- 1 - Welcome to the thirteenth edition of the Dressings Times which contains information on a new type of bandage, advice on the use of dopplers, and details of two interesting wound management queries received recently by SMTL. New developments in bandaging During the last few years, numerous articles on bandages and bandaging have appeared in the medical and nursing press and a performance-based classification system for these materi- als has also been described.1 In particular, much attention has been given to the importance of compression in the treatment of circulatory disorders of the leg and the need for adequate compression in the prevention and management of venous leg ulcers. Several papers have described the use of high performance compression bandages such as Setopress and Tensopress,2,3 whilst others have discussed the use of the four layer bandage system.4 `Short-stretch' bandages, which do not contain elastomeric yarns, are unsuitable for the sustained application of high levels of compression,5 although they are able to provide lower levels of intermittent pressure to ambulant patients. Being relatively inextensible, they form a semi-rigid cover- ing to the leg which resists the changes in limb geometry that occur cyclically during walking. This constriction generates local pressure on the surface of the leg which in turn is transmitted inwards onto the veins and thus facili- tates venous return. Because the pressure developed beneath such bandages is not continuous, they may sometimes be ap- plied to ambulant patients with venous leg ulcers that have an arterial component. However, in such situations, all forms of compression should only be applied on medical ad- vice, for excess or inappropriate compression can have seri- ous consequences for the patient.6 In addition to their use in applying compression, bandages, particularly the non-elastomeric type, have other functions such as the provision of support to injured joints The short-stretch bandages most commonly used in the United Kingdom are the familiar `crepe' products made from simple woven fabrics that have a limited degree of elasticity im- parted by heavily twisted cotton yarns. The official Crepe Bandage of the British Pharmacopoeia, which contains wool and cotton threads in the warp, was first described in the 1922 supplement to the British Pharmaceutical Codex of 1911. This supplement also contained a specification for Cotton Crepe Bandage, more familiarly known by its brand name of Elastocrepe. Although numerous other types of woven cotton bandages have been developed - frequently to reduce or contain manufactur- ing costs, the only other crepe-type bandage to achieve of- ficial status was Cotton Stretch Bandage. Unlike Crepe and Cotton Crepe, this failed to gain a place in the Drug Tariff and is therefore not available on prescription in the commu- nity. Whilst the existence of structural standards for bandages ensures that the products concerned are of uniform construc- tion, they also effectively limit more general widespread acceptance of novel bandages manufactured using alternative yarns or improved manufacturing techniques. The bandage classification system referred to previously seeks to over- come some of these problems by defining the performance rather than the structure of the products concerned. Until recently, attempts to produce a cheaper and clinically ac- ceptable support bandage utilising modern materials and techniques have proved disappointing. One product, Tenso- Ideal, despite meeting the laboratory performance require- ments for a support bandage, was not universally accepted by medical and nursing staff as it was considered to be too lightweight with limited conformability. Recognising these criticisms, the manufacturers of Tenso-ideal, Smith and Nephew, are about to replace it with two new developments. The first of these contains 65% cotton and 35% nylon and is of woven construction. Called Soffcrepe, it is intended to compete with Crepe and Cotton Crepe BP. The second develop- ment, simply known as HQ Crepe although similar in construc- tion, is more lightweight and contains 53% cotton and it is intended to be an alternative to the cheaper non-official crepes in use at the present time. When tested in the laboratory, both new bandages meet the requirements of the performance test for a Type 2 bandage, but in addition, unlike Tenso-ideal, their construction is such that they also look and feel more like traditional `crepe' bandages which should greatly enhance user accept- ability. Neither bandage is available on the Drug Tariff as yet, but if clinical assessments prove satisfactory, and the bandages achieve an early listing, their anticipated costs are such that their inclusion could result in annual UK savings of about 40% (0.5m) compared with Cotton Crepe and 10% (0.2m) compared with Crepe. We await developments with interest. References 1. Thomas S., Bandages and Bandaging: The science behind the art, Care Science and Practice, 1990, 8, (2), 56-60. 2. Thomas S., et al., Compression therapy in an obese pa- tient, J Wound Care, 1992, 1, (1), 19-21. 3. Logan R.A., et al., A comparison of sub-bandage pressures produced by experienced and inexperienced bandagers, J Wound Care, 1992, 1, (3), 19-21. 4. Backhouse C.M., et al., Controlled trial of occlusive dressings in healing venous ulcers, Br J Surg 1987,74,626-627. 5. Raj T.B., et al., How long do compression bandages main- tain their pressure during ambulatory treatment of varicose veins? Br J Surg, 1980, 67, 122-124. 