VOL: 98, ISSUE: 44, PAGE NO: 44
John Mears, BSc, MSc, RGN, DipN, Cert Ed, RNT, is senior lecturer, Thames Valley University
Christine Moffatt, PhD, MA, RGN, NDN, is co-director, Centre for Research and Implementation of Clinical Practice, Thames Valley University
When discussing bandaging in association with leg ulcers we generally mean venous ulcers that are primarily caused by problems associated with deep vein thrombosis and varicose veins, both of which lead to chronic venous insufficiency, this in turn leading to ulceration.
Compression bandaging is the treatment of choice in modern leg ulcer management to reverse the effects of chronic venous insufficiency such as oedema, ulcers and excess exudate from the ulcers (Moffatt, 1992). The compression bandages are used in conjunction with other bandages that act as padding and protective layers to reduce the complications associated with compression bandaging.
Bandaging technique has changed little over the years. In the UK bandages are applied using a spiral or figure-of-eight technique and run from the base of the toes to just below the tibial plateau (Moffatt and Harper, 1997). In other countries other patterns of application may be used.
By starting at the base of the toes there is less chance of the bandage trapping interstitial fluid produced by normal systemic hydrostatic and osmotic pressure. In short, if the bandages started further up the foot or at the ankle there would be considerable swelling of the toes and forefoot. Application of the bandages up to the knee, just below the tibial plateau, ensures that the calf muscles are assisted in their pumping action, reducing superficial capillary and venous hydrostatic pressure by increasing the velocity of venous blood returning to the heart.
Changes in bandage technique
Bandage technology has developed somewhat since compression was first used. This is due to the development of elastomers which enable bandages to be designed for specific performance, giving accurate sub-bandage pressures. Care needs to be taken when applying compression bandages because an even pressure gradient is required along the length of the bandage between the ankle and the knee. In order to achieve this even tension has to be applied to the bandage while it is being applied.
The correct tension is indicated in manufacturers’ product information. It is also necessary to ensure that the required overlap is achieved with each turn, especially when a spiral technique is being used. Fifty per cent overlap is usually recommended. Some bandages have a line running along the middle of the bandage to guide the practitioner’s hand.
Achieving effective pressure
The ability to achieve a reliable effective outcome is a matter of supervised practice associated with an understanding of the principles involved. An experienced eye will be able to spot the gaps along the bandage that indicate poor alignment, which leads to a loss in the continuity of the pressure gradient and therefore lack of healing.
It is important that practitioners are aware of the requirements for effective and safe application of bandages because of the consequences for the patient of bandages that are not applied correctly. At best there will be no healing, with its consequences for the patient’s quality of life. At worst there may be pressure damage to the tissues that could lead to further ulceration or even amputation. The guidelines available in the UK state that a competent practitioner should apply the bandages (RCN Institute, 1997; NHS Centre for Reviews and Dissemination, 1997) (Box 1).
Effect of compression bandaging
The effect of compression bandaging can be summarised by La Place’s law (Box 2), which demonstrates the relationship between the pressure exerted on the leg and the parameters involved in creating that pressure (Moffatt and Harper, 1997).
Choice of bandages
Since the inception of the Charing Cross four-layer system (Moffatt, 1992) a number of different bandages have been developed for treating venous ulcers. This creates difficulties for practitioners and purchasers who have to make decisions about which system to use. In addition, purchasing protocols may lead to a discrepancy in the provision between primary and secondary providers.
Decision-making is further complicated by the potential presence of lower-limb arterial and microvascular disease, which can significantly affect the treatment of venous ulcers. If the patient is to receive the best evidence-based practice the practitioner needs to be familiar with the characteristics, indications for use and contraindications of the full range of bandages available.
In order to help simplify the problems associated with assessment, diagnosis and treatments an expert panel recently devised an algorithm or management pathway for leg ulcers (Stacey et al, 2002).
