Bruce A. Cairns

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.

Effects of oxandrolone on outcome measures in the severely burned: a multicenter prospective randomized double-blind trial.

Severe burns induce pathophysiologic problems, among them catabolism of lean mass, leading to protracted hospitalization and prolonged recovery. Oxandrolone is an anabolic agent shown to decrease lean mass catabolism and improve wound healing in the severely burned patients. We enrolled 81 adult subjects with burns 20% to 60% TBSA in a multicenter trial testing the effects of oxandrolone on length of hospital stay. Subjects were randomized between oxandrolone 10 mg every 12 hours or placebo. The study was stopped halfway through projected enrollment because of a significant difference between groups found on planned interim analysis. We found that length of stay was shorter in the oxandrolone group (31.6 ± 3.1 days) than placebo (43.3 ± 5.3 days; P < .05). This difference strengthened when deaths were excluded and hospital stay was indexed to burn size (1.24 ± 0.15 days/% TBSA burned vs 0.87 ± 0.05 days/% TBSA burned, P < .05). We conclude that treatment using oxandrolone should be considered for use in the severely burned while hepatic transaminases are monitored.

Positive fungal cultures in burn patients: A multicenter review

Fungal infections are increasingly common in burn patients. We performed this study to determine the incidence and outcomes of fungal cultures in acutely burned patients. Members of the American Burn Association’s Multicenter Trials Group were asked to review patients admitted during 2002–2003 who developed one or more cultures positive for fungal organisms. Data on demographics, site(s), species and number of cultures, and presence of risk factors for fungal infections were collected. Patients were categorized as untreated (including prophylactic topical antifungals therapy), nonsystemic treatment (nonprophylactic topical antifungal therapy, surgery, removal of foreign bodies), or systemic treatment (enteral or parenteral therapy). Fifteen institutions reviewed 6918 patients, of whom 435 (6.3%) had positive fungal cultures. These patients had mean age of 33.2 ± 23.6 years, burn size of 34.8 ± 22.7%TBSA, and 38% had inhalation injuries. Organisms included Candida species (371 patients; 85%), yeast non-Candida (93 patients, 21%), Aspergillus (60 patients, 14%), other mold (39 patients, 9.0%), and others (6 patients, 1.4%). Systemically treated patients were older, had larger burns, more inhalation injuries, more risk factors, a higher incidence of multiple positive cultures, and significantly increased mortality (21.2%), compared with nonsystemic (mortality 5.0%) or untreated patients (mortality 7.8%). In multivariate analysis, increasing age and burn size, number of culture sites, and cultures positive for Aspergillus or other mold correlated with mortality. Positive fungal cultures occur frequently in patients with large burns. The low mortality for untreated patients suggests that appropriate clinical judgment was used in most treatment decisions. Nonetheless, indications for treatment of fungal isolates in burn patients remain unclear, and should be developed.

Composite Tissue Engineering on Polycaprolactone Nanofiber Scaffolds

Tissue engineering has largely focused on single tissue-type reconstruction (such as bone); however, the basic unit of healing in any clinically relevant scenario is a compound tissue type (such as bone, periosteum, and skin). Nanofibers are submicron fibrils that mimic the extracellular matrix, promoting cellular adhesion, proliferation, and migration. Stem cell manipulation on nanofiber scaffolds holds significant promise for future tissue engineering. This work represents our initial efforts to create the building blocks for composite tissue reflecting the basic unit of healing. Polycaprolactone (PCL) nanofibers were electrospun using standard techniques. Human foreskin fibroblasts, murine keratinocytes, and periosteal cells (4-mm punch biopsy) harvested from children undergoing palate repair were grown in appropriate media on PCL nanofibers. Human fat-derived mesenchymal stem cells were osteoinduced on PCL nanofibers. Cell growth was assessed with fluorescent viability staining; cocultured cells were differentiated using antibodies to fibroblast- and keratinocyte-specific surface markers. Osteoinduction was assessed with Alizarin red S. PCL nanofiber scaffolds supported robust growth of fibroblasts, keratinocytes, and periosteal cells. Cocultured periosteal cells (with fibroblasts) and keratinocytes showed improved longevity of the keratinocytes, though growth of these cell types was randomly distributed throughout the scaffold. Robust osteoinduction was noted on PCL nanofibers. Composite tissue engineering using PCL nanofiber scaffolds is possible, though the major obstacles to the trilaminar construct are maintaining an appropriate interface between the tissue types and neovascularization of the composite structure.

Early enteral nutrition does not decrease hypermetabolism associated with burn injury

BACKGROUND A prospective, randomized study was performed to compare the effects of early versus late enteral feeding on postburn metabolism. METHODS Burn patients were randomized to receive enteral feedings either within 24 hours (early) or 7 days (late) of injury. Basal energy expenditure (BEE) was calculated from Harris-Benedict equations and resting energy expenditure (REE) was obtained from indirect calorimetry. The average daily energy expenditure (DEE) was expressed as REE/BEE. RESULTS Average age, burn size, infections, and length of stay were similar between groups. Mortality between groups was similar (early, 28%; late, 38%) and not significantly influenced by inhalation injury. When controlled for percentage of total body surface area burn, inhalation injury, and age, the early group had an increased rather than decreased DEE, with a mean DEE calorie 0.17 more than the late group (p = 0.07). CONCLUSION Early enteral feeding does not decrease the average energy expenditure associated with burn injury.

