Muscle atrophy in mechanically-ventilated critically ill children

Area of Science:

• Pediatric Critical Care Medicine
• Muscle Physiology
• Ultrasound Imaging

Background:

• ICU-acquired muscle atrophy is common in adults, worsening outcomes.
• The incidence and severity of muscle atrophy in critically ill children are not well understood.

Purpose of the Study:

• To determine the incidence, severity, and risk factors of muscle atrophy in critically ill children.
• To characterize muscle changes using bedside ultrasound and electrical impedance myography (EIM).

Main Methods:

• Prospective cohort study of 34 children (1 week-18 years) on mechanical ventilation for ≥48 hours.
• Serial bedside ultrasound assessed muscle thickness (diaphragm, biceps, quadriceps, tibialis anterior).
• Electrical impedance myography (EIM) assessed fat percentage and muscle quality in children >1 year old.

Main Results:

• Diaphragm thickness decreased by 11.1% and quadriceps by 8.62% over a median of 6 days.
• 47% of patients showed diaphragm atrophy (≥10% thickness decrease); 83% had atrophy in at least one muscle group.
• Increasing age and traumatic brain injury (TBI) were associated with greater muscle loss; EIM showed increased fat and decreased muscle quality.

Conclusions:

• Muscle atrophy, particularly in the diaphragm and quadriceps, is common and rapid in mechanically ventilated children.
• Older age and TBI may be risk factors for more severe limb muscle atrophy.
• Further research is needed to correlate muscle atrophy with functional outcomes in pediatric critical illness.