Prevalence of muscle atrophy in pediatric patients during ICU hospitalization.

To evaluate the muscle thickness and prevalence of muscle atrophy of the biceps brachii/brachialis (BB) and quadriceps femoris (QF) in critically ill children using ultrasound (US). The prospective longitudinal study was conducted in the pediatric intensive care unit (PICU) of a tertiary hospital in southern Brazil with children and adolescents of both sexes, aged 1 month to 12 years, on invasive mechanical ventilation for 24 h. US measurements were taken up to 24 h after admission, 72 h after, and weekly until discharge from the PICU. One hundred one patients were selected, of whom 97 underwent two evaluations, 68 three evaluations, and 26 four ultrasound evaluations. The median age was 6 months, with 63 (62.4%) < 1 year old. The most prevalent clinical diagnosis was respiratory diseases (70.3%). There was a reduction in BB thickness from 1 to 2 weeks (- 0.10 cm, p = 0.009) and in QF from 24 h to 2 weeks (- 0.20 cm, p = 0.013) and 72 h to 2 weeks (- 0.18 cm, p = 0.045). The prevalence of muscle atrophy (decrease > 10% in thickness) was 41.2% in at least one muscle group between 24 and 72 h, 39.7% between 24 h and 1 week, and 59.3% between 24 h and 2 weeks. The US allows the evaluation of BB and QF muscle thickness in critically ill children, and monitoring muscles during PICU hospitalization is important. The prevalence of muscle atrophy was 30.8% in the biceps brachii and 46.2% in the quadriceps femoris at the end of 2 weeks of PICU hospitalization, regardless of age and diagnosis. What is Known: • Ultrasound has emerged as a promising method, being a clinically valuable tool for bedside muscle monitoring in critical patients. • Using the ultrasound to measure the muscle thickness in adults has demonstrated good sensitivity for detecting muscle atrophy. However, this method has only been previously validated in few studies with small sample of pediatric patients. What is New: • Using the ultrasound, we observed that critically ill children experienced a loss of muscle thickness and muscle atrophy, especially during the second week of intubation. • The significant prevalence of muscle atrophy at the end of PICU hospitalization highlights the importance of ultrasound in identifying muscle loss.