Functional genomics unique to week 20 post wounding in the deep cone/fat dome of the Duroc/Yorkshire porcine model of fibroproliferative scarring

BACKGROUND

Hypertrophic scar was first described over 100 years ago; PubMed has more than 1,000 references on the topic. Nevertheless prevention and treatment remains poor, because 1) there has been no validated animal model; 2) human scar tissue, which is impossible to obtain in a controlled manner, has been the only source for study; 3) tissues typically have been homogenized, mixing cell populations; and 4) gene-by-gene studies are incomplete.

METHODOLOGY/PRINCIPAL FINDINGS

We have assembled a system that overcomes these barriers and permits the study of genome-wide gene expression in microanatomical locations, in shallow and deep partial-thickness wounds, and pigmented and non-pigmented skin, using the Duroc(pigmented fibroproliferative)/Yorkshire(non-pigmented non-fibroproliferative) porcine model. We used this system to obtain the differential transcriptome at 1, 2, 3, 12 and 20 weeks post wounding. It is not clear when fibroproliferation begins, but it is fully developed in humans and the Duroc breed at 20 weeks. Therefore we obtained the derivative functional genomics unique to 20 weeks post wounding. We also obtained long-term, forty-six week follow-up with the model.

CONCLUSIONS/SIGNIFICANCE

1) The scars are still thick at forty-six weeks post wounding further validating the model. 2) The differential transcriptome provides new insights into the fibroproliferative process as several genes thought fundamental to fibroproliferation are absent and others differentially expressed are newly implicated. 3) The findings in the derivative functional genomics support old concepts, which further validates the model, and suggests new avenues for reductionist exploration. In the future, these findings will be searched for directed networks likely involved in cutaneous fibroproliferation. These clues may lead to a better understanding of the systems biology of cutaneous fibroproliferation, and ultimately prevention and treatment of hypertrophic scarring.

Spatial and temporal localization of the melanocortin 1 receptor and its ligand α-melanocyte-stimulating hormone during cutaneous wound repair

Growing evidence indicates that the melanocortin 1 receptor (MC1R) and its ligand α-melanocyte-stimulating hormone (α-MSH) have other functions in the skin in addition to pigment production. Activation of the MC1R/α-MSH signaling pathway has been implicated in the regulation of both inflammation and extracellular matrix homeostasis. However, little is known about the role of MC1R/α-MSH signaling in the regulation of inflammatory and fibroproliferative responses to cutaneous injury. Although MC1R and α-MSH localization has been described in uninjured skin, their spatial and temporal expression during cutaneous wound repair has not been investigated. In this study, the authors report the localization of MC1R and α-MSH in murine cutaneous wounds, human acute burns, and hypertrophic scars. During murine wound repair, MC1R and α-MSH were detected in inflammatory cells and suprabasal keratinocytes at the leading edge of the migrating epithelial tongue. MC1R and α-MSH protein levels were upregulated in human burn wounds and hypertrophic scars compared to uninjured human skin, where receptor and ligand were absent. In burn wounds and hypertrophic scars, MC1R and α-MSH localized to epidermal keratinocytes and dermal fibroblasts. This spatiotemporal localization of MC1R and α-MSH in cutaneous wounds warrants future investigation into the role of MC1R/α-MSH signaling in the inflammatory and fibroproliferative responses to cutaneous injury. This article contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Mesenchymal stem cells: paracrine signaling and differentiation during cutaneous wound repair

Cutaneous wounds persist as a health care crisis in spite of increased understanding of the cellular and molecular responses to injury. Contributing significantly to this crisis is the lack of reliable therapies for treatment of wounds that are slow to heal including chronic wounds and deep dermal wounds that develop hypertrophic scars. This article will review the growing evidence demonstrating the promise of multipotent mesenchymal stem/stromal (MSCs) for the treatment of impaired wound healing. MSCs are often referred to as mesenchymal stem cells despite concerns that these cells are not truly stem cells given the lack of evidence demonstrating self-renewal in vivo. Regardless, abundant evidence demonstrates the therapeutic potential of MSCs for repair and regeneration of damaged tissue due to injury or disease. To date, MSC treatment of acute and chronic wounds results in accelerated wound closure with increased epithelialization, granulation tissue formation and angiogenesis. Although there is evidence for MSC differentiation in the wound, most of the therapeutic effects are likely due to MSCs releasing soluble factors that regulate local cellular responses to cutaneous injury. Important challenges need to be overcome before MSCs can be used effectively to treat wounds that are slow to heal.