6. Callam M.J., et al., Hazards of compression treatment of the leg - an estimate from Scottish surgeons, Br Med J, 1987, 295, 1382. The use of Dopplers Ulcers that develops as a result of arterial disease should not be subjected to compression as this could compromise the blood supply to the affected limb and thus cause further se- rious damage. An accurate diagnosis to differentiate be- tween venous ulcers and those associated with ischaemia is therefore essential before treatment with compression is commenced. One technique that is widely used to assess arterial blood flow is continuous wave ultrasound in which low intensity sound waves are directed through the tissue toward the blood vessels. As the sound waves strike the moving blood cells, they are reflected back and the change in frequency is re- lated to blood velocity (the Doppler effect). A number of hand-held Doppler instruments are available with a range of probes that are suitable for a variety of appli- cations. For leg ulcer work however, a transducer probe that works in the range of 4-10 MHz is generally used. This is connected by means of a flexible lead to a power supply and audio unit. A comprehensive review of the theory and prac- tical applications of Doppler ultrasound in medical diagno- sis was published by Wells in Care Science and Practice 1990, 8, (1), 12-30. The Doppler technique is relatively easy to perform, and is very useful for detecting pedal (foot) pulses, particularly in patients with venous oedema. The presence of arterial insufficiency is determined by dividing the ankle systolic pressure by the brachial systolic pressure to obtain the `ankle pressure index' or API. Patients with normal API ra- tios will have a ratio greater than 0.9, Values in the range of 0.5 - 0.9 indicate varying degrees of ischaemia but pa- tients with an API < 0.5 would be considered to be highly ischaemic, and would probably be experiencing rest pain. Most experts would be unlikely to apply compression to a leg with an API < 0.8. The following practical advice on the use of Dopplers has been abstracted from the work of Janice Cameron, Senior Nurse, Department of Dermatology, Churchill Hospital, Ox- ford. With the patient in a supine position, the blood pressure is first measured in the arm at the brachial artery in the nor- mal way. The sphygmomanometer cuff is then placed around the ankle above the malleoli. If there is an ulcer present at this point, it should first be covered with a piece of plastic film prior to the application of the cuff. Alternatively, if this is too painful for the patient, the cuff may be placed proximal to the ulcer. Coupling gel is placed on the skin at the position of the dorsalis pedis and the Doppler trans- ducer is slid over the area at an angle of 45, ensuring that the gel fills the space between the probe and the skin, un- til a strong pulsatile sound is detected. Once the pulse has been located, the cuff is inflated in the normal way un- til the pulse can no longer be heard. The cuff is then slow- ly deflated until the pulse becomes audible once again. The pressure recorded at this point is a measure of the ankle systolic pressure. (If the dorsalis pedis pulse cannot be located, the posterior tibialis can be used instead.) Is is essential that the transducer remains in position over the artery while the pressure is being taken for if it slips slightly out of position the sound is lost and a false low reading is recorded. If there is any doubt, the process should be repeated. Where there is no arterial insufficiency, the ankle pressure should be the same as, or greater than that of the arm and this would result in an API>1.O. If, however, the arteries have calcified, they may not occlude with pressure and this would result in an erroneous reading. Where the reading is clearly inconsistent with the clinical picture, or very low API values are recorded, referral of the patient to a vascu- lar assessment clinic should be considered. The use cotton wool in wound management In these enlightened times most experts would agree that there is little place for cotton wool in wound management because of the problem of fibre loss. This has not always been the case however, and for many years absorbent cotton, as it is more correctly known, was used extensively in the form of pads or compresses. The following account of the use of cotton wool in the treatment of a necrotic pressure sore appeared in the Lancet in 1850. I was summoned to visit a young girl, aged 16, residing some distance in the country, who had been laid up with typhus fever for the previous month. I had seen her for the first time about a fortnight before. It is probable that I might not have been called to this case, had not the nurse ob- served (to use her expression) that the patient was getting as black as a coal under her. Having examined the poor girl, I found that matters were almost as bad as the nurse had stated; the integuments covering the nates were quite black, and the posterior spine and crest of the ilium almost laid bare; the discharge therefrom was very profuse and offen- sive. She was very weak, and dreadfully emaciated. Her tongue being clear, and bowels open, I desired them at once to give her some wine and bark, at the same time allowing her some nourishing broth and beef tea. It occurred to me that I would apply some cotton wadding to the part, with the intention of giving her a soft cushion to lie on, as well as to absorb the abundant discharge; she complained and cried much from her back, but after the application was made she appeared much relieved. I made my second visit in three days after, having desired the nurse not to remove the cotton, except in placed where it became moist from the discharge. On examination, I found things going on favourably, the part covering spine and crest of ilium were granulating very nicely, the slough covering them had already partially sepa- rated, and the parts beneath were looking very well. I did not visit her again until to-day (March 4th), and I find that she is convalescent. I have also treated successfully a few cases of varicose ulcers of the lower extremeties, by the application of the cotton wadding; the manner of apply- ing it is simply to cover the ulcer, and dressing the pa- tient every second or third day, a roller being applied af- ter the cotton. At the same time I enjoin perfect quietness, and keeping the limb in the horizontal position. I have found three weeks or a month a sufficient time to get them well. Robert Jones, M.R.C.S.L., Conway, North Wales. Similar success with absorbent cotton was reported by M. Gurin working in Paris in the 1870s. After washing wounds with strong alcohol, he applied cotton wool in successive layers rolled round and round the limb, each layer being compressed as tightly as possible by a bandage (the fore runner of the four layer bandage system perhaps?). The com- pleted