A reliable and cost-effective in vitro assay of skin viability for skin banks and burn centers.

The tetrazolium salt, MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide), was used to evaluate the viability of fresh native human skin and cryopreserved human skin under a wide variety of conditions. Viability of fresh and cryopreserved skin was determined with our modification of the MTT assay, and compared with the well-described tetrazolium reductase assay. The MTT assay provides a precise and reproducible index of viability for both fresh and cryopreserved skin. In comparison, the tetrazolium reductase assay (1) is subject to higher levels of variability and, (2) underestimates the viability of fresh native skin. The precision, simplicity, and economy of the MTT assay support its utility in the routine assessment of skin viability in skin banks, burn centers, and skin biology research units.

Selective aggressive burn excision for high mortality subgroups.

Traditional teaching recommends major burn procedures be limited to successive 20% total body surface area (TBSA) excision and grafting procedures. This format theoretically reduces the surgical stress and limits the transfusion requirements to a level reasonably tolerated by patients. We have treated 14 patients with thermal burns involving greater than 30% TBSA. These patients underwent excisions ranging from 30 to 70% TBSA at the initial operative escharectomy. Tangential and fascial excisions were employed, depending upon the depth of injury, and autografts and/or allografts were utilized for wound closure. The results of this technique yielded an overall 71% survival. Time from burn to last autograft and hospital stay tended to be shortened or unchanged when compared to national averages. This series demonstrates the feasibility of performing early major escharectomy in a selected burn population without apparent increased surgical risk compared to patients treated by conventional staged excision. Although burn wound sepsis and mortality appeared favorably affected by this technique, the small population size was unsuitable for adequate statistical analysis.

Effectiveness of prophylactic antibiotics in the outpatient treatment of burns.

We compared wound infection rates in 133 outpatient burns treated with prophylactic antibiotics in our emergency room and 161 similar, untreated burns. Infection rates in the treated and untreated groups were 3.8% (5/133) and 3.1% (5/161), respectively. Since this was an observational cohort study, it was necessary to demonstrate the comparability of treated and untreated groups with respect to risk factors for infection, including patient age, size, location, and etiology of the burn injury, time since injury, and presence of co-morbidity. The groups were found to be comparable for all risk factors except size of burn: larger burns were over-represented in the treated group (p less than 0.05). Even after controlling for size, antibiotic use did not lower the infection rate. These results argue strongly against routine use of systemic antibiotics in the treatment of outpatient burns.