Effectiveness of Body Armor Against Shock Waves: Preventing Blast Injury in a Confined Space.

Introduction Blast injuries in modern society often occur owing to terrorist attacks in confined spaces, particularly in urban settings, indoors, and in vehicles, leading to significant damage. Therefore, it is important to focus on blast injuries in confined spaces rather than in conventional open-field experiments. Materials and methods We used an air-driven shock wave generator (blast tube) established indoors in 2017 and conducted basic research to potentially save the lives of patients with blast injuries. Under general anesthesia, pigs were divided into with body armor (BA) and without BA groups. The pigs were fixed in the measurement chamber with their dorsal chest directly exposed to the shock wave. The driving pressure was set at 3.0 MPa to achieve a mortality rate of approximately 50%. A generated shock wave was directly applied to the pigs. Comparisons were made between the groups with respect to cardiac arrest and survival, as well as apnea, bradycardia, and hypotension, which are the triad of blast lung. Autopsies were performed to confirm the extent of the organ damage. Statistical analysis was performed using Fisher's exact test, and statistical significance was set at p<0.05. The animal experimentation was conducted according to the protocol reviewed and approved by the Animal Ethics Committee of the National Defense Medical College Hospital (approval number 19041). Results Eight pigs were assigned to the BA group and seven pigs to the non-BA group. In the non-BA group, apnea was observed in four of seven cases, three of which resulted in death. None of the eight pigs in the BA group had respiratory arrest; notably, all survived. Hypotension was observed in some pigs in each group; however, there were no cases of bradycardia in either group. Statistical analysis showed that wearing BA significantly reduced the occurrence of respiratory and cardiac arrest (p=0.026) but not survival (p=0.077). No significant differences were found in other vital signs. Conclusions Wearing BA with adequate neck and chest protection reduced mortality and it was effective to reduce cardiac and respiratory arrest against shock wave exposure. Mortality from shock wave injury appears to be associated with respiratory arrest, and the avoidance of respiratory arrest may lead to survival.

Proposal and Validation of a Clinically Relevant Modification of the Japanese Association for Acute Medicine Disseminated Intravascular Coagulation Diagnostic Criteria for Sepsis.

BACKGROUND: Japanese Association for Acute Medicine (JAAM) disseminated intravascular coagulation (DIC) criteria were launched nearly 20 years ago. Following the revised conceptual definition of sepsis and subsequent omission of systemic inflammatory response syndrome (SIRS) score from the latest sepsis diagnostic criteria, we omitted the SIRS score and proposed a modified version of JAAM DIC criteria, the JAAM-2 DIC criteria. OBJECTIVES: To validate and compare performance between new JAAM-2 DIC criteria and conventional JAAM DIC criteria for sepsis. METHODS: We used three datasets containing adult sepsis patients from a multicenter nationwide Japanese cohort study (J-septic DIC, FORECAST, and SPICE-ICU registries). JAAM-2 DIC criteria omitted the SIRS score and set the cutoff value at ≥3 points. Receiver operating characteristic (ROC) analyses were performed between the two DIC criteria to evaluate prognostic value. Associations between in-hospital mortality and anticoagulant therapy according to DIC status were analyzed using propensity score weighting to compare significance of the criteria in determining introduction of anticoagulants against sepsis. RESULTS: Final study cohorts of the datasets included 2,154, 1,065, and 608 sepsis patients, respectively. ROC analysis revealed that curves for both JAAM and JAAM-2 DIC criteria as predictors of in-hospital mortality were almost consistent. Survival curves for the anticoagulant and control groups in the propensity score-weighted prediction model diagnosed using the two criteria were also almost entirely consistent. CONCLUSION: JAAM-2 DIC criteria were equivalent to JAAM DIC criteria regarding prognostic and diagnostic values for initiating anticoagulation. The newly proposed JAAM-2 DIC criteria could be potentially alternative criteria for sepsis management.

In vivo visualization of burn depth in skin tissue of rats using hemoglobin parameters estimated by diffuse reflectance spectral imaging.

