 66.5 + (13.75 x weight in kg) + (5.003 x height in cm) – (6.775 x age in years)

  For women: B.E.E / BMR = 655.1 + (9.563 x weight in kg) + (1.850 x height in cm) – (4.676 x age in years)
• Level of Activity


  • Sedentary (little or no exercise)
  • Lightly active (light exercise/sports 1-3 days/week)
  • Moderately active (moderate exercise/sports 3-5 days/week)
  • Very active (hard exercise/sports 6-7 days/week)
  • Extra active (very hard exercise/sports & physical job or 2x training)
• Normometabolic need


  25-30 kcal/kg/day

  
• Hypometabolic need


  20-25 kcal/kcal/day
• Hypermetabolic need


  30-35 kcal/kg/day
• Indirect Calorimetry and Metabolic Cart


  • Measures inspired and expired gas flow, volumes and concentrations of O2 and CO2
  • Determines energy requirements and response to nutrition over time
  • Calculates Respiratory Quotient (CO2 production/O2 consumption) and Resting Energy Expenditure (REE)
  • Energy expenditure = (3.9VO2 – 1.1VCO2) – 2.17 (urinary nitrogen)
  • Abbreviated Weir Equation: REE = (3.94 x VO2) + (1.1 x VCO2)
• Patient 1


  • 57 year old female (53 kg, 159 cm) with ischemic bowel and history of physiologic short gut syndrome admitted for malnutrition. Patient has multiple decubitus ulcers/sacral wounds.
• Calculating Patient 1's Energy Needs


  Option 1: Harris Benedict Equation

  Option 2: Weight-based (kcal/kg) – Use chart

  Option 3: Metabolic Cart Study
• Protein


  Provides 4 kcal/g

  Maintenance, unstressed = 0.8 – 1 g/kg

  Mild stress: 1-1.2g/kg

  Infections, Major surgeries, Cancer, Critically ill = 1.3 – 1.6 g/kg

  Multiple trauma or CHI =1.4 – 1.6 g/kg

  Large wounds, Protein-losing enteropathy = 1.5 – 2 g/kg

  >20% Total Body Surface Area burns = 2 – 3 g/kg
• Glutamine


  Most abundant amino acid in the blood

  Protects the gut epithelia tissue lining
• Choline


  Helps protect the liver from hepatic far deposits (that hinder proper functionin)
• Fluids Estimation


  In general, patients need a minimum of 30 cc fluid/kg body weight to maintain hydration = 30-50 cc/kg

  Most adults will tolerate 1.5 – 2.5 L/day of PN

  Holiday-Segar Method

  
• Fat Needs


  Requirement: 1.0 – 2.5 g fat/kg (or 30-40% of the total calories needed)

  MAXIMAL tolerance level of lipid is considered to be 2.5 g/kg body weight and 60% of energy from fat is also considered to be the upper limit

  10% fat emulsions have 1.1 kcal/cc

  20% fat emulsions have 2.0 kcal/cc

  30% fat emulsions have 3.0 kcal/cc

  Regular IV lipids: fatty acids from safflower and soybean oil that are converted to arachidonic acid

  SMOF Lipids: newer product, contains 30% omega 6 fatty acid, 15% Omega 3, & MCFA do not convert to arachidonic acid

  
• Carbohydrates


  CHO is the main source of fuel to meet energy needs

  CHO (kcal Dextrose) needed: Metabolic need – kcal CHON – kcal fats

  Dextrose provides 3.4 kcal/g

  In TPN, CHO is given as dextrose monohydrate, which yields 3.4 kcal/g

  Dextrose is available in 50 – 70% solutions (D50W, D70W are the most common solutions used to prepare TPN solutions)

  Energy content of one litre (1000 cc) 50% Dextrose solution (D50W)? 1000 cc x 50% = 500 g dextrose x 3.4 kcal/g = 1700 kcal from CHO
• Glucose Utilization Rate (GUR)


  Determines how quickly a patient is storing/depleting the dextrose

  GUR = [(Rate of PN x % dextrose) / (weight in kg x 6)]

  Should not exceed 4 mg/kg-min (fats provide calories for energy requirements; may result to overfeeding)
• Recommended Maximum Electrolytes


  • Sodium (Na) = 130 mEq/L

  Potassium (K) = 80 mEq/L

  Magnesium (Mg) = 12-16 mEq/L

  Calcium (Ca) = 10 mEq/L

  Phosphorus (Phos) = 25 mmol/L
• Trace Elements


  Mn & Cu are metabolized by the liver and trace elements should be omitted if liver function tests are more than twice the upper limit of normal

  Mn toxicity: Parkinson's-like sx

  Copper deficiency: anemia

  Chromium deficiency: glucose intolerance

  Selenium deficiency: cardiomyopathy and other muscle pains

  Zinc deficiency: alopecia, dermatitis, poor wound healing

  *Add extra for wound healing or excessive GI losses
• Osmolarity (mOsm) Calculation


  Total mOsm = (g Dextrose/L) (5) + (g Protein/L) (10) + Osmolarity contributed by electrolytes

  Note: FAT is ISOTONIC and does not contribute to Osmolarity

  NOTE: Hypertonic solutions may contribute to phlebitis therefore, the osmolarity of the parenteral nutrition solution should be between 900-1100 mOsm/L; <900 mOsm/L if peripheral administration
• Mixing different formulas in calculated amounts can be used in developing feeding solutions for most patients
• Dextrose solutions and lipid emulsions are common macronutrients used to provide energy in a parenteral solution
• Nitrogen for protein synthesis is obtained from synthetic crystalline L-amino acid solutions
• Regular IV lipids: fatty acids from safflower and soybean oil that are converted to arachidonic acid, leading to increased inflammatory enzymes
• SMOF Lipids: newer product, contains 30% omega 6 fatty acid, 15% Omega 3, & MCFA do not convert to arachidonic acid
• DM px: insulin regimens will need to be adjusted to keep the patient's glucose under control
• Non-DM px: decrease the dextrose when glucose is >180 mg/dL, to avoid overfeeding
• Mn toxicity: Parkinson's-like sx
• Copper deficiency: anemia
• Chromium deficiency: glucose intolerance
• Selenium deficiency: cardiomyopathy and other muscle pains
• Zinc deficiency: alopecia, dermatitis, poor wound healing
• FAT is ISOTONIC and does not contribute to Osmolarity
• Hypertonic solutions may contribute to phlebitis therefore, the osmolarity of the parenteral nutrition solution should be between 900-1100 mOsm/L; <900 mOsm/L if peripheral administration