Nutrition in the critically ill

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Nutrition in the critically ill

• Amie Kershaw
• Critical Care Dietitian
• Manchester Royal Infirmary

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Overview

• Malnutrition
• Aims of nutrition support
• Nutritional requirements
• Nutrition support
• Potential complications
• Developing areas

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Malnutrition in hospital
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What is malnutrition?

• Malnutrition is a state of nutrition in which a
  deficiency or excess (or imbalance) of energy,
  protein and other nutrients cause measurable
  adverse effects on tissue/body form (body shape,
  size and composition) function and clinical
  outcome.

Elia, (2000)
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Definition of malnutrition

• A body mass index (BMI) lt18.5kg/m
• Unintentional weight loss gt10 in 3 6 months
• A BMI lt20kg/m and unintentional weight loss gt5
  in 3 6 months

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Why does malnutrition develop?

• Impaired intake
• Impaired digestion and absorption
• Altered nutritional requirements
• Excess nutrient losses

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Malnutrition

• Many people are malnourished prior to admission
  to hospital
• People in hospital are at risk of becoming
  malnourished or further malnourished
• Prevalence of malnutrition in hospital has been
  quoted as 40 (McWhirter Pennington, 1994)
• Up to 43 of patients in ICU are malnourished
  (Giner et al, 1996)

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Consequences of malnutrition

• Weight loss
• Weakness and fatigue
• Impaired ventilatory drive
• ? DEATH
• Depression / apathy
• Poor wound healing
• Impaired immune function
• Webb (1999), Garrad (1996)

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Nutritional Screening why?

• Government initiatives recommendations
• 2003 Food, Fluid and Nutritional Care (NHS
  Quality Improvement, Scotland)
• 2002 Nutrition and Catering Framework (Welsh
  Assembly Government)
• 2001 NSF for Older People (DH)
• 2001 Essence of Care (DH)
• 2006 Nice Guidelines

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Malnutrition Universal Screening Tool (MUST)

• Anticipate/prevent malnutrition
• Confirm malnutrition
• To facilitate planning of appropriate nutritional
  support
• To act as a method of monitoring progress
• Takes into account the past, present and future
• Can be used across a variety of settings

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MUST

• To be completed for each patient on admission and
  rescreen weekly (or more often if indicated)
• ACTION to be taken according to the high, medium
  or low risk score
• Completed assessment forms to be kept with
  patient documentation

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Nutrition Support
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Why feed the critically ill?

• Provide nutritional substrates to meet protein
  and energy requirements
• Help protect vital organs and reduce break down
  of skeletal muscle
• To provide nutrients needed for repair and
  healing of wounds and injuries
• To maintain gut barrier function
• To modulate stress response and improve outcome

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Nutritional Requirements

• Energy
• Calculation of basal metabolic rate with
  additional factors for
• Stress
• Activity
• Energy required to metabolise food (diet induced
  thermogenesis)
• Protein
• Typically 0.8 1g protein/kg, increased
  during stress
• Fluid
• 30ml/kg for gt60yrs and 35ml/kg for lt 60yrs

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Metabolic consequences of overfeeding

• Hyperlipidemia (increased fat levels in the
  blood)
• Azotemia (increased urea)
• Hyperglycaemia (high blood sugar levels)

• Fluid overload
• Hepatic dysfunction (abnormal liver function
  tests, fatty deposits in the liver)
• Excess CO2 production
• Respiratory compromise

Klein (1998)
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Enteral feedingIf the gut works use it

• Nasogastric (NG)
• Nasojejunal (NJ)
• Percutaneous Endoscopic Gastrostomy (PEG)
• Percutaneous Endoscopic Jejunostomy (PEJ)
• Radiologically Inserted Gastrostomy (RIG)
• Surgical Gastrostomy
• Surgical Jejunostomy (JEJ)

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Common feeds used on ICU
Type of feed Features Uses
Standard / multifibre 1kcal/ml Most patients
Energy / energy multifibre 1.5kcal/ml Increased requirements Fluid restriction
Concentrated 2kcal/ml Low electrolytes (i.e. Potassium, phosphate) Fluid restriction Renal with high blood electrolytes
Oxepa 1.5kcal/ml High fat omega-3 fats High antioxidants (vitamins) ARDS 1 study
Low sodium 1kcal/ml Low in salt intracranial hypertension
Peptisorb Predigested malabsorption
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Indications for Parenteral Nutrition

• Short term
• Severe pancreatitis
• Mucositis post-chemo with intolerance of enteral
  nutrition
• Gut failure
• Prolonged nil by mouth (NBM) post major
  excisional surgery
• High output or enterocutaneous fistula
• Intractable vomiting
• Malnourished patient unable to establish enteral
  nutrition

