EN TPN

• These notes cover energy and protein needs in hospitalized patients, clinical situations that require calorimetry, indirect calorimetry, estimating needs, activity and injury factors, estimating energy needs, calorie estimations, protein needs, enteral and parenteral nutrition

Energy & Protein Needs

• A prediction provides an estimate, while indirect calorimetry tells exactly how much the patient needs

Clinical Situations Requiring Calorimetry

• Hypermetabolic states
• Malnutrition or starvation
• Obesity
• Peripheral edema
• Hypoalbuminemia
• Limb amputation
• Non-healing wounds
• Postoperative conditions

Refeeding Syndrome

• Starting nutrient administration slowly is critical
• Rapid initiation can cause fatal fluid and electrolyte shifts, especially in malnourished patients on artificial refeeding

Indirect Calorimetry

• An accurate method for calculating Resting Energy Expenditure (REE)
• Uses Respiratory Quotient (RQ) by measuring oxygen (VO2) and carbon dioxide (VCO2) exchange
• RQ is the ratio of CO2 produced to O2 consumed

Data Provided by Machine

• Energy Expenditure (EE) can be calculated using the formula: EE = (3.94 x VO2) + (1.11 x VCO2)
• Respiratory Quotient (RQ) is calculated as VCO2/VO2

RQ Interpretation

• RQ < 0.82 indicates underfeeding, posing a risk for refeeding syndrome
• RQ > 1 indicates overfeeding, leading to excessive CO2 production and potential fatty liver development
• Optimal RQ goal is .85
• Macros RQ:
  • Carbohydrates (CHO): 1
  • Protein (PRO): 0.8-0.9
  • Fat: 0.7 (least amount of CO2 as a waste product)
  • A mixed diet should be at .85
• It is important to avoid overfeeding patients' total calories

Estimating Needs

• Parameters include:
  • Height
  • Weight (current/actual, usual body weight (UBW), dry weight)
  • Weight for Height (BMI), which influences prediction equations, especially in obese patients
  • Significant weight change (%)
  • % > or < Ideal Body Weight (IBW)

Metabolic Rate

Basal Metabolic Rate (BMR) or Basal Energy Expenditure (BEE)

• Considered the MOST ACCURATE measurement
• Conducted under strict conditions such as a dark room, after 8 hours of sleep and 12 hours of fasting

Resting Metabolic Rate (RMR) or Resting Energy Expenditure (REE)

• Complete
• Conditions are less restricted than BMR
• It is usually slightly higher (5%) than BMR/BEE
• RMR and REE are often used interchangeably
• Different prediction equations may use different terms

Activity Factor (AF) and Injury Factor (IF)

• Can be used with Mifflin-St Jeor and Harris-Benedict equations
• Common AFs:
  • Bedrest: 1.2
  • Ambulatory: 1.3 (normal ADL's: 1.5)
• Common IFs:
  • Minor Surgery: 1.2
  • Skeletal Trauma: 1.35
  • Major Sepsis: 1.60
  • Burns: 2.10
• These factors are multiplied by the metabolic rate result from the prediction equation

Estimating Energy Needs

• Adult Weight Management (AWM) involves determining Resting Metabolic Rate
• Estimate energy needs based on RMR, preferably measured by indirect calorimetry
• If RMR measurement isn't an option, use the Mifflin-St. Jeor equation with actual weight for overweight/obese individuals

Mifflin-St. Jeor Equation

• An equation used to estimate RMR
• Men: (9.99 x weight in kg) + (6.25 x height in cm) – (4.92 x age) + 5
• Women: (9.99 x weight in kg) + (6.25 x height in cm) – (4.92 x age) – 161
• It is suitable for hospitalized patients who are not critically ill
• Use actual body weight for obese patients

Critically III Patients on Ventilation

• Normal Weight or Obese <60 y.o.: use PSU(2003b) (Penn State Equation)
• RMR = Mifflin(0.96) + VE (31) + Tmax (167) – 6212
• VE = minute ventilation, from the vent (expired air per minute, affects CO2)
• Tmax= max temp. last 24 hours temp in Celsius
• Obese, Ventilated (Age ≥ 60): use PSU (2010) (Modified Penn State Equation)

PSU(2010)

