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Abstract Beneficial effects could be achieved by various agents such as nitroglycerin, botulinum toxin A (BoTA), and clopidogrel to improve skin flap ischaemia and venous congestion injuries. Eighty rats were subjected to either arterial ischaemia or venous congestion and applied to a bipedicled U-shaped superficial inferior epigastric artery (SIEA) flap with the administration of nitroglycerin, BoTA, or clopidogrel treatments. After 7 days, all rats were sacrificed for flap evaluation. Necrotic area percentage was significantly minimized in flaps treated with clopidogrel (24.49%) versus the ischemic flaps (34.78%); while nitroglycerin (19.22%) versus flaps with venous congestion (43.26%). With ischemia, light and electron microscopic assessments revealed that nitroglycerin produced degeneration of keratinocytes and disorganization of collagen fibers. At the same time, with clopidogrel administration, there was an improvement in the integrity of these structures. With venous congestion, nitroglycerin and BoTA treatments mitigated the epidermal and dermal injury; and clopidogrel caused coagulative necrosis. There was a significant increase in tissue gene expression and serum levels of vascular endothelial growth factor (VEGF) in ischemic flaps with BoTA and clopidogrel, nitroglycerin, and BoTA clopidogrel in flaps with venous congestion. With the 3 treatment agents, gene expression levels of tumor necrosis factor-α (TNF-α) were up-regulated in the flaps with ischemia and venous congestion. With all treatment modalities, its serum levels were significantly increased in flaps with venous congestion and significantly decreased in ischemic flaps. Our analyses suggest that the best treatment option for ischemic flaps is clopidogrel, while for flaps with venous congestion are nitroglycerin and BoTA.

PATIENTS AND METHODS:Surgically managed burn patients admitted between 2010-14 were included. Operative stay was defined as the time from admission until the last operation, postoperative stay as the time from the last operation until discharge. The difference in variation was analysed with F-test. A retrospective review of medical records was done to explore reasons for extended postoperative stay. Multivariable regression was used to assess factors associated with operative stay and postoperative stay. RESULTS:Operative stay/TBSA% showed less variation than total duration/TBSA% (F test = 2.38, p

Abstract To investigate if donor and recipient site morbidity (healing time and cosmesis) could be reduced by a novel, modified split-thickness skin grafting (STSG) technique using a dermal component in the STSG procedure (DG). The STSG technique has been used for 150 years in surgery with limited improvements. Its drawbacks are well known and relate to donor site morbidity and recipient site cosmetic shortcomings (especially mesh patterns, wound contracture, and scarring). The Dermal graft technique (DG) has emerged as an interesting alternative, which reduces donor site morbidity, increases graft yield, and has the potential to avoid the mesh procedure in the STSG procedure due to its elastic properties. A prospective, dual-centre, intra-individual controlled comparison study. Twenty-one patients received both an unmeshed dermis graft and a regular 1:1.5 meshed STSG. Aesthetic and scar assessments were done using The Patient and Observer Scar Assessment Scale (POSAS) and a Cutometer Dual MPA 580 on both donor and recipient sites. These were also examined histologically for remodelling and scar formation. Dermal graft donor sites and the STSG donor sites healed in 8 and 14 days, respectively (p

Abstract Transdermal iontophoresis offers an in vivo alternative to the strain-gauge model for measurement of vascular function but is limited due to lack of technical solutions for outcome assessment. The aims of this study were to, after measurement by polarized reflectance spectroscopy (PRS), use pharmacodynamic dose–response analysis on responses to different concentrations of acetylcholine (ACh); and to examine the effect of three consecutively administered iontophoretic current pulses. The vascular responses in 15 healthy volunteers to iontophorised ACh (5 concentrations, range 0.0001% to 1%, three consecutive pulses of 0.02 mA for 10 min each) were recorded using PRS. Data were fitted to a four-parameter logistic dose response model and compared. Vascular responses were quantifiable by PRS. Similar pharmacodynamic dose response curves could be generated irrespectively of the ACh concentration. Linearly increasing maximum vasodilatory responses were registered with increasing concentration of ACh. A limited linear dose effect of the concentration of ACh was seen between pulses. Polarized reflectance spectroscopy is well suited for measuring vascular responses to iontophoretically administrated ACh. The results of this study support further development of iontophoresis as a method to study vascular function and pharmacological responses in vivo.

