J.C. Lawrence

Burn bacteriology during the last 50 years.

By nature bums contain devitalized tissue. The wound is surrounded by damaged and oedematous tissue kept moist by a flow of serous exudate at a temperature approaching 37”C, hence excellent conditions are available to support the growth of a wide variety of bacterial species. Up to half a century ago bacterial colonization of bums was considered inevitable and septicaemic complications were not regarded as unusual. Infective problems of bums were largely ignored because bums did not seem amenable to Listerian antisepsis (Lowbury, 1985). Artz and Reiss (195 7) reported that at least half of the deaths following burning could be attributed to bacterial infection. Despite many major advances infection remains an important factor in the mortality and morbidity associated with bums (Pruitt, 1984). Much of the bacteriological work considered in this paper draws on the experience of the Bums Unit at Birmingham which holds a complete bacteriological record from 1950 to 1989. This account is, therefore, somewhat parochial, but the principles probably apply to other bum treatment centres. Although a comparison between Birmingham, whose unit comprises two elderly converted Nightingale wards, and Billericay, Essex, having a modem purposedesigned unit, showed no major differences in the incidence of wound colonization (Lawrence, 1985), other centres could differ as the nature of the problem depends on a variety of factors such as: the workload, the number and expertise of staff and the arrangement of the treatment unit (Lawrence, 1987a).

The treatment of small burns with a chlorhexidine-medicated tulle gras

Abstract The effect of a tulle gras dressing medicated with chlorhexidine was shown to reduce significantly the incidence of Staphylococcus aureus in experimental burns made on guinea-pigs. This dressing apparently did not interfere with wound healing. A controlled clinical trial is described which compared the effects of non-medicated tulle gras with tulle gras containing 0.5 per cent chlorhexidine on the incidence of S. aureus and other bacteria in burns treated in an outpatient department. The medicated dressing significantly reduced the incidence of S. aureus in these wounds. A high proportion of antibiotic-resistant staphylococci were isolated from patients in the trial; the value of chlorhexidine in this situation is discussed.

The perinecrotic zone in burns and its influence on healing

THREE well defined zones can be discerned in a typical thermal burn of the skin; these have been characterized by Sevitt (1949) and Jackson (1953). Contact of the skin with sources of heat frequently causes immediate coagulation of tissue protein (Moritz, 1947) and this zone of coagulation is surrounded by a region of capillary stasis and this, in turn, is bounded by an area of hyperaemia (Fig. 1); these zones which can often be discerned on the surface (Fig. 2) also occur in depth (Fig. 3). Heat coagulation of tissue protein due to burning can almost certainly be regarded as irreversible whereas hyperaemia, on the other hand, possibly represents minimum tissue damage and rarely presents any local problem other than pain, though pigmentation sometimes occurs and this may be permanent. There are also changes in capillary permeability within this region which may persist for 2 days or sometimes longer (Sevitt, 1957). Until recently the tissue damage associated with the capillary stasis that develops following a burn was considered irreversible (Jackson, 1969). The development of stasis and its subsequent pathology has been described by Sevitt (1949, 1957); the condition develops within a short time of burning and persists for some days. During this time the trapped blood ceils and the surrounding tissue become necrotic and eventually indistinguishable from coagulated tissue. Thus, if the zone of stasis penetrates below the plane of the deepest epithelial structures (hair follicles, sweat glands, etc.) the burn will be full skin thickness in depth (see also Fig. I). Many full skin thickness burns require surgical intervention to facilitate healing; surgery may either be performed early by excising all damaged tissue and applying skin grafts to the obviously viable bed thus exposed or grafting is delayed until necrotic tissue has formed a slough and granulation tissue has appeared below the burn eschar. Some years ago Janzekovic (1968) showed that some burns did not require as complete an excision as hitherto supposed in order to provide

The aetiology of scars

THE Oxford English Dictionary defines a scar as “the mark resulting from the healing of a wound or disease process” or “a fault or blemish remaining as a trace of some former condition or resulting from a particular cause”. Thus, as might be expected, a substantial proportion of scars arise either as a consequence of mishap or by reason of planned surgery. Some scars, such as striae gravidarum, arise ‘naturally’ as a consequence of changes in body shape. Apart from pregnancy, breast development in some women and gross obesity in’some individuals can produce similar appearances. The ageing process often causes non-congenital permanent wrinkles to form; the dermal matrix may also change-this, together with alterations in connective tissue fibres, may cause the skin to sag and become deeply furrowed by wrinkles. A few scars are induced deliberately for purpose of body decoration-the ritual markings of certain African tribes (Fig. 1) and the duelling scars popular with officers in the Prussian army during the nineteenth century (Fig. 2) afford examples. Tattooing can, perhaps, be regarded as a form of self-inflicted scar, although disturbance of the skin contours is usually minimal (Fig. 3). Accidental tattooing can arise as a consequence of trauma-impacted road dirt and penetration of the skin by detritus following an explosion are not uncommon (see Groves, these proceedings, Fig. 3). Sometimes trauma, particularly burns, causes a permanent reduction in hair density or permanent changes in skin pigmentation even though otherwise the skin appears to have regained a normal texture and appearance. infection is a common cause of scarring; boils and carbuncles due to staphylococcal infection frequently leave a permanent scar. Severe acne and vaccination afford other examples as do conditions such as leprosy. Possibly the majority of Fig. 1. Keloid scars deliberately produced for purposes of body decoration.