• RMR = Mifflin (0.71) + VE (64) + Tmax (85) – 3085
• VE = minute ventilation, reading off the vent (expired air per minute, affects CO2)
• Tmax = max temp. last 24 hours in Celsius

Ireton-Jones Equation

• B=Diagnosis of burn (present=1, absent=0)
• O=Obesity, body mass index (BMI) >27 kg/m² (present=1, absent=0)
• S=Sex (male=1, female=0)
• T=Diagnosis of trauma (present=1, absent=0)
• Legend:
  • Spontaneously breathing: 629–11(A)+25(W)-609(O)
  • Ventilator-dependent (revised, 2002): 1784–11(A)+5(W)+244(S)+239(T)+804(B)

Obese Patients in Critical Care

• Use permissive underfeeding or hypocaloric feedings
• Obese patients under stress are more likely to be insulin resistant
• For BMI >30, the goal of the Enteral Regimen should not exceed 60-70% of needs or:
  • 11-14 kcal/kg of actual body weight
  • 22-25 kcal/kg of ideal body weight

Calorie Estimations (Nomograms)

• Basal Energy Needs: 25-30 kcal/kg/IBW (Ideal Body Weight)
• Ambulatory with weight maintenance: 30-35 kcal/kg
• Malnutrition with stress: 35-40 kcal/kg
• Severe injuries and sepsis: 40-50 kcal/kg
• Extensive Burns: 50+ kcal/kg
• These values should not be multiplied by an Activity Factor (AF) or Injury Factor (IF)

Fever Considerations

• For every 1-degree Fahrenheit increase, add 7% to BEE

Protein Needs in Critically Ill Patients

• (based on ideal body weight, NOT actual weight)
• Normal: 0.8-1.0 g/kg
• Critically III: 1.5-2.0 g/kg
• Fever, Fracture, Wounds: 1.5-2.0 g/kg
• Burns: 1.5-3.0 g/kg
• Sepsis: 1.2-1.5 g/kg
• Obese patients need protein:
  • Class I and II obesity (BMI 30-40): 2.0 g/kg of IBW
  • BMI >40: 2.5 g/kg of IBW

Enteral Nutrition (EN)

• Nutritional support through tube placement through the nose, esophagus, stomach, or small bowel (duodenum or jejunum)
• Preferred mode of feeding if the gut is functional

Principles of EN

• A functioning GI tract is a pre-requisite.
• Utilizes the GI tract to provide nutrition, must exhaust all oral methods first
• Start EN within 24-48 hours of injury
• For patients with 2-3 ft of functioning GI tract, enteral nutrition is preferrable to parenteral
• Progressively advance towards the target goal
• It is provided via a tube or catheter when oral intake is inadequate

Advantages of EN

• Allows easy and accurate monitoring of intake
• Provides nutrition when oral intake is insufficient
• Costs less than parenteral nutrition
• Readily available
• Reduced risks associated with disease state

Benefits of EN

• Preserves gut integrity: Complete bowel rest can cause breakdown of mucosal barrier and increase permeability to bacteria, contributing to sepsis

• Decreases the likelihood of bacterial translocation

• Preserves immunologic function of the gut: Component of mucosa is GALT (gut associated lymphoid tissue) and provides immunoglobulins to defend against pathogens

Parenteral Nutrition (PN)

• Provision of nutrition intravenously (via bloodstream)
• PPN (Peripheral Parenteral Nutrition): uses small veins in the arm (IV)
• CPN (Central Parenteral Nutrition): uses central veins (vena cava), increases risk for sepsis, puncturing lungs/muscles, precipitates (iron or calcium), bacterial infection
• PN is an option if EN isn't possible for 7-10 days

Conditions that Require Nutrition Support

Enteral (EN)

• Inability to consume adequate nutrition orally
• Impaired ingestion
• Impaired digestion, absorption, or metabolism
• Severe wasting or depressed growth

Parenteral (PN)

• Gastrointestinal incompetency
• Hypermetabolic state with poor enteral tolerance or accessibility

EN Access Considerations

• Depends on the anticipated length of time
• Degree of risk for aspiration or displacement
• Presence or absence of normal digestion and absorption
• Planned surgical interventions
• Administration rates for viscosity and volume

