Faradic Current: Uses, Effects and Safe Application

1. Definition of Faradic Current

• Faradic (faradism) current is a short-duration, interrupted direct current, typically 0.1–1 ms pulse width at 50–100 Hz.

• It stimulates innervated motor nerves, causing tetanic-like muscle contractions.

2. Physiological Effects

• Sensory nerve stimulation produces mild prickling and superficial vasodilation (redness).

• Motor nerve activation leads to muscle contraction and, when surged, approximates voluntary tetanic contractions without fatigue.

• Boosts local circulation, metabolism, and venous/lymphatic flow, aiding in waste clearance and tissue nutrition.

3. Indications and Therapeutic Uses

• Facilitation of pain-inhibited muscles

• Muscle re-education, especially after disuse or neurological impairment

• Training new muscle actions (e.g., tendon transfer rehab)

• Prevention and loosening of adhesions

• Enhancement of venous and lymphatic drainage (especially with the “under pressure” technique)

• Management of spasticity or painful knee syndromes

• Temporary use in neuropraxia to maintain muscle tone

4. Contraindications and Precautions

Contraindications: skin lesions (psoriasis, eczema), infection or inflammation, thrombosis, sensory loss, cancer, pacemakers, cardiac disease.

Precautions: risk of burns and electric shock; take care in uncontrolled epilepsy.

5. Preparation of the Patient and Machine Testing

a. Machine Testing

• Check the unit via hand-held electrodes or a dry pad until mild tingling and contraction occur.

• Electrodes: the active electrode (smaller) covers the motor point; the passive/indifferent electrode (larger) reduces current density.

• Ensure pads are soaked in warm saline, lead connections are proper, and the surge waveform is selected.

b. Patient Preparation

• Position the patient comfortably, with muscles slightly shortened.

• Expose and clean the skin to reduce resistance.

• Explain sensations and obtain consent.

• Place electrodes over the motor point or along the nerve trunk.

• Use straps or body wraps for stable contact.

6. Stimulation of Motor Point and Muscle Group

1. Motor point stimulation: place the active electrode on the motor point and the passive electrode over the nerve; adjust current until optimal contraction is achieved at minimal intensity.

2. Group stimulation: position electrodes at the ends of the muscle group to recruit the entire muscle belly.

7. Faradism Under Pressure

A specialized technique to manage edema and improve fluid return, combining electrical stimulation with mechanical compression:

• Setup: apply faradic current over muscle motor areas.

• Apply compression: use an elastic or crepe bandage, snug but not constrictive, from distal to proximal.

• Elevate the limb to assist venous return.

• Cycle: 2–3 minutes of contraction, then 5 minutes of rest; total session approximately 15–35 minutes.

• Alternative: if motor points are inaccessible (e.g., wounds), stimulate over superficial nerve trunks.

• Indications: edema (e.g., diabetic foot, lymphedema, elephantiasis, post-phlebitic syndrome). Contraindications include infection, DVT, malignancy, pacemakers, etc.