Serial measurements increase the accuracy of laser Doppler assessment of burn wounds.

Traditional methods of judging burn depth by clinical evaluation of the wound based on appearance and sensation remain in wide use but are subject to individual variation by examiner. In addition to the clinical difficulties with burn wound management, observer dependency of wound assessment complicates clinical trials of burn wound therapy. A laser Doppler flowmeter with a multichannel probe was used to measure burn wound perfusion as a tool to predict wound outcome. Serial measurement with laser Doppler flowmetry had an 88% specificity and a positive predictive value of 81% for identifying nonhealing wounds. These results suggest that laser Doppler flowmetry is a potentially useful tool for burn wound assessment.

Assessment of tissue viability in complex extremity injuries: utility of the pyrophosphate nuclear scan.

BACKGROUND: Extensive extremity injuries often require difficult decisions regarding the necessity for amputation or radical debridement. During the past decade, we have used technetium-99 pyrophosphate (PyP) scanning as an adjunct in this setting. This study was performed to assess the accuracy of PyP scan in predicting the need for amputation in relation to clinical, operative, and pathologic findings. METHODS: Review of our computerized registry identified 11 patients (10 men, age 36.1 +/- 14.9 years) admitted from 1990 to 1999 who underwent PyP scan. Using operative and pathologic findings, accuracy of the PyP scan was graded as supporting or refuting the clinical assessment of the need for amputation. RESULTS: Eight patients suffered high-voltage electrical injuries, one had severe frostbite, and two suffered soft-tissue infections. In most cases, PyP scan showed clear demarcation of viable and nonviable tissue, verifying the need for amputation (positive); those that demonstrated viable distal tissues confirmed at operation were considered negative. PyP scan had a sensitivity of 94%, a specificity of 100%, and an accuracy of 96% in this setting. CONCLUSION: Technetium-99 PyP scanning is a useful adjunct in predicting the need for amputation in extremities damaged by electrical injury, frostbite, or invasive infection. In addition, by providing an objective "picture" of extremity perfusion, PyP scans can be helpful in convincing patients of the need for amputation.

Burn center management of necrotizing soft-tissue surgical infections in unburned patients.

BACKGROUND: Patients with necrotizing soft-tissue infections present great challenges in management from initial presentation through definitive care. Because burn centers concentrate expertise in critical care, wound management, and rehabilitation, we examined the effectiveness of burn center care for patients with necrotizing infections. METHODS: We reviewed our burn center's experience with all patients admitted from 1990 through 1999 with a primary diagnosis of necrotizing fasciitis (NF) or Fournier's gangrene (FG). RESULTS: Fifty-seven patients were identified, 18 with FG and 39 with NF. Patients had a high incidence of preexisting medical problems, including diabetes (37%), obesity defined as greater than 20% above ideal body weight (33%), and hypertension (33%). Seven of 57 (12%) patients died. Patients required a mean of 4.1 operative procedures (range 1 to 15) for definitive wound closure. The mean length of stay (survivors only) was 28.5 days, (range 3 to 70). Although costs increased throughout this period, a formal program of cost-containment resulted in no increase in actual charges per day, from a mean of $4,735 in 1991 to $5,202 in 1999. CONCLUSIONS: Burn centers can provide successful and cost-effective acute care, definitive wound closure, and rehabilitation for patients with NF and FG.

Chemical paralysis reduces energy expenditure in patients with burns and severe respiratory failure treated with mechanical ventilation.

