J. Kevin Bailey

Identification of Cutaneous Functional Units Related to Burn Scar Contracture Development

The development of burn scar contractures is due in part to the replacement of naturally pliable skin with an inadequate quantity and quality of extensible scar tissue. Predilected skin surface areas associated with limb range of motion (ROM) have a tendency to develop burn scar contractures that prevent full joint ROM leading to deformity, impairment, and disability. Previous study has documented forearm skin movement associated with wrist extension. The purpose of this study was to expand the identification of skin movement associated with ROM to all joint surface areas that have a tendency to develop burn scar contractures. Twenty male subjects without burns had anthropometric measurements recorded and skin marks placed on their torsos and dominant extremities. Each subject performed ranges of motion of nine common burn scar contracture sites with the markers photographed at the beginning and end of motion. The area of skin movement associated with joint ROM was recorded, normalized, and quantified as a percentage of total area. On average, subjects recruited 83% of available skin from a prescribed area to complete movement across all joints of interest (range, 18–100%). Recruitment of skin during wrist flexion demonstrated the greatest amount of variability between subjects, whereas recruitment of skin during knee extension demonstrated the most consistency. No association of skin movement was found related to percent body fat or body mass index. Skin recruitment was positively correlated with joint ROM. Fields of skin associated with normal ROM were identified and subsequently labeled as cutaneous functional units. The amount of skin involved in joint movement extended far beyond the immediate proximity of the joint skin creases themselves. This information may impact the design of rehabilitation programs for patients with severe burns.

Randomized, Paired-Site Comparison of Autologous Engineered Skin Substitutes and Split-Thickness Skin Graft for Closure of Extensive, Full-Thickness Burns.

Stable closure of full-thickness burn wounds remains a limitation to recovery from burns of greater than 50% of the total body surface area (TBSA). Hypothetically, engineered skin substitutes (ESS) consisting of autologous keratinocytes and fibroblasts attached to collagen-based scaffolds may reduce requirements for donor skin, and decrease mortality. ESS were prepared from split-thickness skin biopsies collected after enrollment of 16 pediatric burn patients into an approved study protocol. ESS and split-thickness autograft (AG) were applied to 15 subjects with full-thickness burns involving a mean of 76.9% TBSA. Data consisted of photographs, tracings of donor skin and healed wounds, comparison of mortality with the National Burn Repository, correlation of TBSA closed wounds with TBSA full-thickness burn, frequencies of regrafting, and immunoreactivity to the biopolymer scaffold. One subject expired before ESS application, and 15 subjects received 2056 ESS grafts. The ratio of closed wound to donor areas was 108.7 ± 9.7 for ESS compared with a maximum of 4.0 ± 0.0 for AG. Mortality for enrolled subjects was 6.25%, and 30.3% for a comparable population from the National Burn Repository (P < .05). Engraftment was 83.5 ± 2.0% for ESS and 96.5 ± 0.9% for AG. Percentage TBSA closed was 29.9 ± 3.3% for ESS, and 47.0 ± 2.0% for AG. These values were significantly different between the graft types. Correlation of % TBSA closed with ESS with % TBSA full-thickness burn generated an R 2 value of 0.65 (P < .001). These results indicate that autologous ESS reduce mortality and requirements for donor skin harvesting, for grafting of full-thickness burns of greater than 50% TBSA.

Thrombocytopenia in the pediatric burn patient.

Thrombocytopenia is initially seen in patients with burn injury as a transient occurrence during the first week after injury. Subsequent decreases occur later in the course of treatment and are commonly due to sepsis, dilutional effects, and medication exposure. Although studies have demonstrated that thrombocytopenia in the critically ill patients is associated with a worse prognosis, there is limited literature as to the significance of thrombocytopenia in the pediatric burn patients. In this study, the authors evaluate the prognostic implications of thrombocytopenia in the pediatric burn patients. They performed a 5-year retrospective chart of patients aged 18 years or younger with burns >20% TBSA admitted to their institution. Data collected included patient demographics, burn etiology and %TBSA involvement, length of stay, pertinent laboratory values, and in-hospital morbidity and mortality. Of the 187 patients studied, thrombocytopenia occurred in 112 patients. Eighty-two percent demonstrated thrombocytopenia within the first week of injury and 18% demonstrated additional episodes of thrombocytopenia after this time. A reactive thrombocytosis occurred in 130 (70%) patients. The incidence of thrombocytopenia could not be attributed to age, gender, or burn etiology. However, patients with thrombocytopenia were more likely to have inhalation injury and extensive TBSA involvement than those without (P < .05). Sepsis was the cause of significant thrombocytopenia after the first week of hospitalization. Of the 187 patients, 14 died (7%). The incidence of thrombocytopenia in survivors and nonsurvivors was statistically significant in that nonsurvivors demonstrated a more profound drop in platelet count during the first week after injury and had a more depressed platelet recovery curve than survivors. The authors conclude that the early development of thrombocytopenia with depressed thrombocytosis in the pediatric burn patient is associated with increased mortality risk and is influenced by the extent of burn, inhalation injury, and the development of sepsis.