Significance: Burn injuries represent a global public health problem that kills an estimated 180,000 people annually. Non-fatal burns result in prolonged hospitalization, disfigurement, and disability. The most common, convenient, and widely used method for assessing burn depth is physical or visual examination, but the accuracy of this method is reportedly poor (60% to 75%). Rapid, correct assessment of burn depth is very important for the optimal management and treatment of burn patients. New methods of burn depth assessment that are inexpensive, simple, rapid, non-contact, and non-invasive are therefore needed. Aim: The aim of this study was to propose an approach to visualize the spatial distribution of burn depth using hemoglobin parameters estimated from spectral diffuse reflectance imaging and to demonstrate the feasibility of the proposed approach for differentiating burn depth in a rat model of scald burn injury. Approach: The new approach to creating a spatial map of burn depth was based on canonical discriminant analysis (CDA) of total hemoglobin concentration, tissue oxygen saturation, and methemoglobin saturation as estimated from spectral diffuse reflectance images. Burns of three different degrees of severity were created in rat dorsal skin by 10-s exposure to water maintained at 70°C, 78°C, and 98°C, respectively. Spectral images for dorsal regions were acquired under anesthesia immediately after burn injury and at 24 h, 48 h, and 72 h after injury. Results: Most areas of images in the group with skin exposed to 70°C water and 98°C water were classified as 70°C burn and 98°C burn, respectively. In contrast, no significant difference between areas classified as 78°C burn and 98°C burn from 24 h to 72 h was evident in the group with skin exposed to 78°C water, suggesting that burn depth was heterogeneous. Conclusions: The proposed approach combining diffuse reflectance spectral imaging and CDA appears promising for differentiating 70°C burns from 78°C burns and 98°C burns, and 98°C burns from 70°C burns and 78°C burns at 24 to 72 h after burn injury in a rat model of scald burn injury.

COAGULOPATHY PARAMETERS PREDICTIVE OF OUTCOMES IN SEPSIS-INDUCED ACUTE RESPIRATORY DISTRESS SYNDROME: A SUBANALYSIS OF THE TWO PROSPECTIVE MULTICENTER COHORT STUDIES.

ABSTRACT: Background: Although coagulopathy is often observed in acute respiratory distress syndrome (ARDS), its clinical impact remains poorly understood. Objectives: This study aimed to clarify the coagulopathy parameters that are clinically applicable for prognostication and to determine anticoagulant indications in sepsis-induced ARDS. Method: This study enrolled patients with sepsis-derived ARDS from two nationwide multicenter, prospective observational studies. We explored coagulopathy parameters that could predict outcomes in the Focused Outcome Research on Emergency Care for Acute Respiratory Distress Syndrome, Sepsis, and Trauma (FORECAST) cohort, and the defined coagulopathy criteria were validated in the Sepsis Prognostication in Intensive Care Unit and Emergency Room-Intensive Care Unit (SPICE-ICU) cohort. The correlation between anticoagulant use and outcomes was also evaluated. Results: A total of 181 patients with sepsis-derived ARDS in the FORECAST study and 61 patients in the SPICE-ICU study were included. In a preliminary study, we found the set of prothrombin time-international normalized ratio ≥1.4 and platelet count ≤12 × 10 4 /µL, and thrombocytopenia and elongated prothrombin time (TEP) coagulopathy as the best coagulopathy parameters and used it for further analysis; the odds ratio (OR) of TEP coagulopathy for in-hospital mortality adjusted for confounding was 3.84 (95% confidence interval [CI], 1.66-8.87; P = 0.005). In the validation cohort, the adjusted OR for in-hospital mortality was 32.99 (95% CI, 2.60-418.72; P = 0.002). Although patients without TEP coagulopathy showed significant improvements in oxygenation over the first 4 days, patients with TEP coagulopathy showed no significant improvement (ΔPaO 2 /FiO 2 ratio, 24 ± 20 vs. 90 ± 9; P = 0.026). Furthermore, anticoagulant use was significantly correlated with mortality and oxygenation recovery in patients with TEP coagulopathy but not in patients without TEP coagulopathy. Conclusion: Thrombocytopenia and elongated prothrombin time coagulopathy is closely associated with better outcomes and responses to anticoagulant therapy in sepsis-induced ARDS, and our coagulopathy criteria may be clinically useful.

In vivo monitoring of hemoglobin derivatives in a rat thermal injury model using spectral diffuse reflectance imaging.

