How can muscle power be increased in a moribund patient?

Management of Muscle Power in Moribund Patients

In a moribund patient, prioritize neuromuscular electrical stimulation (NMES) combined with passive mobilization, as these are the only feasible interventions when voluntary muscle contraction is impossible, and early intervention should begin immediately to prevent irreversible muscle atrophy.

Understanding the Clinical Context

A moribund patient represents the most severe category of illness, with approximately 53% mortality at 30 days post-operatively, though 47% survival demonstrates these patients are not uniformly futile cases 1. These patients cannot participate in active exercise, making passive interventions essential.

Primary Intervention: Neuromuscular Electrical Stimulation (NMES)

NMES is the cornerstone intervention for moribund patients unable to perform voluntary contractions, as it can recruit muscle fibers electrically when volitional effort is impossible 2.

NMES Protocol Parameters

• Frequency: Use tetanic frequencies of 25-75 Hz to produce fused muscle contractions that maximize muscle tension and prevent atrophy 2
• Pulse Duration: 0.2-0.5 ms, which is the standard range used in most NMES studies 2
• Intensity Progression: Start with low intensity during the first 2-5 sessions to avoid muscle damage, then gradually increase to maximum tolerable intensity 2
• Session Duration: Begin with 10 minutes and gradually increase to 30-60 minutes per day 2
• Duty Cycle: Use short duty cycles initially (e.g., 2 seconds on/2 seconds off) 2
• Frequency of Sessions: Daily stimulation is recommended, as these patients require continuous intervention 2

Target Muscle Groups

• Prioritize large muscle groups: Focus on quadriceps, hamstrings, and gluteal muscles, as these are critical for future functional recovery 2
• Consider whole-body NMES when feasible, as it produces greater strength improvements than isolated muscle stimulation 2

Secondary Intervention: Passive Mobilization

Passive mobilization must be instituted early alongside NMES to preserve joint mobility and skeletal muscle length 2.

Passive Mobilization Protocol

• Positioning: Use head tilt and positions approximating upright posture to increase gravitational stress, improve lung volumes, and stimulate autonomic activity 2
• Passive Range of Motion: Perform passive mobilization and muscle stretching to preserve joint mobility in patients unable to move spontaneously 2
• Splinting: Apply splinting as needed to maintain optimal joint positioning 2

Critical Safety Considerations for Moribund Patients

Hemodynamic Monitoring

• Avoid aggressive mobilization in patients with hemodynamic instability, high FiO2 requirements, or high levels of ventilatory support 2
• Monitor blood pressure carefully: Long on-times (>4 seconds) may be contraindicated when stimulating large muscle mass in patients at risk for blood pressure elevation 2
• Weigh mobilization risks against the documented risks of immobility and recumbency 2

Device Compatibility

• NMES is safe in patients with pacemakers and implantable cardiac defibrillators for lower extremity stimulation 2
• NMES does not interfere with left ventricular assist device performance 2

Algorithmic Approach to Implementation

Step 1: Assess Hemodynamic Stability

• If unstable (high vasopressor requirements, severe hypotension): Begin with positioning only
• If relatively stable: Proceed to NMES + passive mobilization

Step 2: Initiate NMES Protocol

• Day 1-5: Low intensity, 10-20 minutes, 25 Hz, 2s on/2s off
• Day 6+: Increase intensity to maximum tolerable, extend to 30-60 minutes, maintain 25-75 Hz

Step 3: Add Passive Mobilization

• Perform passive range of motion exercises 2-3 times daily
• Position patient in semi-upright posture when hemodynamically tolerated
• Apply splinting to prevent contractures

Step 4: Monitor Response

• Assess for muscle damage (excessive soreness, elevated CK)
• Monitor hemodynamic response during sessions
• Adjust intensity and duration based on tolerance

Common Pitfalls and How to Avoid Them

Pitfall 1: Delaying Intervention

Solution: Begin NMES and passive mobilization within 48 hours of ICU admission, as every critically ill patient staying more than 48 hours should be considered at risk for malnutrition and muscle wasting 2.

Pitfall 2: Using Inadequate Stimulation Intensity

Solution: After the initial 2-5 sessions, progressively increase intensity to maximum tolerable levels, as high current intensity is necessary to maximize muscle fiber recruitment 2.

Pitfall 3: Focusing Only on Lower Extremities

Solution: Include upper extremity NMES when feasible, as whole-body stimulation produces superior outcomes 2.

Pitfall 4: Neglecting Hemodynamic Monitoring

Solution: Continuously monitor blood pressure and oxygen saturation during NMES sessions, particularly when stimulating large muscle masses 2.

Realistic Expectations

• Muscle power is significantly reduced in survivors of critical illness (43% reduction compared to healthy controls) 3
• NMES cannot fully prevent muscle loss but can minimize atrophy during the acute phase 2
• The goal is preservation, not improvement, in the moribund phase—functional gains occur during recovery 2
• Muscle function assessment (handgrip strength, MRC score) should be performed when the patient becomes conscious to guide ongoing therapy 2

Contraindications to NMES

• Uncontrolled cardiac arrhythmias
• Unstable angina or recent myocardial infarction
• Seizure disorder
• Severe skin problems at electrode sites 4