For pediatric burn patients, the percentage of total body surface area affected remains the strongest predictor of survival, according to a report published online Jan. 31 in the Lancet.
"We have established that, in a modern pediatric burn care setting, a burn size of roughly 60% total body surface area is a crucial threshold for postburn morbidity and mortality," wrote Dr. Robert Kraft of Shriners Hospitals for Children, Galveston, Texas, and his associates.
For decades, burn size has been the main prognostic factor for both adults and children with burn injuries. But recent improvements in burn care – including novel drug treatments, new grafting techniques and materials, and improved life-support systems and monitoring methods – have dramatically improved survival, according to the investigators. Because treatment decisions, including whether to transfer a patient to a specialized burn center, are based on the probability of survival, it was important to determine whether burn size was still predictive of major complications and mortality under current treatment conditions.
To do so, Dr. Kraft and his colleagues examined outcomes in all 952 patients admitted over a 1-year period to Galveston’s Shriners Hospital with burns involving 30% or more of their total body surface area. Most of the study patients were burned on 40%-49% of their bodies.
Burn size proved to be the strongest predictor of survival, with mortality rising significantly as burn size increased. "In patient groups with burns smaller than 60% total body surface area, there were only minor increases in mortality starting at 3% and reaching up to 7%," the investigators wrote.
A large increase in mortality was noted when burn size reached 62% of the total body surface area. Such patients had a tenfold higher risk of death, compared with those who had smaller burns, the investigators reported (Lancet 2012 [doi:10.1016/S0140-6736(11)61345-7]).
Large burns also were associated with significant increases in multiorgan failure, infection during ICU stay, and the need for more surgeries to excise tissue. The rate of multiorgan failure was 6%-12% and the rate of sepsis was only 2%-6% for burns involving up to 59% of the body surface area. These rates ballooned as high as 27%-45% for multiorgan failure and 15%-26% for sepsis when burns involved 60% or more of the body surface area.
In addition, blood glucose and insulin levels rose significantly with burns involving 60% or more of the total body surface area, as did resting energy expenditure. Together with concomitant changes in liver structure and function, these findings reflect a massive hypermetabolic response to burn injury, Dr. Kraft and his associates reported.
Cytokine levels also differed by size of burn. With burns involving 60% or more of the body surface area, the levels of interleukin-6, -8, -10, and -13; macrophage inflammatory protein 1beta; tumor necrosis factor–alpha; granulocyte colony-stimulating factor; interferon-gamma; granulocyte-macrophage colony stimulating factor; and C-reactive protein rose substantially for an extended period of time.
Given these findings, "we recommend that pediatric patients with greater than 60% total body surface area burns be immediately transferred to a specialized burn center. Furthermore, at the burn center, patients should be treated with increased vigilance and improved therapies, in view of the increased risk of poor outcome associated with this burn size," the researchers wrote.
After burn size, the presence of inhalation injury in addition to external burn injury was a significant predictor of mortality. Patients who sustained inhalation injury had a threefold higher risk of death than did patients with no inhalation injuries. "We recommend that the treating physician [keep] in mind that the presence of inhalation injury significantly affects postburn outcomes," they noted.
Patient age and sex showed no association with survival, and neither did the time interval between sustaining the burn and presenting for admission.
It was noteworthy that mortality rates in this study were relatively low, even among patients who had the most extensive burns. "In our opinion, [high survival was] attributable to an improved and aggressive treatment regimen," they added.
This study was supported by Shriners Hospitals for Children, the National Institutes of Health, the National Institute on Disability and Rehabilitation Research, the Institute for Translational Sciences, the CFI Leaders Opportunity fund, and Physicians’ Services Incorporated Foundation. The investigators reported having no financial conflicts of interest.