INTRODUCTION: To demonstrate the feasibility of our previously proposed Diffuse reflectance spectral imaging (DRSI) method for in vivo monitoring of oxygenated hemoglobin, deoxygenated hemoglobin, methemoglobin, tissue oxygen saturation, and methemoglobin saturation in a rat scald burn wound model and assess whether the method could be used for differentiating the burn depth groups in rats based on the hemoglobin parameters. METHODOLOGY: Superficial dermal burns (SDBs), deep dermal burns (DDBs), and deep burns (DBs) were induced in rat dorsal skin using a Walker-Mason method. An approach based on multiple regression analysis for spectral diffuse reflectance images aided by Monte Carlo simulations for light transport was used to quantify the hemoglobin parameters. Canonical discriminant analysis (CDA) was performed to discriminate SDB, DDB, and DB. RESULTS: CDA using the total hemoglobin concentration, tissue oxygen saturation, and methemoglobin saturation as the independent variables showed good performance for discriminating the SDB, DDB, and DB groups immediately after burn injury and the SDB group from the DDB and DB groups 24-72 h after burn injury. CONCLUSIONS: The DRSI method with multiple regression analysis for quantification of oxygenated hemoglobin, deoxygenated hemoglobin, and methemoglobin proved to be reliable for monitoring these hemoglobin derivatives in the rat experimental burn injury model. The parameters of tissue oxygen saturation, methemoglobin saturation, and total hemoglobin concentration are promising for the differentiating the degree of burn injury using CDA.

Early treatment with Fibrinogen γ-chain peptide-coated, ADP-encapsulated Liposomes (H12-(ADP)-liposomes) ameliorates post-partum hemorrhage with coagulopathy caused by amniotic fluid embolism in rabbits.

BACKGROUND: Amniotic fluid embolism is an unpredictable and sometimes lethal complication of childbirth. Fibrinogen γ-chain peptide-coated, ADP-encapsulated Liposomes (H12-(ADP)-liposomes), which were developed as a platelet substitute, may be useful to control postpartum hemorrhage with consumptive coagulopathy. OBJECTIVE: This study aimed to establish a hemodynamically stable amniotic fluid embolism animal model and evaluate the efficacy of H12-ADP-liposome infusion in the initial management of postpartum hemorrhage complicated with amniotic fluid embolism-involved coagulopathy. STUDY DESIGN: Pregnant New Zealand white rabbits (28th day of pregnancy or normal gestation period of 29-35 days) underwent cesarean delivery, followed by intravenous administration of amniotic fluid (a total of 3.0 mL administered in 4 doses over 9 minutes). Thereafter, uncontrolled postpartum hemorrhage was induced by transecting the right midartery and concomitant vein in the myometrium. After initial bleeding for 5 minutes, rabbits received isovolemic fluid resuscitation through the femoral vein with an equivalent volume of blood loss every 5 minutes for 60 minutes. The transfusion regimens included platelet-rich plasma, platelet-poor plasma, and a bolus administration of H12-ADP-liposomes followed by platelet-poor plasma transfusion (8 rabbits per group). Moreover, 60 minutes after initiation of bleeding, rabbits received surgical hemostasis by ligation of bleeding vessels, except in cases with spontaneous hemostasis. RESULTS: The administration of amniotic fluid caused thrombocytopenia (56±3 × 103/µL) and prolonged both clotting time (before administration: 130.0±3.0 to 171.0±5.0 seconds) and prothrombin time (4.5±0.1 to 4.7±0.1 seconds). After the initial 5-minute bleeding in the rabbits, the mean arterial pressure fell to 43±2 mm Hg. Platelet-poor plasma transfusion alone further prolonged clotting time and prothrombin time at 60 minutes (192.0±10.0 and 5.2±0.1 seconds, respectively) with decreasing mean arterial pressure to <40 mm Hg. By contrast, the administration of H12-ADP-liposomes followed by platelet-poor plasma transfusion reduced the prolonged clotting time (153.0±5.0 seconds) and prothrombin time (4.9±0.1 seconds) similar to platelet-rich plasma transfusion (154.0±11.0 and 4.9±0.1 seconds, respectively) at 60 minutes. These rabbits maintained a mean arterial pressure of >45 mm Hg throughout the experiment. H12-ADP-liposome infusion and platelet-poor plasma transfusion and platelet-rich plasma transfusion yielded spontaneous hemostasis in 4 of 8 rabbits, whereas platelet-poor plasma transfusion did not stop bleeding in any of the rabbits. The total blood loss was 59±17 mL in the H12-ADP-liposomes and platelet-poor plasma group, which was half of that in the platelet-poor plasma group (124±10 mL). CONCLUSION: H12-ADP-liposome infusion may be effective in the initial management of postpartum hemorrhage complicated with amniotic fluid embolism, resulting in mitigation of consumptive coagulopathy.

Hyperoxia for sepsis and development of acute lung injury with increased mortality.

