Electro Physical Agents: Limb Compression Modalities

Limb Compression Modalities

• Limb compression is the application of mechanical external compressive forces over the upper and lower limbs to improve venous, arterial, and lymphatic circulation.
• The history of limb compression dates back to around 500 BC, with the use of elastic compression to treat leg ulcers in the 18th century and as a prophylactic measure against deep vein thrombosis in the 19th century.

Compression Garments

• Compression garments are specialized elastic stretch pieces of clothing designed to exert compression on the upper and lower extremities.
• They provide mechanical elastic energy to deliver constant pressure gradients, ranging from 10- to 80-mm Hg, on the limbs.
• Types of compression garments include:
  • Bandages (Inelastic Short Stretch, Elastic Long Stretch, Semi-Elastic Multilayer) for short-term treatment.
  • Stockings and sleeves for long-term treatment of venous problems.
• Disadvantages of compression garments include improper fitting, pain, skin irritation, and breakdown, which can lead to skin ulceration and tourniquet effect.

Pneumatic Pumps

• Pneumatic pumps are electric pumps that provide intermittent mechanically compressed air into inflatable garments, generating pressure gradients ranging from 1 to 130 mm Hg.
• Pneumatic garments are available in various shapes, sizes, and number of chambers.
• Advantages of pneumatic pumps include delivering variable intermittent compression.
• Pneumatic pumps are used for improving arterial blood flow in patients with critical limb ischemia and intermittent claudication.

Parameters

• Limb pressure gradient:
  • Upper extremities: 30-60 mm Hg.
  • Lower extremities: 40-80 mm Hg, up to 130 mm Hg in some cases.
• Foot pressure gradient: intermittent larger pressure gradients, up to 130 mm Hg, to effectively empty the plantar venous plexus.
• Inflation and deflation time: programmable, ranging from 1 to 120 seconds.
• Treatment duration and frequency:
  • Compression garments: wearable for several hours or 24 hours, applied daily or consecutively.
  • Pneumatic pumps: applied for up to 1 hour at a time, 1-3 times daily.

Biophysical Characteristics

• Mechanical principle: using mechanical energy to compress blood and lymph from underlying vessels, creating an upward volumetric displacement and enhancing oxygenation.
• Pressure:
  • Compression garments: exerting constant pressure, with pressure gradients directly proportional to garment tensile force and inversely proportional to limb circumference.
  • Pneumatic pumps: exerting intermittent pressure, with single chamber garments providing uniform pressure and multiple chamber garments providing sequential uniform or graded pressure.

Therapeutic Effects

• Compression garments:
  • Apply pressure during rest and work, enhancing muscle contraction and vessel squeezing.
• Pneumatic pumps:
  • Mimic the calf muscle pump and venous foot pump, enhancing venous return and promoting blood flow.

Physiological Effects

• Increase venous emptying from the leg.
• Increase venous velocity.
• Reduce blood volume in the veins.
• Improve arterial blood flow and skin perfusion.
• Enhance endothelial cell function.
• Improve transcutaneous oxygen pressure.

Clinical Application

• Indications:
  • Prevent deep venous thrombosis (DVT) and venous thromboembolism (VTE) in bedridden and surgical patients.
  • Treat edema, venous leg ulcers, and vascular intermittent claudication.
• Contraindications:
  • Peripheral arterial insufficiency.
  • Acute dermatitis.
  • Acute microbial infection.
  • Malignant tumor.
  • Neuropathy.

Application of Pneumatic Pump

• Remove clothing and jewelry.
• Support and elevate the limb during treatment.
• Apply the sleeve over a layer of tub gauze, including the hand and foot.
• Assess joint range and muscle strength before treatment.

Procedure

• Pressure cycle: 30-45 seconds inflation and 15 seconds deflation.
• Start with 40 mmHg for 30 minutes, assess, and repeat twice daily.
• Gradually increase pressure and time over the course of treatment.