nutrition in the critically ill amie kershaw critical care dietitian manchester royal infirmary
TRANSCRIPT
OverviewMalnutrition
Aims of nutrition support
Nutritional requirements
Nutrition support
Potential complications
Developing areas
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 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)
Consequences of malnutrition
Weight loss
Weakness and fatigue
Impaired ventilatory drive DEATH
Depression / apathy Poor wound healing
Impaired immune functionWebb (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
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 RequirementsEnergy
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 >60yrs and 35ml/kg for < 60yrs
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)
Enteral feeding“If 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)
Common feeds used on ICUType 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 restrictionRenal 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
Indications for Parenteral Nutrition
Long term:
Inflammatory bowel disease Radiation enteritis Motility disorders Extreme short bowel syndrome Chronic malabsorption
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
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
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
“Severe fluid and electrolyte shifts and related metabolic complications in
malnourished patients undergoing refeeding.”
Solomon &Kirby (1990)
Refeeding Syndrome
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 breakdownCatabolism of fat and muscle loss of lean
body mass, water and minerals
Refeeding Syndrome
During refeeding Switch from fat to carbohydrate metabolism Insulin release stimulated by glucose load cellular glucose, phosphorus, potassium
and water uptakeExtracellular depletion of phosphate,
potassium, magnesiumClinical symptoms
Clinical SymptomsElectrolytes 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
Clinical SymptomsElectrolytes 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
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
Immunonutrition
Potential to modulate the activity of the immune system by interventions with
specific nutrients
ImmunonutritionNutrients 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 – support immune cell functions.
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