shock

摘要： 1 Introduction and Main Results The studies of transonic shock solutions for inviscid compressible flows in different kinds of nozzles had a long history and had obtained many important new achievements during the past twenty years.Courant and Friedrichs[1]had described the transonic shock phenomenain a de Laval nozzle whose cross section decreases first and then increases.

摘要： BACKGROUND:The Clinical Randomisation of an Anti-fibrinolytic in Significant Hemorrhage-2(CRASH-2)is the largest randomized control trial(RCT)examining circulatory resuscitation for trauma patients to date and concluded a statistically significant reduction in all-cause mortality in patients administered tranexamic acid(TXA)within 3 hours of injury.Since the publication of CRASH-2,significant geographical variance in the use of TXA for trauma patients exists.This study aims to assess TXA use for major trauma patients with hemorrhagic shock in Ireland after the publication of CRASH-2.METHODS:A retrospective cohort study was conducted using data derived from the Trauma Audit and Research Network(TARN).All injured patients in Ireland between January 2013 and December 2018 who had evidence of hemorrhagic shock on presentation(as defined by systolic blood pressure[SBP]1(70.68%vs.57.43%)and higher Injury Severity Score(ISS>25;49.62%vs.23.76%).Administration of TXA was not associated with mortality at hospital discharge(odds ratio[OR]0.86,95%CI 0.31–2.38).CONCLUSIONS:Among injured Irish patients presenting with hemorrhagic shock,TXA was administered to 56.8%of patients.Patients administered with TXA were on average more severely injured.However,a mortality benefit could not be demonstrated.

摘要： In this paper,we are concerned with the long time behavior of the piecewise smooth solutions to the generalized Riemann problem governed by the compressible isothermal Euler equations in two and three dimensions.A non-existence result is established for the fan-shaped wave structure solution,including two shocks and one contact discontinuity which is a perturbation of plane waves.Therefore,unlike in the one-dimensional case,the multi-dimensional plane shocks are not stable globally.Moreover,a sharp lifespan estimate is established which is the same as the lifespan estimate for the nonlinear wave equations in both two and three space dimensions.

摘要： Cardiogenic shock(CS)following acute myocardial infarction(AMI)is a major challenge in cardiovascular care.Mortality remains high with 40%-50%after thirty days.Randomised controlled trials(RCTs)play a key role to generate evidence on optimal care in this field.However,the number of completed or ongoing RCTs is still relatively low compared to the gaps in evidence.Challenges in the conduct of these trials are in particular the selection of patients and ethical issues in the informed consent process.When determining eligibility criteria,special attention should be paid to the severity of CS,to the inclusion of patients with cardiac arrest and to potential age limits.Median age of AMI-CS patients is increasing.Age limits are therefore controversial as it is important to include elderly patients in RCTs in order to make the results generalisable and to address the special needs of this group.As patients with AMI-CS are in most cases unable to provide informed consent themselves,a step-wise approach with acute consent by a legal representative or independent physicians and later informed consent by the patient if possible might be established depending on regularities of the respective ethical review board and country legislation.Multicenter studies should be sought to generate adequate power.

摘要： Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of nonthermal particles and high-energy radiation.In the absence of particle collisions in the system,theory shows that the interaction of an expanding plasma with a pre-existing electromagnetic structure(as in our case)is able to induce energy dissipation and allow shock formation.Shock formation can alternatively take place when two plasmas interact,through microscopic instabilities inducing electromagnetic fields that are able in turn to mediate energy dissipation and shock formation.Using our platform in which we couple a rapidly expanding plasma induced by high-power lasers(JLF/Titan at LLNL and LULI2000)with high-strength magnetic fields,we have investigated the generation of a magnetized collisionless shock and the associated particle energization.We have characterized the shock as being collisionless and supercritical.We report here on measurements of the plasma density and temperature,the electromagnetic field structures,and the particle energization in the experiments,under various conditions of ambient plasma and magnetic field.We have also modeled the formation of the shocks using macroscopic hydrodynamic simulations and the associated particle acceleration using kinetic particle-in-cell simulations.As a companion paper to Yao et al.[Nat.Phys.17,1177–1182(2021)],here we show additional results of the experiments and simulations,providing more information to allow their reproduction and to demonstrate the robustness of our interpretation of the proton energization mechanism as being shock surfing acceleration.

摘要： BACKGROUND Critically ill patients are at risk of developing stress cardiomyopathy(SC)but can be under-recognized.AIM To describe a case series of patients with SC admitted to critical care units.METHODS We conducted a retrospective observational study at a tertiary care teaching hospital.All adult(≥18 years old)patients admitted to the critical care units with stress cardiomyopathy over 5 years were included.RESULTS Of 24279 admissions to the critical care units[19139 to medical-surgical intensive care units(MSICUs)and 5140 in coronary care units(CCUs)],109 patients with SC were identified.Sixty(55%)were admitted to the coronary care units(CCUs)and forty-nine(45%)to the medical-surgical units(MSICUs).The overall incidence of SC was 0.44%,incidence in CCU and MSICU was 1.16%and 0.25%respectively.Sixty-two(57%)had confirmed SC and underwent cardiac catheterization whereas 47(43%)had clinical SC,and did not undergo cardiac catheterization.Forty-three(72%)patients in the CCUs were diagnosed with primary SC,whereas all(100%)patients in MSICUs developed secondary SC.Acute respiratory failure that required invasive mechanical ventilation and shock developed in twenty-nine(59%)MSICU patients.There were no statistically significant differences in intensive care unit(ICU)mortality,in-hospital mortality,use of inotropic or mechanical circulatory support based on type of unit or anatomical variant.CONCLUSION Stress cardiomyopathy can be under-recognized in the critical care setting.Intensivists should have a high index of suspicion for SC in patients who develop sudden or worsening unexplained hemodynamic instability,arrhythmias or respiratory failure in ICU.

