From the Guidelines
ICU-acquired weakness (ICUAW) is a neuromuscular disorder characterized by symmetrical limb weakness that develops during an intensive care unit stay with no other identifiable cause, typically affecting both the peripheral nerves and muscles, resulting in a combination of critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) 1.
Definition and Characteristics
ICUAW occurs in approximately 25-50% of patients who are critically ill for more than 7 days, particularly those with sepsis, multi-organ failure, or prolonged mechanical ventilation. The condition manifests as diffuse muscle weakness, reduced or absent deep tendon reflexes, and difficulty weaning from mechanical ventilation due to respiratory muscle involvement.
Diagnosis and Risk Factors
Diagnosis involves clinical examination using the Medical Research Council (MRC) sum score to assess muscle strength, electrophysiological studies, and sometimes muscle biopsy. Risk factors include sepsis, systemic inflammatory response syndrome, multiple organ failure, hyperglycemia, immobility, and certain medications like corticosteroids and neuromuscular blocking agents 1.
Prevention and Treatment
Prevention strategies focus on minimizing sedation, early mobilization, glycemic control, and avoiding unnecessary corticosteroids or neuromuscular blockers. Treatment primarily involves supportive care, physical therapy, and treating the underlying critical illness, with recovery potentially taking weeks to months and some patients experiencing long-term disability. According to the most recent guideline on positioning and early mobilisation in the critically ill by an expert panel, early mobilisation can minimize the development of ICUAW 1.
From the Research
Definition of ICU Acquired Weakness Neuromuscular
ICU acquired weakness (ICU-AW) is defined as clinically detected weakness in critically ill patients in whom there is no plausible etiology other than critical illness 2. This condition can be classified into three subcategories using electrophysiological methods:
- Critical illness polyneuropathy
- Critical illness myopathy
- Critical illness neuromyopathy
Causes and Risk Factors
The exact causes of ICU-AW are not fully understood, but several risk factors have been identified, including:
Diagnosis and Management
Diagnosis of ICU-AW is clinical, supported by electrophysiology and other diagnostic tests such as muscle ultrasound 4. Management is essentially preventive, focusing on avoiding modifiable risk factors, especially duration of sedation and immobilization 2. Pharmacological approaches have been studied, but none have proven efficacy 2.
Impact on Patients
ICU-AW can result in longer hospital stays and increased mortality 2. It is a substantial contributor to long-term disability in survivors of critical illness, with some patients experiencing slow and incomplete recovery 4. Early mobilization and aggressive treatment of sepsis may improve outcomes 4.