Burn Excision Research Articles

Succinylcholine Hyperkalemia after Burns

Professor of Anesthesiology; Harvard Medical School; Massachusetts General Hospital; Boston, Massachusetts 02114;martyn@etherdome.mgh.harvard.eduDennis Fisher was Acting Editor-in-Chief for this correspondence exchange.* Martyn JAJ, Nosek M: Increased expression of transcripts of [Greek small letter gamma]-subunit of acetylcholine receptor (AChR) in area immediately beneath burn injury. Anesthesiology 1996; 85:A700In Reply:-MacLennan et al. [1] probably have taken the more conservative and safer approach when they suggest that succinylcholine should not be used beyond 24 h after a burn injury. However, there are no reports in the literature of succinylcholine-induced hyperkalemia in humans occurring within 1 week after a burn injury. Based on published human studies, some other investigators might therefore assert that succinylcholine is safe up to 1 week after burn injury. Nevertheless, it is important to point out that these studies, relative to succinylcholine and burns, were performed almost 30 yr ago. [2–4] In these reports, the number of patients studied within 1 week after burn injury totaled only three in the three publications.The treatment modality at that time (three decades ago) was that most burn patients, especially those with big burns, did not undergo excision and grafting procedures until the burn eschar had separated from the wound. This spontaneous separation of eschar takes at least 2 weeks. Early excision and grafting of burns, especially of major burns, was not routine at that time. Therefore, it is not surprising that only a total of three-patient studies were reported for the first week in three publications. Most likely, the three patients reported suffered only minor burns.In contrast to the conservative approach to treatment of burns of the past, current practice advocates early excision and grafting of burn wounds, especially of patients with major burns. [1] The upregulation of acetylcholine receptors (AChRs) after burns occurs at sites immediately beneath and distant from the burn [5]; a positive correlation between AChR number and the intensity of the hyperkalemia after succinylcholine has been confirmed. [6] The upregulation of AChRs that occurs in muscles beneath the area of the burn is as profound as after denervation and occurs as early as 72 h after burn.* Evidence for upregulation of the immature isoform has also been provided by assessment of messenger RNAs for the [Greek small letter gamma]-subunit. When depolarized, the immature isoform has a prolonged open channel time, which may exaggerate the K+efflux that occurs with depolarization. We have recently reconfirmed this AChR upregulation with expression of the [Greek small letter gamma]-subunit as early as 3 days after a 5% burn over the tibialis anterior muscle in the rat (unpublished). Thus, the potential for profound, denervation-type upregulation of AChRs is present as early as 3 days after burn injury when the burn-injured area is adjacent to muscle. The dramatic upregulation of AChRs on all muscles beneath the burn is also accompanied by the expression of the immature isoform of the receptor. In fact, burn injury of a single limb (8–9% body surface area) is sufficient to cause potentially lethal hyperkalemia. [4] The concomitant presence of immobilization with and without prolonged administration of muscle relaxants can accentuate the upregulation of AChRs. [6] Immobilization alone can induce modest upregulation as early as 3–4 days. [7]Thus, the lack of clinical reports of hyperkalemia before 7 days after burn injury is probably a result of the following:(1) the previous treatment philosophy of not treating major burns aggressively with early excision and grafting did not provide the opportunity for challenge of major burns with succinylcholine within the first week; and (2) increased awareness of the dangers of hyperkalemia with succinylcholine has resulted in its lack of use in burn patients as early as 1 week during early excision and grafting of major burns.Thus, it is my view that succinylcholine is probably safe up to 48 h after burn injury, but it may be wise to avoid it beyond that period. Patients may be particularly vulnerable if they have been immobilized in bed because of severity of illness or concomitant disease (e.g., inhalation injury and fractures) or if they have received prolonged muscle relaxant therapy to facilitate mechanical ventilation. [6]J. A. Jeevendra Martyn, M.D.Professor of Anesthesiology; Harvard Medical School; Massachusetts General Hospital; Boston, Massachusetts 02114;martyn@etherdome.mgh.harvard.edu(Accepted for publication February 25, 1999.)