dressing was left in-situ for two or three weeks un- til the pus soaked through. M. Gurin claimed that the suc- cess of this treatment was due to the filtration of the air by the cotton wool, the uniform elastic compression of the wound and the immobility of the injured limb. In 1880, in a letter to the Lancet, Dr Samson Gamgee de- scribed how he produced the prototype of the first commer- cial dressing pads by wrapping absorbent cotton in a layer of fine gauze similar to that used by nurserymen to stretch under the roofs of their conservatories. The gauze he used initially was unbleached and therefore not absorbent, as he demonstrated by floating a pad of absorbent cotton covered with a single layer of gauze on the surface of water for many days. He further showed that if the gauze was bleached, a process which removes the natural oils from the cotton fi- bres, the fabric became absorbent and the pad rapidly became saturated with fluid. This combination of absorbent gauze and cotton fibre was soon produced commercially by Robinson and Son under the name of Gamgee Tissue. Current controversies Vitamin C and the formation of pressure sores. Vitamin C is an essential co-factor for the hydroxylation of proline and lysine prior to their incorporation into colla- gen and depletion can lead to decreased wound strength and dehiscence. For this reason, vitamin C supplements are some- times given to patients with leg ulcers, pressure sores, and other wounds in an attempt to facilitate or accelerate heal- ing. An article in the British Medical Journal (1992,305,925) has recently suggested that depressed levels of total leucocyte vitamin C (TLVC) may be associated with the development of pressure sores in high risk patients (elderly patients with femoral neck fractures). A study revealed that of 21 pa- tients aged 75 or over who were admitted to the orthopaedic unit at St James University hospital in Leeds, 10 subse- quently developed pressure sores during their hospital stay. Biochemical analysis revealed that the TLVC of those pa- tients who developed sores was less than half that of pa- tients who did not. The reason for this is not clear, but it is known that in addition to its effect upon collagen production, Vitamin C has a powerful antioxidant effect and it also stimulates the activity of lymphocytes and neu- trophils. The authors concluded that a deficit would proba- bly have an adverse effect on tissue recovery after a period of ischaemia. It could be argued therefore, that all pa- tients who are judged to be at risk of developing pressure sores should be given vitamin C supplements prophylactically unless the results of biochemical studies indicate that TLVC levels are normal. Eusol: the ultimate solution. Readers of the Dressing Times will recall that we have pre- viously published a number of articles on the use of hypochlorites. For those with an interest in this area, a recent issue of The Journal of Wound Care (November 1992) contains what must be the most definitive and unbiased re- view on the subject yet produced. Containing some 94 refer- ences, we believe is essential reading for all those who wish are interested in the great `Eusol' debate. The effect of NSAIDs on wound healing. From time to time we receive requests for information on the effect of non-steroidal anti-inflammatory drugs (NSAIDs) up- on wound healing. Unlike the corticosteroids, which are known to have a marked effect upon both the skin and the healing process, hard evidence of any wound healing problems associated with the use of NSAIDs is hard to find, although they are often cited as a potential source of problems in this area. This topic was discussed in recent editions of the British Medical Journal (1992 305, 812 and 1161) with particular reference to their use in the management of perioperative pain. For this application, NSAIDs given in combination with opioids are said to offer several advantages over the use of opioids alone. In the absence of hard evidence to the contrary, it was concluded that the benefits which re- sult from the perioperative administration of NSAIDs appear to outweigh any theoretical adverse effects on subsequent wound healing but clearly this is an area where controlled studies are urgently required. From the postbag An environmentally-friendly patient? The Dressing Times recently received a query from a reader who was concerned that one of their patients was changing colour! The unfortunate individual had a leg ulcer that suddenly started to produce copious amounts of bright green exudate that stained their dressings and bed linen. The pa- tients was receiving zinc supplements and the enquirer want- ed to know if these could be responsible for this effect. As it was considered most unlikely that the administration of oral zinc could cause this colour change, an alternative explanation was required. It is well known that certain species of bacteria can produce coloured pigments, and one organism, Pseudomonas aeruginosa, forms a blue-green colour similar to that described. The enquirer was therefore ad- vised to send a wound swab for bacteriological examination which in due course showed a heavy growth of this microor- ganism. A new wound cleansing agent? A second query proved rather more difficult to answer. A consultant in one hospital has apparently recommended that patients with open and cavity wounds be instructed to bathe with Badedas foam bath as part of their treatment. A nurse working in the hospital concerned has asked for any informa- tion or data to support this practice. We have been unable to find any references in the literature so if any Dressing Times readers have used this product in wound management, we would be very pleased to hear from them. Future of the Dressings Times Due to financial constraints within the NHS, the future of the Dressing Times as a free publication is now in some doubt. We would be very interested to hear from readers or organisations who would consider taking out subscriptions should this become necessary. The Dressings Times is produced by the Surgical Materials Testing Laboratory, (SMTL) Bridgend General Hospital, Quarella Road, Bridgend, Mid Glamorgan. Telephone No.(0656) 752820, Fax 0656 752830.