Cheng-Hui Fang

Enteral Feeding in Burn Hypermetabolism: Nutritional and Metabolic Effects of Different Levels of Calorie and Protein Intake

Enteral nutrition was provided by continuous pump-controlled gastrostomy tube feeding for 14 days in 97 guinea pigs bearing a 30% full thickness burn. Seven defined combinations of caloric and protein intake were studied. With a caloric intake of 175 kcal/kg/day, equaling the measured energy expenditure, the animals receiving 10% of calories as protein had a significantly greater postburn weight loss (p less than 0.05) and muscle mass depletion (p less than 0.05), and a significantly lower muscle nitrogen concentration (p less than 0.05), serum albumin level (p less than 0.01) and liver nitrogen content (p less than 0.01). With the same caloric intake but with more than 20% of calories as protein, the weight loss and the muscle wasting were reduced, but not abolished, and the serum albumin level and liver nitrogen content were normalized. Also with the diets containing 200 kcal/kg/day the muscle tissue depletion could not be abolished. However, with this caloric intake, the animals given 20% of calories as protein had a lower weight loss and a higher serum albumin level (p less than 0.01), but also a greater fat infiltration of the liver (p less than 0.01). At both levels of caloric intake, the nitrogen balance correlated significantly with the level of nitrogen intake but did not correlate with the changes of body weight. The incidence of diarrhea was lowest in animals fed 20% protein calories at a caloric intake of 175 kcal/kg/day. All things considered, the best metabolic and nutritional results were obtained with diets containing 20 to 30% of calories as protein and providing a caloric intake that paralleled the measured energy expenditure.

Observations on stability and contraction of composite skin grafts: xenodermis or allodermis with an isograft overlay.

Composite skin grafts of xenodermis or allodermis with a thin split-thickness isograft overlay were evaluated for stability and contraction. Male inbred Lewis rats were used as recipients, with Buffalo rats serving as allogeneic dermis donors. Cryopreserved human skin was used for xenodermis grafts. The two components of the composite graft, the xenodermis or allodermis and the isograft overlay, were grafted in one operation to a surgically created wound. Wounds were observed for 1 year. The composite skin grafts took fairly well, although spotty loss of the overlaid isograft was noted. The xenodermis and allodermis remained grossly intact even at 1 year after grafting. However, composite skin grafts in this animal model contracted more than did sheet isografts alone.

Wound contraction following transplantation of microskin autografts with overlaid skin allograft in experimental animals

The wound contraction associated with a new grafting technique, transplantation of microskin autografts with overlaid skin allograft, was evaluated in a rat model. Male inbred Lewis rats were used as microskin autograft recipients while Buffalo rats were used as allogeneic skin graft donors providing a sheet allograft for overlay. This technique was compared with the use of sheet isografts. Wound contraction was observed for 4 months. The results showed that the application of autologous microskin grafting with allograft overlay was associated with more scar contraction than was the use of a sheet isograft. Maximum contraction to 43 per cent of the original size appeared at 7 weeks postgrafting in the microskin grafting group, while in the sheet isografting group the greatest contraction occurred at 4 weeks postgrafting when it retained 72 per cent of the original size.

Prospective clinical study of Hydron, a synthetic dressing, in delivery of an antimicrobial drug to second-degree burns.

This clinical trial prospectively evaluates the potential beneficial effects of antimicrobial drug delivery from a synthetic dressing (Hydron-AgSD) formed on second-degree burn wounds. A paste composed of polyethylene glycol-400, poly 2-OH ethylmethacrylate, and silver sulfadiazine (AgSD 1%-3%) matured within one hour to form a solid dressing. In 27 patients, comparable areas of second-degree wounds on the same patient were selected at random for test and control (silver sulfadiazine 1% only) sites. The mean total time of the synthetic dressing application per patient was about nine days, and each dressing remained in place for nearly four days. During this interval the control sites required four dressings changes. In 17 tests for infections, the control areas were contaminated but no bacteria were detected under the synthetic dressing; in three tests, the controls had no bacteria, whereas the synthetic dressing did. Healing of burns was similar under both types of dressing. Benefits of Hydron treatment included increased patient comfort because of the reduced number of dressing changes and, in some cases, greater freedom from contaminating bacteria.

A Preliminary Report on Transplantation of Microskin Autografts Overlaid with Sheet Allograft in the Treatment of Large Burns

The technique of transplantation of autologous microskin grafts (MG) with overlays of split-thickness skin allografts was used in the treatment of nine extensively burned patients. Preparation of MG includes: 1) mincing small pieces of split-thickness skin autografts into skin particles (SPs); 2) dispersing the SPs evenly on a piece of silk cloth; 3) transferring SPs to the dermal surface of an allograft sheet (20/1000 in.); 4) transplanting the allograft with SPs to the excised wound. The mean burn area (total/3 degrees, mean +/- SEM) of this group was 74.9 +/- 16.6/62.1 +/- 18.1% TBSA (range 40 to 94/28 to 90%). The mean age was 27 years (range 19 to 38). Early staged excisions followed immediately by MG applications were performed on 35 large body sites, including extremities, chests plus abdomens and backs. The mean area excised and grafted with MG was 41.7 +/- 11.0% TBSA (range 26 to 62%). The average time for complete healing was about six to seven weeks postgrafting. Eight patients survived; one died of overwhelming pulmonary infection 22 days postburn. Advantages of this technique are: 1) the great potential of MG to provide a large expansion ratio of 8:1 to 15:1, average greater than 10:1 in this series; 2) good maintenance of the healed graft to withstand trauma except in areas of repeated flexion; 3) ease of preparation and application with less cost compared to cultured epidermal sheet grafts; 4) prevention of infection in extremely large burns by providing continuous epidermal coverage following sheet allograft application.