BACKGROUND: Supraphysiological oxygen administration causes unfavourable clinical outcomes in various diseases. This study aimed to determine whether hyperoxia would be associated with increased mortality in patients with severe infection. METHODS: A post-hoc analysis of a nationwide multicentre prospective observational study on sepsis (SPICE Study) was conducted, including adult patients admitted to the intensive care unit with available arterial partial pressure of oxygen (PaO2) at the treatment initiation for severe infection. Hyperoxia was defined as a PaO2 level of ≥300 mm Hg and in-hospital mortality was compared between patients with and without hyperoxia. RESULTS: Of the 563 patients eligible for the study, 49 had hyperoxia at treatment initiation for severe infection. The in-hospital all-cause mortality rates of patients with and without hyperoxia were 14 (29.2%) and 90 (17.6%), respectively. Inverse probability weighting analyses with propensity scores revealed the association between hyperoxia and increased in-hospital mortality rate (28.8% vs 18.8%; adjusted OR 1.75 (1.03 to 2.97); p=0.038), adjusting for patient demographics, comorbidities, site of infection, severity of infection, haemodynamic and respiratory status, laboratory data and location of patient at infection development. Acute lung injury developed more frequently in patients with hyperoxia on the following days after infection treatment, whereas sepsis-related mortality was comparable regardless of hyperoxia exposure. CONCLUSION: Hyperoxia with PaO2 ≥300 mm Hg at treatment initiation of severe infection was associated with an increased in-hospital mortality rate in patients requiring intensive care. The amount of oxygen to administer to patients with severe infection should be carefully determined. TRIAL REGISTRATION NUMBER: University Hospital Medical Information Network Clinical Trial Registry (UMIN000027452).

Characteristics of the patients consulted with emergency medicine physicians at a large-scale COVID-19 vaccination center: Prospective observational study.

OBJECTIVE: We aimed to clarify the characteristics of patients consulted by the medical staff with emergency medicine (EM) physicians after vaccination and EM physicians transferred to an outside hospital. DESIGN: The Japanese Self-Defense Force established a large-scale coronavirus disease 2019 (COVID-19) vaccination center. Overall, 1,306,928 citizens received the Moderna vaccine, which targeted the first and second vaccinations between May 24, 2021 and November 30, 2021. EM physicians were always available in the emergency room (ER). The medical staff could consult the patients with EM physicians; however, the criteria were ambiguous. We conducted signal detection analysis on the patients who experienced adverse events to detect characteristics. RESULTS: Of the 3,312 patients experienced adverse events after vaccination, the medical staff consulted 344 with EM physicians. The patients whose respiratory rate and systolic blood pressure (BP) were more than 18 per minute and 162 mmHg, respectively, were considerably consulted. In addition, the patients whose systolic BP was more than 186.5 mmHg were transferred to an outside hospital. No patients were seriously ill or died after being transferred to an outside hospital. CONCLUSIONS: The medical staff consulted the patients with a high respiratory rate or BP with EM physicians. In addition to BP, the respiratory rate would also be necessary as a finding that suggests a patient's severity after vaccination. Therefore, it appears safer that EM physicians are always available to ensure the recipients' safety when running a new large-scale vaccination center against unknown diseases, such as COVID-19.

Association between length of hospital stay and fractures in the spine, pelvis, and lower extremity among patients after intentional fall from a height: an analysis of the Japan Trauma Databank.

Objective: This study investigated the association between the number of regions with fractures in the spine, pelvis, and lower extremity (NRF) and the proportion of patients with a length of hospital stay (LOS) ≥30 days among those who attempted suicide by falling from a height. Methods: Data recorded between January 1, 2004 and May 31, 2019 in the Japan Trauma Databank of patients aged ≥18 years injured by suicidal falls from a height and with ≥72 hours of LOS (period from admission to discharge home or to another hospital) were analyzed. Patients with an Abbreviated Injury Scale score ≥5 in the head region or those who died after admission were excluded. Multivariate analyses including clinically relevant variables as covariates were performed to determine the association, expressed as risk ratio with 95% CI, between NRF and LOS. Results: Among 4724 participants, the multivariate analysis revealed significant factors related to LOS ≥30 days, including NRF=1 (1.64, 95% CI 1.41 to 1.91), NRF=2 (2.00, 95% CI 1.72 to 2.33), NRF=3 (2.01, 95% CI 1.70 to 2.38), systolic blood pressure in the emergency department (ED; 0.999, 95% CI 0.998 to 0.9997), heart rate in the ED (1.002, 95% CI 1.00 to 1.004), Injury Severity Score (1.007, 95% CI 1.00 to 1.01), and intubation in the ED (1.21, 95% CI 1.10 to 1.34). However, history of psychiatric diseases was not a significant factor. Conclusion: An increase in NRF was associated with an increase in LOS of patients injured by intentional falls from a height. This finding can help both emergency physicians and psychiatrists in acute care hospitals to develop better treatment strategies with attention to time constraints. Further investigation of the association between LOS and both trauma and psychiatric treatment is required to evaluate the effect of NRF on treatment in acute care hospitals. Level of evidence: Level III, retrospective study with up to two negative criteria.