Predictive formulas often overestimate energy requirements, particularly in patients being treated with mechanical ventilation, resulting in significant overfeeding. The purpose of this study was to quantify the effect of chemical paralysis on energy expenditure in patients with burn injuries receiving ventilation treatment, and compare measured energy expenditure with estimates of energy expenditure based on predictive formulas. The study was a retrospective review of 14 patients with burn injuries treated with mechanical ventilation that required chemical paralysis to reduce inspiratory pressures or improve oxygenation. Indirect calorimetry was performed before, during, and after paralysis. Measured energy expenditure (MEE) was compared with the energy predictions of the Harris-Benedict (HBEE) and Curreri (CEE) estimates. During paralysis, mean MEE was significantly lower than pre- or postparalysis (19.65 +/- 1.65 versus 26.00 +/- 2.42 and 29.49 +/- 2.83 kcal/kg/24 hr, respectively). Mean HBEE (2031 +/- 145 kcal/24 hr) approximated MEE pre-(1989 +/- 350 kcal/24 hr) and postparalysis (2237 +/- 269 kcal/24 hr), but overestimated MEE during paralysis (1532 +/- 208 kcal/24 hr; p < 0.05). Mean CEE (2957 +/- 229 kcal/ 24 hr) estimates significantly overestimated MEE before, during, and after paralysis (1989 +/- 350, 1532 +/- 208, and 2237 +/- 269, respectively p < 0.05). Predictive formulas significantly overestimate measured energy requirements in these patients. Indirect calorimetry should guide nutrition support in patients requiring prolonged mechanical ventilation.

Randomized trial of immune-enhancing enteral nutrition in burn patients.

BACKGROUND: "Immune-enhancing" diets (IEDs) are aimed at improving outcomes in patients suffering trauma and infection. This study was conducted to evaluate a popular IED in patients suffering burn injury. METHODS: Fifty burned patients were randomized to receive either Impact (Sandoz Nutrition, Minneapolis, Minn), an IED enhanced with omega-3 fatty acids, arginine, and RNA, or Replete (Clintec, Deerfield, Ill), our standard high-protein diet. Feedings were begun within 48 hours of injury, and continued until patients supported themselves with oral intake. RESULTS: Forty-nine patients completed the study. The two feeding groups did not differ with respect to age, burn size, incidence of inhalation injury, or the quantity of calories and protein received. There were no differences between groups in mortality, length of hospitalization, hospital charges, days of ventilator support, or incidence of complications. Patients with inhalation injuries required more ventilatory support, and had longer lengths of hospitalization and higher costs. CONCLUSIONS: Administration of an IED has no clear advantages over the use of less expensive high-protein enteral nutrition in burn patients.

Return to work as a measure of outcome in adults hospitalized for acute burn treatment.

Rehabilitation of patients with burn injuries is receiving renewed interest because survival has improved, and health reform has mandated outcomes assessment. To determine factors affecting return to work, a survey was conducted among 234 employed patients treated from 1986 through 1993. The mean burn size was 13.3% total body surface area. Patients returned to work in a mean of 14.3 weeks; a number initially returned to light-duty or part-time jobs as a "bridge" to full-time employment. Length of hospitalization, number of surgeries, total and full-thickness burn size, and subjective assessments by patients of their functional ability correlated with time off work. Patients with health insurance were more likely to resume work than was expected, whereas those covered by Medicaid and those involved in injury-related lawsuits were less likely to return to work. It is hoped that this information can be used to design interventions aimed at improving this outcome of burn treatment.

Recent outcomes in the treatment of burn injury in the United States: a report from the American Burn Association Patient Registry.

This article reports outcomes of 6417 patients treated during 1991-1993 in 28 burn centers. Data were gathered by use of the ABA's computerized patient registry. Mean burn size was 14.1% total body surface area. There were 6087 survivors (95.9%); mortality rate among patients with inhalation injury was 29.4%. A probit analysis was used to construct a series of survival curves; the LA50 (which is defined as the burn size lethal to 50% of patients) for young adults was 81% total body surface area. Mean length of hospital stay was 13.5 days. Total mean charges were $39,533, with resource utilization related to clinical comorbidity factors and length of stay. No reliable method could be found to predict survival on admission. Mean charges for the most intensive diagnosis-related group (No. 472) exceeded $198,000 per patient. Pooled data and related summary statistics used in this study have some limitations, which are discussed. Additional accurate information regarding the outcomes of thermal injury treatment is needed by the burn care community.

