Study on Dynamic Characteristics and Parameter Influence of a Kind of Bilateral Restraint Impact Vibration System

In this paper, the hinge in the articulated structure is studied, the gap hinge is described as a nonlinear bilateral constraint, and the equivalent modeling and analysis of the hinge connection collision vibration are carried out based on the Lankarani–Nikravesh nonlinear contact force model. With the help of the method of nonlinear system dynamics analysis research, the Poincaré mapping of hinge joint collision vibration is constructed, the bifurcation diagram of the system with different parameters is solved, and the variation law of the system motion and the influence of parameters are analyzed by combining the time response diagram, phase diagram, Poincaré cross section diagram, and spectrum diagram of the typical motion of the system. The simulation results show that the system moves in a single degree of freedom and varies with parameters with multiplicative period bifurcation and rubbing edge bifurcation leading to chaos; the system’s periodic motion has shock state mutation and mirror jump transformation.

A Possible Role for Arterial Duplex and Hand Acceleration Time in Diagnosing and Managing Shock

Shock represents a state when arterial perfusion is inadequate to supply the needs of cellular respiration, leading to anerobic metabolism, acidosis, and cell death. Although typically described in terms of blood pressure and heart rate, these measures can both lead to delayed recognition of shock and under appreciation of the severity of end-organ malperfusion. Recently, there has been increased interest in monitoring peripheral perfusion both to detect early shock and monitor the response to treatment. However, current methods are variable and, in some cases, require specialized equipment. We present a case in which duplex ultrasound assessment of peripheral palmar acceleration time identified a post-hemorrhagic shock state before it was clinically apparent. Bedside arterial duplex and hand acceleration time may provide a simple tool to assess the degree of shock and response to intervention.

Optimizing Fluid Resuscitation and Preventing Fluid Overload in Patients with Septic Shock

Intravenous fluid administration remains an important component in the care of patients with septic shock. A common error in the treatment of septic shock is the use of excessive fluid in an effort to overcome both hypovolemia and vasoplegia. While fluids are necessary to help correct the intravascular depletion, vasopressors should be concomitantly administered to address vasoplegia. Excessive fluid administration is associated with worse outcomes in septic shock, so great care should be taken when deciding how much fluid to give these vulnerable patients. Simple or strict “recipes” which mandate an exact amount of fluid to administer, even when weight based, are not associated with better outcomes and therefore should be avoided. Determining the correct amount of fluid requires the clinician to repeatedly assess and consider multiple variables, including the fluid deficit, organ dysfunction, tolerance of additional fluid, and overall trajectory of the shock state. Dynamic indices, often involving the interaction between the cardiovascular and respiratory systems, appear to be superior to traditional static indices such as central venous pressure for assessing fluid responsiveness. Point-of-care ultrasound offers the bedside clinician a multitude of applications which are useful in determining fluid administration in septic shock. In summary, prevention of fluid overload in septic shock patients is extremely important, and requires the careful attention of the entire critical care team.

A rare interesting case of fatal air embolism after intravenous contrast during computed tomography

We are reporting a fatal case of air embolism. Although minor cases of air embolism may go unnoticed, this is a case of fatal air embolism after intravenous entry of air, which presented with sudden onset of pulseless electrical activity during a computed tomography scan in the radiology department, requiring cardiopulmonary resuscitation for 15 min. Subsequently, after admission to the intensive care unit, we achieved return of spontaneous circulation. The patient was intubated and ventilated in a shock state. He remained in refractory shock despite of supportive care. Cardiaс arrest was registered again in the catheterization lab and the patient could not be revived after 4 h from the initial cardiac arrest. А computed tomography scan was reported to reveal a significant amount of intra-cardiac air, which was the likely cause patient’s death. The case is a rare condition, which highlights the importance of early diagnosis and delivers a message to the medical staff to have a high index of suspicion in patients who have risk factors, and who develop sudden shock with hypoxemia, in order to treat this potentially life-threatening condition effectively in a timely manner.

Unusual Esophageal Foreign Bodies in a Schizophrenic Patient: A Case Report

Introduction: The possibility of foreign body ingestion should be considered in psychiatric patients. In some complicated cases, foreign bodies become problematic and require immediate surgical intervention. Case presentation: A 45-year-old man with schizophrenia swallowed razor blades and pieces of glass resulting in esophageal perforation, pneumothorax, pneumomediastinum and urgent need for surgery. He was presented in shock state but successfully passed post-operative period in the intensive care unit and surgical ward and was ultimately transferred to the psychiatric ward. Conclusion: Management of asymptomatic patients depends on the demographic factors of patients as well as the site affected in the gastrointestinal tract.

Usefulness of Simultaneous Measurement of Brain and Muscle rSO2 (Regional Oxygen Saturation) in Shock Patients: a Report of Three Cases

