H. D. Peterson

Effect of inhalation injury, burn size, and age on mortality: a study of 1447 consecutive burn patients

The relative impact of inhalation injury, burn size, and age on overall outcome following burn injury was examined in 1447 consecutive burn patients over a five and a half year period. The overall mortality for all patients was 9.5% (138 of 1447). The presence of inhalation injury, increasing burn size, and advancing age were all associated with an increased mortality (p < 0.01). The incidence of inhalation injury was 19.6% (284 of 1447) and correlated with increasing percent total body surface area (%TBSA) burn (r = 0.41, p < 0.01) and advancing age (r = 0.15, p < 0.01). The overall mortality for patients with inhalation injury was 31% (88 of 284) compared with 4.3% (50 of 1163) for those without inhalation injury. Using multivariate analysis inhalation injury was found to be an important variable in determining outcome, but the most important factor in predicting mortality was %TBSA burn (accuracy = 92.8%) or a combination of %TBSA burn and patient age (accuracy = 93.0%). Adding inhalation injury only slightly improved the ability to predict mortality (accuracy = 93.3%). The presence of inhalation injury is significantly associated with mortality after thermal injury but adds little to the prediction of mortality using %TBSA and age alone.

Etiology and outcome of pediatric burns

A 6-year retrospective review of burn victims hospitalized at a major burn center was conducted to determine the etiology and outcome of pediatric burns. Four hundred forty-nine patients under age 16 years were identified and stratified by age, sex, burn size, presence or absence of inhalation injury, cause of burn, and county of residence. The mean patient age was 4.3 +/- 0.2 years, and the male:female ratio was 1.9:1. There were 21 deaths overall (4.7%), the majority of which (18) were among children under 4 years of age. With respect to large burns, defined as > and = 30% total body surface area (TBSA), the mortality rate for children under age 4 was significantly higher than that for older children (46.9% v 12.5%; P < .01), despite the nearly identical mean burn size of the two groups. Except for burn incidence, there were no significant differences between males and females. The mean burn size was 15.1% +/- 0.7%, and was significantly larger for nonsurvivors than survivors (55.3% +/- 5.7 v 13.1% +/- 0.5%; P < .01). Inhalation injuries were strongly associated with large burns and were present in all 15 flame-burn fatalities. Scalds were the most common type of burn among children under 4 years of age; flame burns predominated in older children. There were 6 deaths related to scalds, all of which occurred in children under 4. Burn type, size, and mortality rate did not differ between children from urban and rural counties. Large burn size was the strongest predictor of mortality, followed by (in order) age less than 4 and the presence of inhalation injury. Infants and young children have the highest risk of death from burn injury. Burns smaller than 30% TBSA without an inhalation injury (such as small scald injuries) occasionally are lethal in infants and small children, despite modern therapy.

Wound coverage with cultured autologous keratinocytes: use after burn wound excision, including biopsy followup.

Cultured autologous keratinocytes (CAK) have been used in eight patients as part of their definitive treatment for burn wound closure. The CAK grafts were placed on surgically excised wounds rather than mature granulation tissue. This technique guaranteed that permanent skin coverage derived from cultured cells, and not residual epidermal cells from surviving dermis. Graft take was variable, ranging from zero in the case of one of the children to 85%. Long-term assessment noted adequate permanent coverage, confirmed by biopsy. Electron micrographs demonstrated no well formed anchoring fibrils, which may account for the graft fragility which has been reported as much as 1 year postgraft. Advantages of using CAK are that an acceptable permanent wound closure can be achieved without depending on donor site availability. An almost unlimited quantity of skin is available because the original biopsy can be expanded manyfold in the laboratory.