Early acute kidney injury predicts progressive renal dysfunction and higher mortality in severely burned adults

The incidence and prognosis of acute kidney injury (AKI) developing during acute resuscitation have not been well characterized in burn patients. The recently developed Risk, Injury, Failure, Loss, and End-stage (RIFLE) classification provides a stringent stratification of AKI severity and can allow for the study of AKI after burn injury. We hypothesized that AKI frequently develops early during resuscitation and is associated with poor outcomes in severely burned patients. We conducted a retrospective review of patients enrolled in the prospective observational multicenter study "Inflammation and the Host Response to Injury." A RIFLE score was calculated for all patients at 24 hours and throughout hospitalization. Univariate and multivariate analyses were performed to distinguish the impact of early AKI on progressive renal dysfunction, need for renal replacement therapy, and hospital mortality. A total of 221 adult burn patients were included, with a mean TBSA burn of 42%. Crystalloid resuscitation averaged 5.2 ml/kg/%TBSA, with urine output of 1.0 +/- 0.6 ml/kg/hr at 24 hours. Sixty-two patients met criteria for AKI at 24 hours: 23 patients (10%) classified as risk, 32 patients (15%) as injury, and 7 (3%) as failure. After adjusting for age, TBSA, inhalation injury, and nonrenal Acute Physiology and Chronic Health Evaluation II > or =20, early AKI was associated with an adjusted odds ratio 2.9 for death (95% CI 1.1-7.5, P = .03). In this cohort of severely burned patients, 28% of patients developed AKI during acute resuscitation. AKI was not always transient, with 29% developing progressive renal deterioration by RIFLE criteria. Early AKI was associated with early multiple organ dysfunction and higher mortality risk. Better understanding of how early AKI develops and which patients are at risk for progressive renal dysfunction may lead to improved outcomes.

Surgical excision of the burn wound

Early excision of the burn eschar has been one of the most significant advances in modern burn care. Historical advances in understanding of the pathophysiology of burn injury and the systemic inflammatory response fueled by the burn wound, and refinements in the techniques of tangential and fascial excision, have led to earlier excision and grafting of the burn wound with improvements in morbidity and mortality. Efforts to control blood loss, and good operative planning and attention to special areas, can lead to the safe excision and grafting of large burns.

Acute management of hand burns

Hand burns occur commonly either as part of more extensive burn injuries or in isolation. Optimal management requires careful examination, appropriate wound care, timely surgical excision if warranted, and aggressive range-of-motion therapy.

Geographic access to burn center hospitals

CONTEXT

The delivery of burn care is a resource-intensive endeavor that requires specialized personnel and equipment. The optimal geographic distribution of burn centers has long been debated; however, the current distribution of centers relative to geographic area and population is unknown.

OBJECTIVE

To estimate the proportion of the US population living within 1 and 2 hours by rotary air transport (helicopter) or ground transport of a burn care facility.

DESIGN AND SETTING

A cross-sectional analysis of geographic access to US burn centers utilizing the 2000 US census, road and speed limit data, the Atlas and Database of Air Medical Services database, and the 2008 American Burn Association Directory.

MAIN OUTCOME MEASURE

The proportion of state, regional, and national population living within 1 and 2 hours by air transport or ground transport of a burn care facility.

RESULTS

In 2008, there were 128 self-reported burn centers in the United States including 51 American Burn Association-verified centers. An estimated 25.1% and 46.3% of the US population live within 1 and 2 hours by ground transport, respectively, of a verified burn center. By air, 53.9% and 79.0% of the population live within 1 and 2 hours, respectively, of a verified center. There was significant regional variation in access to verified burn centers by both ground and rotary air transport. The greatest proportion of the population with access was highest in the northeast region and lowest in the southern United States.

CONCLUSION

Nearly 80% of the US population lives within 2 hours by ground or rotary air transport of a verified burn center; however, there is both state and regional variation in geographic access to these centers.

Mesenchymal stem cells induce dermal fibroblast responses to injury

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury.