The use of GORE-TEX bags for hand burns

Clinical and laboratory studies were made to compare the water vapour permeability, bacteriological properties and clinical performance of polythene and polytetrafluoroethylene fabric (GORE-TEX) bags in the treatment of hand burns. Polythene bags are virtually impermeable to saline, whereas GORE-TEX bags containing silver sulphadiazine cream show a water vapour permeability of 0.53 ml/cm2/day, resulting in a 30 per cent weight reduction of added water after 48 h. Clinically, hand maceration and accumulation of exudate are significantly reduced in hands treated in GORE-TEX bags. The mean daily volume of accumulated exudate for GORE-TEX bags was 37 ml compared to 83 ml for polythene (P less than 0.01). When adjusted for the percentage area of the hand surface burned, this reduction remained significant (P less than 0.005). A tendency for less pain and better hand movement was noted with GORE-TEX bags. There were no significant differences in rate of healing or bacterial colonization of the burned hand between the two type of bags. GORE-TEX bags prevent skin maceration and accumulation of exudate, allowing ease of burn assessment and improved hand function. They are also durable and non-slip, thus increasing patient independence.

A century after Gamgee

THE ready availability in every developed society of two common dressing materials, absorbent cotton wool and absorbent gauze, is probably taken for granted. They were partly invented and certainly popularized just over 100 years ago by a Birmingham surgeon, Joseph Sampson Gamgee (Fig. 1). Joseph Sampson Gamgee, the eldest son of a veterinary surgeon, was born in Leghorn, Italy, in April 1828. At the age of 19 he decided to follow in his father’s career, and in 1847 came to -London where he gained his veterinary diploma. While still a student in this discipline he was allowed to attend lectures at University College Hospital. Gamgee’s work was so outstanding that he was persuaded to qualify in medicine. By the time he was admitted to membership of the Royal College of Surgeons in 1854 he had not only won five gold medals and the Liston prize for surgery but also published several articles concerning the treatment of fractures, including the first account in Britain of plaster-of-Paris bandages (Gamgee. 1854; Bishop, 1959). In 1855 Gamgee was appointed Surgeon to the British Italian Legion and became Superintendent of the Legion Hospital stationed in Malta during the Crimean War. Here he gained valuable experience in wound care. After the Crimean campaign Gamgee spent a brief period as Assistant Surgeon to The Royal Free Hospital before being appointed Surgeon to the Queen’s Hospital Birmingham, in 1857. Gamgee would probably recognize the building today (Fig. 2) (it has been the Birmingham Acci-

Tulle-gras dressings

Abstract Tulle-gras backed with a soluble polyvinyl alcohol film has been compared with standard tulle-gras to treat patients with minor burns. The new material although less comformable to body contours offered the advantages of decreased dressing time and improved patient comfort. No adverse effects were observed on wound flora or healing rate.

Bilateral metastatic endophthalmitis as a complication of major burns

Metastatic infection of the eye is a rare complication of burns. The following report describes a patient with endophthalmitis occurring as a complication of major burns. The diagnostic difficulties that arose are discussed and the recommended treatment outlined.

Principles of design of burn units: report of a working group of the British Burn Association and Hospital Infection Society

The overall design of burns units will depend on the required size and available finance. The Working Party has considered the optimal location and specific requirements of a unit, including dressing, operating and isolation rooms, intensive care and ancillary facilities. Various possibilities for ventilation systems in these areas have also been discussed.

The healing of tangentially excised and grafted burns

Abstract Recent work has shown that certain types of burn do not need complete excision to provide an adequate bed for grafting, this procedure has been named tangential excision. The principles of the operation are described and it has been shown that the clinical situation can be simulated by suitable animal experiments. The graft bed exposed by tangential excision will successfully accept a graft provided certain criteria are met even though this bed contains tissue that is metabolically and histologically abnormal. If such beds are not grafted, this abnormal tissue becomes necrotic and forms a slough. Tangential excision and grafting not only prevents this secondary necrosis but also permits some of the damaged tissue to recover. The mechanism of healing is described both in relation to the take of grafts and to the recovery of altered tissue in the graft bed. The theoretical and practical implications of these findings are discussed.