Early versus delayed vasopressor administration in patients with septic shock.

Aim: This study aimed to investigate the association of early vasopressor initiation with improved septic shock outcomes. Methods: This multicenter observational study was conducted in 17 intensive care units in Japan and included adult patients with sepsis admitted to the intensive care unit from July 2019 to August 2020 and treated with vasopressor therapy. Patients were divided into the early vasopressor group (≤1 h from sepsis recognition) and the delayed vasopressor group (>1 h). The impact of early vasopressor administration on risk-adjusted in-hospital mortality was estimated using logistic regression analyses adjusted by an inverse probability of treatment weighting analysis with propensity scoring. Results: Among the 97 patients, 67 received vasopressor therapy within 1 h from sepsis recognition and 30 received vasopressor after 1 h. In-hospital mortality was 32.8% in the early vasopressor group and 26.7% in the delayed vasopressor group (p = 0.543). The adjusted odds ratio for in-hospital mortality was 0.76 (95% confidence interval 0.17-3.29) when comparing patients in the early vasopressor with those in the delayed vasopressor group. The fit curve from the mixed-effects model showed a relatively lower trend toward an infusion volume over time in the early vasopressor group than in the delayed vasopressor group. Conclusion: Our study did not reach a definitive conclusion for early vasopressor administration. However, early vasopressor administration may help avoid volume overload in the long course of sepsis care.

Variation in the utilization of angioembolization for splenic injury in hospitals: a nationwide cross-sectional study in Japan.

Aim: Substantial variations in the utilization of angioembolization have been reported internationally. However, the existence of variations in the utilization of angioembolization in Japan is currently unknown. Methods: This was a cross-sectional study using data from a nationwide trauma registry in Japan. Of the 4,896 registered adult patients with splenic injury, we investigated 3,319 patients in the top 25% of the hospitals that registered the highest number of splenic injury patients in the Japan Trauma Data Bank. The primary outcome of this study was initial angioembolization. We calculated the expected initial angioembolization rates using multiple regression analysis adjusted for patient factors. In addition, we evaluated the range of observed-to-expected initial splenic angioembolization ratio for each hospital. Moreover, we assessed whether this ratio was increased with time. Results: The frequency of initial splenic angioembolization ranged from 0% to 52%. The median expected initial angioembolization rate, calculated through multiple logistic regression analysis, was 19.7%. The observed-to-expected initial splenic angioembolization ratio for each hospital ranged from 0 to 2.36. The observed initial angioembolization rate tended to increase with time (P < 0.001). Conclusions: Despite adjustment for patient factors, substantial variations were observed in the utilization of splenic angioembolization among hospitals in Japan.

Cultivation and Transplantation of Three-Dimensional Skins with Laser-Processed Biodegradable Membranes.

For the treatment of irreversible, extensive skin damage, artificial skins or cultured skins are useful when allogeneic skins are unavailable. However, most of them lack vasculature, causing delayed perfusion and hence delay or failure in engraftment of the tissues. We previously developed a prevascularized three-dimensional (3D) cultured skin based on the layer-by-layer cell coating technique (LbL-3D skin), in which cells are seeded and laminated on a porous polymer membrane for medium supply to the thick cultured tissue. Recent animal studies have demonstrated that LbL-3D skin can achieve rapid perfusion and high graft survival after transplantation. However, there were practical issues with separating LbL-3D skins from the membranes before transplantation and the handling separated LbL-3D skins for transplantation. To address these problems, in this study, we examined the use of biodegradable porous polymer membranes that enabled the transplantation of LbL-3D skins together with the membranes, which could be decomposed after transplantation. Thin films made from poly (lactic-co-glycolic acid) (PLGA) were irradiated with femtosecond laser pulses to create micro through-holes, producing porous membranes. We designed and fabricated culture inserts with the PLGA membranes and cultivated LbL-3D skins with 2 × 106 neonatal normal human dermal fibroblasts and 1 × 104 human umbilical vein endothelial cells in the dermis of 20 cell layers and 1 × 105 neonatal human epidermal keratinocytes in the epidermis. Histological analyses revealed that the skins cultured on the PLGA membranes had thickness of about 400 µm and that there were no defects in the quality of the skins cultured on the PLGA membranes when compared with those cultured on the conventional (nonbiodegradable) commercial membranes. The cultured LbL-3D skins were then transplanted together with the PLGA membranes onto full-thickness excisional wounds in mice. At 7 days posttransplantation onto a mouse, the tissues above and below the membrane were connected through the holes with collagen-positive fibers that appeared to migrate from both the host and donor sides, and favorable reepithelization was observed throughout the transplanted skin region. However, insufficient engraftment was observed in some cases. Thus, further optimization of the membrane conditions would be needed to improve the transplantation outcome.

