Bedside Ultrasound Assessment to Detect Muscle Loss in Critically Ill Children

Objectives
To evaluate the feasibility and inter-rater reliability of bedside muscle ultrasonography for detecting muscle loss in critically ill pediatric patients. Design: A single-center prospective cohort study was conducted (January 2024–January 2025).

Methods
Critically ill children frequently experience rapid muscle loss, a complication associated with intensive care unit (ICU)–acquired weakness, prolonged mechanical ventilation, and increased morbidity. Early detection of muscle wasting may enable targeted interventions to mitigate these adverse outcomes. Patients: Critically ill children (aged 2–18 years) requiring invasive mechanical ventilation for >24 hours. Interventions: Serial ultrasound assessments of the quadriceps femoris muscle thickness and cross-sectional area were performed at baseline and during ICU stay. Potential risk factors (eg, corticosteroid use, neuromuscular blockade, hyperglycemia, and nutritional status) were recorded.

Results
Of the 35 patients enrolled in the study, 14 (40%) had significant muscle loss (defined as loss of ≥10% of muscle mass compared to the baseline assessment) detected by decreased muscle thickness, and 20 (57%) had muscle loss detected by reduced cross-sectional area. Muscle loss occurred 3–10 days into their critical illness and invasive mechanical ventilation. Stepwise multivariable logistic associations showed that patients with a lower ratio of actual-to-goal protein intake at the time of scan had higher odds of muscle loss, as it was associated with >10% decrease in cross-sectional area (adjusted OR 3.2, CI 1.22, 3.56) and that a higher mean level of C-reactive protein was associated with a significant decrease in muscle thickness (adjusted OR 1.7, CI 1.23, 3.34).

Conclusion
Bedside muscle ultrasonography is a feasible, and practical tool for early detection of muscle loss in critically ill children. Its noninvasive nature, portability, and cost-effectiveness support its potential integration into routine ICU monitoring to guide early rehabilitative or nutritional interventions. Further multicenter studies are warranted to validate these findings.