THE EFFECTS OF COMPRESSION THERAPY
Without the beneficial support provided by both forms of compression (garments and bandages), lymphedema physical therapy treatment would not be possible. It is helpful to understand precisely how these forms achieve the desired affect (limb reduction) and how they complement each other in the successful lymphedema training and treatment.
BANDAGING/GARMENTS REDUCE THE ULTRAFILTRATION RATE
Lymph originates as a clear, protein-rich fluid in tissue spaces throughout the body. This fluid (1-2 liters/day) is usually carried by lymph vessels, passes through regional lymph nodes, and joins the venous blood shortly before this blood enters the heart. The circulation of lymph is important in maintaining normal tissue homeostasis throughout the body. The balance between the fluid leaving the arterial side of the capillaries (ultrafiltration) on the one hand and the re-absorption that occurs in the venous capillaries plus the drainage via the lymphatics on the other, is known as Starling's Equilibrium. Because of the disturbed lymph drainage in lymphedema, this equilibrium collapses, protein-rich fluid accumulates in the tissue spaces, the colloid-osmotic pressure rises, and all of these events favor ultrafiltration. By raising the tissue (interstitial) pressure by means of an external force (the compression bandage), the effective ultrafiltration pressure is reduced, less fluid accumulates, and less fluid has to be removed from the tissue spaces, thereby improving the lymphedema.
BANDAGING/GARMENTS IMPROVE THE EFFICIENCY OF THE MUSCLE AND JOINT PUMPS
Lymph is propelled through the various lymph vessels by muscular activity, by contraction of the lymph vessels themselves, by the movements of the diaphragm (breathing), and by negative pressures within the chest during the breathing cycle. In the extremities, the activity of the skeletal muscles is an important factor in lymph transport. During contraction of an arm or a leg muscle, the venous and lymphatic systems propel the fluids they contain toward the heart. This results in a more rapid flow and a decompression of both systems. In order to preserve this process, normal tissue (skin and muscle) and joints are essential. In lymphedema these elements are damaged. The skin is overstretched and, following decongestion of the lymphedema via CDT, skin and tissue pressure is further diminished. The use of external compression bandages compensates for this diminished tissue pressure and thus improves the efficiency of the muscle and joint pumps.
BANDAGING/GARMENTS PREVENT THE RE-ACCUMULATION OF EVACUATED LYMPH FLUID
Manual Lymph Drainage (MLD) involves specific manual motions that follow lymphatic pathways, emptying and decompressing obstructed lymph vessels in the swollen body part. Each MLD treatment decongests the limb and helps return it to a more normal size. The reduction of edema volume and the elastic insufficiency of the skin make refilling of the limb with edema fluid quite easy. Because compression bandages make up for the diminished tissue pressure of the skin, they prevent the re-accumulation of evacuated, stagnating lymph fluid and thereby maintain the result of the MLD treatment.
MLD AND BANDAGING BREAK UP DEPOSITS OF ACCUMULATED SCAR AND CONNECTIVE TISSUE
First stage lymphedema is caused by an accumulation of protein-rich edema fluid. Lymphedema in a later stage is associated with thickening of the skin and hardening of the limb. This hardening is due to the proliferation of connective and scar tissue. In order to soften this connective tissue buildup, special techniques during the MLD treatment are needed. Additional softening and breakdown of this fibrotic tissue is obtained by including foam rubber padding materials within a moderately-tight bandage. This achieves a localized pressure increase in the affected area. Muscular activity further acts upon these fibrotic areas, loosening and breaking up accumulated deposits of scar and connective tissue. In addition to the listed beneficial effects of compression bandages in lymphedema, they are also valuable in venous disorders.
THE TWO FORMS OF COMPRESSION: BANDAGES AND GARMENTS
The nature of compression varies greatly when a comparison is made between short stretch bandages and elastic compression garments. Both are necessary complements to a program of Complete Decongestive Therapy but must only be utilized by competent and well-trained therapists. The distinction lies in the working and resting forces generated by these two forms of compression.
QUALITIES OF COMPRESSION: WORKING AND RESTING PRESSURE
When a short stretch compression bandage is applied to the lymphedematous limb it supports the tissues without squeezing because its fabric does not contain elastic materials. This means that the bandage is not capable of shortening around the limb after application and is therefore not exerting ever-increasing pressure during inactivity. This dynamic is called resting pressure and is considered safe and comfortable for long-term treatment. Conversely, the stability of the bandage creates a very high resistance to stretch when pressure is applied through internal muscle contraction and joint movement. This force is called working pressure. The multi-layering of these bandages creates a soft, cast-like environment which fully resists these forces and further prevents refilling of evacuated lymph fluid. Additionally, the exercise regimen prescribed for each patient is maximized by this working pressure as these forces promote further lymph removal.
Garments are considered a necessary complement to effective lymphedema management for various reasons. The compression garment liberates the patient from continual wearing of bandages which, due to the multi-layering and integrated padding components, become quite bulky and cumbersome. The single layer support of compression garments is a welcome addition to daily homecare. Typically patients remove bandages upon awakening in the morning and apply either a compression sleeve (arm patients) or stocking (leg patients). The compression garment allows for a non-bulky and natural limb contour while maintaining limb size in a nearly edema-free state. Another important benefit to compression garments is the integrated medically-correct compression gradient. This implies that the support is graduated from distal to proximal along the limb allowing for an overall decrease in compression at the trunk and more compression at the ends of the extremity. A gradient is of paramount importance for effective lymphedema management because lymph fluid must be allowed to flow toward the trunk efficiently, thus allowing for drainage and limb reduction. Whereas bandages generate high working pressures, compression garments generate low working pressures due to the elastic materials utilized in their construction. Garments generate very high resting pressures while bandages generate low resting pressure. For these reasons the comfort of a garment is not as high at night as is therefore discouraged for nighttime use. Also, due to their low working pressures, garments will permit some fluid to return to the limb. It is for these reasons that a well-rounded approach to compression therapy involves a daily rotation between both bandages and garments. Daily accumulations of lymph are removed during bandaging sessions and limb cosmesis is maintained through daily garment application.
COMPRESSION GRADIENT AND MOBILITY
After the compression bandage is applied, care should be taken to insure that the proper pressure gradient exists. To maintain normal blood and lymph circulation within a rigid bandage sheath on an arm or a leg, the bandaged pressure is moderately strong in the distal areas of the extremity (hand/foot) and less in the proximal areas (upper arm/thigh). In a medically-correct compression garment the gradient is automatically integrated into the construction materials through sophisticated manufacturing and testing methods. The compressive strength of the garment can then be prescribed according to the desired support indicated for each patient's unique requirements.