Allogeneic fibroblasts used to grow cultured epidermal autografts persist in vivo and sensitize the graft recipient for accelerated second-set rejection

INTRODUCTION Cultured epidermal autografts (CEAs) have been used for wound coverage in patients with massive burns and other skin defects. However, CEAs often display late breakdown, which may be immunologically mediated and initiated by persistent foreign fibroblasts used as a feeder layer to optimize keratinocyte growth. This study investigates whether these fibroblasts, previously shown to persist in vitro, survive after grafting and induce host sensitization to alloantigen. METHODS CEAs from CBA donors (H-2k) were grown on allogeneic NIH 3T3 (H-2q) or syngeneic LTK (H-2k) fibroblasts, which were removed by trypsinization 7 days later. CBA mice (n = 85) were flank-grafted with NIH allografts (positive control), CEA/3T3s, CEA/LTKs, or CBA autografts (negative control). Hosts were challenged with second set NIH tail allografts 3 weeks later. Median graft survival was compared between groups by Wilcoxon rank and chi 2 analysis. Additional CBA mice (n = 15) received CEAs that were biopsied 0, 4, and 8 days after grafting. The presence of allogeneic fibroblasts was determined by Western immunoblotting, using KL295, a monoclonal antibody that recognizes H-2q (but not H-2k) class II histocompatibility antigens. RESULTS Allogeneic fibroblasts persisted after grafting but decreased over time, as determined by alloantigen expression on Western immunoblots. Accelerated tail graft rejection occurred in hosts primed by NIH allografts (9 days, p < 0.05), as well as by CEAs growth with an allogeneic (10 days, p < 0.05) but not a syngeneic feeder layer (12 days, NS). Mice receiving flank autografts rejected second set tail allografts at 12 days. CONCLUSIONS Immunogenic fibroblasts used to grow CEAs survive in vivo and sensitize the graft recipient for accelerated second-set rejection. These persistent cells may initiate an inflammatory response that may result in late graft breakdown and limit the utility of CEAs grown with a foreign fibroblast feeder layer.

Antigenic cross-reactivity between media supplements for cultured keratinocyte grafts

Patients who were grafted with cultured human keratinocytes have been shown to make antibodies to the xenogeneic proteins, which supplement the culture media. An immune response to these antigens may lead to late graft loss or accelerated rejection of subsequent cultured keratinocyte grafts. Methods to eliminate this potential problem include growing cells in a serum-free medium with bovine pituitary extract as a serum substitute. To determine whether bovine pituitary extract would be subject to an immune response similar to that which is evoked by fetal bovine serum, we investigated their antigenic cross-reactivity. When compared by sodium dodecylsulfate-polyacrylamide gel electrophoresis, considerable similarity was identified between the two supplements. Immunostaining with antibodies to both bovine pituitary extract and fetal bovine serum confirmed antigenic cross-reactivity. Inhibitory enzyme-linked immunosorbent assay studies demonstrated specific cross-reactivity that ranged from 60% to 68%. When tested for antibody cross-reactivity to bovine pituitary extract, serum samples from five patients who were receiving human-keratinocyte grafts that were grown in fetal bovine serum-supplemented media and that exhibited a positive antibody titer to fetal bovine serum showed cross-reactivity that ranged from 30% to 141%. Bovine pituitary extract contains proteins that cross-react with fetal bovine serum. Human keratinocytes that are cultured in media that is supplemented with bovine pituitary extract would therefore be subject to an immune response similar to that which is evoked by human keratinocytes that have been cultured in fetal bovine serum.

Bilateral simultaneous fractures of the femoral neck : case report

A case of bilateral fractures of the femoral neck resulting from high-voltage electric injury is reported. Surgeons caring for patients with electrical injuries must be aware of the possibility of this injury as well as other skeletal injuries which may result from muscle contraction or falls related to electric shock. Without vigilance for these injuries, diagnosis may be delayed.

Antibody response to xenogeneic proteins in burned patients receiving cultured keratinocyte grafts.