Cirrhosis with steatohepatitis after adjuvant tamoxifen

healing, hyaluronic acid promotes epithelial migration and differentiation, improves angiogenesis, and enhances collagen production. 4 Methods of chemically modifying natural polymers for clinical use have been applied to hyaluronic acid, to produce materials that have different physico-chemical properties but similar biological properties to the native compound. 5 Hyaff-NW (Fidia Advance Biopolymers, Padua, Italy) is a 100% benzyl-esterified derivative of hyaluronic acid processed into fibres and prepared as a flat, non-woven pad dressing, which can be seeded with fibroblasts before application. Laserskin (Fidia Advanced Biopolymers) is a 100% benzyl-esterified hyaluronic acid-membrane for the culture and delivery of autologous keratinocytes. Laser-drilled microperformations allow keratinocytes to migrate through the membrane onto the wound bed. A 45-year-old man sustained 50% full-thickness flame burns to both arms, right chest, and lower abdomen, with a further 30% partial-thickness burns to his legs. On admission, a 4 cm 3 4 cm piece of split-skin was harvested to initiate keratinocyte and fibroblast cultures. Early tangential excision and grafting of the burns with cadaveric allograft or Hyaff-NW containing autologous fibroblasts was then done. 14 days later, allografted areas were demabraded to remove the cadaveric epidermis and produce a dermal bed. 30 Laserskin membranes (3000 cm 2 ), seeded with autologous keratinocytes, were then applied on two separate occasions. 24 days after the first application, 80% of the cadaveric dermis/Laserskin areas and all of the Hyaff-NW/Laserskin areas were covered with epithelium. Histology of both areas revealed an acanthotic, continuous epidermis with interdigitations at the dermo-epidermal junction that resembled the rete ridge pattern seen in normal skin. The underlying wound bed of Hyaff-NW/Laserskin treated areas showed evidence of new collagen synthesis and organisation into a dermis-like structure. The wounds were completely healed 7 weeks after burn excision with no unusual scarring so far. Long-term studies of these biomaterials are required to establish if they improve the survival of patients and reduce morbidity compared with conventional split-skin or keratinocyte grafting. A new era in the management of extensive burns may have begun.

The effect of clysed and topical epinephrine on intraoperative catecholamine levels.

Epinephrine administration for hemostasis during burn wound excision may produce potential anesthetic risks. Two patient groups were studied to determine the absorption of either topical concentrated epinephrine or exogenously injected dilute epinephrine. For the topical group (10 patients, 10 procedures), excision of wounds under tourniquet was performed, followed by epinephrine (1 mg/10 mL) gauze with pressure wrapping. For the clysis group (9 patients, 12 procedures), donor sites were injected with 0.5 mg epinephrine/1,000 mL lactated Ringer's solution before harvest. Nine intraoperative serum samples were collected and frozen during each procedure for epinephrine and norepinephrine assay. Concentrated epinephrine (67 mL) was topically applied to excise 1,362 cm2. Dilute epinephrine (1,350 mL) was clysed to obtain 1,950 cm2 autograft. No significant increases in the serum catecholamines or changes in the cardiovascular profiles occurred. The administration of either topical or clysed epinephrine during acute burn excision does not cause any side effects for safe anesthetic management; there were no detectable increased plasma levels of epinephrine or norepinephrine. Epinephrine provides the burn surgeon with two safe methods for controlling intraoperative blood loss.

Burn management in a patient with autism

The successful use of elective post-operative sedation and ventilation following tangential surgical excision of burns in an autistic child, non-compliant with conventional management is reported. Other strategies for treating autistic children are discussed.

Carbon dioxide laser ablation with immediate autografting in a full-thickness porcine burn model.

To compare the long-term clinical and histologic outcome of immediate autografting of full-thickness burn wounds ablated with a high-power continuous-wave CO2 laser to sharply débrided wounds in a porcine model. Continuous-wave CO2 lasers have performed poorly as tools for burn excision because the large amount of thermal damage to viable subeschar tissues precluded successful autografting. However, a new technique, in which a high-power laser is rapidly scanned over the eschar, results in eschar vaporization without significant damage to underlying viable tissues, allowing successful immediate autografting. Full-thickness paravertebral burn wounds measuring 36 cm2 were created on 11 farm swine. Wounds were ablated to adipose tissue 48 hours later using either a surgical blade or a 150-Watt continuous-wave CO2 laser deflected by an x-y galvanometric scanner that translated the beam over the tissue surface, removing 200 microm of tissue per scan. Both sites were immediately autografted and serially evaluated clinically and histologically for 180 days. The laser-treated sites were nearly bloodless. The mean residual thermal damage was 0.18+/-0.05 mm. The mean graft take was 96+/-11% in manual sites and 93+/-8% in laser sites. On postoperative day 7, the thickness of granulation tissue at the graft-wound bed interface was greater in laser-debrided sites. By postoperative day 180, the manual and laser sites were histologically identical. Vancouver scar assessment revealed no differences in scarring at postoperative day 180. Long-term scarring, based on Vancouver scar assessments and histologic evaluation, was equivalent at 6 months in laser-ablated and sharply excised sites. Should this technology become practical, the potential clinical implications include a reduction in surgical blood loss without sacrifice of immediate engraftment rates or long-term outcome.

