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Compression therapy: choosing the bandages

Caroline Dowsett
MSc BSc(Hons) DipN RGN
Nurse Consultant
Tissue Viability
Newham Primary Care NHS Trust
London
E:caroline.dowsett@newhampct.nhs.uk

Compression has been used for many centuries in the treatment of oedema and other venous and lymphatic disorders of the lower limb. It is the standard recommended treatment of uncomplicated venous leg ulcers.(1) The application of external compression initiates a variety of complex physiological and biochemical effects involving the venous, arterial and lymphatic systems. Provided that the level of compression does not adversely affect arterial blood flow, and the correct application technique and materials are used, compression will reduce oedema and pain and will promote healing of venous ulcers.(2) Research indicates that for a typical venous ulcer there should be 30-40mmHg compression at the ankle, reducing at the calf to around 15-20mmHg.(3)
Accurate patient assessment is essential to ensure that the correct aetiology of the ulceration has been identified and to exclude the presence of arterial disease, for which compression is dangerous. Assessment should include measurement of the ankle-brachial pressure index (ABPI) using a handheld Doppler and measurement of the ankle circumference to determine the level of compression required, if appropriate. The clinician needs to take into consideration the patient's past medical history, current history and clinical presentation. Venous ulcers usually present in the gaiter area of the leg, and often the patient has skin straining and varicose veins (see Figure 1).

[[NIP24_fig1_78]]

Sustained compression is provided by multilayer elastic or inelastic bandage systems. There is now considerable evidence to show that graduated, sustained, high compression improves ulcer healing and provides quality of life and cost benefits. A systematic review of the literature has shown that compression therapy does increase the healing rate of venous leg ulcers, that high compression (35-45mmHg) is more effective than low compression (15-25mmHg), and that elastic or inelastic multilayer systems are more effective than single-layer systems.(4 )Inelastic bandages produce a low resting pressure and high pressure when moving. Elastic bandages produce sustained compression, with minor variations during walking.

Bandage pressure
The degree of compression produced by any bandage system over a period of time is determined by complex interactions between four principle factors:

  • The structure and elastomeric properties of the bandage.
  • The size and shape of the limb.
  • The skill and technique of the clinician putting the bandage on.
  • The nature of physical activities undertaken by the patient.

The pressure generated by any bandage is determined principally by the tension in the fabric, the number of layers applied and the degree of curvature of the limb. The relationship between these factors is governed by "Laplace's Law". This states that sub-bandage pressure is directly proportional to bandage tension, but inversely proportional to the radius of curvature of the limb to which it is applied. This means that a bandage applied with constant tension and overlap to a limb of normal proportions will automatically produce graduated compression with the highest pressure at the ankle. This pressure will gradually reduce up the leg as the circumference increases. Marked variations in pressure will be found over bony prominences such as the malleolus and tibial rest, and therefore padding should be applied to protect these areas.
Therefore graduated compression is achieved by exploiting the natural shape of the leg, which is generally narrower at the ankle and wider at the knee. However, some patients may have reduced calf muscle (straight leg), and this means that the leg may be the same circumference at all points, requiring extra padding around the calf to achieve optimum pressures. Other patients may have a very small ankle and large calf, often referred to as an "inverted champagne bottle"-shaped limb, and these require extra padding around the ankle to achieve the correct pressures. The limb shape and size therefore needs to be assessed before applying compression therapy.
Other important factors to consider are the condition of the skin, as delicate friable skin can be damaged by high levels of pressure, and the presence of neuropathy where the absence of protective response increases the risk of sub-bandage pressure damage. Patients who suffer from heart failure should seek medical advice before applying compression as rapid fluid shifts can increase the preload of the heart.

Bandage classification
Currently there are no International or European standards relating to the performance of compression bandages. The British Standard classifies bandages into one of six categories as outlined in Table 1, with type 3 bandage classifications relating to various degrees of compression.

[[NIP24_table1_80]]

Compression systems

High-compression elastic bandages
These elastic, highly extensible (long-stretch) bandages expand to accommodate changes in leg geometry during walking, with the result that pressure changes over the calf are fairly small. They also sustain applied pressures for extended periods, even when the patient is at rest.

High-compression inelastic bandages
These inelastic, minimal extensible (short-stretch) cotton bandages, when firmly applied, cannot accommodate changes in limb circumference. As a result the pressures beneath such bandages tend to increase during the walking cycle as the calf muscle attempts to expand against the relatively rigid and inextensible fabric. The bandage therefore reinforces the action of the calf muscle pump.
The bandages tend to lose pressure and therapeutic effect over time. Cohesive inelastic bandages are less likely to slip down, which can reduce the frequency of reapplication.

Multilayer bandaging
There are a variety of multilayer systems available. They all tend to have three or four layers and include either elastic or inelastic compression bandages, cohesive/adhesive bandages, crepe bandages and padding layers. The concept of multilayer is that pressure is applied in layers, giving an accumulation of pressure. For this reason it is very useful in patients who are unable to tolerate full compression or for those with mixed-aetiology disease where reduced compression is recommended.

Dynamic compression
The role of dynamic compression or intermittent pneumatic compression (IPC) in the management of venous ulcers suggests that it may be advantageous in the immobile patient with a slow or nonhealing ulcer. The therapy can be combined with compression bandaging.

