Nutrition in the critically ill

Amie Kershaw Critical Care Dietitian Manchester Royal Infirmary

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Malnutrition

Overview

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Aims of nutrition support

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Nutritional requirements

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Nutrition support

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Potential complications

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Developing areas

Malnutrition in hospital

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)

Definition of malnutrition

 A body mass index (BMI) <18.5kg/m  Unintentional weight loss >10% in 3 – 6 months  A BMI <20kg/m and unintentional weight loss >5% in 3 – 6 months

Why does malnutrition develop?

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

Malnutrition

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Many people are malnourished prior to admission to hospital

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People in hospital are at risk of becoming malnourished or further malnourished

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Prevalence of malnutrition in hospital has been quoted as 40% (McWhirter & Pennington, 1994)

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Up to 43% of patients in ICU are malnourished (Giner et al, 1996)

Consequences of malnutrition

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Weight loss

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Weakness and fatigue

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Impaired ventilatory drive

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DEATH

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Depression / apathy

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Poor wound healing

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Impaired immune function

Webb (1999), Garrad (1996)

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

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

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

Nutrition Support

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

Nutritional Requirements

Energy Calculation of basal metabolic rate with additional factors for:

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Stress Activity Energy required to metabolise food (diet induced thermogenesis) Protein Typically 0.8 – 1g protein/kg, increased during stress Fluid 30ml/kg for >60yrs and 35ml/kg for < 60yrs

Metabolic consequences of overfeeding

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Hyperlipidemia (increased fat levels in the blood)

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Azotemia (increased urea)

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Fluid overload

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Hepatic dysfunction (abnormal liver function tests, fatty deposits in the liver)

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Excess CO 2 production

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Hyperglycaemia (high blood sugar levels)

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Respiratory compromise

Klein (1998)

Enteral feeding

“If the gut works – use it” 

Nasogastric (NG)

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Nasojejunal (NJ)

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Percutaneous Endoscopic Gastrostomy (PEG)

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Percutaneous Endoscopic Jejunostomy (PEJ)

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Radiologically Inserted Gastrostomy (RIG)

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Surgical Gastrostomy

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Surgical Jejunostomy (JEJ)

Common feeds used on ICU

Type of feed Standard / multifibre Energy / energy multifibre Concentrated Oxepa Low sodium Peptisorb Features 1kcal/ml Uses

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Most patients 1.5kcal/ml 2kcal/ml Low electrolytes (i.e. Potassium, phosphate)

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Increased requirements

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Fluid restriction

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Fluid restriction

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Renal with high blood electrolytes

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ARDS – 1 study 1.5kcal/ml High fat – omega-3 fats High antioxidants (vitamins) 1kcal/ml Low in salt Predigested

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intracranial hypertension malabsorption

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

Complications of Nutrition Support

Prokinetics

- Gut motility medication Indication for use

- High gastric aspirates

Possible causes

- Medications - Gut failure - Diabetic stasis

Prokinetics of choice

- Metoclopramide - Erythromycin - Major cause of underfeeding

Diarrhoea

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Nosocomial (hospital acquired)

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Non-infectious causes:

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medications

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sorbitol, magnesium salt containing

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antibiotics – 5 – 30% incidence (McFarland)

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feed malabsorption, faecal impaction, low albumin - not major risk factors Fibre in EN - a combination of soluble & insoluble fibre

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colonic blood flow, promote sodium & water retention and therefore may help control diarrhoea

Refeeding Syndrome

 “Severe fluid and electrolyte shifts and related metabolic complications in malnourished patients undergoing refeeding.” Solomon &Kirby (1990)

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  body mass, water and minerals loss of lean

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

Electrolytes

Clinical Symptoms

Cardiac Respiratory Hepatic Renal Low phosphorus Low potassium Altered myocardial function Arrhythmia CHF Arrhythmia Cardiac arrest Low magnesium Arrhythmia Tachycardia Acute ventilatory drive Liver dysfunction Respiratory depression Exacerbation of hepatic encephalopat hy Polyuria Polydipsia Decrease d GFR Respiratory depression

Electrolytes Low phosphorus Low potassium Low magnesium

Clinical Symptoms

GI Constipation Ileus Abdo pain Anorexia Diarrhoea Constipation Neuromuscular Lethargy, weakness, seizures, coma, confusion, paralysis, rhabdomyolysis Paralysis, rhabdomyolysis Ataxia Confusion Muscle tremors Weakness Tetany Haematologic Haemolytic anaemia, WBC dysfunction, thrombocytope nia

Who is at risk?

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

Who is at risk?

High risk:  One or more of the following: - BMI < 16kg/m - unintentional weight loss > 15% in last 3 – 6 months - Little or no nutritional intake for >10days - Low levels of potassium, phosphate or magnesium prior to feeding

Who is at risk?

High risk:  Two or more of the following: - BMI < 18.5kg/m - Unintentional weight loss > 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

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

Developments in Nutrition Support

Immunonutrition

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

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 acid’s cell functions.

– support immune Omega 3 fatty acids – lowers magnitude of inflammatory response, modulate immune response.

Immunonutrition

Espen guidelines (2006):  Immune modulating formula beneficial in the following patient groups: - upper GI surgery - mild sepsis - trauma  If unable to tolerate <700ml/d immune modulating formula should be stopped.

 Not recommended for routine use in ICU patients

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