Electro Physical Agents: Limb Compression Modalities

Study Notes

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.

Description

Explore the application of mechanical external compressive forces for improving venous, arterial, and lymphatic circulation in the upper and lower limbs. Learn about its history and uses in treating leg ulcers and as a prophylactic measure.