Abstract Risk adjustment and mortality prediction models are central in optimising care and for benchmarking purposes. In the burn setting, the Baux score and its derivatives have been the mainstay for predictions of mortality from burns. Other well-known measures to predict mortality stem from the ICU setting, where, for example, the Simplified Acute Physiology Score (SAPS 3) models have been found to be instrumental. Other attempts to further improve the prediction of outcome have been based on the following variables at admission: Sequential Organ Failure Assessment (aSOFA) score, determinations of aLactate or Neutrophil to Lymphocyte Ratio (aNLR). The aim of the present study was to examine if estimated mortality rate (EMR, SAPS 3), aSOFA, aLactate, and aNLR can, either alone or in conjunction with the others, improve the mortality prediction beyond that of the effects of age and percentage total body surface area (TBSA%) burned among patients with severe burns who need critical care. This is a retrospective, explorative, single centre, registry study based on prospectively gathered data. The study included 222 patients with median (25th–75th centiles) age of 55.0 (38.0 to 69.0) years, TBSA% burned was 24.5 (13.0 to 37.2) and crude mortality was 17%. As anticipated highest predicting power was obtained with age and TBSA% with an AUC at 0.906 (95% CI 0.857 to 0.955) as compared with EMR, aSOFA, aLactate and aNLR. The largest effect was seen thereafter by adding aLactate to the model, increasing AUC to 0.938 (0.898 to 0.979) (p

Abstract Background: The pectoralis major flap, which is usually harvested bilaterally, is considered a workhorse flap in the reconstruction of sternal defects. After a median sternotomy for open heart surgery, 1%-3% of patients develop deep infection and dehiscence of the sternal wound, some of which will eventually require reconstructive surgery. Our aim was to describe the clinical feasibility and associated complications of the unilateral pectoralis major advancement flap in the reconstruction of sternal defects. Methods: A retrospective analysis of all adult patients who were operated on using a unilateral pectoralis major flap for reconstruction of the chest wall at the Linköping University Hospital during 2008–18 was made using data retrieved from medical records. Results: Forty-three patients had reconstructions with unilateral pectoralis major flaps. Three flaps failed completely, and another 10 patients developed complications that required further operation. The factors that were independently associated with loss of the flaps and complications were: older age, male sex, the number of different antibiotics used, and a long duration of treatment with negative wound pressure. Fewer wound revisions before the reconstruction resulted in more complications. The factors that were independently associated with prolonged time to complete healing were emergency reoperation after the initial operation and complications after reconstruction. Conclusion: The unilateral pectoralis major advancement flap has proved to be a useful technique in the reconstruction of most sternal defects after sternal wound infection in older patients. There is, however, need for a follow-up study on a larger number of procedures to evaluate the long-term outcome compared with other methods of sternal reconstruction.

Abstract Background Disparity between medical treatment for men and women has been recorded worldwide. However, it is difficult to find out if the disparities in both the use of resources and outcome depend entirely on sex-related discrimination. Our aim was to investigate if there are differences in burn treatments between the sexes. Methods All patients admitted with burns to Linköping University Hospital during the 16-year period 2000–2015 were included. Interventions were prospectively recorded using the validated Burn SCoring system (BSC). Data were analysed using a multivariable panel regression model adjusted for age, percentage total body surface area (%TBSA), and in-hospital mortality. Results A total of 1363 patients were included, who generated a total of 22,301 daily recordings while they were inpatients. Males were 70% (930/1363). Sex was not an independent factor for daily scores after adjustment for age, %TBSA, and mortality in hospital (model R 2=0.60, p

Severe burns are often treated by means of autologous skin grafts, preferably following early excision of the burnt tissue. In the case of, for example, a large surface trauma, autologous skin cells can be expanded in vitro prior to transplantation to facilitate the treatment when insufficient uninjured skin is a limitation. In this study we have analyzed the impact of the enzyme (trypsin or accutase) used for cell dissociation and the incubation time on cell viability and expansion potential, as well as expression of cell surface markers indicative of stemness. Skin was collected from five individuals undergoing abdominal reduction surgery and the epidermal compartment was digested in either trypsin or accutase. Trypsin generally generated more cells than accutase and with higher viability; however, after 7 days of subsequent culture, accutase-digested samples tended to have a higher cell count than trypsin, although the differences were not significant. No significant difference was found between the enzymes in median fluorescence intensity of the analyzed stem cell markers; however, accutase digestion generated significantly higher levels of CD117- and CD49f-positive cells, but only in the 5 h digestion group. In conclusion, digestion time appeared to affect the isolated cells more than the choice of enzyme.