Influence of comorbidities and age on outcome following burn injury in older adults

Despite advances in medical and surgical techniques, older adults tend to be at high risk for adverse outcomes following burn injury. The purpose of this study was to examine the relative impacts of age and medical comorbidities on outcome following injury in a cohort of older adults. This was a retrospective study of all patients age 55 and over admitted to the University of Washington Burn Center from 1999 to 2003. To examine the effect of baseline medical comorbidities on outcome, a Charlson Comorbidity Index score was calculated for each patient. Multivariate regression analyses were used to examine the impact of age and comorbidities on mortality and other complications. Patient records were also matched with the National Death Index to determine the effects of age and comorbidities on mortality within 1 year following hospital discharge. A total of 325 patients who were of 55 years and older were admitted to the burn center during the 5-year study period. The overall mortality rate was 18.5%. Mortality was independently associated with age, inhalation injury, and burn size. One-year mortality was significantly associated with those older than age 75 and the Charlson score. Longer length of stay was significantly associated with burn size, inhalation injury, and total number of in-hospital complications. This study demonstrates that patient age-independent of baseline medical comorbidities-and TBSA burn are the most significant factors impacting in-hospital mortality risk following burn injury. Higher number of medical comorbidities was associated with increased mortality risk within 1 year following discharge.

Epidemiology and outcomes of older adults with burn injury: an analysis of the National Burn Repository

Improvements in outcomes for older adults sustaining burn injuries have lagged far behind those of younger patients. As this segment of the population grows, there has been an increasing interest in better understanding the epidemiology and outcomes of injury in older adults. The National Burn Repository (NBR) provides a unique opportunity to examine burn injuries on a national level. We aimed to characterize specific injury and outcome trends in older adult with burns through analysis of the NBR. We examined the records of all patients in the NBR aged 55 and older. To characterize age effects on injury and outcomes, patients were stratified into three age categories: 55 to 64 years, 65 to 74 years, and 75 years and older. Baseline characteristics, details of hospital treatment, mortality, and disposition were compared among these three age groups using chi or analysis of variance. Logistic regression analysis was performed to assess the impact of age on burn mortality. A total of 180,401 patient records were available from 1991 to 2005, of which 23,180 (14%) met age inclusion criteria. Mean burn size (9.6% TBSA) and percent with inhalation injury (11.3%) did not markedly differ by age. Men predominated overall (ratio 1.4:1), although women (4290) outnumbered men (3439) in the oldest age category. Length of stay per TBSA and median hospital charges increased with increasing age category, suggesting higher resource consumption with aging. Mean number of operations per patient, however, decreased with age. Mortality rates and discharge to nonindependent status increased with age. By logistic regression, the adjusted odds ratio for mortality was 2.3 (95% CI 2.1-2.7) in the 65 to 74 age group, and 5.4 (95% CI 4.8-6.1) in the oldest group when compared with the 55 to 64 age group. Mortality rates decreased significantly after 2001 across all age groups. This analysis demonstrates age-dependent differences in resource utilization and mortality risk within the older burn population and highlights the need for a national research agenda focused on management practices and outcomes in older adult with burns.

Topical substance P increases inflammatory cell density in genetically diabetic murine wounds

The neuropeptide substance P (SP) is a known inflammatory mediator released from cutaneous peripheral nerve terminals. SP effects on cellular composition in the cutaneous response to injury remain unclear. Based on our previous observations about SP effects on wound repair, we hypothesized that topical SP increases inflammatory cell density infiltration early after injury. A full-thickness 1.5 x 1.5 cm(2) wound was created on the dorsum of 8-9-week-old C57BL/6J-m+Lepr(db) mice (db/db). Wounds were treated daily with 300 muL of either normal saline (0.9% NaCl) or 10(-9) M SP for 7 days. Three wounds from each group were harvested at 2, 3, 7, 14, and 28 days. Samples underwent enzymatic digestion and were incubated with fluorescent-labeled antibodies. Using flow cytometry, cellular content and density for each sample was derived. Masson Trichrome stained histology specimens were prepared to confirm results. Cell density in the SP-treated wounds (11.3 x 10(7) cells/g tissue, standard deviation [SD]+/-1.5 x 10(7)) was greater than in NaCl-treated wounds (7 x 10(7) cells/g tissue, SD+/-2.3 x 10(7), p<0.05) at day 7 postwounding. SP significantly increased the density of leukocytes (2.1 x 10(7), SD +/-3.6 x 10(6) vs. 1.8 x 10(7), SD+/-4.9 x 10(5), p<0.02) 3 days after wounding and the density of macrophages (2.9 x 10(7), SD+/-7.5 x 10(6) vs. 1.3 x 10(7), SD+/-1.4 x 10(6), p<0.05) 7 days after wounding. There were no significant differences in endothelial cell, leukocyte, or macrophage density at later time points. Topical SP treatment increases early inflammatory density in the healing wounds of db/db mice. These data support a role for nerve-mediated inflammation in cutaneous wound repair.