Laser resurfacing and remodeling of hypertrophic burn scars: The results of a large, prospective, before-After cohort study, with long-term follow-up

Objectives:Hypertrophic burn scars produce significant morbidity, including itching, pain, stiffness, and contracture, but best management practices remain unclear. We present the largest study to date that examines long-term impact of laser therapies, a potentially transformative technology, on scar remodeling. Methods:We conducted a prospective, before-after cohort study in burn patients with hypertrophic scars. Pulsed-dye laser was used for pruritus and erythema; fractional CO2 laser was used for stiffness and abnormal texture. Outcomes included (1) Vancouver Scar Scale (VSS), which documents pigmentation, erythema, pliability, and height, and (2) University of North Carolina “4P” Scar Scale (UNC4P), which rates pain, pruritus, paresthesias, and pliability. Results:A total of 147 burn patients (mean age, 26.9 years; total body surface area, 16.1%) received 415 laser sessions (2.8 sessions/patient), 16 months (median) after injury, including pulsed dye laser (n = 327) and CO2 (n = 139). Laser treatments produced rapid, significant, and lasting improvements in hypertrophic scar. Provider-rated VSS dropped from 10.43 [standard deviation (SD) 2.37] to 5.16 (SD 1.92), by the end of treatments, and subsequently decreased to 3.29 (SD 1.24), at a follow-up of 25 months. Patient-reported UNC4P fell from 5.40 (SD 2.54) to 2.05 (SD 1.67), after the first year, and further decreased to 1.74 (SD 1.72), by the end of the study period. Conclusions:For the first time, ever, in a large prospective study, laser therapies have been shown to dramatically improve both the signs and symptoms of hypertrophic burn scars, as measured by objective and subjective instruments. Laser treatment of burn scars represents a disruptive innovation that can yield results not previously possible and may displace traditional methods of operative intervention.

Inhaled nitric oxide for primary pulmonary hypertension in pregnancy

BACKGROUND Primary pulmonary hypertension is a rare and dangerous entity in pregnancy. Previous studies have found a 35–50% maternal mortality rate in the peripartum period. To date, most reports have described treatment of these patients with diuretics, digoxin, and calcium-channel blockers. CASE We describe the successful treatment of a primigravida with severe primary pulmonary hypertension. We used elective intubation before labor, inhaled nitric oxide therapy, and assisted vaginal delivery with epidural anesthesia that resulted in a viable infant and survival of the mother. CONCLUSION Nitric oxide can be used to successfully treat primary pulmonary hypertension in pregnancy.

Prospective, before-after cohort study to assess the efficacy of laser therapy on hypertrophic burn scars.

IntroductionHypertrophic burn scars produce significant morbidity, including itching, pain, stiffness, and contracture. Best practices for management continue to evolve. Lasers have recently been added to treatment algorithms, but indications and efficacy have not been fully defined. We studied the impact of laser therapies on hypertrophic burn scars. MethodsWe conducted a prospective, before-after study in burn patients with hypertrophic scars. Procedures were performed more than 6 months after burn injury and were repeated monthly. The pulsed-dye laser was used for pruritus and erythema, whereas the fractional CO2 laser was used for stiffness and abnormal texture. All procedures were performed in the OR, with anesthesia. Outcomes are as follows: (1) Vancouver Scar Scale (objective changes in pigmentation, erythema, pliability, height; range, 0–15) and (2) UNC Scar Scale (subjective changes in pain, itching, tingling, stiffness; range, 0–12). Before-after scores were compared by Student t test, with significance assigned to P values of <0.05. ResultsDuring 2011, we treated 147 patients (mean age, 26.9 years; mean TBSA, 16.1%) over 415 sessions (2.8 sessions/patient), including pulsed dye laser (n = 327) and CO2 (n = 139), mean surface area of 83 cm2. Etiology included flame (75), scald (37), and other (35). Treatments occurred 16 months (median) and 48 months (mean) after burn injury. Vancouver Scar Scale decreased from 10.4 (SD, 2.4) to 5.2 (1.9) (P < 0.0001). UNC Scar Scale decreased from 5.4 (2.5) to 2.1 (1.7) (P < 0.0001). Mean length of follow-up was 4.7 months. ConclusionsLaser therapies significantly improve both the signs and symptoms of hypertrophic burn scars, as measured by objective and subjective instruments.

Nanofiber applications for burn care.

Nanotechnology is a growing field of manufactured materials with sizes less than 1 &mgr;m, and it is particularly useful in the field of medicine because these applications replicate components of a cell’s in vivo environment. Nanofibers, which mimic collagen fibrils in the extracellular matrix (ECM), can be created from a host of natural and synthetic compounds and have multiple properties that may be beneficial to burn wound care. These properties include a large surface-area-to-volume ratio, high porosity, improved cell adherence, proliferation and migration, and controlled in vivo degradation rates. The large surface area of nanofiber mats allows for increased interaction with compounds and provides a mechanism for sustained release of antibiotics, analgesics, or growth factors into burn wounds; high porosity allows diffusion of nutrients and waste. Improved cell function on these scaffolds will promote healing. Controlled degradation rates of these scaffolds will promote scaffold absorption after its function is no longer required. The objective of this article is to review the current literature describing nanofibers and their potential application to burn care.