The range of bandages
There is now a considerable range of compression and related bandages available for the treatment of leg ulcers. They provide a range of pressures that vary to suit a range of circumstances. There have been a number of reviews of compression bandaging systems (NHS Centre for Reviews and Dissemination, 1997; Cullum et al, 2001; Eagle, 2001).
Eagle (2001) identifies the following bandage systems: multi-layer systems, long-stretch single bandages, short-stretch bandages providing minimal stretch, cotton crepe and tubular bandages.
With all compression bandage systems, padding using orthopaedic wool is used to redistribute pressure from bony prominences and to help provide even distribution of pressure under the compression bandages where the shape of the leg may militate against even graduated pressure.
Stacey et al (2002) define compression bandages as follows:
- Sustained compression - this includes any bandage system that can maintain sub-bandage pressures for a least one week;
- Multi-layered (elastic) compression - this group includes bandages with more than 50% stretch;
- Multi-layered (inelastic) compression - this group includes bandages with less than 50% stretch;
- Reduced compression - this group contains systems that deliver 15-25 mmHg sub-bandage pressure for patients with narrow ankles or an ankle brachial pressure index (ABPI) between 0.8 and 0.5;
- Compression stockings - primarily used for prevention of recurrence or in the care of varicose veins;
- Intermittent pneumatic compression - systems capable of delivering high compression for short periods of time.
There is some evidence to show that four-layer bandaging gives better healing rates than other systems (Nelson et al, 1995).
Inelastic systems tend to give a lower sub-bandage pressure when the patient is resting but give rigid support to the calf muscles when the patient is exercising - so much so that oedema may be reduced very quickly, requiring re-application of the bandage within 36 hours.
In the multi-layer system the total pressure exerted is the sum of the pressures exerted by the individual bandage layers.
To ensure the safe and effective application of bandages competent practitioners should undertake a holistic assessment of the patient before any bandages are applied. This should follow a clearly identified and logical path (RCN Institute, 1997; Morison and Moffatt, 1994; NHS Centre for Reviews and Dissemination, 1997).
Stacey et al (2002) see ultrasonography and plethysmography as fundamental methods of assessing the state of the arterial and venous systems of the lower leg. Assessment should also encompass all aspects of the ulcer, the condition of the leg and the health and past medical history of the patient. It should include consideration of the factors influencing the health-related quality of life (Franks et al, 1994). In relation to bandaging, the assessment should include the following: circumference of the ankle, prominences of bones, level of activity of the patient, position and size of the ulcer, level of exudate, ABPI, signs of ischaemia in the leg, history of cardiac disease, presence or absence of diabetes mellitus, and previous experience of compression bandaging
The ABPI simply gives the ratio between the highest brachial arterial pressure and the highest of the foot and ankle pulses (Vowden and Vowden, 2001). It is essential to remember that the ABPI determination should also be carried out by a competent practitioner and no patient should have compression bandaging applied unless they have had an ABPI assessment.
Prominences of bone
There is an ever-present danger of local tissue damage and possible necrosis related to elevated sub-bandage pressure over bony prominences, such as the tibial crest. This can be overcome by noting their presence and adding padding as appropriate to reduce pressure.
The measurement of ankle circumference is vital to safe compression bandaging. As the circumference of the ankle decreases, the pressure exerted by a bandage of a given width increases (La Place’s Law). Most of the standard bandage systems are designed to fit ankle circumferences between 18-25cm.
Above 25cm the pressure exerted by standard bandage systems are somewhat reduced, therefore bandages with a greater degree of elasticity need to be used. Similarly an ankle circumference of less than 18cm needs padding to increase the circumference or a lower level of compression.
Referral criteria for problematic leg ulcers includes allergy, inability to tolerate compression, uncontrolled pain, no reduction in ulcer size in one month, ulcer duration greater than six months, cellulitis unresponsive to treatment and frequent recurrence (Stacey et al, 2002; RCN Institute, 1998).
Compression therapy remains the mainstay of treatment for venous leg ulcers. However, treatment evolves and changes. Practitioners need to seek out best practice to ensure that their actions have a positive outcome for their clients.