Martha Lydon

Early burn center transfer shortens the length of hospitalization and reduces complications in children with serious burn injuries.

Prompt transfer of the child with acute burns can be difficult from distant or inaccessible locations, and it is believed that the outcomes of children with serious burns whose transfer to a specialized burn care facility is delayed may be compromised. A 4-year experience with 16 consecutive children with serious burns (> or =20% of the body surface area) whose transfer to a burn care facility was delayed for 5 or more days was reviewed to document the difficulties that can follow such delays. These 16 children had an average age of 8.6+/-1.6 years and an average wound size of 57.6%+/-5.8% of the body surface area, and they arrived a mean of 16.3+/-3.4 days after the injury (range, 5 to 44 days). These children had undergone an average of 1 operation, excluding escharotomies, at referring facilities. Only 4 (25%) of the children had no infectious focus at transfer, and at admission resistant bacteria were recovered from 9 (56%) of the children and fungal organisms were found in 10 (63%). Compared with a concurrently managed matched control group of patients admitted to the burn center within 24 hours of injury, the delayed-transfer group had statistically significantly more bacteremia, renal dysfunction, wound sepsis, and central venous catheter days. It was also more expensive to manage these children; the delayed-transfer group required statistically significantly longer to achieve 95% wound closure, and they had greater total lengths of hospital stay and more rehabilitation days. The early transfer of children with serious burns to a specialized burn center may truncate hospitalization and thereby reduce costs.

Initial experience with a composite autologous skin substitute

Patients with large burns are surviving in increasing numbers, but there remains no durable and reliable permanent skin replacement. After initial favorable small animal experiments, a pilot trial of a composite skin replacement was performed in patients with massive burns. A composite skin replacement (CSR) was developed by culturing autologous keratinocytes on acellular allogenic dermis. This material was engrafted in patients with massive burns and compared to a matched wound covered with split thickness autograft. With human studies committee approval, 12 wounds in 7 patients were grafted with CSR while a matched control wound was covered with split thickness autograft. These 7 children had an average age of 6.4+/-1.4 yr and burn size of 75.9+/-5.0% of the body surface. Nine wounds were acute burns and three were reconstructive releases. Successful vascularization at 14 days averaged 45.7+/-14.2% (range 0-100%) in the study wounds and 98+/-1% (range 90-100%) in the control sites (P<0.05). Reduced CSR take seemed to correlate with wound colonization. All children survived. While CSR did not engraft with the reliability of standard autograft, this pilot experience is encouraging in that successful wound closure with this material is possible, if not yet dependable. It is hoped that a more mature epidermal layer may facilitate engraftment, and trials to explore this possibility are in progress.

Treatment of the seriously burned infant

Infants (younger than 12 months) with large (more than 30%) burns are reported to have poorer chances for survival than older children with similar injuries. However, recent experience with such infants has been positive, prompting a 5-year review of management techniques. The injuries were approached in an organized fashion that included precise fluid support, excision, and biologic closure of full-thickness wounds within 5 days, limited exposure to high inflating pressures (more than 40 cm H2O), weekly replacement of central venous catheters, and intensive nutritional support via the enteral route whenever possible. Twelve such infants were treated during the 5-year interval. Their average age was 7.8 months (range, 1 to 12 month[s]), average weight was 8.8 kg (range, 4.3 to 13 kg), and average burn size was 42% (range, 30% to 90%). Inhalation injury was present in two of the children, and one child aspirated hot liquid. Six (50%) of the infants required the support of a mechanical ventilator for an average of 11.6 days (range, 4 to 18 days). Eight children required an average of 5.7 operations (range, 1 to 18 operation[s]), seven required central venous catheters, and five required arterial cannulae. Major infectious complications were seen in four children. Complications included pneumonia (two), catheter sepsis (two), peritonitis from a perforated ulcer (one), and wound sepsis (two). Six children required parenteral nutritional support for an average of 15 days (range, 5 to 36 days), and six children required enteral tube feedings for an average of 23 days (range, 9 to 55 days). Anabolic agents were not used. Discharge weights averaged 8.6 kg (range, 4.9 to 10.5 kg). The average ratio of the childrens discharge to admission weight was 101% (range, 73% to 120%). All children survived and were discharged home. We conclude that these difficult injuries can be approached successfully with a strategy that emphasizes precise fluid repletion; early excision and biologic closure of wounds; avoidance of ventilator-induced lung injury; and intensive nutritional support.

