Whats New in ICU Nutrition

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Whats New in ICU Nutrition?
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A slender and restricted diet is always
dangerous in chronic and in acute diseases

• Hippocrates 400 B.C.

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• do not let your patients starve and when you
  offer them nutrition support, do so by the
  safest, simplest, most effective route.
• Dr Mike Stroud Feb 2006
• Chair of NICE committee

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ICU Beginnings
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ICU Nutrition development

• 1970s TPN - separate CH, AAs and Lipids
• Single lumen C/Lines, no pumps
• 2500-3000kcals/day Lactic acidosis, high glucose
  loads, fatty livers, high insulin reqt
• 1980s Scientific studies of metabolism
  recognition of overfeeding, excess nitrogen
• 1990s nitrogen limitation 0.2g/kg/24hr, start
  of immuno-nutrition trials
• 2000s glucose control, specific nutrients

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Metabolic Responses in Severe illness

• Aims to mobilize substrate (amino acids and fatty
  acids) from body stores to support vital organs
  catabolism -
• Protein redistribution from skeletal muscle to
  support the central viscera wasting
• Aims to enhance resistance to infection
  inflammatory cascade

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Metabolic Demands and Response in Severe Illness

• Extreme physiological stress/organ failure
• Increased oxygen requirements
• High body temperature
• Acute phase response cytokines
• Sympathetic nervous system stimulation
• Immuno-suppression
• Insulin resistance hyperglycaemia
• Impaired gut function

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Starvation

• Bobby Sands lost 7 kg in first 17 days
• Died at 65 days (9 weeks)
• Not expending excess energy, not in ICU
• Weight loss approx 0.3kg/day after first week
  depending on activity/health
• Loss of muscle and fat
• Eventual death from slowing of all metabolic
  processes

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Metabolic response to starvation

• Aims to minimize impact on vital organs and
  conserve energy
• Decreased metabolic rate
• Decreased temperature
• Reduction in physical activity
• ICU patients often have starvation AND
  increased metabolic demands
• Complex metabolic and inflammatory processes
•  

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Consequences of malnutrition

• Increased morbidity and mortality
• Prolonged hospital stay
• Impaired tissue function and wound healing
• Defective muscle function, reduced respiratory
  and cardiac function
• Prolonged weaning from ventilation
• Immuno-suppression, increased risk of infection
• Depression, lethargy

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Scale of the problem

• McWhirter and Pennington 1994
• gt40 of hospital patients malnourished on
  admission
• Recent Scottish data 35
• Estimated cost to hospitals 3.8bn/yr
• Many ICU patients malnourished or at risk on ICU
  admission

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The Downward Spiral of Malnutrition in ICU
Morbidity / Mortality
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SICS Nutrition Network

• Set up in June 2006
• Links dietitians, pharmacists, ICU nurses,
  physios and doctors. Meets 3x/year
• Forum for sharing ideas
• Current projects on assessment/weighing
• Guidelines on practical issues
• Website with protocols/guidelines/teaching
• Educational meetings
• Encouraging projects in nutrition

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National Initiatives

• QIS Standards
• MUST (BAPEN)
• NICE guidelines on Hospital Nutrition
• Charge Nurse Review

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What are we good at?

• Feeding within 48 hours
• Reminding the surgeons about it
• Putting tubes in
• Giving TPN
• Looking after lines

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What are we less good at?

• Nutritional screening
• Weighing patients
• Keeping tubes in
• Maintaining NG intake
• NJ feeding practical issues
• Treating complications
• Identifying refeeding risk or syndrome
• Feeding in HDU

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Nutritional State
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Nutritional Assessment

• Various nutritional screening tools
• None very good for ICU
• Malnutrition Universal Screening Tool from the
  Malnutrition Advisory Group of BAPEN
• Uses BMI, weight loss, acute illness/intake
• Low risk-routine care, Medium - observe High
  risk treat- refer to dietitian/local protocols

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Screening in ICU

• MUST not very helpful in guiding decisions
• Almost all patients require artificial nutrition-
  cannot observe
• What about refeeding syndrome?
• Needs adaptation using NICE Guidelines
• Adapted MUST for ICU Uses BMI/weight loss/food
  intake refeeding risk assessment linked to
  feeding flowchart

