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Home > Clinical Nutrition Services > Inpatient Clinical Nutrition Services > Digestive Health > Nutrition Support Team Blog > Nutrition Support Blog: Muscle Loss and Gain in the ICU

Nutrition Support Blog: Muscle Loss and Gain in the ICU

Posted by SF8N at Sep 16, 2014 04:20 PM |
September 16, 2014
Nutrition Support Blog:  Muscle Loss and Gain in the ICU

by Joe Krenitsky, MS, RD

It is now more than 30 years since I started my quest to understand the workings of anabolism and catabolism in the human body.  My initial motivation for avidly reading everything I could find about muscle loss and gain was more mercenary than medical, since I was originally seeking to optimize my own sports performance.  At the time there was very little solid research that applied directly to athletes, so I read everything from old CIBA* endocrine illustrated guides, to all of the early branched-chain, glutamine and parenteral nutrition studies.  Although early on I was convinced I would never, ever work in a hospital, I was unintentionally developing a solid foundation for nutrition support in the ICU.

Attention to nutrition support can reduce muscle losses, and support anabolism once patients enter the rehabilitation phase of their illness. Unfortunately, the process of rebuilding muscle loss is slow: some patients such as those with recurrent stressors, or prolonged systemic corticosteroids seem to never enter an anabolic phase.

I ultimately had to accept the research and realities that nutritional manipulations have a limit to their effect on whole body and muscle protein metabolism.  Especially in older patients and those with extended admissions where physical activity is not possible, the idea of modulation of the endocrine system along with good nutrition support is an attractive idea.  To me, it seemed like a “slam-dunk” that improving nitrogen balance and revving-up protein synthesis would be a good thing in patients with failure to thrive in the ICU.  However, early enthusiasm for growth hormone1 was replaced with caution when randomized studies revealed that growth hormone increased mortality in some populations2.  The anabolic steroid Oxandrolone improved nitrogen balance, but may delay ventilator weaning and increase ICU stay – without any apparent overall benefit in surgical patients3.  Oxandrolone also did not help pressure ulcer healing, but did increase liver enzymes in patients with spinal cord injury4

These studies are a great example of why we need to do randomized studies before breaking out interventions that look like a no-brainer to use (“Don’t believe everything you think”).  There is still ongoing debate about the potential role of anabolic agents in the adult ICU because it may be that that these agents need to be used at the right time, or just in the right population.  Patients with burn injury do seem to benefit from oxandrolone use5.  Additionally, the studies of growth hormone were done without “modern” ICU glucose control.

New drugs are also on the horizon.  Agents such as selective androgen receptor modulators (SARMs) can reverse muscle wasting and osteoporosis with much less impact on the liver, prostate in men, or masculinizing effects in women.  One SARM just completed phase 3 testing in patients with non-small-cell lung cancer undergoing chemotherapy6.   Obviously, more research will be required before we see any new anabolic agents in the ICU, but it is nice to know that we may have light at the end of the tunnel for helping nourish those difficult cases.

 

*Chemische Industrie Basel, re-named with the acronym, CIBA in 1945, merged with J. R. Geigy Ltd in 1971 to become Ciba-Geigy, merged with Sandoz to become Novartis in 1996.

 

“…Wherever they's a fight so hungry people can eat, I'll be there….”

       - John Steinbeck, The Grapes of Wrath, 1939

 

“Prediction is very difficult, especially about the future.”

                           —Niels Bohr

 

References:

1.  Voerman HJ, Strack van Schijndel RJ, et al.  Growth hormone: secretion and administration in catabolic adult patients, with emphasis on the critically ill patient.  Neth J Med. 1992;41(5-6):229-244.

2.  Takala J, Ruokonen E, Webster NR, et al.  Increased mortality associated with growth hormone treatment in critically ill adults.  N Engl J Med. 1999;341(11):785-792.

3.  Bulger EM, Jurkovich GJ, Farver CL, et al.  Oxandrolone does not improve outcome of ventilator dependent surgical patients.  Ann Surg. 2004;240(3):472-478.

4.  Bauman WA, Spungen AM, Collins JF, et al.  The effect of oxandrolone on the healing of chronic pressure ulcers in persons with spinal cord injury: a randomized trial.  Ann Intern Med. 2013;158(10):718-726.

5.  Miller JT, Btaiche IF.   Oxandrolone treatment in adults with severe thermal injury.  Pharmacotherapy. 2009;29(2):213-226.

6.  Srinath R, Dobs A.  Enobosarm (GTx-024, S-22): a potential treatment for cachexia.  Future Oncol. 2014 Feb;10(2):187-94.

 

 

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