Cytomegalovirus reactivation in critically ill immunocompetent patients

CONTEXT

Cytomegalovirus (CMV) infection is associated with adverse clinical outcomes in immunosuppressed persons, but the incidence and association of CMV reactivation with adverse outcomes in critically ill persons lacking evidence of immunosuppression have not been well defined.

OBJECTIVE

To determine the association of CMV reactivation with intensive care unit (ICU) and hospital length of stay in critically ill immunocompetent persons.

DESIGN, SETTING, AND PARTICIPANTS

We prospectively assessed CMV plasma DNAemia by thrice-weekly real-time polymerase chain reaction (PCR) and clinical outcomes in a cohort of 120 CMV-seropositive, immunocompetent adults admitted to 1 of 6 ICUs at 2 separate hospitals at a large US tertiary care academic medical center between 2004 and 2006. Clinical measurements were assessed by personnel blinded to CMV PCR results. Risk factors for CMV reactivation and association with hospital and ICU length of stay were assessed by multivariable logistic regression and proportional odds models.

MAIN OUTCOME MEASURES

Association of CMV reactivation with prolonged hospital length of stay or death.

RESULTS

The primary composite end point of continued hospitalization (n = 35) or death (n = 10) by 30 days occurred in 45 (35%) of the 120 patients. Cytomegalovirus viremia at any level occurred in 33% (39/120; 95% confidence interval [CI], 24%-41%) at a median of 12 days (range, 3-57 days) and CMV viremia greater than 1000 copies/mL occurred in 20% (24/120; 95% CI, 13%-28%) at a median of 26 days (range, 9-56 days). By logistic regression, CMV infection at any level (adjusted odds ratio [OR], 4.3; 95% CI, 1.6-11.9; P = .005) and at greater than 1000 copies/mL (adjusted OR, 13.9; 95% CI, 3.2-60; P < .001) and the average CMV area under the curve (AUC) in log(10) copies per milliliter (adjusted OR, 2.1; 95% CI, 1.3-3.2; P < .001) were independently associated with hospitalization or death by 30 days. In multivariable partial proportional odds models, both CMV 7-day moving average (OR, 5.1; 95% CI, 2.9-9.1; P < .001) and CMV AUC (OR, 3.2; 95% CI, 2.1-4.7; P < .001) were independently associated with a hospital length of stay of at least 14 days.

CONCLUSIONS

These preliminary findings suggest that reactivation of CMV occurs frequently in critically ill immunocompetent patients and is associated with prolonged hospitalization or death. A controlled trial of CMV prophylaxis in this setting is warranted.

Substance P enhances wound closure in nitric oxide synthase knockout mice

INTRODUCTION

The neuropeptide, substance P (SP), up-regulates nitric oxide production (NO). The purpose of this study was to determine whether SP enhances response to cutaneous injury in nitric oxide synthase knockout (NOS null) mice.

METHODS

We studied mice with targeted deletions of the 3 NOS genes, neuronal NOS, inducible NOS, or endothelial NOS. Full thickness dorsal wounds were treated daily (d 0-6) with topical SP or normal saline (NaCl). Wounds were analyzed by flow cytometry for macrophage, leukocyte, endothelial, and dendritic cells. Healing time and wound epithelialization were compared using analysis of variance.

RESULTS

Wound closure in the 3 NOS null mice was slower than the control mice (P < 0.05). SP treatment enhanced wound closure in NOS null mice (P < 0.02). NOS null wounds exhibited reduced inflammation. SP increased macrophage, leukocyte, and dendritic cell densities at d 3 and d 7 (P < 0.05) in all NOS null mice. SP increased endothelial cell number in neuronal NOS and inducible NOS null mice, but not in endothelial NOS null mice (P > 0.05).

CONCLUSIONS

SP ameliorated the impaired wound healing response observed in NOS null mice by enhancing wound closure kinetics and epithelialization. SP increased inflammatory cell density in the wounds supporting the essential role of inflammatory cells, especially macrophages, in wound repair.