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SNACC

• 1. Pilot study of Fife ICU screening tool 08
• 2. Systematic review of nutritional assessment in
  critical care 09
• 3. Large study of screening tool in Scotland to
  compare it with other screens and look at outcome
  data results may be useful to target
  interventions 2010-11

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Weighing Patients

• Craig Hurnauth ICU S/N at SJH
• Audit of 13/14 NHS trusts in Scotland
• 12 trusts do not weigh patients in ICU on
  admission use estimate/notes/family
• 1 weighs every day with hoist weekly
• 5 use MUST
• 7 do not screen, 1 adapted screening tool
• 7 units in England similar results

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Weighing Patients

• Important for nutrition screening
• Drug dosages
• Cardiac output monitoring LIDCO, PAFC, PICCO
• Fluid balance

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Weighing Patients

• Estimation of weight can be up to 20 out
• i.e. 80 kg instead of 100kg and vice versa
• Estimation of height also inaccurate but
  measuring height with tape fairly accurate
• We need to weigh patients in ICU and measure
  height

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Methods of Weighing

• Hoist time consuming, needs several nurses,
  risky for unstable patients or trauma patients
• Weigh beds 16000 each
• Digital bed scales scales for each wheel of
  the bed weighs bed patient, mobile, minimal
  manpower, no disruption to patient

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Methods of Weighing

• Progress since audit
• 2 units have bought weigh beds
• 5 are considering bed scales

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Keeping tubes in

• Sedation
• Stitching
• Posey Mitts
• Nasal Bridles

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Maintaining NG intake

• Follow a protocol
• Gastric residuals do not stop or reduce feed
  until you have 3 residuals of gt250mls (check
  clinical signs) 400mls may be ok
• Starting and stopping feed
• Extubations, fasting for theatre, scans, minor
  procedures
• Can catch up on feed that is missed
• Keep 10mls/hr if possible gut protection

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NJ feed patient use per year
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NJ feeding

• Bypasses the stomach
• Good for high residuals gastroparesis
• High anastomoses
• Nervous surgeon syndrome
• Insertion theatre, bedside, radiology, endoscopy
• May reduce aspiration, will increase feed given
  in selected patients

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Complications

• Ileus trickle of feed may be beneficial
• Avoid opioids, optimise fluid balance and
  electrolytes, consider Neostigmine
• Constipation treat with appropriate drugs
• Diarrhoea exclude infections, optimise fluid
  balance and electrolytes, replace loss
• ??fibre feeds
• Intolerance ? Sepsis, prokinetics, NJ feeding,
  avoid opioids
• Line sepsis - SPSP

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Overfeeding

• Lactic acidosis
• Hyperglycaemia
• Increased infections
• Liver impairment (Alk phos, ALT, GGT, acalculous
  cholecystitis)
• Persistent pyrexia
• Exact requirements calculated by dietitians
  (generally less than in the fit)
• 25kcal/kg/24hours rough guide, 10 in refeeding
  risk

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Refeeding Syndrome

• Prisoners of war 1944-5, 1944 conscientious
  objectors in USA studied
• Starvation early use of glycogen stores for
  amino acids - gluconeogenesis
• 72 hrs fatty acid oxidation use of fatty acids
  and ketones for energy source, low insulin levels
• Atrophy of organs, reduced lean body mass

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Refeeding syndrome

• Carbohydrate feeding shift to CH metabolism
• Insulin release
• Phosphate and potassium shift into cells.
• Magnesium, potassium and phosphate drop
• May get Lactic acidosis
• Sodium and water shift out of cells oedema
• Insulin causes sodium retention
• Protein synthesis needs potassium and phosphate
  - these drop more
• Thiamine deficiency occurs (co-factor in CH
  metabolism) encephalopathy, weakness

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Refeeding Syndrome in ICU

• Unlikely to be a clear diagnosis
• Many effects oedema, arrhythmias, pulmonary
  oedema, cardiac decompensation, respiratory
  weakness, fits, hypotension, leukocyte
  dysfunction, diarrhoea, coma, rhabdomyolysis,
  sudden death
• Screen nutritional history and electrolytes
• Remember in HDU patients/malnourished ward
  patients
• Poor awareness among doctors!