Intraoperative blood salvage in excisional burn surgery: an analysis of yield, bacteriology, and inflammatory mediators.

The diminution of intraoperative hemorrhage remains a fundamental goal of the burn surgeon. We hypothesized that intraoperative blood salvage during burn excisions would be feasible if predicated on yield, bacteriology, and concentration of inflammatory mediators in the washed product. Reinfusion of culture-positive blood has a clear precedent in the trauma literature. Eight operations with immediate and complete collection of shed blood into a cell-saver device were prospectively studied. A median salvage rate of 43% of total shed red blood cells was estimated to have been recovered. Actual volumetric measurement of intraoperative blood loss was achieved. Bacterial contamination was consonant with the abdominal trauma experience. The levels of C3a, C5a, TNF alpha, and IL-1 beta in the final cell-saver product were all found to be at clinically insignificant levels.

In vitro engineering of human skin‐like tissue

Coverage of large, full-thickness burns presents a challenge for the surgeon due to the lack of availability of the patient's own skin. Currently, tissue engineering offers the possibility of performing a suitable therapeutic wound coverage after early burn excision by using cultured keratinocyte sheets supported by a dermal layer. The aim of this study was to develop and characterize a skin substitute composed of both epidermal and dermal elements. For this purpose we grew keratinocytes and fibroblasts separately for 15 days within two different types of biomaterials. Cells then were co-cultured for an additional period of 15 days, after which samples were taken and processed with either classic or immunohistochemical stainings. Results showed that (1) human fibroblasts and keratinocytes can be cultured on hyaluronic acid-derived biomaterials and that (2) the pattern of expression of particular dermal–epidermal molecules is similar to that found in normal skin. The data from this study suggest that our skin equivalent might be useful in the treatment of both burns and chronic wounds. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 187–194, 1998.

In vitro engineering of human skin-like tissue.

Coverage of large, full-thickness burns presents a challenge for the surgeon due to the lack of availability of the patient's own skin. Currently, tissue engineering offers the possibility of performing a suitable therapeutic wound coverage after early burn excision by using cultured keratinocyte sheets supported by a dermal layer. The aim of this study was to develop and characterize a skin substitute composed of both epidermal and dermal elements. For this purpose we grew keratinocytes and fibroblasts separately for 15 days within two different types of biomaterials. Cells then were co-cultured for an additional period of 15 days, after which samples were taken and processed with either classic or immunohistochemical stainings. Results showed that (1) human fibroblasts and keratinocytes can be cultured on hyaluronic acid-derived biomaterials and that (2) the pattern of expression of particular dermal-epidermal molecules is similar to that found in normal skin. The data from this study suggest that our skin equivalent might be useful in the treatment of both burns and chronic wounds.

A retrospective analysis of early excision and skin grafting from 1993–1995

Early excision and skin grafting (EEG) is an established and accepted procedure for deep burn management. This is a retrospective analysis of 100 patients treated with early excision and grafting in burns of all types and up to 65 per cent TBSA. Excisional surgery was performed in the period from day 2 to day 7 post-burn in patients who did not have significant infection (<10 5) in one to two stages. The average mortality rate in all age groups and including smoke inhalation injury in our unit was 43.4 per cent. The mortality in the operated group was 10.2 per cent. The main causes of mortality were smoke inbalation injury, septicaemia (probably originating from the non-excised tissue) and extensive burn injury. The functional and aesthetic outcome in EEG patients was far superior in comparison with the conventional method of treatment.

Does Epinephrine Prevent Blood Loss in Total Burn Excision?

Does Epinephrine Prevent Blood Loss in Total Burn Excision?

Staged High Dose Epinephrine Clysis in Pediatric Burn Excision

Staged High Dose Epinephrine Clysis in Pediatric Burn Excision

Plasma concentrations of tumour necrosis factor-α and interleukin-6 during burn wound surgery or dressing

Background: Clinical deterioration after burn wound manipulation may be related to the release of cytokines including tumour necrosis factor-α (TNF) and interleukin-6 (IL-6). Methods: The two cytokines were assayed by immunoenzymetric assay in blood samples taken before and during manipulation of the burn wound. An antibiotic, teicoplanin, was administered to half the patients at the start of the procedure in a randomized fashion as part of a separate trial. Findings: Sixty patients with a median burn size of 8% (range 1–56%) were studied during dressing change ( n = 40) or burn excision ( n = 20). There was little change in TNF levels between preoperative and recovery samples but IL-6 concentrations increased three-fold, particularly in those with large recent burns or bacteraemia, and were correlated with poor clinical outcome. The presence of teicoplanin did not significantly affect the levels of either cytokine. Interpretation: The systemic cytokine response to burn wound dressing or debridement is predominantly that of IL-6 and it is not significantly reduced by preventing Gram-positive bacteraemia during the procedure.