The selenium status of pediatric patients with burn injuries.

BACKGROUND Dietary selenium (Se) requirements during critical illness are not well known. The objective of this study was to assess the longitudinal Se status of pediatric patients with burns. METHODS Twenty patients admitted to our hospital with burns exceeding 10% of their total body surface area were studied longitudinally during the first 8 weeks of admission or until 95% wound closure was achieved. Dietary Se intake was calculated daily, and plasma and urine samples were collected weekly for analyses of plasma Se, urinary Se, and glutathione peroxidase activity. RESULTS Patients included in this study were individuals with an average age of 6.5 years ± 5.3 years and with burn injury of a mean total body surface area of 42% ± 21%. Dietary Se intake throughout the study (mean = 60 μg/d ± 39 μg/d) was consistent with established standards for healthy children and did not change throughout the study. Plasma Se (mean = 1.08 μmol/L ± 0.34 μmol/L) and plasma glutathione peroxidase (mean = 3.2 U/g protein ± 1.42 U/g protein) were below reported normal values for healthy American children. Mean urinary Se excretion (65.9 μg/L ± 50 μg/L) exceed dietary Se intake. Plasma Se was inversely related to incidence of total infection (p = 0.04). CONCLUSIONS Results from this study indicate that Se status is depressed among pediatric patients with burns and that recommended Se intake for healthy children is likely insufficient for this population. Further studies are necessary to elucidate the amount of dietary Se required to maximize Se stores among pediatric patients with burn injuries.

Laser ablation of burns : Initial clinical trial

BACKGROUND Scanning, high-powered carbon dioxide laser ablation of eschar may facilitate blood conservation in patients with burns. METHODS Twenty-one children with full-thickness burns that required serial excisions were enrolled in a Human Studies Committee approved protocol in which a full-thickness wound was ablated with a rapidly scanned continuous wave carbon dioxide laser system. A control wound was sharply excised, and both wounds were immediately autografted. End points were engraftment at 7 days and serial Vancouver scar scores. RESULTS The children had an average age of 8.3 +/- 1.2 years, weight of 36.3 +/- 4.9 kg, and burn size of 40% +/- 5.1%. The study wounds were ablated with an average energy of 99.2 +/- 5.7 W; there was no bleeding from 19 successfully ablated wounds. Initial engraftment averaged 94.7% +/- 3.5% in the control sites and 94.7% +/- 3.3% in the study sites (P = 1.0). There was no significant difference in Vancouver scar scores at an average follow-up of 32.0 +/- 5.2 weeks. CONCLUSIONS This pilot study follows a successful trial of this concept in a porcine model and demonstrates the technical feasibility of laser vaporization of burn eschar in humans with immediate autografting. Further refinement of the technique is required before it can be generally recommended.

Tunable dye laser neovessel ablation as an adjunct to the management of hypertrophic scarring in burned children: pilot trial to establish safety.

Hypertrophic scarring is a major source of morbidity in patients with burns. The physiologic characteristics are poorly understood, but increased neovascularity is typically seen in those wounds destined to become hypertrophic. We theorize that ablation of the developing neovasculature may favorably influence the development of the hypertrophic scar. The goal of this pilot trial was to establish the practicality and safety of tunable dye laser neovessel ablation at 585 nm. Ten sites of evolving hypertrophic scar in nine children were treated with a series of 450 msec 6.75 J/cm2 pulses at 585 nm. Although all children had the expected transient posttreatment purpura, no pain, ulceration, pruritus, or worsening of the lesions was seen. The technique appears safe and is worthy of continuing investigation. Investigations with higher fluences and multiple treatments are in progress.

Production of Pseudomonas aeruginosa Intercellular Small Signaling Molecules in Human Burn Wounds.

