Nutrition in the critically ill
Amie Kershaw
Critical Care Dietitian
Manchester Royal Infirmary
Overview
 Malnutrition
 Aims of nutrition support
 Nutritional requirements
 Nutrition support
 Potential complications
 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
 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 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:
 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 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
Fluid restriction
Low electrolytes (i.e.
Renal with high blood
Potassium, phosphate)
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
Short term:
Long 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





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
 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
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  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 uptake
 Extracellular depletion of phosphate,
potassium, magnesium
 Clinical symptoms
Clinical Symptoms
Electrolytes
Cardiac
Respiratory Hepatic
Low
Altered
phosphorus myocardial
function
Arrhythmia
CHF
Acute
ventilatory
drive
Low
potassium
Arrhythmia
Cardiac
arrest
Respiratory Exacerbation
depression of hepatic
encephalopat
hy
Low
magnesium
Arrhythmia
Tachycardia
Respiratory
depression
Renal
Liver
dysfunction
Polyuria
Polydipsia
Decrease
d GFR
Clinical Symptoms
Electrolytes
GI
Low
phosphorus
Neuromuscular
Haematologic
Lethargy,
weakness,
seizures, coma,
confusion,
paralysis,
rhabdomyolysis
Haemolytic
anaemia, WBC
dysfunction,
thrombocytope
nia
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
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 – 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
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