june2007jc.html

University of Virginia Health System

Nutrition Support E-Journal Club

June 2007

Greetings,

June has been a whirlwind of activity.  Vacations, kids out of school, arrival of new physicians, and a class of dietetic interns preparing to graduate...but the journal club must go on!

June Citation: 

Hise ME, Halterman K, Gajewski BJ, et al.  Feeding practices of severely ill intensive care unit patients: an evaluation of energy sources and clinical outcomes.  JADA 2007;107:458-465.

Summary: 

This was a prospective observational study of 77 medical and surgical patients admitted to an ICU with an anticipated stay of at least 5 days.  The investigators recorded the amount of enteral (EN) and/or parenteral nutrition (PN) (IV dextrose and propofol were also accounted for) that was actually provided to the patient and compared it to the recommendations of the registered dietitian (RD).  The researchers compared the mean percent of the calorie goal and the net energy balance to survival, ICU length of stay and total hospital length of stay.

There were no pre-determined protocols for calorie goals or the start and advancement of feedings.  The dietitians provided individualized assessments with a commonly used goal of 25-35 calories/kg.

Inclusion and Exclusion Criteria were:

Anticipated ICU length of stay of at least 5 day. Patients were excluded if they were discharged from the ICU within 5 days of admission or if they were able to begin an oral diet in the ICU in < 5 days (?).

Major Results reported by authors:

Nutrition support was initiated significantly sooner in the medical ICU patients compared to the surgical ICU (2.6 [range 1-6] days versus 3.9 [range 1-10] days, respectively p = 0.005).  One patient in the medical ICU and 7 patients in the surgical ICU did not receive any nutrition support.  Use of EN versus PN was similar between the ICUs.  PN was provided to 12 medical (33%) and 10 surgical (24%) ICU patients; EN was provided to 32 medical (89%) and 30 surgical (73%) ICU patients.

There was no significant difference in mean percent of nutrition goal between the medical and surgical ICU (50 versus 56% respectively), but both units had a negative cumulative energy balance -11,327 +/- 5952 (SICU) and - 8,675 +/- 6099 (MICU) (p = 0.058).  When the cumulative energy balance was normalized to length of ICU stay there was a significantly larger negative energy balance in the SICU patients (- 1045 +/- 562) vs. MICU (-784 +/- 390, p= 0.0195).

Patients that received > 82% of their nutrition needs had a significantly longer ICU stay than those that received < 82% (24 vs 12 days respectively).  Those patients that received > 81% of their nutrition needs had a significantly longer hospital length of stay than those that received < 81% of nutrition needs (47 vs 22 days respectively).

The investigators also reported that patients receiving at least 82% of their nutrition needs obtained a significantly greater percentage of PN than those that received less than 81% of goal calories (66.7% vs 18.5% respectively).

Author's Conclusions:

The authors concluded that many ICU patients received insufficient feeding, compared to the RD recommendations.  Medical ICU patients received earlier nutrition support, more EN, and fewer calories from intravenous fluids and lipid-based sedatives (propofol).

The authors also concluded that based on length of stay, the most severely ill patients may not benefit from delivery of full nutrient needs in the ICU.

Evaluation:

We applaud our colleagues for undertaking this kind of study.  This study presents valuable information, but it must be remembered that it is an observational study.  Observational studies document associations, and are extremely valuable to form theories for randomized studies, but they should never be used to imply cause and effect.  The author's state that the data suggest that the most severely ill patient may not benefit from delivery of full nutrient needs in the ICU because the patients that received more nutrition had a longer ICU and hospital stay.  However, just because full feeding and longer stay are associated, there is no evidence that one caused the other.  Another way to state the findings of this study is that those patients with a longer stay are more likely to receive full feedings.

In addition, the group with the longer stay also received a greater percentage of their needs from PN; the number of patients fed at least 81 or 82% of their needs was very small (n = 9, n = 10, respectively).  Glucose control, nor total lipid content from all sources (propofol and PN) were not monitored or controlled for.

Despite these limitations, it is important to recognize that there is very limited data that patients in the ICU require, or benefit from, feedings that match their calorie expenditure.  This study adds to the retrospective and observational data that IS available suggesting that feeding a patient within 10% of their resting energy expenditure may actually be detrimental (which begs the question, "why advocate and discuss ad nauseum a longer formula for calculating needs without any outcome data what-so-ever?).

Our Take home message: 

This study provides further support for the need of a randomized study that will investigate the level of calories (for Dr. Koretz: vs. if any...) that will result in the best outcome for critically ill patients. 

Other News:

Check out the latest Practical Gastroenterology articles/info at: http://www.uvadigestivehealth.org/ .  Scroll down to GI Nutrition on the far left column and click on link.  This leads to a pull down menu with links within the GI nutrition site including the Nutrition Articles in Practical Gastroenterology.  May's articles are:

  • Obrero T. Management of Dialysis Patients With Celiac Disease.  Practical Gastroenterology 2007;XXXI(6):70.
  • Duro D, Duggan C.  The Brat Diet.  Practical Gastroenterology 2007;XXXI(6):60.

 

Joe Krenitsky MS, RD

Carol Parrish RD, MS

PS - Please feel free to forward this on to friends and colleagues.