摘要： BACKGROUND Cardiogenic shock continues to be a highly morbid complication that affects around 7%-10% of patients with acute myocardial infarction or heart failure.Similarly,obesity has become a worldwide epidemic.AIM To analyze the impact of higher body mass index(BMI) on outcomes of patients with cardiogenic shock.METHODS A systematic and comprehensive search was undertaken on the electronic databases of PubMed,Embase,ScienceDirect,CENTRAL,and Google Scholar for all types of studies comparing mortality outcomes of patients with cardiogenic shock based on BMI.All studies defined overweight or obese patients based on the World Health Organization BMI criteria.The data were then extracted and assessed on the basis of the Reference Citation Analysis(https://www.referencecitationanalysis.com/).RESULTS Five studies were included.On pooled analysis of multivariable-adjusted ratios,we noted a statistically significantly reduced risk of mortality in overweight/obese vs normal patients(three studies;odds ratio [OR] = 0.92,95% confidence interval [CI]:0.85-0.98,I~2 = 85%).On meta-analysis,we noted that crude mortality rates did not significantly differ between overweight/obese and normal patients after cardiogenic shock(OR = 0.95,95%CI:0.79-1.15,I~2 = 99%).The results were not stable on sensitivity analysis and were associated with substantial heterogeneity.CONCLUSION Current evidence on the association between overweight/obesity and mortality after cardiogenic shock is scarce and conflicting.The obesity paradox might exist in patients with cardiogenic shock but could be confounded by the use of mechanical circulatory support.There is a need for further studies to clarify this relationship.

摘要： BACKGROUND Shock is among the most common conditions that clinicians face in intensive care unit(ICU),of which hypovolemic shock is encountered most frequently;some patients instead suffer from neurogenic,cardiogenic,or infectious forms of shock.However,there are additional types of shock from unusual causes that are often undiagnosed.Here,we report the case of a patient who was initially misdiagnosed with hypovolemic shock,but exhibited persistent hypotension because of continuous fluid replacement and vasoactive drug administration,and was eventually diagnosed with hypopituitarism with crisis.CASE SUMMARY A 73-year-old Chinese man was admitted to the neurosurgery department following injury caused by a heavy object with symptoms of anemia and high fever.He was transferred to the ICU on the fourth day after hospitalization because of hypotension and unconsciousness.Blood analysis indicated that the patient was suffering from anemia and thrombocytopenia.Ultrasonography showed that there was no apparent abnormality in the cardiac structure but there was mild tricuspid regurgitation.Computed tomography revealed that there were signs of hemorrhage at the right basal ganglia;accordingly,hypovolemic shock,possibly septic shock,was initially considered.Even after routine treatment for shock,the hypotension remained severe.The patient was again thoroughly examined to investigate the underlying cause.The antishock therapy was supplemented with corticosteroids to counter potential hypopituitarism.The patient made a full recovery,and the blood pressure returned to normal.CONCLUSION A case of pituitary adenoma with multiple injuries was identified.Because of hypopituitarism,functionality of the corresponding endocrine system was restricted,with the most pronounced manifestation being unstable blood circulation requiring hormone replacement therapy.Such cases are relatively rare but may occur if multiple injuries are sustained.The present case represents a reference for the clinical treatment of patients with multiple injuries.

摘要： The ongoing outbreak of severe acute respiratory syndrome coronavirus-2[SARSCoV-2,or coronavirus disease 2019(COVID-19)]was declared a pandemic by the World Health Organization on March 11,2020.Worldwide,more than 65 million people have been infected with this SARS-CoV-2 virus,and over 1.5 million people have died due to the viral illness.Although a tremendous amount of medical progress has been made since its inception,there continues to be ongoing research regarding the pathophysiology,treatments,and vaccines.While a vast majority of those infected develop only mild to moderate symptoms,about 5%of people have severe forms of infection resulting in respiratory failure,myocarditis,septic shock,or multi-organ failure.Despite maximal cardiopulmonary support and invasive mechanical ventilation,mortality remains high.Extracorporeal membrane oxygenation(ECMO)remains a valid treatment option when maximal conventional strategies fail.Utilization of ECMO in the pandemic is challenging from both resource allocation and ethical standpoints.This article reviews the rationale behind its use,current status of utilization,and future considerations for ECMO in critically ill COVID-19 patients.

摘要： 最近一份令人震惊的报告显示,超过五分之一的枫树品种濒临灭绝,原因究竟是什么呢?More than one in five species of maple trees faces extinction,a shocking new report has revealed.