Noninvasive assessment of metabolism in wounded skin by 31P-NMR in vivo.

Phosphorus-31 nuclear magnetic resonance techniques using shallow penetrating coils have been used to noninvasively monitor severity and metabolic changes over time in skin wounds in rats. Ratios of phosphocreatine (PCr) to inorganic phosphate (Pi) indicate energy status in both thermal wounds and surgical flaps. In partial and full-thickness scald wounds, reductions in PCr/Pi ratios correlated with burn depth and improved over time postinjury, suggesting wound revascularization. No decrease in intracellular pH was noted in these wounds; the phosphate shifts may be primarily the result of tissue degradation followed by restoration of the microvasculature. Distal regions of caudally based dorsal 3 x 10 cm full-thickness skin flaps reveal progressively lower PCr/Pi ratios to 3-6 hours after elevation as well as drops in pH up to 0.5 units, presumably as a result of anaerobic glycolysis in these tissues. After 24 hours, the intracellular pH returned to normal (7.1-7.2) and the PCr/Pi ratios approached 70%-90% of the well-perfused proximal regions within 3-7 days. These results indicate the establishment of a microvasculature from the underlying bed as the distal regions survive as free grafts. The data demonstrate the potential usefulness of the technique in noninvasive measurement of the biochemical response to injury and wound healing in living organisms.

The continuing challenge of burn care in the elderly.

Recent improvements in survival have stimulated interest in the care of elderly patients with burn injuries. We reviewed 278 patients aged 45 years and older treated during a 10-year period. The survival rate was 80% overall and 67% for patients over 75 years of age. Mortality rates correlated with patient age, burn size, presence of inhalation injury, number of complications of care, and fluid resuscitation requirements, but not with the number of preexisting medical problems. Burn wound excision and skin grafting were performed frequently and were well tolerated. During this period, hospital charges increased fourfold and were twice as great in nonsurvivors. Reimbursements based on diagnosis-related groups during the last 3 years of the review (75 patients) resulted in a total deficit of $1.2 million. Aggressive care for most elderly patients with burn injuries appears justified by the improved outcomes demonstrated. This has increased the difficulty of decisions regarding patient salvability and the allotment of resources. Elderly patients with burn injuries illustrate many contemporary dilemmas in patient care in this era of cost consciousness.

Complications of burn care in patients with neurologic disorders.

Patients with neurologic disorders are frequently burned in mishaps related directly to their diseases. Once burned, these patients face a mortality rate significantly greater than that of the burn population as a whole. To assess the impact of neurologic disease on burn care, we reviewed the records of 37 patients admitted to our burn center with burns and neurologic illness. Thirty-three patients (89%) sustained injuries directly related to their neurologic problems, the most frequent being bathtub scalds (29.8%) and scald/spills (24.3%). We compared 31 of these patients having nonextensive burn injuries (less than or equal to 25% total body surface area) to a control population with similar-sized burns from our burn unit during the study period. This comparison revealed significantly longer length of stay for the neurologically impaired sample. We presume that costs of care are also increased for this sample. The high frequency of burn injury among neurologically impaired persons, coupled with the greater difficulty in caring for them, suggests that this group should receive intensive burn prevention educational efforts.

Calculation of metabolic expenditure and substrate utilization from gas exchange measurements.

At least nine different equations have been published for calculating metabolic expenditure by indirect calorimetry. This study examined the differences between equations when they are used for the nutritional assessment in an intensive care unit (ICU). Oxygen consumption and carbon dioxide production were measured in 36 ICU patients and used to calculate metabolic expenditure with the nine equations. The equations produced differences in metabolic expenditure which averaged from 0.8-96 kcal/day. The largest difference produced by any two of the nine equations was 189 kcal/day. Although differences in original stoichiometric data have resulted in numerous different equations for the calculation of metabolic expenditure, these differences are not clinically important. It makes little difference which equation is used for nutritional assessment in an ICU.