Pseudomonas aeruginosa has developed a complex cell-to-cell communication system that relies on low-molecular weight excreted molecules to control the production of its virulence factors. We previously characterized the transcriptional regulator MvfR, that controls a major network of acute virulence functions in P. aeruginosa through the control of its ligands, the 4-hydroxy-2-alkylquinolines (HAQs)—4-hydroxy-2-heptylquinoline (HHQ) and 3,4-dihydroxy-2-heptylquinoline (PQS). Though HHQ and PQS are produced in infected animals, their ratios differ from those in bacterial cultures. Because these molecules are critical for the potency of activation of acute virulence functions, here we investigated whether they are also produced during human P. aeruginosa acute wound infection and whether their ratio is similar to that observed in P. aeruginosa-infected mice. We found that a clinically relevant P. aeruginosa isolate produced detectable levels of HAQs with ratios of HHQ and PQS that were similar to those produced in burned and infected animals, and not resembling ratios in bacterial cultures. These molecules could be isolated from wound tissue as well as from drainage liquid. These results demonstrate for the first time that HAQs can be isolated and quantified from acute human wound infection sites and validate the relevance of previous studies conducted in mammalian models of infection.

Ultrasonic imaging as an adjunct to femoral venous catheterization in children.

Central venous catheterization is critically important to the management of burned children, but major morbidity is associated with the technical misadventures that can occur when inserting these devices. We used a bedside ultrasound device to facilitate placement of femoral venous catheters in eight edematous children with an average age of 7.0 years, weight of 23 kg, and burn size of 54%. To our knowledge, this is the first report of this technique in children. All children had central venous catheters placed in the femoral position requiring an average of 2 (range, 1 to 4) venepuncture attempts. There were no mechanical complications. We found the needle guide too cumbersome for our small patients, but found that the ability to mark the anatomy with a pen facilitated accurate catheter placement. In most patients, standard external anatomic landmarks are adequate for accurate catheter placement, however, in this initial experience, we found bedside ultrasound imaging to be a useful adjunct in selected patients with massive soft tissue edema.

The safety and efficacy of parenteral nutrition among pediatric patients with burn injuries.

Objective: Although enteral nutrition is the ideal mode of nutritional support following burn injury, it is often interrupted during episodes of severe sepsis and hemodynamic instability, leading to significant energy and protein deficits. Parenteral nutrition is not commonly used in burn centers due to concerns that it will lead to hyperglycemia, infection, and increased mortality. However, parenteral nutrition is often utilized in our burn unit when goal rate enteral nutrition is not feasible. To determine the safety and efficacy of a standardized protein-sparing parenteral nutrition protocol in which glucose infusion is limited to 5–7 mg/kg/hour. Design: Retrospective observational study. Setting: Pediatric burn hospital. Patients: A retrospective medical record review of all children admitted to our hospital with burns ≥ 30% total body surface area was conducted. Only patients admitted within one week of injury and who survived > 24 hours after admission were included in this study. Interventions: None. Measurements and Main Results: Of the 105 patients who met the inclusion criteria, 96 (91%) received parenteral nutrition or a combination of parenteral nutrition and enteral nutrition at some point during their care. Nine patients received only enteral nutrition. Demographic data were similar between groups. Protein intake was significantly higher in the parenteral nutrition group. Incidence of catheter-related blood infections did not differ between groups. Use of parenteral nutrition was not associated with blood or respiratory infections. Overall mortality rate was low (4%), as most patients (96%) achieved wound closure and were discharged home. Conclusions: Judicious use of parenteral nutrition is a safe and effective means of nutritional support when goal enteral nutrition cannot be achieved. A hypocaloric, high-nitrogen parenteral nutrition solution can reduce energy and protein deficits while minimizing complications commonly associated with parenteral nutrition usage.

Initial experience with a prototype staple detector

Stainless steel staples can be overgrown by granulation tissue or skin grafts and become buried in tissue. Although they are generally asymptomatic, they can on rare occasion erode to the surface or complicate the radiographic evaluation of pain not related to the staples. A device to facilitate detection of retained staples would be desirable, but it has been difficult to develop because stainless steel staples have poor magnetic and conductive properties. A prototype device, based on the presence of metal disturbing a low-power electromagnetic field, was developed. With human studies committee approval, this miniaturized detector was used in 13 burn patients to detect staples during planned removal of large numbers of staples. Staples were first removed using visual inspection and palpation of the wounds. This was followed by use of the staple detector. The age of the patients was 10.8 +/- 3.3 years, and burn size was 54.6 +/- 8.8% of the body surface. In 8 (62%) of the patients one or more additional staples were detected by the device that would otherwise have been overlooked. In 4 (31%) of the patients there was a false-positive signal, possibly related to topical silver in the wounds, that required additional focused physical examination. A portable staple detector has been developed. Initial experience with the device is favorable and warrants an expanded trial, which is in the planning stages.