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Risk of re-feeding syndrome

• Two or more of the following
• BMI less than 18.5 kg/m2 (lt16)
• unintentional weight loss greater than 10 within
  the last 3-6 months (gt15)
• little or no nutritional intake for more than 5
  days (gt10)
• Hx alcohol abuse or drugs including insulin,
  chemotherapy, antacids or diuretics
• (Critically low levels of PO42-, K and Mg2)

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Managing refeeding problems

• provide Thiamine (Pabrinex)/multivitamin/trace
  element supplementation
• start nutrition support at 10 kcal/kg/day
• increase levels slowly
• restore circulatory volume
• monitor fluid balance and clinical status
• replace phosphate, magnesium and K
• Reduce feeding rate if problems arise

NICE Guidelines for Nutrition Support in Adults
2006
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Intake in HDU
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Feeding in HDU
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ACTION

• Establish guidelines for feeding
• Identify high-risk patients/refeeding risk
• Aim for oral/NG supplementation in these patients
• Aim to improve fluid administration
• ERAS/Pre-op supplements
• Monitoring of calorific requirements/intake
• Dietitian follow-up to wards

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Immuno-nutrition

• The immune system a complex and interactive
  biological system that coordinates the detection,
  destruction and elimination of any foreign
  material or organism entering the body.
• Oxidants cytokines, NFkB, genes, inflamn
• Nutrients glutamine, FFAs, protein
• Glutathione oxidant defence
• Anti-inflammatory molecules

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THE ICU GAMBLEHow to tip the scales?
LIFE
DISABILITY
Inflammation and resolution
Inflammation, organ failure
DEATH
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Critical Illness

• Small reductions in mortality over years
• Increasing problems with infection
• Advances in treatment have limited effects
• Patho-physiology complex
• The future replacement of the bodys own stress
  substrates
• Disease-modulating nutrients
• Reduce oxidant and metabolic stress
• Favourably modulate immune response

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Glutamine

• Amino acid essential in sepsis/major trauma
• Levels drop after injury, exercise and stress.
  Very low in critical illness first 72 hours
• Vital to gut, immune cells, and kidney
• Serves as metabolic fuel precursor to DNA
  synthesis, decreases inflammation
• Glutamine deficiency at onset of critical
  illness/sepsis correlated with increased
  mortality
• Studies in burns/trauma show improvement
• Big studies in all ICU patients awaited

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PROBIOTICS

• live micro-organisms which when administered in
  adequate amounts confer a health benefit on the
  host

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Probiotics

• Critical illness causes virulence of gut
  bacteria treatment worsens gut function
• Probiotics inhibit growth of pathogenic enteric
  bacteria, eliminate pathogenic toxins
• block epithelial invasion by pathogens
• enhance T-cell and macrophage function
• Potential to cut VAP and C. diff
• BUT safety concerns dose, type,storage
• unforeseen effects more research needed

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Polyunsaturated Fatty Acids
Omega-6 ?-Linoleic acid (GLA) borage oil
Arachidonic Acid precursor Omega-3 Fish oils
Eicosapentanoic acid (EPA) and Docosahexanoic
acid (DHA)
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Dietary Lipids

• Ratios in paleolithic diet ?6?-3 11
• Current Western diet 161
• Current UK PN Soybean oil base 71
• New PN (SMOF) 2.51
• Cell membrane composition depends on balance
• AA, DHA and EPA are present in inflammatory cell
  membrane phospholipids
• Increased ?-3 levels reduce the inflammatory
  response in various ways gene expression, cell
  activity, adhesion molecules, cytokines

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Antioxidants

• Oxidative stress in critically ill patients
  contributes to organ damage / malignant
  inflammation (free radicals, mitochondrial
  damage)
• Glutathione, Vitamins A, C and E
• Zinc, copper, manganese, iron, selenium
• Already added to feeds
• Should we give extra?
• Results of SIGNET and REDOXs awaited

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What is the evidence in ICU?

• Early enteral feeding is best
• Hyper/hypoglycaemia/overfeeding are bad
• Starvation and refeeding are bad
• Nutritional deficit a/w worse outcome
• EN a/w aspiration and VAP
• PN if cant have EN soon if malnourished
• Combination can be used to achieve goals
• Protocols improve delivery of feed
• Some nutrients show promising results