Nutrition in Critical Care

1
Nutrition in Critical Care

• Part I Enteral Nutrition
• Chris Miller, MEd, RD, CNSD

2
The Stress Response Nutrition Implications

• Fasting/Non-Stressed
• Decreased BMR
• Energy Fat/Ketones
• Conserves
• Glucose
• Protein
• Net loss 5-7 g N
• Equivalent to 1-1.5 oz protein/day

• Metabolic Stress
• Very High BMR
• Energy Sources
• Glucose, Fatty Acids
• Protein (No Reservoir)
• Poor Utilization of Nutrients
• Hyperglycemia
• Hypertriglyceridemia
• Net Protein Losses
• gt15 g.N gt3 oz protein
• Depletes heart, resp. muscles, gut barrier
• Increases GI permeability

3
Nutrition Support Goals

• Minimize nitrogen/ protein losses
• Maintain weight/ minimize losses
• Minimize infection risk
• Maintain gut function
• Mucosal barrier function (need gt 50 TF)
• Digestive enzymes
• Gallbladder contraction
• Facilitate weaning from vent
• ? Immune modulation

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Enteral Feeding Contraindications

• ShockHigh Risk for GI Ischemia/ Perforation
• Controversial- No clear guidelines
• Hold TF for distention, high residuals,
  unexplained acidosis
• Ileus- Small Intestine
• Small Intestine-motility returns within hours of
  insult
• Stomach- may take 1-4 days for return of motility
  
• Intestinal Obstruction/ Perforation
• Severe Acute Pancreatitis Without Jejunal Access
• Intractable N/V/D
• GIB with hemodynamic compromise
• High Output Fistula (gt 500 cc/day)

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Enteral Feeding Formulary Selection

• See Formulary Card
• Standard Polymeric require digestion
• Isotonic
• Fiber vs. No Fiber
• Vary in Protein Content/ Caloric Density
• Specialty
• Disease Specific
• Pulmonary Diabetic
• Low CHO/ High Fat
• Differ in Kcals/ ml
• Concern re potential immune effects of N-6
  (Corn/Soy oil) fat load
• Elemental
• Low Fat
• Pre-digested

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Immune Modulating Enteral Feedings

• Immune Nutrients
• Glutamine Preserves Gut Integrity, Fuels Immune
  Cells
• Arginine Stimulates Wound Healing, Activates
  Immune Cells
• N-3 Fatty Acids (Fish Oils) Immune enhancing/
  anti-inflamatory
• Reported Effects
• ? Infection rate, LOS, Vent Days
• Formulas
• Oxepa ARDS (Contains Fish Oil/ Borrage Oils)
• Impact GI Surgeries(Arginine, N-3 Fatty Acids,
  Nucleotides)
• Administration Guidelines
• Notify RD ASAP- must be approved
• Start within 48 hrs. of dx/ OR
• Advance as rapidly as tolerated (25 cc q 8-12 hr)
• Continue for minimum of 5-7 days

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Enteral FeedingAspiration Prevention

• Residuals Poor Correlation with other
  parameters!!
• Only found with gastric feeds (Not Small
  Intestinal)
• Do Not Hold unless gt 125- 200 cc
• Reinfuse to maintain acid-base balance
• GI Symptoms More Reliable
• Nausea/ Vomiting
• Distention/ Constipation
• Positioning
• HOB gt 30 at all times
• Hold x 1 hour before lying flat for procedures
• Blue Dye? NO
• Only detects lt 25 of aspirations
• Potential Harms Infection/ Toxicity/ ? Deaths

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Acute Care Monitoring Nutrition Adequacy

• Nitrogen Balance Gold Standard
• Requires accurate intake/output data
• Enteral/ Parenteral Intake
• Requires accurate 24hr Urine for Urea N
• Not accurate in Renal Failure/ Hepatic
  Encephalopathy
• Calculation
• Pro Intake (g)/ 6.25g - (UUN 4)
• Use factor of 6 for high output GI losses
• Goal 2-4 g/day
• Plateau Effect
• Metabolic response to stress may result in
  catabolism impaired ability to use high N
  loads.

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MonitoringNutrition Adequacy Acute Care

• Albumin
• Poor Nutritional Indicator
• Good Prognostic Indicator
• Half Life 20 days
• Not an acute phase protein
• Low in liver dz, infection, post-op,
  overhydration, inflammation

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MonitoringNutrition Adequacy Acute Care

• Pre-albumin
• Good indicator in absence of acute stress
• Half life 2-3 days
• Not an acute phase protein
• Low in liver dz, infection, post-op,
  inflammation, hemodialysis
• High in renal failure

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MonitoringNutrition Labs
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Case Study Diarrhea

• Potential Cause
• Infection/ C-dif
• Promotility Agents/ Laxatives
• Hypertonic Meds(K,PO4)
• Sorbitol
• Gut Fluora Changes
• Gut Edema/3rd Spacing
• Tube Feeding Rate

• Treatment
• Clean TF Technique
• Antibiotics
• D/C Reglan Dulcolax
• Change Lytes to IV
• ? D/C Guaifenesin, Change tylenol to crushed tabs
• Start Lactinex granules
• Diuresis as tolerated
• Decrease to 30 cc/hr

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Nutrition in Acute Care

• Part II Parenteral Nutrition

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Parenteral NutritionRoute/ Timing

• See Decision Tree on Back of TPN form
• Indications for Parenteral Nutrition
• Nonfunctioning GI Tract
• Severe PCM NPO/Clears x 3-5 days
• All others 7-9 days
• gt 14 days before TPN- Increased complication
  rate
• Pre-op Feeding for Severely Malnourished Only
• Requires gt 7 days
• Severe Acute Pancreatitis without jejunal access
• Prolonged Hemodynamic Instability

