There is currently no standardized procedure to assess sarcopenia in long-stay catabolic patients. Our aim is to analyze a novel ultrasound muscle assessment protocol in these patients versus healthy controls, by carrying out a prospective observational study. We designed a new ultrasound protocol that assesses quadriceps rectus femoris (QRF) muscle quality in real-time B-mode, color-Doppler, and M-mode ultrasound, and evaluates QRF intramuscular central tendon thickness, cross-sectional area, and muscle thickness in ultrasound B-mode. Logistic regression was performed as a multivariable analysis on 29 cases and 19 controls. The QRF muscle area and thickness were shown to significantly decrease (p ≤ 0.001), and the central tendon thickness significantly increased (p = 0.047) in cases versus controls. The QRF muscle echogenicity and angiogenic activity fasciculations, subcutaneous edema, and intramuscular fluid were also significantly different between the two groups (p < 0.001). The selected variables in the multivariate logit analysis were the muscle area (OR per cm² = 0.07; 95% confidence interval (CI) = 0.012⁻0.41) and the central tendon thickness (OR per mm 1.887; 95% CI = 2.66⁻13.38).
Keywords: Bayesian prediction; critical illness; muscle mass; muscle weakness; quadriceps femoris; sarcopenia; ultrasound.