Sepsis-related coagulopathy treatment based on the disseminated intravascular coagulation diagnostic criteria: a post-hoc analysis of a prospective multicenter observational study.

BACKGROUND: The development of disseminated intravascular coagulation (DIC) in patients with sepsis has been repeatedly confirmed as a factor associated with poor prognosis. Anticoagulant therapy has been expected to improve sepsis patient outcomes, whereas no randomized controlled trials have demonstrated the survival benefit of anticoagulant therapies in non-specific overall sepsis. Patient selection based on the component of "high disease severity" in addition to "sepsis with DIC" has recently proved important in identifying appropriate targets for anticoagulant therapy. The aims of this study were to characterize "severe" sepsis DIC patients and to identify the patient population benefiting from anticoagulant therapy. METHODS: This retrospective sub-analysis of a prospective multicenter study included 1,178 adult patients with severe sepsis from 59 intensive care units in Japan from January 2016 to March 2017. We examined the association of patient outcomes, including organ dysfunction and in-hospital mortality, with the DIC score and prothrombin time-international normalized ratio (PT-INR), one of the components of the DIC score, using multivariable regression models including the cross-product term between these indicators. Multivariate Cox proportional hazard regression analysis with non-linear restricted cubic spline including a three-way interaction term (anticoagulant therapy × the DIC score × PT-INR) was also performed. Anticoagulant therapy was defined as the administration of antithrombin, recombinant human thrombomodulin, or their combination. RESULTS: In total, we analyzed 1013 patients. The regression model showed that organ dysfunction and in-hospital mortality deteriorated with higher PT-INR values in the range of < 1.5 and that this trend was more pronounced with higher DIC scores. Three-way interaction analysis demonstrated that anticoagulant therapy was associated with better survival outcome in patients with a high DIC score and high PT-INR. Furthermore, we identified a DIC score ≥ 5 and PT-INR ≥ 1.5 as the clinical threshold for identification of optimal targets for anticoagulant therapy. CONCLUSIONS: The combined use of the DIC score and PT-INR helps in selecting the optimal patient population for anticoagulant therapy in sepsis-induced DIC. The results obtained from this study will provide valuable information regarding the study design of randomized controlled trials examining the effects of anticoagulant therapy for sepsis. TRIAL REGISTRATION: UMIN-CTR, UMIN000019742. Registered on November 16, 2015.

Evans Blue and Fluorescein Isothiocyanate-Dextran Double Labeling Reveals Precise Sequence of Vascular Leakage and Glial Responses After Exposure to Mild-Level Blast-Associated Shock Waves.

Abstract Blast-induced shock waves (BSWs) are responsible for several aspects of psychiatric disorders that are collectively termed mild traumatic brain injury (mTBI). The pathophysiology of mTBI includes vascular leakage resulting from blood-brain barrier (BBB) disruption. In this study, the precise sequence of BBB breakdown was examined using an Evans blue and fluorescein isothiocyanate (FITC)-dextran double labeling technique. Evans blue solution was injected into the tail vein of male C57BL6/J mice just before and 4 h, 1 day, 3 days, and 7 days after a single BSW exposure at as low as 25-kPa peak overpressure. In contrast, the FITC-dextran solution was transcardially injected just before perfusion fixation. Differences in the labeling time-point revealed that BBB breakdown was initiated after approximately 3 h, with significant remodeling by 1 day, and continued until 7 days after BSW exposure. BBB breakdown was upregulated in three distinct regions, namely the brain surface and subsurface areas facing the skull, regions closely associated with capillaries, and the circumventricular organ and choroid plexus. These regions showed distinct responses to BSW; moreover, clusters of reactive astrocytes were closely associated with the sites of BBB breakdown. In severe cases, these reactive astrocytes recruited activated microglia. Our findings provide important insights into the pathogenesis underlying mTBI and indicate that even mild BSW exposure affects the whole brain.

Impact of COVID-19 pandemic on the care of severe burns in Japan: Repeated survey of specialized burn care facilities.

