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.

Prognostic value of respiratory quotients in severe polytrauma patients with nutritional support.

OBJECTIVE: The association between energy metabolism and prognosis in polytrauma patients has not yet been defined. The aim of this study was to describe energy metabolism and analyze the prognostic value of respiratory quotient (RQ) and nonprotein respiratory quotient (npRQ) in fasting polytrauma patients (fPP) and polytrauma patients with nutritional support (nsPP). METHODS: Twenty-two polytrauma patients (before and after parenteral nutrition administration) and 22 healthy controls (after overnight fasting) were examined on day 4 (median) after admission to the intensive care unit. To evaluate energy expenditure in nsPP and resting energy expenditure in fPP and controls with RQ and npRQ in all groups, we used indirect calorimetry. With regression analysis, the descriptive models of intensive care unit (ICU) length of stay (LOS) and mechanical ventilation time (VT) were derived. RESULTS: RQ and npRQ were significantly lower in fPP than in controls (P < 0.05 and P < 0.01, respectively) and in nsPP (P < 0.05). In nsPP, relationships between RQ or npRQ and the ICU LOS or mechanical VT were demonstrated (P < 0.0001, r = -0.78 for RQ and VT; P < 0.0001, r = -0.78 for npRQ and VT; P < 0.001, r = -0.69 for RQ and LOS; P < 0.001, r = -0.72 for npRQ and LOS). CONCLUSIONS: RQ and npRQ parameters measured by indirect calorimetry in polytrauma patients with parenteral nutrition on the fourth day of ICU stay related to clinical outcomes such as duration of mechanical ventilation and ICU LOS.