Making sense of hypertrophic scar: a role for nerves

Healed partial thickness wounds including burns and donor sites cause hypertrophic scar formation and patient discomfort. For many patients with hypertrophic scars, pruritus is the most distressing symptom, which leads to wound excoriation and chronic wound formation. In spite of the clinical significance of abnormal innervation in scars, the nervous system has been largely ignored in the pathophysiology of hypertrophic scars. Evidence that neuropeptides contribute to inflammatory responses to injury include inflammatory cell chemotaxis, cytokine and growth factor production. The neuropeptide substance P, which is released from nerve endings after injury, induces inflammation and mediates angiogenesis, keratinocyte proliferation, and fibrogenesis. Substance P activity is tightly regulated by neutral endopeptidase (NEP), a membrane bound metallopeptidase that degrades substance P at the cell membrane. Altered substance P levels may contribute to impaired cutaneous healing responses associated with diabetes mellitus or hypertrophic scar formation. Topical application of exogenous substance P or an NEP inhibitor enhances wound closure kinetics in diabetic murine wounds suggesting that diabetic wounds have insufficient substance P levels to promote a neuroinflammatory response necessary for normal wound repair. Conversely, increased nerve numbers and neuropeptide levels with reduced NEP levels in human and porcine hypertrophic scar samples suggest that excessive neuropeptide activity induces exuberant inflammation in hypertrophic scars. Given these observations about the role of neuropeptides in cutaneous repair, neuronal modulation of repair processes at two extremes of abnormal wound healing, chronic non-healing ulcers in type II diabetes mellitus and hypertrophic scars in deep partial thickness wounds, may provide therapeutic targets.

Review of the female Duroc/Yorkshire pig model of human fibroproliferative scarring

Hypertrophic scarring after burns is an unsolved problem and remains as devastating today as it was in the 40s and it may be that the main reason for this is the lack of an accepted, useful animal model. The female, red Duroc pig was described as a model of hypertrophic scarring nearly 30 years ago but then vanished from the literature. This seemed strange since the authors reported that 12 of 12 pigs developed thick scar. In the mid 90s we explored the model and found that, indeed, the red Duroc pig does make thick scar. Other authors have established that the Yorkshire pig does not heal in this fashion so there is the possibility of a same species control. We have continued to explore the Duroc/Yorkshire model and herein describe our experiences. Is it a perfect model of hypertrophic scarring? No. Is it a useful model of hypertrophic scarring? Time will tell. We have now obtained gene expression data from the Duroc/Yorkshire model and analysis is underway.

Topical application of laminin-332 to diabetic mouse wounds

BACKGROUND

Keratinocyte migration is essential for wound healing and diabetic wound keratinocytes migrate poorly. Keratinocyte migration and anchorage appears to be mediated by laminin-332 (LM-332). Impaired diabetic wound healing may be due to defective LM-332 mediated keratinocyte migration.

OBJECTIVE

To evaluate LM-332 expression in diabetic (db/db) and control (db/-) mice and to test LM-332 wound healing effects when applied to mouse wounds.

METHODS

LM-332 expression in mouse wounds was evaluated using immunohistochemistry. LM-332 wound healing effects were evaluated by directly applying soluble LM-332, a LM-332 biomaterial, or a control to mouse wounds. Percent wound closure and histology score, based on healing extent, were measured.

RESULTS

Precursor LM-332 expression was markedly reduced in db/db when compared to db/- mice. In vitro, soluble LM-332 and LM-332 biomaterial demonstrated significant keratinocyte adhesion. In vivo, soluble LM-332 treated wounds had the highest histology score, but significant differences were not found between wound treatments (p>0.05). No differences in percentage wound closure between treatment and control wounds were found (p>0.05).

CONCLUSION

The db/db wounds express less precursor LM-332 when compared to db/-. However, LM-332 application did not improve db/db wound healing. LM-332 purified from keratinocytes was primarily physiologically cleaved LM-332 and may not regulate keratinocyte migration. Application of precursor LM-332 rather than cleaved LM-332 may be necessary to improve wound healing, but this isoform is not currently available in quantities sufficient for testing.

The association between fluid administration and outcome following major burn: a multicenter study

OBJECTIVE

To determine patient and injury variables that influence fluid requirements following burn injury and examine the association between fluid volume received and outcome.

