Early Mobilization in ICU

ICU-acquired weakness (ICUAW) encompasses critical illness polyneuropathy (CIP) and critical illness myopathy (CIM), affecting up to 80% of mechanically ventilated patients by day 7 of ICU stay. The pathophysiology involves mitochondrial dysfunction in skeletal muscle, microvascular ischemia of peripheral nerves, direct muscle protein catabolism driven by inflammatory cytokines (TNF-alpha, IL-1, IL-6), prolonged immobility causing disuse atrophy at rates of 1-3% muscle mass loss per day, and sodium channel dysfunction in nerve and muscle membranes from systemic inflammation. Hyperglycemia, corticosteroid use, and neuromuscular blocking agents exacerbate the process. Diaphragmatic atrophy develops within 18-69 hours of controlled mechanical ventilation, contributing to ventilator dependence. Early progressive mobilization (starting within 24-48 hours of ICU admission when clinically stable) counteracts these mechanisms by preserving neuromuscular function, maintaining muscle protein synthesis, improving insulin sensitivity, reducing delirium risk through sensory stimulation, and facilitating ventilator weaning through respiratory muscle conditioning. The clinician screens patients for mobilization safety, prescribes progressive activity levels, manages hemodynamic and respiratory parameters during activity, and coordinates interdisciplinary rehabilitation.