A 76-year-old male is admitted to the ICU with acute lung injury causing respiratory failure, secondary to acute pancreatitis.

a) Outline how you would establish enteral nutrition in this patient, including in the answer your nutritional targets.

b) List the complications that need to be considered with the use of enteral nutrition.

c) When might you consider parenteral nutrition?

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College Answer

a)
Access: Nasojejunal tube although nasogastric (appears safe and well tolerated)
Any reasonable approach OK

1) Determine target rate for enteral nutrition, commencing 30ml/hour and increasing as tolerated and
delivered as a continuous infusion to maximise chances of achieving nutritional target rates.

2) Prokinetics could be considered if large aspirates are experienced. A feeding protocol should be
utilised to maximise the chances of achieving nutritional target rates.

3) Nutritional targets in the critically ill can be determined by either indirect calorimetry, predictive
equations (e.g.: Harris-Benedict equation) or simplistic formulae (25-30kcal/kg/day) with at least 1.2-
2g/kg/day of protein.

b)

1) Tube complications

  • Misplacement: Pneumothorax, inadvertent pulmonary infusion
  • Sinusitis
  • Pressure areas on nose/lip
  • Trauma to nasopharynx, oesophagus, stomach and haemorrhage

2) Feed complications

  • Inadequate caloric intake from gastric stasis
  • Diarrhoea
  • Ventilator associated pneumonia
  • Aspiration
  • Electrolyte abnormalities
  • Hyperglycaemia

c)
Despite following a rigorous enteral feeding protocol, there is inadequate caloric intake after five
days. Combined enteral and parenteral nutrition to meet targets may be beneficial.
NEJM article June 2011 comparing early (day 2) with late (day 8) TPN in ICU patients not meeting
nutritional targets with EN showed better outcomes in late TPN group

Discussion

a) Outline how you would establish enteral nutrition in this patient, including in the answer your nutritional targets.

For this, the candidate could fall back on either the ASPEN guidelines (2009) or the ESPEN guidelines (2002).

A comparison of these guidelines is offered below.

A Comparison of Nutrition Guidelines for Severe Acute Pancreatitis

ASPEN guidelines

  • For mild or moderate pancreatitis:
    • It is safe to fast these people for up to 7 days! They "... do not require nutrition support therapy (unless ... there is failure to advance to oral diet within 7 days)" - pp. 207
  • For severe pancreatitis:
    • Enteral (nasogastric) feeding should commence as soon as initial resuscitation is complete.
    • Feed tolerance may be enhanced by the following measures:
      • Early enteral nutrition (to minimise ileus)
      • Pushing the NGT distally (into the jejunum) -  it doesn't seem to matter in terms of pain or pancreatitis severity, but feed tolerance may improve
      • Changing to elemental feeds (small peptides, medium-chain triglycerides)
      • Using continuous infusion rather than bolus feeding
    • TPN should not be initiated until after you have made a solid attempt with enteral nutrition for at least 5 days, i.e. when it is obvious that there is profound enteral feed intolerance in spite of various "tolerance-enhancing " measures.

ESPEN guidelines :

  • For mild or moderate pancreatitis:
    • "There is no evidence that either enteral or parenteral nutrition has a beneficial effect on clinical outcome"
  • For severe pancreatitis:
    • Enteral feeding should be attempted in all patients
    • Nutritional requirements should be:
      • 25-35 kcal/kg of total body weight per day
      • 1.2 to 1.5g/kg of protein
      • 3-6g/kg of carbohydrate
      • go easy on the lipiuds (up to 2g/kg)
    • Start feeding via a jejunal tube (remember, this is a 2002 statement)
    • If enteral nutrition is poorly tolerated and caloric goals are not being achieved, add some TPN but keep going with small-volume or elemental enteral feeding

The college seems to be using generic guidelines for nutrition in the critically ill in their answer, rather than any specific pancreatitis guidelines. "Any reasonable approach OK".

As far as specific guidelines go, apart from the elderly 2002 ESPEN position and the somewhat less elederly 2009 ASPEN statement, we can turn to the  2012 "International consensus guidelines for nutrition therapy in pancreatitis."

In summary, these guidelines make the following recommendations:

  • For mild or moderate pancreatitis:
    • Fast for the first 3-4 days
    • Advance to normal diet after this
    • Only progress to enteral nutrition of the patient has been fasted for 5-7 days
  • For severe pancreatitis:
    • EN is preferable to PN
    • Tube position does not matter (gastric vs jejunal)
    • Elemental feeds are preferred
    • Nutritional requirements are 25-35kcal/kg/day, and 1.2-1.5g/kg/day of protein
    • When to use parentral nutrition? These guidelines are much less prescriptive than previous statements. "when EN is contraindicated or not well tolerated", they say.

b) List the complications that need to be considered with the use of enteral nutrition.

Complications of enteral nutrition are well describe in a chapter from the "Required reading" section.
In brief, the complications are:

  • Aspiration
  • Diarrhoea
  • Constipation
  • Dehydration
  • Malnutrition (owing to intolerance)
  • Complications relating to the feeding tube:
    • Poor placement, eg. into the lung
    • Oesophageal or gastric perforation
    • Increased tendency towards gastro-oesophageal reflux
    • Pressure areas due to prolonged tube dwell time (eg. pressure on the nares)
    • Sinusitis (for nasal tubes)
    • Poor oral hygiene( for oral tubes)
    • Oesophageal stricture
    • Discomfort in the awake patient

c) When might you consider parenteral nutrition?

The college refer to a certain 2011 NEJM study, which I assume is the "early vs late PN" trial by Casaer et al. "Late initiation of parenteral nutrition was associated with faster recovery and fewer complications", they said. Of course, that is not a study which regarded pancreatitis specifically.

The ASPEN guidelines recommend you wait for 5 days of good-quality EN trials before you resort to TPN. Both ASPEN and ESPEN recommend the addition of TPN if it is clear that nutritional goals are not being met. The 2012 international guidelines recommend PN "when EN is contraindicated or not well tolerated".

References

Casaer, Michael P., et al. "Early versus late parenteral nutrition in critically ill adults." N Engl J Med 365.6 (2011): 506-517.

ASPEN guidelines

Specifically, section K of the 2009 statement

ESPEN guidelines :
specifically,
MACFIE, J., and ESPEN CONSENSUS GROUP. "ESPEN guidelines on nutrition in acute pancreatitis." Clinical Nutrition 21.2 (2002): 173-183.

Mirtallo, Jay M., et al. "International consensus guidelines for nutrition therapy in pancreatitis." Journal of Parenteral and Enteral Nutrition (2012): 0148607112440823.