BACKGROUND: The spread of coronavirus disease 2019 (COVID-19), which began in 2020, has had a major impact on healthcare systems. The spread of COVID-19 has been reported to have affected the readiness to treat patients with burns worldwide. However, the existing reports have evaluated burn care status within a limited time period during the pandemic, and no report clarifies the change in the impact of infection status on burn care from the beginning of the pandemic to the present. METHODS: Japanese Society for Burn Injuries-accredited burn care facilities were surveyed using questionnaires on April 9-23, 2020; June 23-July 6, 2020; July 9-21, 2021; and January 21-31, 2022. Differences between groups were evaluated using Friedman's test or Bonferroni's multiple comparison test, as appropriate. RESULTS: From the 103 facilities included in the study, we received 85, 55, 56, and 58 responses in the first, second, third, and fourth surveys, respectively. We could continuously observe 34 facilities. The rate of acceptance of patients with severe burns improved significantly over time (P < 0.05). However, in the second and third surveys, there was an increase in the number of respondents who did not accept patients with burns irrespective of COVID-19 status. CONCLUSIONS: The number of facilities treating patients with burns who have COVID-19 is increasing; however, COVID-19 care may negatively impact routine burn care. It is necessary to continuously examine medical resource allocation through methods such as information sharing by academic societies.

The survival rate of patients with burns induced by explosions was significantly higher than that of common burn cases: A nationwide observational study using the Japan Trauma Data Bank.

BACKGROUNDS: Blast injuries have a variety of mechanisms, with some cases resulting in immediate death and others resulting in burns as a fourth type of blast injury when the energy of the explosion is relatively low. We reported in 2020, as an incidental result, that burns caused by explosions had a higher survival rate than usual burns caused by other mechanisms. The present study confirmed whether or not burns caused by explosions had higher survival rates than those caused by other mechanisms using the Japan Trauma Data Bank (JTDB), a leading nationwide trauma registry in Japan. METHODS: Burn patients registered to the JTDB database from January 2004 to March 2019 were analyzed retrospectively. The 338,744 patients registered to the JTDB database published in 2021 were identified. After exclusion, 7127 patients met the criteria for inclusion in this study. Logistic regression analyses were conducted for in-hospital survival rates using patients with burns, including cases complicated by usual trauma and burned patients without usual trauma. The survival rates by External burn grade AIS98 were compared between the explosion group and other cause groups using burn cases without usual trauma. RESULTS: The cause of the explosion significantly influenced the survival according to logistic regression analyses using burn groups with and without usual trauma. For AIS 4 and 5, we found significant differences between the explosion group and other cause groups in survival rates among burn cases without usual trauma. CONCLUSION: The survival rate of patients with burns induced by explosions was higher than that of common burn cases according to analyses based on a burn grade of AIS98 among burn cases without common trauma. Multivariate analyses also showed that explosion burns had a significantly better outcome than those induced by other causes.

Burn depth assessment by dual-wavelength light emitting diodes-excited photoacoustic imaging in rats.

Accurate burn depth assessment is crucial to determine treatment plans for burn patients. We have previously proposed a method for performing burn depth assessments based on photoacoustic (PA) imaging, and we have demonstrated the validity of this method, which allows the successful detection of PA signals originating from the blood under the bloodless burned tissue, using rat burn models. Based on these findings, we started a clinical study in which we faced two technical issues: (1) When the burn depth was shallow, PA signals due to skin contamination and/or melanin in the epidermis (surface signals) could not be distinguished from PA signals originating from the blood in the dermis; (2) the size of the system was too large. To solve these issues, we propose a burn depth diagnosis based on dual-wavelength light emitting diodes (LEDs)-excited PA imaging. The use of LEDs rendered the system compact compared to the previous one that used a conventional solid-state laser. We replicated human burned skin by applying a titrated synthetic melanin solution onto the wound surface in albino rat burn models and measured their burn depths by PA excitation at 690 and 850 nm, where melanin and haemoglobin show greatly different absorption coefficients. As a result, the surface signals were eliminated by subtracting the PA signals at 690 nm from those at 850 nm. The resultant estimated burn depths were strongly correlated with the histological assessment results. The validity of the proposed method was also examined using a burn model of rats with real melanin.

Association of antithrombin with development of trauma-induced disseminated intravascular coagulation and outcomes.

