P.D. Thomson

Superoxide dismutase prevents lipid peroxidation in burned patients

Animal models and human studies have shown that conjugated dienes rise in the plasma after thermal injury. These dienes may serve as a marker of oxygen radical-mediated tissue injury. Twelve burn patients were randomized to receive the antioxidant enzyme polyethylene glycol-conjugated superoxide dismutase (PEG-SOD). Patients received either 500 or 1000 units per kilogram of PEG-SOD intravenously within 6 h of injury. Plasma samples were collected and conjugated diene levels were compared to diene levels of burn patients not treated and to diene levels from normal volunteers. Conjugated diene levels were increased in burn patients. PEG-SOD in either dose initially decreased conjugated diene levels in the plasma of both treatment groups. By 72 h, the diene levels increased in the 500 unit/kg group, but remained at near control levels in the 1000 unit/kg group for up to 200 h after injury. These data suggest that PEG-SOD is capable of preventing conjugated dienes formed as the result of oxygen radical production. It appears that 1000 units/kg is more effective than 500 units/kg in preventing conjugated diene formation.

A review of the reconstructive surgery needs of 3167 survivors of burn injury

A retrospective review of all patients admitted for acute care over the past 15 years was undertaken to identify readmission for reconstructive surgery. Of 3167 survivors 629 or 19.9 per cent were readmitted for at least one reconstructive procedure. Those patients requiring readmission for reconstructive surgery were younger and had larger total body surface burns compared to the group that were not readmitted for reconstructive surgery. The percentage of patients now being readmitted for reconstructive surgery is decreasing significantly and covers all size burns. The most common area of reconstruction, by frequency, involved the hand and wrist, arm and forearm, face, and neck. These data indicate that the goal of reducing the incidence of burn scar contractures in this patient population is being achieved. However, further work needs to be done to reduce the frequency of reconstructive surgery and to identify those variables which predispose patients to burn scar contractures which are amenable to intervention.

Metabolic alterations in burn patients: detection of adenosine triphosphate degradation products and lipid peroxides.

Seven patients admitted to the University of Michigan Burn Center with greater than 20 per cent total body surface area burns were studied for evidence of oxygen radical production, as demonstrated by serum lipid peroxides, and adenosine triphosphate (ATP) degradation, based upon ATP degradation products in blood (serum purines) and urine (urine purines and urine uric acid). Lipid peroxides (conjugated dienes) were elevated beginning on day 1 postburn and remained elevated up to day 5, the duration of the study. ATP degradation products were elevated during the initial 24 h postburn but rapidly fell to normal levels. This study provides evidence of biochemical alterations in thermally injured patients similar to observations in animal models which demonstrate that ATP degradation and the production of oxygen radicals are part of the initial response to thermal trauma.

Microbiology and healing of the occluded skin-graft donor site

Delayed healing of skin-graft donor sites may be costly and life-threatening, especially in patients with large body surface area burns. A donor site dressing should maximize the ability of the wound to heal without increasing the risk of local infection, systemic infection, or both. Specifically, the possibility of a secondary infection may either slow the healing process or ultimately convert the donor site into a full-thickness skin loss. A number of materials ranging from gauze to biologicals have been investigated for use as donor site dressings. The use of hydrocolloids for donor sites has been widely studied and has shown improved healing rates over the rates reported for conventional dressings. Our recent study using hydrocolloids confirmed earlier research that showed fewer infections and more rapid donor site healing.

A survey of wound monitoring and topical antimicrobial therapy practices in the treatment of burn injury.

A survey was done to determine how burn wound microbial monitoring is performed and how topical antimicrobial agents are employed. The survey was sent to 90 burn-care facilities, which comprised most of the major burn centers in the United States. The survey contained questions concerning frequency and techniques of wound monitoring, personnel involved in monitoring, as well as questions about how decisions were made to initiate topical antimicrobial therapy, which agents were selected, and how they were administered. Sixty of 90 facilities (66%) responded to the survey. Although there were few areas of unanimous agreement, several trends did emerge. Most facilities monitored burn wounds for microbes (92%). Wound monitoring was typically done at least twice weekly by either surface swab or quantitative biopsy. Nursing staff played a significant role in specimen collection in 69% of facilities and were solely responsible for obtaining biopsy specimens in 29% of facilities that used biopsies exclusively. All responding facilities used topical antimicrobial agents; silver sulfadiazine was the most popular (95%). Only 33% of facilities surveyed had their own laboratory for microbial monitoring. Rapid techniques for early diagnosis of wound sepsis were used in 20% of units, and topical antimicrobial testing was used in 17% of facilities surveyed.