Compression hosiery
For those patients who are active, self-caring and have a small ulcer of short duration, elastic compression hosiery can be used as an alternative to bandages. However, it should be acknowledged that pressures will be lower in class-two compression hosiery, and this may mean that the ulcer takes longer to heal. The advantages are that the patient can be self-caring and no adaptations to footwear are necessary.

Choosing compression
The type of compression therapy that the clinician chooses will be dependent on a number of factors, including:

  • The evidence to support the compression system - this can vary from case study evidence to more robust randomised clinical trials.
  • The patient's mobility - four-layer compression bandaging is usually more appropriate for immobile patients, while short-stretch is useful for more mobile patients.
  • The duration and size of the ulcer - small ulcers of short duration can be managed in compression hosiery.
  • The patient's tolerance to compression - multilayer systems allow for reduced compression.
  • The patient's preference - the patient's previous experiences and quality of life need to be addressed.
  • The patient's ability to provide self-care - short-stretch bandages and compression hosiery may be more useful for self-caring patients who do not want to be dependent on a healthcare provider.

Marston and Vowden (2003) suggest the following benchmarks for an ideal compression system:(5)

  • Clinical effectiveness - evidence-based treatment.
  • Sustained compression - ability to provide and maintain clinically effective levels of compression for at least a week during walking and rest.
  • Enhances calf muscle pump function.
  • Nonallergenic.
  • Ease of application and ease of training.
  • Conformable and comfortable (nonslip).
  • Durable.

Multilayer bandages are predominantly used in the UK. They were developed as a result of research at Charing Cross Hospital, London. A trial of multilayer bandages in the treatment of venous leg ulcers found 74% complete ulcer healing in 12 weeks.(6) A randomised clinical trial of four-layer and short-stretch compression bandages for venous leg ulcers concluded that venous leg ulcers treated with a four-layer bandage system healed more quickly than those treated with short-stretch.(7)
The four-layer bandage system is made up of:

  • Layer 1. Orthopaedic wool, which absorbs exudate and protects bony prominences. This layer is also used to reshape legs so that the ankle is smaller than the calf. It is also used to increase the circumference of the ankle when it measures less than 18cm (see Figure 2).
  • Layer 2. The second layer is a crepe bandage applied in 50% overlap at 50% extension to provide further absorbency and a smooth base to begin the compression layers (see Figure 3).
  • Layer 3. The third layer is an elastic conformable compression bandage applied at 50% extension and 50% overlap in the figure-of-eight technique to give approximately 17mmHg compression at the ankle (see Figure 4).
  • Layer 4. This is the final layer and is a cohesive bandage with latex coating that maintains its self-adhesive properties for one week and can therefore remain in place securely without the need for tape (see Figure 5).

[[NIP24_fig2_81]]

[[NIP24_fig3_81]]

[[NIP24_fig4_81]]

[[NIP24_fig5_81]]

The standard compression system is for an ankle circumference of 18-25cm. There are other kits available for patients with smaller ankles and those with large ankles. It is important to always follow the manufacturer's recommendations and to seek advice if further training is needed before applying the bandages. Compression bandaging is a treatment in its own right, and pressure-induced tissue damage can lead to amputation in extreme cases, therefore accurate assessment and appropriate training is essential.

Application
The ankle should be bandaged using a figure-of-eight technique to allow freedom of movement. The heel and Achilles tendon area must be carefully bandaged to prevent localised oedema and bandage slippage, which can result in extensive pressure damage and lead to the loss of tendon. Care should be taken to avoid overextension of the bandage around the ankle as high pressures can lead to necrosis. It is recommended that patients with venous leg ulcers have bandaging from toe to knee, with room to insert a finger above the bandage in the popliteal space (behind the knee) to ensure full knee movement. Some patients find that layer 1, the orthopaedic wool layer, can cause itching, especially if they suffer from dry skin or eczema. For these patients a layer of cotton tubular bandage can be used under the wool layer.

Dressing selection
A Cochrane systematic review recommends that for the majority of venous ulcers a simple nonadherent, absorbent dressing should be the first choice for use under compression.(4) It is important, however, that when choosing a dressing the clinician considers the patient's pain, the type of tissue at the wound bed, the amount of exudate, the presence of infection and the condition of the surrounding skin. Good skin care is a necessary component of managing venous leg ulcers. The leg should be washed in warm water and an emollient used to prevent the skin from becoming dry, which can lead to further breakdown.

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References

  1. Royal College of Nursing. Clinical practice guidelines: the management of patients with venous leg ulcers. London: RCN; 2001.
  2. Partch H. Understanding the pathophysiological effects of compression. Understanding compression therapy. London: EWMA; 2003.
  3. Stemmer R. Ambulatory elastocompressive treatment of the lower extremities with elastic stockings. Z Arztl Fortbild 1969;3:1-8.
  4. Cullum N, Nelson EA, Fletcher AW, Sheldon TA. Compression for venous leg ulcers (Cochrane Review). Oxford: The Cochrane Library; 2001.
  5. Marston W, Vowden K. Compression therapy: a guide to safe practice. Understanding compression therapy. London: EWMA; 2003.
  6. Moffat CJ, Franks PJ, Oldroyd M, et al. Community clinics for leg ulcers and impact on healing. BMJ 1992;305:1389-92.
  7. Nelson WA, Iglesias CP, Cullum N, et al. Randomised clinical trial of four-layer and short-stretch compression bandages for venous leg ulcers (VenUS 1). Br J Surg 2004;91:1292-9.