BACKGROUND

Fluid resuscitation remains the cornerstone of acute burn management. Recent studies suggest that patients today are receiving more fluid per percent total body surface area (TBSA) than in the past. Therefore, there is a need to better define the factors that impact fluid requirements and to determine the effects of fluid volumes on outcome.

METHODS

This study was part of a federally funded multicenter study. Multilinear regression analyses were performed to determine the patient and injury characteristics that most influenced fluid resuscitation volumes received. To assess the association of fluid volumes on outcome, propensity scores were developed to provide a predicted volume of fluid for each patient. Logistic models were then used to assess the impact of excess fluid beyond predicted volumes on outcome.

RESULTS

Seventy-two patients were included in this analysis. Average patient age was 40.6 years and average TBSA was 44.5%. Average fluid volume received during the first 24 hours after injury was 5.2/mL/kg/TBSA. Significant predictors of fluid received included % TBSA, age, intubation status, and weight. Increased fluid volume received increased risk of development of pneumonia (odds ratio [OR] = 1.92), bloodstream infections (OR =2.33), adult respiratory distress syndrome (OR = 1.55), multiorgan failure (OR= 1.49), and death (OR = 1.74).

CONCLUSION

TBSA, age, weight, and intubation status on admission were significant predictors of fluid received. Patients who received larger volumes of resuscitation fluid were at higher risk for injury complications and death.

Standard operating procedures for the clinical management of patients enrolled in a prospective study of Inflammation and the Host Response to Thermal Injury

As part of the National Institutes of General Medical Sciences (NIGMS)-funded Inflammation and the Host Response to Injury study, participating investigators created a database, a clinical data collection protocol, and web-based case report form. To obtain high-quality clinical endpoints for correlation with genomic data, a uniform approach to patient management between centers was required. Standard operating procedures (SOPs) were generated to minimize variability and promote a uniform standard of patient care. The SOPs are necessary to enable validation of the clinical endpoints to be used for comparison with genomic and proteomic information derived from samples of blood and tissue obtained from thermally injured patients. Participating investigators identified areas of potential practice variation and developed a set of SOPs based on available data and sound clinical principles. In the absence of sufficient clinical data to identify a single management strategy, SOPs were designed to apply the best approach to management without interfering with local standards of care. The data- collection instrument, or case report form, was constructed concurrently with the SOPs. Wherever possible, the case report form was modified to collect data that might resolve controversial management issues. Modifications in management strategies that were necessary for children are delineated as needed. Data queries and site visits were conducted to audit compliance. SOPs for 10 areas of clinical care were developed. The institution of the SOPs required minor changes in clinical practice patterns and personnel training but did not require participating centers to procure new technology or alter the utilization of clinical resources significantly. The SOPs represent current management strategies applied to the study population to reduce variation in patient management. The SOPs are easily adaptable to other burn-related clinical protocols as well as to the routine daily management burn patients.

Time to School Re-Entry After Burn Injury Is Quite Short

Returning to school is an important indicator of functional aptitude and emotional adjustment in school-aged patients after burn injury. Only two reports in the burn literature provide objective data on time to school re-entry. However, these analyses did not address the impact of patient and burn injury characteristics on time to return to school. The purpose of this study was to determine the time for school re-entry and to identify the factors associated with re-entry time in a cohort of burned children treated at our burn center. We performed a retrospective review of all school age children treated at our burn center from 1997 to 2003 who were entered into a federally funded longitudinal research database for patients with severe burn injury. Time to school re-entry after discharge was calculated for each patient, and multivariate regression was used to identify the factors associated with longer time to return to school. A total of 64 patients were included in this study. The average time to school re-entry was 10.5 days (range, 0-40) and the median time was 7.5 days. Gender (male), age, and length of hospital stay were significantly associated (P < .05) with longer time to return to school. The average time to school return is quite short. Further studies are needed to increase understanding of the factors influencing longer time to re-entry and also to examine children's experiences upon re-entry.