BackgroundHeparin-binding protein (HBP) is released by neutrophils upon activation, and elevated plasma levels are seen in inflammatory states like sepsis, shock, cardiac arrest, and burns. However, little is known about the elimination of HBP. We wanted to study renal clearance of HBP in healthy individuals and in burn patients in intensive care units (ICUs). We also wished to examine the levels of HBP in the effluent of renal replacement circuits in ICU patients undergoing continuous renal replacement therapy (CRRT).MethodsWe measured plasma and urine levels of HBP and urine flow rate in 8 healthy individuals and 20 patients in a burn ICU. In 32 patients on CRRT, we measured levels of HBP in plasma and in the effluent of the CRRT circuit.ResultsRenal clearance of HBP (median (IQR) ml/min) was 0.19 (0.08-0.33) in healthy individuals and 0.30 (0.01-1.04) in burn ICU patients. In ICU patients with cystatin C levels exceeding 1.44 mg/l, clearance was 0.45 (0.15-2.81), and in patients with cystatin C below 1.44 mg/l clearance was lower 0.28 (0.14-0.55) (p = 0.04). Starting CRRT did not significantly alter plasma levels of HBP (p = 0.14), and the median HBP level in the effluent on CRRT was 9.1 ng/ml (IQR 7.8-14.4 ng/ml).ConclusionIn healthy individuals and critically ill burn patients, renal clearance of HBP is low. It is increased when renal function is impaired. Starting CRRT in critically ill patients does not alter plasma levels of HBP significantly, but HBP can be found in the effluent. It seems unlikely that impaired kidney function needs to be considered when interpreting concentrations of HBP in previous studies. Starting CRRT does not appear to be an effective way of reducing HBP concentrations.

Heparin-binding protein (HBP) is released by granulocytes and has been shown to increase vascular permeability in experimental investigations. Increased vascular permeability in the lungs can lead to fluid accumulation in alveoli and respiratory failure. A generalized increase in vascular permeability leads to loss of circulating blood volume and circulatory failure. We hypothesized that plasma concentrations of HBP on admission to the intensive care unit (ICU) would be associated with decreased oxygenation or circulatory failure.This is a prospective, observational study in a mixed 8-bed ICU. We investigated concentrations of HBP in plasma at admission to the ICU from 278 patients. Simplified acute physiology score (SAPS) 3 was recorded on admission. Sequential organ failure assessment (SOFA) scores were recorded daily for three days.Median SAPS 3 was 58.8 (48-70) and 30-day mortality 64/278 (23%). There was an association between high plasma concentrations of HBP on admission with decreased oxygenation (p

Ventilator-induced or ventilator-associated lung injury (VILI/VALI) is common and there is an increasing demand for a tool that can optimize ventilator settings. Electrical impedance tomography (EIT) can detect changes in impedance caused by pulmonary ventilation and perfusion, but the effect of changes in the position of the body and in the placing of the electrode belt on the impedance signal have not to our knowledge been thoroughly evaluated. We therefore studied ventilation-related and perfusion-related changes in impedance during spontaneous breathing in 10 healthy subjects in five different body positions and with the electrode belt placed at three different thoracic positions using a 32-electrode EIT system. We found differences between regions of interest that could be attributed to changes in the position of the body, and differences in impedance amplitudes when the position of the electrode belt was changed. Ventilation-related changes in impedance could therefore be related to changes in the position of both the body and the electrode belt. Perfusion-related changes in impedance were probably related to the interference of major vessels. While these findings give us some insight into the sources of variation in impedance signals as a result of changes in the positions of both the body and the electrode belt, further studies on the origin of the perfusion-related impedance signal are needed to improve EIT further as a tool for the monitoring of pulmonary ventilation and perfusion.

Microvascular changes in the skin due to pharmacological and physiological provocations can be used as a marker for vascular function. While laser Doppler flowmetry (LDF) has been used extensively for measurement of skin microvascular responses, Laser Speckle Contrast Imaging (LSCI) and Tissue Viability Imaging (TiVi) are novel imaging techniques. TiVi measures red blood cell concentration, while LDF and LSCI measure perfusion. Therefore, the aim of this study was to compare responses to provocations in the skin using these different techniques.Changes in skin microcirculation were measured in healthy subjects during (1) iontophoresis of sodium nitroprusside (SNP) and noradrenaline (NA), (2) local heating and (3) post-occlusive reactive hyperemia (PORH) using LDF, LSCI and TiVi.Iontophoresis of SNP increased perfusion (LSCI: baseline 40.9±6.2 PU; 10-min 100±25 PU; p

Outcome after burn injury, as also paralleled by other trauma, has been improving steadily over the years. In this aspect a significant improvement was seen especially in the 1970-ties when the 50% survival chance from a burn injury increased from 45% total body surface area burned (TBSA%) in a 21 year old patient up to almost 80% (TBSA%). Although this improvement may be claimed to have many reasons, a significant one that needs to be stressed is the introduction of more thorough use of protocolized fluid treatment strategies