Leukopenia in acute thermal injury: evidence against topical silver sulfadiazine as the causative agent.

White blood cell data from time of admission to 4 days after burn injury was retrospectively reviewed to determine differences in the incidence of leukopenia in patients with burn injuries treated topically with either silver sulfadiazine or silver nitrate. WBC counts decreased in both groups of patients during the first 3 days after burn injury. An incidence of leukopenia (WBC count less than or equal to 5000/mm3) was observed in of 40 (47.5%) patients treated with silver sulfadiazine and in 13 of 30 (43.3%) patients treated with silver nitrate. There was no statistical difference in the incidence of leukopenia between the two treatment groups. These data suggest that silver sulfadiazine may not be the cause of the leukopenia observed early after burn injury.

Rapid quantification of bacterial and fungal growth in burn wounds: biopsy homogenate Gram stain versus microbial culture results

A prospective analysis of 370 burn wound biopsies was done to correlate Gram-stain results from biopsy homogenates with quantitative culture results. The number of bacteria seen in a total of 10 oil immersion microscope fields of Gram-stained homogenates was correlated with significant microbial growth (1 x 10(5) organisms/gram of tissue) of the same biopsy homogenate plated on trypticase soy agar. Of the biopsies examined, Gram-negative rods were present in 36.8 per cent, Gram-positive cocci in 49.7 per cent and yeast in 15.9 per cent. Mixtures of organisms were present in 24.3 per cent. When Gram stains showed one or more organisms per oil immersion microscope field, the correlation with significant microbial growth was 94.5 per cent or more. When five or more organisms were seen per field, the correlation with significant growth became 97 per cent or greater. When no organism was seen on Gram stain, the cultures grew significant numbers of organisms 19.1 per cent of the time or less. This false-negative rate was considered to be high. It is believed, however, that this method of early detection of significant burn wound microbial growth may prove to be valuable in the management of severely burned patients.

Gastrointestinal haemorrhage in burn patients.

Gastrointestinal haemorrhage after burn injury remains a potentially lethal problem. A retrospective review of 3852 burn patients over 15 years revealed an incidence of gastrointestinal haemorrhage of 2.2 per cent and a mortality of 0.16 per cent. This low incidence of haemorrhage and mortality can be directly related to an aggressive prophylactic treatment with antacid and titration of the gastric pH to 5.5 or above. With this aggressive management programme, few operative procedures were required. A review of autopsy data showed that the site of haemorrhage was distributed throughout the gastrointestinal tract with the predominant site being the stomach.

Burn wounds: Infection and healing☆

Early wound closure is the ultimate goal of burn care. While excisional therapy is necessary in the treatment of both large, full-thickness and deep, partial skin-thickness burns, the majority of burns are superficial partial skin-thickness injuries requiring a different clinical approach. In superficial wounds, cosmetic and functional restoration in conjunction with relief from pain and prevention of infection is as important as rapid wound closure. The moist wound healing associated with hydrocolloid dressings may provide an alternative treatment modality for certain partial-thickness injuries. In comparable wounds, these dressings produce good functional and cosmetic results, rapid reepithelialization, and improved patient comfort.

Donor site repair.

Delayed healing of skin donor sites may be costly and life threatening, especially in patients with large body-surface area burns. A donor site dressing should maximize the ability of the wound to heal without increasing the risk of local infection, systemic infection, or both. Specifically, the possibility of a secondary infection may either slow the healing process or ultimately convert the donor site to a full-thickness wound. A number of materials, ranging from gauze to biological agents, have been investigated for use as donor site dressings. The use of hydrocolloids for donor sites has been studied extensively, and, compared with conventional dressings, improved healing rates are reported. Our recent study using a hydrocolloid dressing confirmed earlier research showing fewer infections and more rapid donor site healing.