Wound closure with human keratinocytes cultured on a polyurethane dressing overlaid on a cultured human dermal replacement

Burn excision followed by immediate wound coverage has become the clinical standard for managing extensive burn injuries in much of the world. When sufficient autograft skin to achieve permanent wound closure is unavailable, cell culture technology has made the use of cultured human keratinocyte (HK) sheets clinically feasible. Whereas previous techniques have focused on development of multilayered, differentiated HK sheets, our attention has been drawn to using HK in a highly proliferative, less differentiated state. Time requirements for preparation of multistratified cultured HK are high, and preparatory steps may destroy important integrin adhesion molecules. We describe the use of HK cultured to single layer confluence on a polyurethane membrane(HD), with serum-free medium. HK-HD grafts were transplanted to full-thickness wounds on athymic mice (n = 31). A second group of mice (DG-HK-HD), n = 28) received a living human dermal replacement containing cultured fibroblasts before placement of HK-HD. Control mice received HD alone (n = 4). Basement membrane proteins on healed wounds and surface integrins on cultured HK were identified by means of immunostaining and direct microscopic visualization. HK cultured just to the confluent state on polyurethane membrane were positive for integrins alpha(5) and alpha(6), major integrins on proliferating HK. Histologic analysis showed epithelialized wounds in all groups after 21 days. Using an anti-human involucrin antibody we demonstrated the presence of HK in 64.5% of the HK-HD group, 61% of the DG-HK-HD group, and 0% in the HD group. Mice that received the living human dermal replacement containing cultured fibroblasts in combination with HK-HD grafts developed a thick, well-vascularized neodermis. Strong laminin and collagen IV staining was observed in wound areas covered with HK. These data show that full-thickness wounds can be closed by application of a single layer of proliferating HK cultured on a biocompatible polyurethane membrane. This technique is an alternative to the use of multilayered, differentiated HK sheets. Preparation times for HK-HD grafts should be significantly shorter than required for multilayered HK sheets, technical efforts should be less, and more extensive wound areas could be covered.

Steam press hand burns: A serious burn injury

Steam presses cause full-thickness burns when the operator's extremity is caught between the buck and the head of the steam press. Patients with serious steam press burns should be referred to a regional burn center for excision of the full-thickness burn and coverage by either a split-thickness skin graft or a flap. The safety features in steam presses that could prevent this serious injury include: (1) emergency safety releases, (2) peripheral safety bars, and (3) two-hand operator control.

Effects of early and delayed wound excision on pulmonary leukosequestration and neutrophil respiratory burst activity in burned mice

Tissue myeloperoxidase (MPO) is a marker of neutrophil (PMN) accumulation in tissues (leukosequestration). We measured MPO in the livers, guts, and lungs of mice after burn injury and studied the additive effect of burn excision on lung MPO. Lung histologic characteristics were also examined. PMN respiratory activity was assessed by measuring intracellular H2O2 content. Mice received 32% total body surface area (TBSA) burns; some underwent burn excision followed by wound closure with allograft skin, either immediately or 48 hours after burn. Tissue MPO was measured by a colormetric assay, and intracellular H2O2 was quantified by flow cytometry. MPO was elevated in lungs 8 to 24 hours after burn (p < 0.05) but not in the liver or ileum. Other burned mice received either immediate or 48-hour-delayed wound excision and allografting. In controls a similar-size area was excised and grafted with normal or burned skin. Burned animals had increased lung MPO compared with nonburned animals (p < 0.05). Highest lung MPO levels were seen after burn/immediate excision (p < 0.001). Lung MPO levels were not different comparing unburned mice undergoing skin excision and grafting with either nonburned or burned skin. When burn excision was delayed 48 hours, lung MPO was increased moderately (p < 0.05) but remained far below levels in mice that were excised immediately after burn. PMN influx into lung tissues was confirmed by histologic examination. PMN H2O2 production was increased in burned mice and was additionally increased after immediate wound excision. Although burn injury produces pulmonary leukosequestration, the phenomenon is unrelated to local effects of burned skin. In this experimental model immediate postburn wound excision increased pulmonary leukosequestration to higher levels than after burn injury alone, and intracellular H2O2 content also increased. Pulmonary leukosequestration may predispose to lung injury, possibly limiting the benefits of wound excision performed extremely early postburn.

