ICU-Acquired Weakness: Complete Guide by

ICU-Acquired Weakness: Comprehensive Guide by Dr. Nikhil Patel

Critical Illness Neuromyopathy

Prevalence Statistics
Initially, the overall prevalence stands at 46%.
Furthermore, it appears higher among COPD patients (35%) and asthmatics (36%).

Definition:

Critical Illness Neuromyopathy (CINM) represents clinically detected weakness in critically ill patients without obvious cause other than critical illness. Moreover, it encompasses a spectrum of neuromuscular disorders that develop during ICU stays.

Risk Factors

Possible Risk Factors

Several factors contribute to the development of ICU-acquired weakness:
Advanced age, Female gender
Higher admission APACHE 2 score
Hypoalbuminemia
Hyperosmolarity
Parenteral nutrition
Renal replacement therapy (RRT)

Probable Risk Factors

Additionally, more strongly associated factors include:
Medications: NMBA, Steroids, Vasopressors
Antibiotics: Aminoglycosides, Colistin, Polymyxin-B
Critical Illness: Sepsis, Septic shock, MODS
Duration factors: Prolonged MV, Prolonged bed rest
Metabolic: Blood sugar fluctuations

Clinical Presentation

Critical Illness Myopathy (CIM)

Typically, CIM manifests with:
Prolonged ICU stay >2 weeks
Difficulty weaning from mechanical ventilation
Muscular weakness (Proximal >> Distal)
Facial symmetrical muscle weakness
Extraocular muscle weakness is rare

Critical Illness Neuropathy (CIN/CINM)

In contrast, CIN/CINM presents with:
Prolonged ICU stay >2 weeks
Difficulty weaning from MV
Limb muscle weakness/atrophy (Distal >> Proximal)
Loss of peripheral sensation (Touch, pinprick)
Reduced deep tendon reflexes
Sparing of cranial nerves

Diagnostic Approach

Clinical Assessment

Clinicians use the MRC Scale: 3 muscle groups per limb, total score of 60. Additionally, motor weakness ranges from monoplegia to quadriplegia. Furthermore, reflexes show absent DTR reflexes. Finally, sensory testing reveals a grimacing response only, with no muscle movement.

Diagnostic Challenges

However, several factors complicate diagnosis:

Poor patient communication
Altered sensorium
Limb edema
Effects of sedation and neuromuscular blockers

Management Strategies

1. Early Physiotherapy

Primarily, implement:

Early mobilization (supine to sitting)
Progressive walking programs
Bedside cycle ergometry
Passive mechanical loading
Functional electrical stimulation (FES)

2. Nutritional Support

Importantly, nutrition management should:

Avoid: Parenteral nutrition (detrimental effect)
Start early: Enteral feeding ASAP
Include: Amino acid supplements
Add: Omega-3 fatty acids

3. Glycemic Control

Furthermore, glucose management requires:

Prevent sugar fluctuations
Target: Euglycemic control (140-180 mg/dL)
Avoid strict glycemic control
Based on NICE-SUGAR study findings

4. Supportive Therapies

Additionally, provide:

Vitamin C & Vitamin E supplementation
Treatment of underlying disease
Avoid precipitating drugs
Optimal rehabilitation programs

Prognostic Implications

CINM significantly increases:

Significantly, CINM increases:

Risk of difficult weaning from the ventilator
ICU mortality (45%)
ICU length of stay
Hospital mortality
Reintubation rates
Tracheostomy requirements
1-year mortality (20%)

Prevention Strategies

To minimize ICU-acquired weakness:

Minimize sedation and neuromuscular blockade duration
Implement early mobilization protocols
Maintain optimal glycemic control
Practice appropriate antibiotic stewardship
Optimize nutritional support
Conduct regular physiotherapy assessment

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