Courtesy of Dr Jason Fletcher and Ms Lauren Ballantyne (ICU dietician) - March 2016

Nutrition in ICU

The provision of adequate energy, protein and nutrients is a key consideration in the care of the critically ill.  The estimated caloric requirements of critically ill patients are:
  1. Energy             25 – 35 kcal /kg
  2. Protein             0.8 – 1.5g / kg

​In order, the preferred routes of nutrition are:
  1. Oral
  2. Enteral
  3. Parenteral

1. Oral feeding

All awake patients should be offered oral nutrition unless there are contraindications.
All uncomplicated planned gastrointestinal surgery (excluding gastro-oesophageal surgery) are to have fluids as tolerated on day zero and diet as tolerated on day one.

2. Enteral feeding

This is the first line route for intubated patients. Most patients will be able to be fed via the enteral route. The only absolute contraindications to enteral feeding are:
  1. Fistula
  2. Fasting for a procedure
  3. Upper GI obstruction
  4. Bowel obstruction or ischaemic bowel
 
Most patients admitted to ICU who need enteral feeding are admitted out of business hours when there is no dietitian available. We aim to commence enteral feeds as soon as possible therefore, there is a guideline to help you commence enteral feeding – Enteral Nutrition Guideline for Intensive Care Unit.
There are a number of feeds available in ICU. These are:
Unless the patient has had recent abdominal surgery or is at high risk of refeeding syndrome (see PROMPT), it is safe to commence enteral feeds at the target rate. Otherwise, start feeds as per Continuous Enteral Feeding Regimen for use in the absence of Dietetic Input In ICU ONLY- Documentation Sheet (see PROMPT).
 
Enteral Feed intolerance
Enteral feed intolerance may be due to:
  1. Gastroparesis, a common scenario in the critically ill.
  2. Ileus
  3. Bowel obstruction
 
Gastroparesis
If gastric residual volume (GRV) > 300ml:
  1. Exclude bowel / gastric outlet obstruction or ileus
  2. Commence prokinetics:
    1. Erythromycin            250mg IV 12-hourly  AND
    2. Metoclopramide        10mg  IV 8-hourly
  3. Review opioid doses if appropriate.
  • Prokinetics do not promote resolution of ileus as their site of action is at the coeliac plexus.
  • Step-down to erythromycin alone or cease prokinetics altogether if GRVs settle (< 300ml).

3. Total Parenteral Nutrition (TPN)

Some patients may not be able to be adequately fed enterally.  Generally, patients who have GIT failure and have not, or will not, tolerate oral and / or enteral feeding for a total of 3 to 7 days will be considered for TPN.  Commencement of TPN is at the discretion of the intensivist.  There is no requirement to start TPN emergently overnight unless directed by the intensivist.  TPN rates are set by the dietitian but out of hours use 1ml/kg/hr up to a maximum of 83ml/hr.

It is important to screen patients for any food allergies that may contraindicate the use of TPN.  The formulation used at Bendigo Health contains fish oil, soya, peanut, corn and egg protein.

See also, Total Parenteral Nutrition (PROMPT) for more information.

Fasting

Fasting is sometimes required before a procedure requiring procedural sedation, anaesthetic, airway manipulation or certain imaging.
 
The fasting regimen for procedures occurring out of ICU (in cath lab or theatre) or for imaging is at the discretion of the proceduralist, anaesthetist or medical imaging guidelines. These will be communicated to you or the ICU nurse.
 
In ICU, patients needing airway manipulation with a nasogastric tube in situ usually do not need to fast as aspirating the NGT can mostly empty the stomach.
  • Prior to extubation - no need to fast, aspirate NGT prior to procedure
  • Prior to percutaneous tracheostomy - no need to fast, aspirate prior to procedure
  • Prior to other ICU procedures - no need to fast
 If in doubt, talk to the intensivist.

Thiamine dosing - patients at risk of Refeeding Syndrome, Alcohol Withdrawal Syndrome or Wernicke's Encephalopathy

Patients at risk of Refeeding Syndrome
  • Loading dose: 300mg IV or oral at least 30 mins prior to commencing feeding, then
  • Maintenance dose: 100mg IV or oral for 5 days 

Patients with/at risk of Alcohol Withdrawal Syndrome OR with/suspected to have Wernicke's Encephalopathy
  • Loading dose: 300mg IV for 5 days, then
  • Maintenance dose: 300mg iv or oral thereafter

Resources

Crit-IQ nutrition                         https://www.crit-iq.com/index.php/Position_Statements
 
Articles
Planned GIT surgery nutrition http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004080.pub2/pdf
 
Clinical practice guidelines 
Canadian Critical Care Nutrition                                          http://www.criticalcarenutrition.com/
European Society for Parenteral and Enteral Nutrition   http://www.espen.org/
American Society for Parenteral and Enteral Nutrition   http://www.nutritioncare.org/