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Nutrition Support Blog: Best Assessment of ICU Malnutrition?

Posted by SF8N at Mar 06, 2015 03:12 PM |
Nutrition Support Blog: Best Assessment of ICU Malnutrition?

by Joe Krenitsky, MS, RDN

March 6, 2015 

I recently wrote about new research and technology that may allow us to quantify muscle loss or gain as a marker of nutrition in the ICU.

Measuring Malnutrition in the ICU, Feb. 2, 2015

While I am convinced that measurements of muscle mass would be a valuable part of our assessment in the ICU, the role of muscle as a sole indicator of nutrition status remains a minefield of controversy because muscle mass is not always directly linked with nutritional adequacy.  If a healthy active adult was sedated, ventilated and bedbound for 10 days, they would lose muscle mass due to inactivity, even if we fed them at 150% of their calorie, protein and micronutrient needs for the entire time.  Would we really consider them “malnourished” after this experiment?  Similarly, we see patients with neuromuscular disorders, malignant disease or severe-heart failure lose muscle and functional status even in the face of full nutrition.

Undoubtedly, inadequate nutritional intake will accelerate lean muscle losses caused by metabolic stress and catabolic conditions, and it seems to me that any assessment of nutrition status should consider recent calorie/protein adequacy as part of our assessment.  A recent study reported that Subjective Global Assessment (SGA) was not a sensitive indicator of patients with severe muscle wasting, as measured by CT-scan.1  Interestingly, SGA may have actually been a better indicator of patient outcome compared to sarcopenia alone.2  Sarcopenia and functional status are important considerations, but it is not clear that they are the only considerations. 

I suspect that in the adult ICU, cumulative deficit of protein and calories over time may be one of the best indicators of nutrition.  A proper nutrition picture would include cumulative calorie/protein deficit, lean muscle loss, functional status (where possible), nutrition status on admission, severity of illness with wound/skin status and consideration of the patient’s current clinical trajectory. To date, no one has been able to devise a single, objective, repeatable measure of this type of overall nutrition assessment. Come to think of it, considering that this type of complete nutritional assessment is the very essence of my, and every other nutrition support practitioner’s “day job,” that is probable OK with me.


1.   Sheean PM, Peterson SJ, Gomez et al.  The prevalence of sarcopenia in patients with respiratory failure classified as normally nourished using computed tomography and subjective global assessment.  JPEN 2014 Sep;38(7):873-879.

2.   Jeejeebhoy K. Subjective Global Assessment versus Sarcopenia Detected by Computed Tomography. JPEN 2015 Mar;39(3):271. 

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