Cultured keratinocytes (CK) have been used to resurface large burn wounds with some success. These CK are grown in the presence of fetal bovine serum (FBS) and mouse fibroblasts (MF). Serum from ten patients who received CK grafts as part of burn wound coverage was studied by ELISA technique for antibody to these xenogeneic antigens. All patients had some amount of antibody to FBS but no detectable antibody to MF. The amount of antibody to FBS varied between patients and with respect to time after graft application. Generally, the levels of antibody to FBS were moderate by 30 days, declined, and then rose slowly by 5 to 6 months. The majority of antibody to FBS was against bovine serum albumin (BSA), demonstrated by Western blot technique. The presence of such antibody to FBS might produce clinical problems of graft rejection, anaphylaxis, and serum sickness in patients receiving CK grown in FBS supplemental medium. Further investigation will need to determine the likelihood and potential severity of such clinical problems.

Persistence of fetal bovine serum proteins in human keratinocytes.

Cultured human keratinocytes are used for skin grafts, but their success is limited by late graft loss. Development of antibody to fetal bovine serum (FBS) protein used in culture media for in vitro keratinocyte growth has been identified. The persistence of FBS antigen in skin grafts is important in the induction of the immune response and the susceptibility of the keratinocytes to immune-mediated injury. The magnitude and longevity of FBS protein persistence on human keratinocytes was studied. Secondary passage human keratinocytes were grown in media supplemented with 5% FBS. The media was changed to one supplemented with pooled human AB serum, and the amount of FBS protein incorporated in the tissue was measured over the following 8 days by an ELISA reaction directed against FBS antigen. Incorporated FBS antigen decreased for the first 3 days to 31% of maximum. There was no further significant decrease for 5 days. Keratinocytes grown in alternative serum supplements (NuSerum [Collaborative Research Inc., Bedford, Mass.] and Serum Plus [Hazelton Research Products Inc., Lenexa, Kan.]), which contain reduced amounts of FBS, offered no significant reduction in FBS protein incorporation. This duration of antigen persistence would make human keratinocytes susceptible to cell destruction by immune response to FBS and may contribute to delayed loss of human keratinocyte grafts.

Causes and time course of acute hemolysis after burn injury in the rat.

Thermal injury can cause acute red blood cell damage and destruction, but the mechanisms of these effects are not well described. To investigate the red blood cell abnormalities that occur after burn injury we studied the time course of red blood cell changes that are seen early after burn injury. Male Sprague-Dawley rats were divided into control, sham-burn, and burn (30% total body surface area full-thickness) groups. Plasma-free hemoglobin, erythrocyte osmotic fragility, and red blood cell membrane deformability were measured in the first 8 hours after burn injury. Plasma-free hemoglobin was significantly increased 1 hour after injury. It fell promptly but remained significantly higher than the control value at 4 and 8 hours after burn injury. Osmotic fragility was also significantly increased when compared with control values, whereas membrane deformability was less than control values for the duration of the experiment. This study identifies an early hemolytic effect of burn injury and documents red blood cell changes in osmotic fragility and membrane deformability that may contribute to accelerated red blood cell loss later in the course of burn management.

Chronic ethanol exposure before injury produces greater immune dysfunction after thermal injury in rats

Chronic alcoholics constitute a small but significant subgroup of burned patients. The effects of chronic alcohol exposure on immune function in burned patients has not to our knowledge been studied. This study was designed to determine the effect of chronic alcohol exposure before burn injury on immune function after injury in rats. Immune function assessed by in vivo chemotaxis and responsiveness of non-adherent splenocytes to both a T-cell mitogen, concanavalin A, and a B-cell mitogen, lipopolysaccharide, was measured at 4 days after a 20% BSA full-thickness burn injury and/or gavage of 2.4 gm/kg/day of ethanol for 14 days. Chronic ethanol ingestion before burn injury produced significant suppression in chemotaxis and response to lipopolysaccharide but not in response to concanavalin A. These results suggest that chronic alcohol exposure before injury can contribute to further impaired immune function after injury, and may lead to increased susceptibility to infection and increased mortality.