The Microvasculature in Cutaneous Wound Healing in the Female Red Duroc Pig Is Similar to That in Human Hypertrophic Scars and Different From That in the Female Yorkshire Pig

The female red Duroc pig has been found to be a promising model of hypertrophic scarring. The female Yorkshire pig has been demonstrated to heal in a very different manner, more resembling human normotrophic scarring. Given these observations, we studied microvessel density, an important aspect of wound healing, in human hypertrophic scars and the scars of the female Duroc and Yorkshire pigs. We studied microvessel density in uninjured skin; hypertrophic scars at 6 months or less, 7 to 12, and longer than 12 months; female Duroc tissues at 3 weeks and 3 and 5 months; and similar Yorkshire tissue, including uninjured skin and shallow and deep wounds. Antifactor VIII-related antigen was used to mark the endothelial cells. Computed assessment of microvessel density was used to quantify the microvasculature. In human hypertrophic scars, the microvessels were increased dramatically, and microvessel density and area were significantly elevated. We found similar results in the Duroc tissues at 5 months after deep wounding. In contrast, we found far less microvasculature and, at 5 months, the values had returned to normal in the Yorkshire tissues. This quantitative study of microvessel density further validates the female Duroc pig as an animal model of hypertrophic scarring and the female Yorkshire pig as a control.

The clinical pulmonary infection score poorly predicts pneumonia in patients with burns

The Clinical Pulmonary Infection Score (CPIS) has been reported to be a useful tool in the diagnosis of ventilator-associated pneumonia (VAP) in the critical care setting. However, the systemic inflammation associated with injury may limit the utility of CPIS in patients with burns. The purpose of this study was to determine the potential utility of CPIS in the management of burn patients. A retrospective review was performed on all burn patients who underwent quantitative culture to diagnose VAP from 2003 to 2005. CPIS was retrospectively calculated for each patient on the day of the procedure. The sensitivity, specificity, and predictive values of a CPIS greater than 6 for VAP diagnosis were calculated. In addition, CPIS scores of patients with and without pneumonia were compared using the Mann-Whitney U test. A total of 46 quantitative cultures were obtained in 28 patients during the study period. Average patient age was 45 +/- 19 years, average TBSA was 33 +/- 18%, and the average APACHE II score on admission was 16 +/- 6. Sixty-eight percent of patients had inhalation injury. Twenty-six quantitative cultures were positive, and 20 were negative. Mean CPIS was 5.7 for patients with negative quantitative cultures and 5.5 for patients with positive cultures (P = .41). The sensitivity of CPIS scoring was 0.3, and its specificity was 0.8. CPIS had a positive predictive value of 0.7 and negative predictive value of 0.5. CPIS--a reported reliable indicator of VAP in critically ill patients--did not accurately predict the presence of pneumonia in burn patients. VAP diagnosis in burn patients should still rely on clinical suspicion verified by quantitative culture.

Thermal and electrical injuries

Through progress in wound management, resuscitation, intensive care treatment, and a coordinated rehabilitation process, modern burn care has been able to deliver substantial increases in survival and improvement in functional outcomes for burn victims. The development of regionalized burn centers has contributed greatly to this progress. As the field of burns matures, burn centers are preparing to meet future challenges through collaborative efforts in disaster management and outcomes research.

Self-reports of anxiety in burn-injured hospitalized adults during routine wound care

The purpose of this investigation was to examine the amount of anxiety patients believed tolerable and the amount of anxiety experienced during routine burn wound care. Participants included 47 hospitalized adults who provided data for four consecutive assessment periods. Patients (mean TBSA, 16%; range, 2-70%) were primarily Caucasian (87%) and had an average hospital stays of 23 days (range, 11-130). Reports of what level of anxiety they would be able to tolerate and what level of anxiety had been experienced were assessed using 10-point Graphic Rating Scales. The use of anxiolytic was recorded, and patient suggestions for reducing anxiety were obtained. The single most commonly endorsed anxiety treatment goal was 0, although 53% consistently chose a treatment goal other than 0 (range, 1-6). Two repeated-measure analyses of variance indicated that the amount of anxiety patients could tolerate and the amount they reported experiencing did not change over the course of time. Paired t-tests revealed that patients routinely reported more anxiety than they considered tolerable. Analyses of anxiety reports of patients treated with anxiolytics (n = 6) vs patients receiving no anxiolytics (n = 41) revealed inconsistent differences in actual anxiety and treatment goals across time. In general, patient suggestions for lessening anxiety included requests for education, communication, additional medications, and manipulation of the hospital environment. Anxiety for burn-injured, hospitalized adults remains a concern. Our findings are consistent with the literature indicating that adult patients hospitalized for burn wound care report appreciable anxiety, over and above what they consider "tolerable." Continued research is needed and should include investigations into the relationship between pain and anxiety during routine wound care.