Comparative assessment of skeletal muscle mass using computerized tomography and bioelectrical impedance analysis in critically ill patients

Abstract

We compared the evaluation of skeletal muscle mass (SMM) using the computed tomography (CT) and bioelectrical impedance analysis (BIA) methods in critically ill patients. We also evaluated whether BIA can be applied for measuring SM with high accuracy to critically ill patients. We included 135 critically ill surgical patients (83 men and 52 women, mean age: 59.3 years) who got the BIA and abdominal CT scan both within 7 days during the intensive care unit (ICU) stay. With CT scan, skeletal muscle area (SMA) measured from the L3 spine level image was used for calculation of the whole body skeletal muscle volume and mass (kg). Body composition data from BIA were obtained using touch-type electrodes and 50kHz current. Subgroup analyses for SMM were performed according to the sex, SMA, and edema status of the patients with Pearson correlation or regression analysis etal. SMM from CT and BIA showed a good correlation (p<0.0001) to sex, SMA, and edema in the subgroup analysis. A stronger correlation was noted between SMM from CT and BIA in male patients or mild edema group than for the other groups. SMM from BIA showed greater values than that from CT (mean difference, 3.35kg) in all groups, except the normal SMA (higher than 170cm2 in men, and 110cm2 in women) group. Male patients and mild edema group showed more SMM as evaluated by BIA when compared to the other groups. SMM measure by BIA in critically ill patients showed high correlation with SMM calculation by CT scan and had greater values than SMM from CT scan. Ajou University Hospital Institutional Review Board DEV-DE4-15-115, Registered Jan 1 2015.