Scar Treatment Variations by Skin Type

Patients and clinicians use skin color attributes such as color uniformity, color distribution, and texture to infer physiologic health status. Normalization of skin color, surface texture, and height are important treatment goals in the treatment of scars. Skin color, structure, and response to trauma, vary with ethnicity. The incidence of hypertrophic and keloid scar formation is influenced by these inherent skin attributes. Skin type influences the response to various modalities including laser therapy and surgical intervention, and skin differences must be considered in treatment planning to achieve optimal results.

Sonographic evaluation of intravascular volume status: Can internal jugular or femoral vein collapsibility be used in the absence of IVC visualization?

Introduction: Inferior vena cava collapsibility index (IVC-CI) has been shown to correlate with both clinical and invasive assessment of intravascular volume status, but has important limitations such as the requirement for advanced sonographic skills, the degree of difficulty in obtaining those skills, and often challenging visualization of the IVC in the postoperative patient. The current study aims to explore the potential for using femoral (FV) or internal jugular (IJV) vein collapsibility as alternative sonographic options in the absence of adequate IVC visualization. Methods: A prospective, observational study comparing IVC-CI and Fem- and/or IJV-CI was performed in two intensive care units (ICU) between January 2012 and April 2014. Concurrent M-mode measurements of IVC-CI and FV- and/or IJV-CI were collected during each sonographic session. Measurements of IVC were obtained using standard technique. IJV-CI and FV-CI were measured using high-frequency, linear array ultrasound probe placed in the corresponding anatomic areas. Paired data were analyzed using coefficient of correlation/determination and Bland-Altman determination of measurement bias. Results: We performed paired ultrasound examination of IVC-IJV (n = 39) and IVC-FV (n = 22), in 40 patients (mean age 54.1; 40% women). Both FV-CI and IJV-CI scans took less time to complete than IVC-CI scans (both, P < 0.02). Correlations between IVC-CI/FV-CI (R 2 = 0.41) and IVC-CI/IJV-CI (R 2 = 0.38) were weak. There was a mean -3.5% measurement bias between IVC-CI and IJV-CI, with trend toward overestimation for IJV-CI with increasing collapsibility. In contrast, FV-CI underestimated collapsibility by approximately 3.8% across the measured collapsibility range. Conclusion: Despite small measurement biases, correlations between IVC-CI and FV-/IJV-CI are weak. These results indicate that IJ-CI and FV-CI should not be used as a primary intravascular volume assessment tool for clinical decision support in the ICU. The authors propose that IJV-CI and FV-CI be reserved for clinical scenarios where sonographic acquisition of both IVC-CI or subclavian collapsibility are not feasible, especially when trended over time. Sonographers should be aware that IJV-CI tends to overestimate collapsibility when compared to IVC-CI, and FV-CI tends to underestimates collapsibility relative to IVC-CI.

Correlation of internal jugular vein/common carotid artery ratio to central venous pressure: a pilot study in pediatric burn patients.

The purpose of this pilot study was to identify the relationship between the ratio of the diameter/cross-sectional area of the internal jugular vein (IJV) and carotid artery and the central venous pressure (CVP). After obtaining approval from our Institutional Review Board, ultrasound images were repeatedly obtained from participants on consecutive days when a thoracic central line was in place. The CVP was then measured in standardized fashion, using our bedside monitors. A blinded observer measured the diameter of the common carotid artery and IJV, for comparison. Similarly, digital images were analyzed to compare an estimate of the cross-sectional areas of the same vessels. Six patients met enrollment criteria, and one patient was excluded after enrollment before any measurements being made. The remaining five patients had a mean age of 7 years (range: 9 months to 15 years) and mean burn size of 64% (SD, ±15), and no patients had inhalation injuries. All patients in this study were mechanically ventilated. Measurements were made from one patient while spontaneously breathing. One patient reading occurred while on vasopressor support (levophed at 2 &mgr;g/kg/hr). CVP values ranged from 1 to 25 mm Hg. Comparison of the ratio of the IJV/common carotid artery cross-sectional area with CVP revealed that a ratio of 2 or greater was associated with a CVP of at least 8 mm Hg (P < .001). These preliminary results suggest that if the cross-sectional area of the vein is at least twice that of the artery, then the CVP seems to be ≥8 mm Hg.