• Long term
• Inflammatory bowel disease
• Radiation enteritis
• Motility disorders
• Extreme short bowel syndrome
• Chronic malabsorption

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• Complications of Nutrition Support

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Prokinetics - Gut motility medication

• Indication for use Possible causes
• - High gastric aspirates - Medications
• - Gut failure
• - Diabetic stasis
• Prokinetics of choice
• - Metoclopramide
• - Erythromycin
• - Major cause of underfeeding

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Diarrhoea

• Nosocomial (hospital acquired)
• Non-infectious causes
• medications
• sorbitol, magnesium salt containing
• antibiotics 5 30 incidence (McFarland)
• feed malabsorption, faecal impaction, low albumin
  - not major risk factors
• Fibre in EN - a combination of soluble
  insoluble fibre
• ? colonic blood flow, promote sodium water
  retention and therefore may help control diarrhoea

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Refeeding Syndrome

• Severe fluid and electrolyte shifts and related
  metabolic complications in malnourished patients
  undergoing refeeding.
• Solomon Kirby (1990)

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Refeeding Syndrome

• During starvation
• Insulin concentrations decrease and glucagon
  levels rise
• Glycogen stores rapidly converted to glucose
• Gluconeogenesis activated glucose synthesis
  from protein and lipid breakdown
• Catabolism of fat and muscle ? loss of lean body
  mass, water and minerals

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Refeeding Syndrome

• During refeeding
• Switch from fat to carbohydrate metabolism
• Insulin release stimulated by glucose load
• ? cellular glucose, phosphorus, potassium and
  water uptake
• Extracellular depletion of phosphate, potassium,
  magnesium
• Clinical symptoms

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Clinical Symptoms
Electrolytes Cardiac Respiratory Hepatic Renal
Low phosphorus Altered myocardial function Arrhythmia CHF Acute ventilatory drive Liver dysfunction
Low potassium Arrhythmia Cardiac arrest Respiratory depression Exacerbation of hepatic encephalopathy Polyuria Polydipsia Decreased GFR
Low magnesium Arrhythmia Tachycardia Respiratory depression
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Clinical Symptoms
Electrolytes GI Neuromuscular Haematologic
Low phosphorus Lethargy, weakness, seizures, coma, confusion, paralysis, rhabdomyolysis Haemolytic anaemia, WBC dysfunction, thrombocytopenia
Low potassium Constipation Ileus Paralysis, rhabdomyolysis
Low magnesium Abdo pain Anorexia Diarrhoea Constipation Ataxia Confusion Muscle tremors Weakness Tetany
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Who is at risk?

• NICE guidelines (2006)
• Some risk
• People who have eaten little or nothing for more
  than 5 days

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Who is at risk?

• High risk
• One or more of the following
• - BMI lt 16kg/m
• - unintentional weight loss gt 15 in last 3
  6 months
• - Little or no nutritional intake for
  gt10days
• - Low levels of potassium, phosphate or
  magnesium prior to feeding

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Who is at risk?

• High risk
• Two or more of the following
• - BMI lt 18.5kg/m
• - Unintentional weight loss gt 10 in last 3
  6 months
• - Little or no nutritional intake for more
  than 5 days
• - History of alcohol abuse or drugs insulin,
  chemotherapy, antacids or diuretics

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Managing refeeding syndrome

• Consider Pabrinex (high dose thiamine) and
  balanced multivitamin/mineral supplement
• Feed cautiously 10kcal/kg for first 2 days,
  5kcal/kg in extreme cases (dietitian will
  advise). Increase slowly (over 4 -7 days)
• Monitor biochemistry regularly including
  phosphate, magnesium and potassium correcting low
  levels as necessary

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• Developments in
• Nutrition Support

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Immunonutrition

• Potential to modulate the activity of the immune
  system by interventions with specific nutrients

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Immunonutrition

• Nutrients most often studied
• Arginine - can enhance wound healing and improve
  immune function. Conditionally essential amino
  acid.
• Glutamine Precursor for rapidly dividing immune
  cells, thus aiding in immune function.
  Conditionally essential.
• Branched chain amino acids support immune cell
  functions.
• Omega 3 fatty acids lowers magnitude of
  inflammatory response, modulate immune response.

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Immunonutrition

• Espen guidelines (2006)
• Immune modulating formula beneficial in the
  following patient groups
• - upper GI surgery
• - mild sepsis
• - trauma
• If unable to tolerate lt700ml/d immune modulating
  formula should be stopped.
• Not recommended for routine use in ICU patients

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Immunonutrition

• Espen Guidelines (2006)
• Glutamine should be added to a standard enteral
  formula in burned and trauma patients
• Insufficient data to support enteral glutamine
  supplementation in surgical or heterogeneous
  critically ill patients