From the Guidelines
ICU-acquired weakness (ICUAW) is a condition characterized by muscle weakness that develops during a critical illness in patients admitted to the intensive care unit, affecting both the limbs and respiratory muscles, and is associated with worsened outcomes, as estimated to affect over 25% of patients who require prolonged mechanical ventilation 1.
Definition and Prevalence
ICUAW typically occurs in patients who have been critically ill for more than 48-72 hours and is more common in those with sepsis, multi-organ failure, prolonged mechanical ventilation, or those receiving certain medications like corticosteroids and neuromuscular blocking agents. The primary mechanisms behind ICUAW include direct muscle damage from inflammation, disuse atrophy from immobility, and nerve dysfunction.
Diagnosis and Prevention
Diagnosis involves physical examination showing symmetrical weakness and specialized tests like electromyography in some cases, with various diagnostic methods available, including physical examination, EMG, nerve conduction studies, direct muscle stimulation, muscle biopsy, and nerve biopsy 1. Prevention strategies include early mobilization, minimizing sedation, controlling blood glucose levels, and judicious use of steroids and neuromuscular blockers.
Treatment and Recovery
Treatment focuses on physical rehabilitation starting as early as possible during the ICU stay and continuing after discharge, with the goal of improving functional status, reducing the duration of delirium, and increasing ventilator-free days 1. Recovery can take weeks to months, with some patients experiencing persistent weakness that affects their quality of life long after hospital discharge. Recent guidelines emphasize the importance of early mobilization and positioning in preventing ICUAW, as well as multimodal rehabilitation for patients with post-intensive care syndrome (PICS) 1.
Key Considerations
- ICUAW is a significant concern in critically ill patients, with a high prevalence and potential for long-term morbidity and mortality.
- Early mobilization and prevention strategies are crucial in reducing the risk of ICUAW.
- Physical rehabilitation and multimodal rehabilitation approaches are essential in improving outcomes and quality of life for patients with ICUAW and PICS.
From the Research
Definition and Characteristics of ICU Acquired Weakness
- ICU acquired weakness (ICUAW) is a condition that occurs in critically ill patients, resulting in sustained disability long after the ICU stay 2.
- It is characterized by weakness, muscle wasting, impaired contractility, neuropathy, and major pathways associated with muscle protein degradation 2.
- ICUAW can be attributed to various factors, including critical illness, muscle atrophy, and impaired muscle function 3, 4.
Risk Factors and Diagnosis
- Risk factors for ICUAW include illness severity, organ failure, age, hyperglycemia, parenteral nutrition, drugs, and immobility 3.
- Diagnosis of ICUAW can be made using electrophysiological methods, and patients can be classified into three subcategories: critical illness polyneuropathy, critical illness myopathy, and critical illness neuromyopathy 3.
- Tools to diagnose ICUAW include the Medical Research Council (MRC) scale, which assesses muscle strength and function 5.
Management and Prevention
- Management of ICUAW is essentially preventive, focusing on avoiding modifiable risk factors, such as duration of sedation and immobilization 3.
- Early mobilization, range of motion exercises, and neuromuscular electrical stimulation (NMES) can help prevent ICUAW by maintaining muscle mass and function 5, 6.
- Pharmacological approaches have been studied, but none have proven efficacy in preventing or treating ICUAW 3.
Prognosis and Recovery
- ICUAW can result in significant activity limitations, often requiring physical assistance for basic activities, and can have a long-term impact on quality of life 6, 4.
- Recovery from ICUAW can be improved with early physical activity, NMES, and other rehabilitation strategies, which can help preserve muscle strength and function 5, 6.