A performance improvement initiative to determine the impact of increasing the time interval between changing centrally placed intravascular catheters.

Existing practice guidelines designed to minimize invasive catheter infections and insertion-related complications in general intensive care unit patients are difficult to apply to the burn population. Burn-specific guidelines for optimal frequency for catheter exchange do not exist, and great variation exists among institutions. Previously, the authors’ practice was to follow a new site insertion at 48 hours by an exchange over a guidewire, which was followed 48 hours later by a second guidewire exchange (48h group). As a performance improvement initiative, the authors attempted to determine whether there would be any advantage or disadvantage to extending these intervals to 72 hours (72h). All patients with centrally placed intravascular catheters from October 2007 to August 2008 were included in the 48h group, and all patients with catheters placed from September 2008 to December 2009 comprised the 72h group. Catheter infection rates were determined using the National Healthcare Safety Network definition for central line–associated bloodstream infections (CLABSIs) and calculated as CLABSIs/1000 catheter days. The two groups were not significantly different for age, sex, burn etiology, total burn size, or percent third-degree burn. There were 3.1 CLABSIs/1000 catheter days for the 48h group and 2.8 CLABSIs/1000 catheter days for the 72h group (NS). The authors conclude that increasing the central catheter change interval from 48 to 72 hours did not result in any increase in their CLABSI rate. Implementation of this change in practice is expected to decrease supply costs by

Comorbidity-polypharmacy score predicts in-hospital complications and the need for discharge to extended care facility in older burn patients.

28,000 annually in addition to reducing clinical support services needed to perform these procedures.

Inflammatory responses, matrix remodeling, and re‐epithelialization after fractional CO2 laser treatment of scars

Advancing age is associated with increased mortality despite smaller burn size. Chronic conditions are common in the elderly with resulting polypharmacy. The Comorbidity-Polypharmacy Score (CPS) facilitates quantitative assessment of the severity of comorbid conditions, or physiologic age. Burn injury in older patients is associated with increasing morbidity and mortality and the CPS may be predictive of outcomes such as mortality, ICU and hospital LOS, complications, and final hospital disposition. Our goal was to evaluate the predictive value of CPS for outcomes in the elderly burn population. A retrospective study was undertaken of 920 burn patients with age ≥45 admitted with acute burn injuries (January 1, 2006 to December 31, 2012). CPS was calculated by adding preinjury comorbidities and medications. Subjects were stratified into three groups according to CPS severity. Data collected included demographics, total body surface area burned (TBSA), presence of inhalation injury, ICU/hospital length of stay, complications, discharge disposition, and mortality. Univariate and multivariate analyses were performed. The mean age was 55.7; 72.9% were males; the mean initial TBSA was 6.93%; and mean CPS was 8.01. The risk of in-hospital complications is independently associated with CPS (OR 1.35). CPS (OR 1.81) was an independent predictor of discharge to a facility CPS but not of mortality. While increasing CPS was associated with lower TBSA, mortality remained unchanged. CPS is an independent predictor of in-hospital complications and need for transfer to extended care facilities in older burn patients, which can be determined at the stage of admission to help direct patient management.

Effects of early combinatorial treatment of autologous split‐thickness skin grafts in red duroc pig model using pulsed dye laser and fractional CO2 laser

Fractional CO2 laser therapy has been used to improve scar pliability and appearance; however, a variety of treatment protocols have been utilized with varied outcomes. Understanding the relationship between laser power and extent of initial tissue ablation and time frame for remodeling could help determine an optimum power and frequency for laser treatment. The characteristics of initial injury caused by fractional CO2 laser treatment, the rates of dermal remodeling and re‐epithelialization, and the extent of inflammation as a function of laser stacking were assessed in this study in a porcine scar model.