In patients with Acute Kidney Injury nutritional variables that assess nutritional status, and more specifically lean body mass (LBM), at the individual level are lacking. In this clinical setting ultrasound (US) of the quadriceps femoris could represent a widely available, non-invasive, affordable, and reliable tool to evaluate skeletal muscle, a clinical surrogate of LBM.
We performed a cross-sectional observational study in adult critically ill patients with KDIGO stage 3 AKI. Quadriceps rectus femoris and vastus intermedius thickness were measured by two assessors. Intra- and interobserver reliability was evaluated using the intraclass coefficient correlation (ICC). The same US measures were obtained before and after dialysis.
In the intraobserver reliability study, assessor 1 performed 288 paired measurements and assessor 2 performed 430 paired measurements in 34 patients, all on dialysis, with an ICC equal to 0.99 and 1.00, respectively. There were 238 paired measurements (34 patients) in the interobserver reliability study, with an ICC = 0.92. No difference was found in the measurements obtained before and after RRT (11.5 (4.2) vs 11.4 (4.1) mm, P = 0.2498), independently from acute body weight changes due to fluid removal by dialysis.
In patients with AKI, US of quadriceps femoris could represent a simple, accurate, and non-invasive method to evaluate quantitative changes in skeletal muscle.
Assessment of quadriceps femoris thickness using ultrasound. Thickness of each muscle is measured from the femur to the inner edge of the vastus intermedius (VI) muscle, or from subcutaneous tissue to the inner edge of the rectus femoris (RF) muscle.