Advantages of early burn excision and grafting in the treatment of burn injuries of the anterior cervical region

Excision and grafting in deep partial and full skin thickness burns of the anterior cervical region in a series of 40 patients treated between 1982 and 1992 is reported. The advantages of surgical management of deep burns in this region in a single staged operation have proved its efficacy compared to the severe sequelae which appear when the standard conservation treatment is used. A comparative study of two groups of patients treated either by early excision and grafting ( n = 19 40 ), or by delayed excision and grafting ( n = 21 40 ) demonstrated the advantages of elective early excision and grafting with respect to: length of hospital care, complications and their severity, and surgical repair.

Management of Pediatrie Facial Burns

The acute management of pediatric facial burns is not uniform. Many surgeons prefer to wait until primary wound separation occurs before grafting. Concerns over early excision are accentuated in small pediatric patients. The possible benefits of early excision results have led to adoption of this technique at our facility. This study presents our recent experience with early excision and grafting. Sixty-six patients with a mean age of 6.2 years underwent early excision and grafting of facial burns. Patients underwent grafting a mean 12.7 days after burn. Procedures were done in two stages. All grafts were dressed open. There were no episodes of acute airway decompensation. No patient required regrafting. Patients wore pressure masks a mean of 15.5 months after grafting. Thirteen patients had releases (10 eyelids, three lips/commissures) in the first postoperative year. These results demonstrate that early excision and grafting of facial burns can be carried out safely in pediatric patients with burns. The benefits of early wound coverage can thus be applied to facial burns in this population of patients.

Effects of fluid resuscitation, burn eschar excision, and blockade of afferent pain responses on bacterial translocation and acid-base balance after murine burn injury.

We tested effects of fluid resuscitation, early burn excision/grafting, and blockade of afferent stimuli from the burn wound on bacterial translocation and acid-base balance after murine burn injury. Burn excisions were performed with patients either 15 minutes or 2 hours after burn injury under anesthesia, and excised wounds were immediately closed with murine allograft skin. Twenty-four hours after 25% total body surface area (TBSA) burn injury and 48 hours after 32% TBSA injury, mesenteric lymph nodes were cultured. Incidences of bacterial translocation in 25% and 32% TBSA burns were 31.6% and 68.4% of animals, respectively. Burned animals were in severe shock, and metabolic acidosis reached a nadir 12 hours after burn injury, with base deficit -27.8 +/- 0.6 mEq/L; 5% to 10% of animals died acutely after burn injury. After excision/grafting of burned mice at 2 hours after burn injury, the incidence of bacterial translocation was unchanged (35.7% with 25% TBSA burn, 73.3% with 32% TBSA burn), and mortality did not change. When 32% TBSA excisions were performed exactly 10 minutes after burn injury, four of the 13 mice died within several hours, and five (55.5%) of the nine survivors translocated. Rates of bacterial translocation in mice receiving anesthesia or excision/grafting without burn injury were 15.0% and 20%, respectively (p = NS compared with normal mice). Subcutaneous implantation of normal or burned skin into normal animals neither elicited shock nor increased the incidence of bacterial translocation. Increasing amounts of fluid resuscitation in the 25% TBSA burn model provided only delayed improvement of acid-base balance; increased amounts of fluid did not decrease bacterial translocation.(ABSTRACT TRUNCATED AT 250 WORDS)

The elderly burn patient

During a 16-year period, 547 patients who were older than 64 years of age with a mean total body surface area (TBSA) (third-degree burns) of 25% were treated. Etiologies were flame/flash in 81% of patients, scald in 11%, solids in 7%, and electrical/chemical in 1%. Seventeen percent of patients had significant causal factors. An inhalation injury was present in 13% of patients, and the mortality in these patients was 100%. Burn excision was performed 239 times in 165 patients. The majority of excisions were for full-thickness burns. Excision did not improve overall survival in patients with third-degree burns of 0% to 10%, but the length of stay (LOS) in excised and nonexcised survivors was improved (9 versus 21 days, respectively). The LOS and survival were not significantly different in patients with burns between 11% and 20%. Postburn complications occurred in 28% of patients. Overall mortality was 50% (mean age: 77 years; TBSA: 40%). There were no survivors with over 47% TBSA burns. The leading cause of death was pulmonary sepsis. Most surviving patients returned to a satisfactory lifestyle after discharge.

Current concepts in pediatric burn care: surgery of severe burns.

Optimal surgical therapy of severe burns in children has been controversial for a long time. A review of the current literature shows that prompt surgical excision of necrotic tissue and immediate autografting have become the standard in most burn centers. The authors present a concept based on prompt excision of third degree burns and discuss the problems of intermediate cover arising in massive burns.