Introduction: Trauma activates the innate immune system to modulate hemostasis and minimize the damage caused by physiological bodily responses, including the activation of coagulation. Sufficiently severe trauma overwhelms physiological responses and elicits the systemic inflammatory response syndrome, which leads to the onset of disseminated intravascular coagulation (DIC), characterized by dysregulated inflammatory coagulofibrinolytic responses. Impaired anticoagulant mechanisms, including antithrombin, constitutes the pathology of DIC, while the dynamics of antithrombin and relevance to outcomes in trauma-induced coagulopathy have not been fully elucidated. This study investigated the associations of antithrombin activity with DIC onset and outcomes in severely injured patients. Methods: This retrospective sub-analysis of a multicenter, prospective study included patients with an injury severity score ≥16. We characterized trauma patients with low antithrombin activity (antithrombin <80% on hospital arrival, n = 75) in comparison with those who had normal antithrombin activity (antithrombin ≥80%, n = 200). Global markers of coagulation and fibrinolysis, molecular biomarkers for thrombin generation (soluble fibrin [SF]), and markers of anticoagulation (antithrombin) were evaluated to confirm the associations of antithrombin with DIC development and outcomes, including in-hospital mortality and the multiple organ dysfunction syndrome (MODS). Results: Patients with low antithrombin activity had higher prevalence of shock, transfusion requirements, and in-hospital mortality. Higher DIC scores and more severe organ dysfunction were observed in the low AT group compared to that in the normal AT group. Antithrombin activity on arrival at the hospital was an independent predictor of the development of DIC in trauma patients, and levels of SF increased with lower antithrombin values (antithrombin activity > 85%). Antithrombin activity at 3 h showed good predictive performance for in-hospital mortality, and a multivariable Cox proportional-hazard regression model with a cross-product term between the antithrombin and DIC showed that the in-hospital mortality in patients with DIC increased with decreased antithrombin activity. A multivariable logistic regression model showed that the odds for the development of MODS in patients with DIC increased with lower antithrombin values. Conclusion: Decreased antithrombin activity in trauma-induced coagulopathy is associated with poor outcomes through worsening of DIC.

Pioglitazone Modifies Kupffer Cell Function and Protects against Escherichia coli-Induced Bacteremia in Burned Mice.

Infectious complications and subsequent sepsis in severely burned patients lead to high morbidity and mortality in response to uncontrolled innate immune responses mediated by macrophages. Peroxisome proliferator-activated receptor gamma (PPARγ) has anti-inflammatory activity and acts as a master regulator of macrophage polarization. In this study, we investigated whether the administration of a PPARγ agonist could modulate the Kupffer cell phenotype and thereby ameliorate the dysregulated innate response during post-burn bacterial infection. C57BL/6 mice were subjected to severe burns and randomized to receive either the PPARγ agonist, pioglitazone, or the vehicle control five days after injury, followed by the subsequent analysis of hepatic macrophages. Survival from the bacterial infection was monitored for seven days. Pioglitazone protected burned mice against bacterial infection. A single treatment with pioglitazone significantly enhanced phagocytosis, phagosome acidification, bacterial clearance, and reduction in inflammatory mediators in Kupffer cells. In conclusion, PPARγ activation by pioglitazone prevents clinical deterioration due to post-burn bacterial infection and improves survival. Our findings suggest that pioglitazone may be an effective therapeutic candidate for post-burn infectious complications.

Effects of tranexamic acid on coagulofibrinolytic markers during the early stage of severe trauma: A propensity score-matched analysis.

Tranexamic acid (TXA) reduces the risk of bleeding trauma death without altering the need for blood transfusion. We examined the effects of TXA on coagulation and fibrinolysis dynamics and the volume of transfusion during the early stage of trauma. This subanalysis of a prospective multicenter study of severe trauma included 276 patients divided into propensity score-matched groups with and without TXA administration. The effects of TXA on coagulation and fibrinolysis markers immediately at (time point 0) and 3 hours after (time point 3) arrival at the emergency department were investigated. The transfusion volume was determined at 24 hours after admission. TXA was administered to the patients within 3 hours (median, 64 minutes) after injury. Significant reductions in fibrin/fibrinogen degradation products and D-dimer levels from time points 0 to 3 in the TXA group compared with the non-TXA group were confirmed, with no marked differences noted in the 24-hour transfusion volumes between the 2 groups. Continuously increased levels of soluble fibrin, a marker of thrombin generation, from time points 0 to 3 and high levels of plasminogen activator inhibitor-1, a marker of inhibition of fibrinolysis, at time point 3 were observed in both groups. TXA inhibited fibrin(ogen)olysis during the early stage of severe trauma, although this was not associated with a reduction in the transfusion volume. Other confounders affecting the dynamics of fibrinolysis and transfusion requirement need to be clarified.