University of Virginia Nutrition
Summer vacations and article deadlines have delayed our June edition. We had a wonderful June traineeship and hosted trainees from Elkhart Indiana , Omaha Nebraska , and Hyannis Massachusetts . We will not have a traineeship this July, so now that we are “recharged” (or is that recovered) from vacation we will post this edition, and plan our next e-journal club for September.
Our article this month was on immunonutrition, which is a topic that tends to lend itself to some very animated discussions around here……
June Citation (and editorial):
- Hans Kieft, Arnout N. Roos, Jenneke D. E. van Drunen, et al. Clinical outcome of immunonutrition in a heterogeneous intensive care population Intensive Care Medicine 2005;31(4):524 – 532.
- Immunonutrition in the critically ill: from old approaches to new paradigms pp. 501 - 503 Daren Heyland and Rupinder Dhaliwal
Study Question (s):
Does an “immunonutrition” enteral formula improve clinical outcome in an ICU population compared to an isocaloric “standard” feeding formula.
Prospective, randomized, double-blind study in a heterogeneous population in 2 general intensive care units – all patients expected to receive enteral nutrition more than 2 days were eligible. Initially 597 patients were randomized, and ultimately 473 patients completed the protocol – 241 control formula and 232 immunonutrition (IMN). Feeding goals were based on Harris-Benedict + stress factors and the goal was to begin enteral nutrition within 48 hours of admission to the ICU. The primary outcome was ICU length-of-stay, and the secondary outcomes were ICU mortality, in-hospital mortality, 28-day mortality, hospital length of stay (LOS), complication rate, and duration of ventilation.
IMN = Stresson Multifibre – 9gm arginine, 13 gm glutamine, 0.8gm EPA, 0.3gm DHA per liter.
There were no significant differences between the IMN and control groups in either the primary or secondary outcomes. The authors did subgroup analysis of surgical vs. nonsurgical, and moderately vs. severely sick patients, but did not find a significant difference in any outcome measure. The authors also performed a post-hoc subgroup analysis by gender and found that the female patients who received the IMN formula had significantly increased rate of infectious complications (53.33 vs. control 35.8%, p = 0.029) and increased hospital LOS (median 42.0 vs. control 26.0 days, p = 0.021).
This is a well-designed study – it is randomized and double-blind, and it is the largest immunonutrition study in a heterogeneous ICU population. All of the patients appear to be accounted for, and analysis was completed on both intention to treat and per-protocol basis.
However, there are some limitations to this study. One limitation is that we do not know how many of the patients received the feedings for only a few days. The minimum time was 2 days, so it is possible that some patients only received enteral feeding for 2-4 days, and the first 2 days they were advancing the formula so there was not adequate formula received, or time to see any difference. The amount of nutrition that was actually provided was low- about 1300 kcals/day.
One point that was raised is that there is limited knowledge about the effect of individual components (arginine, glutamine, fish oils, antioxidants) in immunonutrition formulas. It would not be correct to conclude that just because one immunonutrition formula did not have beneficial effects, that this was necessarily an indictment of all immunonutrition formulas.
Take home message:
Overall this is an excellent study, and our conclusion was that this is sufficient evidence to conclude that Stresson multi fibre did not have beneficial effect on clinical outcomes compared to standard feedings in a heterogeneous ICU population.
- Check out the latest Practical Gastroenterology articles available at:
And editorial that follows:
"Read, every day, something no one else is reading. Think, every
day, something no one else is thinking. Do, every day, something no one
else would be silly enough to do. It is bad for the mind to continually
be part of unanimity."
Joe Krenitsky MS, RD
Carol Parrish RD, MS
PS – Please feel free to forward this on to friends and colleagues.