EN Clinical Conditions

• Duration of tube feeding:
• Nasogastric or nasoenteric tube: for short term (less than 3-4 weeks, normal Gl, gag reflex, check placement)
• Nasoduodenal or Nasojejunal: for patients with gastric motility disorder, esophageal reflux, nausea, vomiting issues (weighted tips)
• Percutaneous Endoscopic Gastrostomy (PEG) and Percutaneous Endoscopic Jejunostomy (PEJ) tubes: for long term ( > 3-4 weeks

Complications of Enteral Nutrition

Diarrhea

• Frequently associated with enteral nutrition, usually due to less fiber
• True diarrhea: bacterial overgrowth, antibiotic therapy, GI motility disorders
• Hyperosmolar medications: Mg containing antacids, high sugars, etc.
• Adjusting medications or administration routes can help
  • Addition of soluble fiber, pectins, and antidiarrheal medications like Imodium

Aspiration Pneumonia

• Can result from enteral feeds
• High-risk patients include those with a poor gag reflex

Strategies to Reduce Aspiration Risk

• Depressed mental status
  • Check gastric residuals if receiving gastric feeds
  • If GR's >300 stop feeding, assess for other symptoms
• Abdominal distention, pain
  • Check if patient has gastroparesis
  • Consider prokinetic agents (Reglan)
  • Check every 4 hours or as needed
• Elevate head of the bed >30 degrees during feedings
• Post-pyloric feeding (into the small intestines)
• Use of Blue Dye is no longer recommended

Enteral Monitoring

• Establish Baseline using common lab tests
  • Preliminary Screen: Na+, Cl-, BUN, Cr, K+, HCO₃, Glucose, CO₂, Mg++, PO₄
  • Baseline Labs: Low levels can indicate risk for refeeding syndrome
• Broad spectrum screening: Albumin, alkaline phosphatase, CRP, Prealbumin, lipase, AST, ALT
  • Indicators of formula tolerance
    • Stool frequency/consistency
    • Vomiting
    • Abdominal distention/bloating
      • May need to stop and restart more conservatively
    • Blood Glucose levels → can become insulin resistant
      • If pt has DM, sepsis or severely stressed, the pt cannot metabolize CHO well
    • The may need insulin
    • Need to go from an intermittent feeding to continuous
  • Hydration
  • Weighed (initially then 3x/wk)
    • If sudden change evaluate hydration status
    • Indicators: Hypernatremia (Na 145-150) elevated BUN, Hct, Dry mucous membranes, thirst, elevated temperature, decreased skin turgor, confusion, decreased urine output, dark color, weight decrease
  • Hydration
    • Increase fluid if: infection, fever, diarrhea, increased protein intake, vomiting, drainage
• Evaluation of Nutritional Response
  • Kcal count
  • N+ Balance
  • Est. Energy expenditure changes
  • Albumin, Iron, Transferrin, TIBC
  • Monitor Mg++ biweekly in malnourished patients.
  • Phosphorous and liver function tests 2x/week

Refeeding Syndrome

• Occurs after a period of starvation when carbohydrate is reintroduced, leading to increased plasma anabolic patients
• Affected by the degree of starvation and rate and content of repletion
• Refeeding syndrome is more likely in TPΝ patients
• Growth of new tissue requires increased glucose, potassium⁺, phosphorous, and magnesium⁺⁺

Fixing Refeeding

• Reduce the Rate
• Supplement Electrolytes (via IV Fluids)
• 7-10 days prior and decrease risk of refeeding

Methods of Delivery

Bolus Feedings

• 300 to 500ml rapid delivery via 60mL syringe several times daily
  • Preferred method for stable patients at home or on long-term tube feedings
  • Less expensive than pump
  • If bloating is severe: Stop, wait 10-15 minutes, then proceed
  • Additional water given after each bolus to rinse tube and prevent clogging
  • Can be poorly tolerated if given too fast or if cold
  • Nausea, distention, cramps, diarrhea
  • Intermittent Feedings
• 4-6 feedings over 20-60 minutes/day via gravity drip or pump
• Pumps:
  • Cyclic feedings—via pump usually at night 7p-7a over 12 hours
  • Continuous feedings —infusion pump, most commonly used when:
    • Critically ill
    • High risk for aspiration
    • Small bowel feedings
    • Always pump fed
• Continuous Method via Pump
  • Start at ¼ to ½ of goal rate (10-50mL) advance to the final rate as tolerated increasing the rate every 8-12 hours
  • Can begin at full strength if GI tract is functioning fully
    • Do not dilute with water (if having problems, decrease to last tolerated rate)
    • If it is a hyperosmolar formula >300-500 mOsm/L start slow and advance conservatively
      • Continuous feeds Usually runs b/t 18-24 hours/day

