Clinical Application of Bioelectrical Impedance Analysis and its Phase Angle for Nutritional Assessment of Critically Ill Patients

Purpose: Phase angle (PA) is objectively determined from resistance and reactance measured by bioelectrical impedance analysis (BIA)-a quick, noninvasive method. The aim of this study was to evaluate the clinical application of PA by BIA for nutritional assessment of critically ill patients. Methods: Eighty nine adult patients admitted to a medical intensive care unit (ICU) of a tertiary academic hospital from August 2012 to September 2013 were analyzed. PA values were measured by direct segmental multi-frequency BIA. As traditional nutrition assessment tools, body mass index (BMI), serum albumin levels, total lymphocyte counts, and our hospital's nutrition screening index (NSI) were also recorded. Correlations between the results of BIA and other traditional parameters were analyzed. Results: PA showed correlation with traditional nutritional parameters, including BMI (r=0.479), serum albumin (r=0.347), and NSI score (r=0.483). Patients with PA lower than the median value (3.5 o ) had significantly lower nutritional status, increased duration of mechanical ventilation (P=0.039), and increased length of ICU stay (P=0.041). Conclusion: PA, as a reflection of body cell mass, measured by BIA could be a potentially useful parameter for nutritional assessment in critically ill patients.