International Journal of Artificial Organs最新文献

In the present work, bone implant materials (BIM) were produced, in sheet form which comprises epoxy resin (synthetic polymer) (ER), calcium carbonate (CaCO₃), and reduced graphene oxide (R-GO), by open mold method, for the possibility uses in bone tissue engineering. The developed BIM was analyzed for its physico-chemical, mechanical, bioactivity test, antimicrobial study, and biocompatibility. The BIM had excellent mechanical properties such as tensile strength (194.44 + 0.21 MPa), flexural strength (278.76 + 0.41 MPa), and water absorption (02.61 + 0.24%). A pore size distribution study using the HR-SEM has proved the 180 and 255 μm average pore was observed in the BIM structure. The Bioactivity test of BIM was examined after being immersed in a simulated body fluids (SBF) solution. The result of BIM formed an excellent deposition of bone tube apatite crystals. High-resolution scanning electron microscopy (HR-SEM) morphology of the bone tube apatite crystals revealed the diameter size in the range from 100 ± 159 to 210 ± 188 nm. BIM has excellent antimicrobial characteristics against E. coli (8.75 + 0.06 mm) and S. aureus (9.82 + 0.08 mm). The biocompatibility of the study MTT (3-(4, 5-dimethyl) thiazol-2-yl-2, 5-dimethyl tetrazolium bromide) assay using the MG-63 (human osteoblast cell line) has proven to be the 78% viable cell presence in BIM. After receiving the necessary approval, the scaffold with the required strength and biocompatibility could be tested as a bone implant material in large animals.

Introduction: Diabetic ketoacidosis (DKA) is a common clinical problem. When patients develop severe shock and/or respiratory failure, extracorporeal membrane oxygenation (ECMO) may be considered. This case series describes the clinical presentation and outcomes of patients with DKA supported with ECMO.

Methods: We conducted a retrospective and anonymized review of 15 patients with DKA who required ECMO at our institution. Demographic and ECMO-specific data were collected. Additional variables include ICU length of stay (LOS), acute kidney injury and use of continuous renal replacement therapy, disposition, and mortality.

Results: All ECMO cannulations were performed by an intensivist using peripheral vascular access. The majority of patients were female (73%) with a median age of 27 (IQR = 21.5-45) years. A diagnosis of diabetes mellitus (DM) prior to ECMO was present in 11 (73%) patients. Venoarterial ECMO was the initial mode used in 11 (73%) patients. The median duration of ECMO support was 7 (IQR = 6-14) days. The median ICU LOS was 12 (IQR = 8.5-20.5) days, and the median hospital LOS was 21 (IQR = 11-36.5) days. Eight patients had cardiac arrest and underwent extracorporeal cardiopulmonary resuscitation (ECPR) of which 4 (50%) patients survived to discharge. Overall, 10 (66.7%) patients were successfully weaned from ECMO and survived to discharge.

Conclusion: This is the largest case series regarding the use of ECMO for patients with refractory shock, cardiac arrest, or respiratory failure related to DKA. The findings suggest that ECMO is a viable support option for managing these patients and has excellent outcomes, including patients with cardiac arrest.

Management of acute respiratory distress syndrome (ARDS) represents one of the greatest challenges in intensive care and despite all efforts mortality remains high. One common phenotype of ARDS is that of a secondary injury to a dysregulated inflammatory host response resulting in increased capillary congestion, interstitial lung edema, atelectasis, pulmonary embolism, muscle wasting, recurring infectious episodes, and multiple organ failure. In cases of hyperinflammation, immunomodulation by extracorporeal cytokine removal such as the CytoSorb hemoadsorption cartridge could conceptually enhance lung recovery during the early course of the disease. The aim of this narrative review is to summarize the currently available data in this field and to provide an overview of pathophysiology and rationale for the use of CytoSorb hemoadsorption in patients with hyperinflammatory ARDS.

Objectives: To evaluate the effects of combined treatment with tannic acid and ferric ions on the biomechanical and anti-calcification properties of glutaraldehyde-fixed bovine jugular veins after xenografting.

Methods: Two-point bending test and uniaxial tensile test were used to evaluate the flexural and biomechanical properties; Subcutaneous implantation in rat and right ventricular outflow tract reconstruction of sheep were used to evaluate the anti-calcification effects; The performance of the graft in sheep models was evaluated every month after the surgery with echocardiography examination. Markers of macrophages, T lymphocytes, smooth muscle cell osteogenic differentiation and matrix metalloproteinases in sheep explants were detected by immunohistochemistry.

Results: The flexibility of the bovine jugular veins cotreated with ferric ions-tannic acid was improved while maintaining biomechanical properties and excellent anti-calcification effects. Echocardiography results showed that the grafts functioned well in the animals without stenosis or reflux of the valve. Immunohistochemical studies showed that the osteogenic differentiation marker (Runx2) was detected in calcified regions and colocalised with the SMC marker (α-SMA). Compared to the glutaraldehyde-treated samples, T-cell marker (CD3), matrix metalloproteinase-2 and 9 expressions were reduced in the ferric ions-tannic acid treated group.

Conclusion: Ferric ions-tannic acid treatment can give the conduits better flexibility with excellent biomechanical properties and anti-calcification effects, making it a promising bovine jugular veins processing method.