Parenteral Nutrition Support

Indications for Total PN

• Are or will become malnourished
• Do not have sufficient Gl function to restore or maintain optimal nutritional status
• Critical Illness with poor enteral tolerance or accessibility
• Severe inflammatory bowel Crohn's, Ulcerated Colitis

Access Decision

• Nonfunctional GI tract is patient meeting Yes-> No further intervention No-> Needs Parenteral Nutrition
• if greater than 3 weeks use a peripheral extended dwell Catheters Peripheral extended catheters /central tunneled /peripheral standard IV Central-Standard Catheters

Administration

• 1.Central Access (preferred)
  • -both long- and short-term placement -Inserted into the subclavian and advanced to the superior vena cava
• Peripherally Inserted Central Catheter
  • used for higher kcal amounts and >10 days
  • 15-20% concentrations per volume

2. peripheral Parenteral Nutrition (PPN) -cannot exceed 800-900 mosm/L

• Principle complication is phlebitis not a good to option for cardiopulmonary, hepatic, or renal.
• 10 % dextrose concentration maximum for PPN.
• (cannont give it a lot of nutrients)
• Vitmins
• Iron not added because it grows bacteria especially with lipids(3-1)!
• Trace

Parenteral Components & Macros

Protein (Amino Acids)

• Formulated to provide Essential AA and Non-Essential AA
• 3-20% of solutions -Ex. If you have a 10% AA stock there would be 100g of protein in a L (1000mL)
• % is usually expressed in final concentration once mixes with other nutrients (usually 2-5%)
  • Protein Requirements: 15-20% of total needs a. 1.2 to 1.5 protein/kg – IBW mild or moderate stress g protein/kg IBW burns or severe trauma

Carbohydrates

• g protein/kg IBW burns or severe trauma
• Glucose or dextrose monohydrate 3.4 kcal/g due to non-caloric water molecule
• Solutions range from 5-70% dextrose/L -Ex. D50 stock would have 500g Dextrose in 1 L Usual final concentrations between 2.5-25 Glucose Infusion Rate (GIR); should not exceed dextrose infusion of 5-6 mg/kg/min, critical patients
• Ex. 576 g x 1000/68 kg/ 1440 min = 5.8
• Excess glucose infusion rates can cause:
• Increased ventilatory drive
• Hyperglycemia -Hepatic abnormalities (fatty liver) -* Typically, AA and lipids are provided and remaining kcals go to dextrose as long as GIR is not too high for patient Example: If patients TPN regimen gives him 350 g of dextrose per day, how many kcals would that provide? 350 g x 3.4 kcals = 1190 kcals

Lipids

• Intravenous Lipid Emulsions (ILE)
• Provides kcals and EFA (Linoleic and Linolenic Acid to prevent EFAD) -2-4% of kcals Linoleic .25% of kcals from Alpha-Linoleic

ILE Rules of Estimation and when to hold (stop)

1. Should not exceed 2.0g/kg of BW daily
2. Usual administration 1-1.5g/kg of BW daily
3. Monitor TG, if >400 HOLD ILE → lead to hypertriglyceridemia, pancreatitis
4. Use a 1.2-micron filter
5. Don't forget to count lipid kcals from Propofol/Diprivan → sedatives provide kcals

Lipid Requirements

• Mixed: Soybean or safflower oil and yolk phospholipids – Check Allergives

Three types of emulsions by %:

• 10% emulsions = 1.1 kcal/mL →

• PPN -20% emulsions = 2 kcal/mL

• typical with central TPN - 30% emulsions = 3 kcal/mL

• Can hang as a separate bottle can reduce irritation lipids are given over 12 hrs/ok for 24 (3 in 1)

Calculating Nutrient Needs

• avoid excess,
• NomagramadultdNormal 25-30
• kcallkcallSurvery29-30
• Seveer 30-40
• Burns >50

Electrolytes

• Use acetate or chloride to mange