Critical evaluation of muscle mass loss as a prognostic marker of morbidity in critically ill patients and methods for its determination

OBJECTIVE: Loss of muscle mass in critically ill patients is associated with serious consequences, such as prolonged mechanical ventilation, intensive care unit confinement, and higher mortality. Thus, monitoring muscle mass, and especially its decline, should provide a useful indicator of morbidity and mortality. Performing evaluations according only to body mass index is imperfect, therefore the aim of this article was to evaluate appropriate methods for muscle mass loss determination in ICU patients. METHODS: For this review, the literature searches were conducted through Embase and Medline, PubMed and Google Scholar databases up to February 2018 for the following Medical Subject Headings terms muscle atrophy, protein catabolism, ICU-aquaired weakness, muscle muss loss, myolysis, critical illness, stress metabolism, computed tomography, magnetic resonance imaging, dual-energy X-ray absorptiometry, neutron activation analysis, anthropometric examination, determination of endogenous metabolites of the skeletal muscles, bioimpedance spectroscopy, ultrasound. RESULT: It appears that ultrasound, which is widely available in hospitals, is the most advantageous method. Muscle ultrasound is non-invasive, relatively inexpensive, and is a bedside method that is free of ionizing radiation. Furthermore, muscle ultrasound also seems to be valid in patients with severe fluid retention, which is a typical complication with other conventional methods. CONCLUSION: Early detection of critical illness neuromyo-pathy could be beneficial for improving the standards of intensive care, and thus reducing the risk of mortality in these patients.