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TPN OrderingGeneral Guidelines

• Patient ID must be on order
• Deadline for TPN Orders 12 00 Noon
• Reordering TPN
• Changes Which Require New Order Form
• Any change in composition of formula
• Dextrose, AA
• Lytes
• Additives/ Insulin
• Increase in rate
• Changes Allowed in MD Order Section
• Renewal ( Must be done daily)
• Decrease in Rate
• Changes in IV lipids

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Parenteral Nutrition How to Start

• MD Ordering
• See Guidelines on back of TPN Order Forms
• Review baseline labs before admin.
• RN Order Sets/ Responsibilities
• Labs
• Wts
• I/Os
• Check infusion rates, components daily

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CPN vs. PPN(Per Liter/ Without Lipids)

• Component CPN PPN
• Kcal (Standard) 680- 1100 408
• Volume 1-3 L ³ 1.5 L
• Duration of Tx. ³7 d lt7 d
• Route of Admin. CVL Periph.
• CHO Limit lt 30 lt 7
• Lipids Optional Essential
• mOsm 2000 6-900

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PN Initiation and Progression

• Peripheral PN
• Initiation ³ 2 L/ day
• Discontinuation
• No Taper Necessary
• Central PN
• Initiation
• Start 1 L/ day or 40 ml/hr
• Advance by 500-100 ml/day if
• Glu 150
• TGs lt 400
• Electrolytes Volume Tolerated Well
• Discontinuation
• High Risk for Rebound Hypoglycemia
• Taper to 30 cc/hr Infusion Rate x 1 hour prior to
  D/C.

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Case Study Refeeding Syndrome
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Refeeding Syndrome

• At Risk Chronically Malnourished
• Wasting of lean tissue/ muscle
• Cardiac/ pulmonary atrophy
• Depletion of intracellular nutrients
• Magnesium
• Potassium
• Phosphorus
• Vitamins(esp. thiamin) and minerals
• Metabolic Complications of Refeeding
• Severe, life-threatening electrolyte shifts
• Hyperglycemia
• Refeeding edema
• Cardiopulmonary Failure

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Guidelines for Refeeding

• Electrolytes
• Check Baseline Labs (K, Mg, PO4)
• Do not start feeding until lytes WNL
• Carbohydrate lt 150-200 g/day
• Fluid may need to restrict to lt 1000ml/day
• Vitamins100 mg Thiamine, MVI, others prn
• Monitoring
• DAILY CMP, PO4- AGGRESSIVE REPLETION!!!
• Glu may need insulin rx.
• Close I/O, wts daily to assess fluid status
  (watch for CHF)

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PN ComplicationsAcuteSource Green, K and
Cress M. Metabolic Complications of Parenteral
Nutrition. Supp. Line. 15(1) 5, 1993.

• Metabolic
• Hyperglycemia
• Elevated Triglycerides
• Immune suppression
• Fluid Electrolyte Imbalances
• Rebound Hypoglycemia
• Hypercapnia
• Infectious
• Line
• Impaired Gut Barrier Function
• Mechanical

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Glycemic Control Outcomes

• Critical Care/ Vent Patients (NEJM, 2001)
• Intensive (80-110) vs Standard (Rx if gt 215)
• Decreased
• Mortality ( 42) due to sepsis/ MOSF
• Bacteremia 46
• ARF --- HD 41
• CC Polyneuropathy 44

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Glycemic Control Outcomes

• Post MI (Lancet, 2000) Meta-analysis
• Non- Diabetics
• Fasting Glu gt 109 mg/dl
• 3.9 fold increase in Mortality
• Fasting Glu gt144
• 3.1 fold increase in CHF/ Cardiogenic Shock
• Diabetics
• Fasting Glu gt 144mg/dl 1.7 fold increase in
  Mortality

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Glycemic Control Basic Guidelines

• Do not start TPN if Glu gt 200
• Glycemic Goals
• Ideal 80-110 (achieved via gtt)
• Minimum Goal lt 140 mid-TPN
• Order SSI for all PPN/TPN patients
• Ask MD to adjust SSI if glucoses gt goal
• Avoid Other CHO sources
• TF, IV Dextrose
• If hyperglycemia exists/ anticipated Add Insulin
  to TPN
• Starting Guideline 0.1 u/ g. Dextrose
• If insulin is added
• Minimum 10 u/L
• Sticks to tubing

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Glycemic Control Treatment Options

• Insulin gtt- most flexible
• Allows tightest control without risk of
  hypoglycemia
• TPN insulin
• Benefit CHO Insulin in same source
• If TPN discontinued abruptly/ insulin also d/cd
• RISK Hypoglycemia with changing status
• Consider reason (meds, stress, pancreatitis)
• Do not cover other sources of CHO with TPN
  insulin!!
• Sub Q
• Caution If TPN is D/Cd
• Decrease Dextrose in TPN
• Increase infusion time (cyclic)

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Acute Complications Lipids

• Pancreatitis
• IV Lipids OK in the absence of TG gt 400
• Hypertriglyceridemia
• Goal mid- lipid infusion lt 4-500
• DO NOT HOLD LIPIDS FOR TRIGLYCERIDE LAB!
• TG gt 800-1000
• High risk for pancreatitis
• Tx
• Hold lipids
• Glycemic Control /- Decreased Dextrose
• Recheck as status changes

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Acute Complications Lipids

• Sepsis/ ARDS
• Omega 6 FAs
• Necessary for EFAs long term
• Exaggerated inflammatory response
• Impaired immune response
• RX limit (1.0 g/kg) or hold lipids