BackgroundIn the field of emergency medical care, we often experience a situation in which we cannot measure pulse oximetric saturation (SpO₂) or blood pressure due to circulatory failure associated with shock. However, as we can measure rSO₂ values of the brain even in patients with shock, we hypothesized that we could evaluate the oxygen supply-demand balance between brain and muscle tissue by simultaneously measuring regional oxygen saturation (rSO₂) values of the brain and muscle tissue of patients with shock.Case presentationWe attached a TOS-OR rSO₂ monitor (TOSTEC CO., Tokyo, Japan) to 10 healthy volunteers and measured the rSO₂ values of their brain and muscle for 3 minutes. The rSO₂ values of their brain cerebral regional oxygen saturation (crSO₂) and muscle regional oxygen saturation (mrSO₂) were 77.6±1.6% and 76.2±1.3% (mean ± SD). There was little difference between crSO₂ and mrSO₂ (cerebro-musculoskeletal difference in regional saturation of oxygen; c-mDrSO₂). However, there were discernible amount of c-mDrSO₂ in three cases with shock, Case 1 showed a prolonged shock state due to septic shock caused by bacterial pneumonia. Her crSO₂ values was always higher than her mrSO₂ value, and there was a c-mDrSO₂. Case 2 showed a decrease in mean arterial pressure (MAP) with the development of septic shock caused by intestinal perforation. His crSO₂ value was higher than that of his mrSO₂, and c-mDrSO₂ increased with the decrease of his MAP. Case 3 had a low MAP due to hemorrhagic shock caused by postpartum hemorrhage. Her crSO₂ value was higher than that of her mrSO₂ and a c-mDrSO₂ was present. After resuscitation, the c-mDrSO₂ decreased with the increase in her blood pressure.ConclusionWe evaluated the usefulness of simultaneous measurement of crSO₂ and mrSO₂ as an objective and non-invasive method in shock management. Even if SpO₂ or blood pressure could not be measured due to circulatory failure associated with shock, it was possible to measure the values of crSO₂ and mrSO₂, which changed in real time with fluctuation of the blood pressure. Unlike previous monitoring devices, the rSO₂ monitor may continuously and clearly reflect the changes in local oxygen supply-demand balance.

Posttraumatic Pancreatitis Four Days after Renal Injury with Massive Retroperitoneal Hematoma

A 25-year-old man accidentally fell from a cliff and hit his right flank on the ground while camping. Initially, he was able to barely walk, but he ultimately became unable to walk at all due to severe flank pain. He had no remarkable personal or family history and was a social drinker. Upon arrival, he showed clear consciousness but was in a hemorrhagic shock state. Enhanced computed tomography (CT) revealed extravasation of contrast medium from the injured right kidney with massive retroperitoneal hematoma. He underwent massive blood transfusion and tracheal intubation followed by renal embolization. His vital signs stabilized on hospital day 2, and he was extubated on day 3. On days 4 and 5, a blood examination revealed increased levels of amylase (360 and 904 IU/L, respectively). Enhanced CT on day 5 did not show signs of severe acute pancreatitis. The maximum amylase level was 1041 IU/L on day 6 and decreased day by day without deterioration of the severity of his acute pancreatitis. He was discharged on day 14. The subacute phase of posttraumatic acute pancreatitis in the present case may have been induced not by direct injury to the pancreas but by several causative factors, such as shock, increased pressure of the retroperitoneal space, or the release of inflammatory mediators from injured tissues or hematoma.

The discovery of biological subphenotypes in ARDS: a novel approach to targeted medicine?

The acute respiratory distress syndrome (ARDS) is a severe lung disorder with a high morbidity and mortality which affects all age groups. Despite active research with intense, ongoing attempts in developing pharmacological agents to treat ARDS, its mortality rate remains unaltered high and treatment is still only supportive. Over the years, there have been many attempts to identify meaningful subgroups likely to react differently to treatment among the heterogenous ARDS population, most of them unsuccessful. Only recently, analysis of large ARDS cohorts from randomized controlled trials have identified the presence of distinct biological subphenotypes among ARDS patients: a hypoinflammatory (or uninflamed; named P1) and a hyperinflammatory (or reactive; named P2) subphenotype have been proposed and corroborated with existing retrospective data. The hyperinflammatory subphenotyope was clearly associated with shock state, metabolic acidosis, and worse clinical outcomes. Core features of the respective subphenotypes were identified consistently in all assessed cohorts, independently of the studied population, the geographical location, the study design, or the analysis method. Additionally and clinically even more relevant treatment efficacies, as assessed retrospectively, appeared to be highly dependent on the respective subphenotype. This discovery launches a promising new approach to targeted medicine in ARDS. Even though it is now widely accepted that each ARDS subphenotype has distinct functional, biological, and mechanistic differences, there are crucial gaps in our knowledge, hindering the translation to bedside application. First of all, the underlying driving biological factors are still largely unknown, and secondly, there is currently no option for fast and easy identification of ARDS subphenotypes. This narrative review aims to summarize the evidence in biological subphenotyping in ARDS and tries to point out the current issues that will need addressing before translation of biological subohenotypes into clinical practice will be possible.

Overview of sepsis associated acute kidney injury: literature review

The incidence of acute kidney injury has been estimated to be around a fifth of the adult patients during their hospital stays. Sepsis is estimated to be the commonest cause for AKI development in critically-ill patients; contributing to the pathology in 20-50% of the cases. We reviewed some aspects of sepsis-associated AKI. Among the risk factors that may contribute to the development of AKI, age, sex, and the presence of comorbidities as diabetes, heart, and liver diseases were reported as significant factors associated with the development of the condition. The pathophysiology of sepsis-induced AKI is still unclear; however, some authors said that it may be related to the hypoperfusion of the renal tissue and subsequently induced ischemia. This theory was supported by animal studies; however, other investigations on humans reported no association between the two events. On the other hand, we believe that sepsis-induced AKI is probably due to the associated severe inflammatory state and hemodynamic instability are the main accusants. The management of this condition requires early diagnosis and early intervention by managing sepsis. Moreover, vasopressors as epinephrines have proved efficient in managing the shock state, even better than renal replacement therapy.