Based on the lumped parameter model (LPM) of the cardiovascular system, an analytic method is developed to derive its hemodynamics theoretically. As soon as the LPM (a series of differential equations) is solved, the hemodynamics would be obtained immediately. However, because of time-varying ventricular elastance and high order, it is difficult to solve analytically. Through simplifying the LPM, the original biventricular system with continuously varying elastance becomes a single ventricular system with discrete elastance which keeps constant during the systolic or diastolic phase. As a consequence, the original time-varying and high-order system becomes a time-invariant and first-order system during each phase. From the analytic solutions of the simplified system, a set of algebraic equations is carried out. Then the hemodynamics are obtained from the solutions of the algebraic equations. The nature of the algebraic equations is an integral form of the differential equations. A connection between the equations and PV loop is established. All of these equations are deduced based on the idealization of replacing the continuous elastance with the discrete elastance. However, there exist algebraic equations, that can be derived directly from volume conservation, still hold for the case of continuous elastance. As a preliminary application, the method is utilized to deduce the hemodynamics of left heart failure (LHF). The results show that the theoretical hemodynamics of LHF are coincident with simulated results. The analytic method can be generalized to investigate biventricular system. A program for developing a more general framework is presented in the last part.

Introduction: Severe COVID-19 is associated with a dysregulated immune response that usually leads to cytokine release syndrome. This study aimed to compare the use of extracorporeal blood purification therapy (Oxiris^®) versus standard continuous renal replacement therapy (CRRT) in critically-ill patients with severe COVID-19.

Methods: This was a national, multicenter, retrospective study of patients with COVID-19 admitted to the intensive care unit (ICU) between March and October 2020 who required CRRT. Patients were categorized into two groups: Oxiris^® CRRT and standard CRRT. The primary outcome was the number of patients alive and ventilator-free at 30-days post-CRRT treatment. Key secondary endpoints included change in inflammatory markers, Sequential Organ Failure Assessment (SOFA) scores, and PaO₂/FiO₂ ratio at 24- and 72-h post Oxiris^® initiation.

Results: Thirty-five patients received Oxiris^® CRRT and 23 patients received standard CRRT. The primary outcome was 31.4% in the Oxiris^® group versus 4.3% in the standard CRRT group (adjusted odds ratio 5.97, 95% confidence interval [CI], 0.64-55.6; p = 0.117). In the Oxiris^® group, interleukin-6 (IL-6) concentrations significantly decreased at 24 and 72-h (p = 0.033) and PaO₂/FiO₂ ratio significantly increased at 24 and 72 h after Oxiris^® initiation (p = 0.001). There was no significant change in SOFA scores at 24- and 72-h after Oxiris^® initiation.

Conclusion: The number of patients alive and ventilator-free at 30-days was higher in the Oxiris^® group than that in the standard CRRT group; however, the difference did not reach statistical significance after adjusting for the baseline severity of illness. There was a significant reduction in IL-6 and significant improvement in PaO₂/FiO₂ ratio after Oxiris^® CRRT initiation.

Severe left ventricular failure can progress to right ventricular failure, necessitating alternatives to heart transplantation, such as total artificial heart (TAH) treatment. Conventional TAHs encounter challenges associated with miniaturization and hemocompatibility owing to their reliance on mechanical valves and bearings. A magnetically levitated TAH (IB-Heart) was developed, utilizing a magnetic bearing. The IB-Heart features a distinctive biventricular shunt channel situated between the flow paths of the left and right centrifugal blood pumps, simplifying and miniaturizing its control system. However, the impact of these shunt channels remains underexplored. This study aimed to investigate the effects of shunt flow on pump characteristics and assess the IB-Heart's potential to regulate flow balance between systemic and pulmonary circulation. At a rotational speed of 2000 rpm and flow rate range of 0-10 L/min, shunt flow exhibited a minor impact, with a 1.4 mmHg (1.3%) effect on pump characteristics. Shunt flow variation of about 0.13 L/min correlated with a 10 mmHg pressure difference between the pumps' afterload and preload conditions. This variance was linked to changes in the inlet flow rates of the left and right pumps, signifying the ventricular shunt structure's capacity to mirror the function of an atrial shunt in alleviating pulmonary congestion. The IB-Heart's ventricular shunt structure enables passive regulation of left-right flow balance. The findings establish a fundamental technical groundwork for the development of IB-Hearts and TAHs with similar shunt structures. The innovative coupling of centrifugal pumps and the resultant effects on flow dynamics contribute to the advancement of TAH technology.

In recent years, normothermic machine perfusion (NMP) has emerged in conversation surrounding organ preservation and transplantation techniques with the goal of improving patient and clinical outcomes. This is in great attempt to address the rate of non-utilization and the shortage of available organs in kidney transplantation. This focus in mind, normothermic perfusion presents itself as a potential tool to mimic physiological conditions and improve current preservation methods, such as static cold storage. This review serves to improve understanding of the observed connection between the consequences of ischemia and reperfusion injury and traditional preservation techniques as well as how renal NMP may mitigate these issues. Previous studies suggest that reducing time in static cold storage methods by promoting the normothermic perfusion model results in decreased delayed graft function and post-transplant complications. This review also aims to present the immense clinical potential NMP has on future kidney transplantation success and what this means for the fields of nephrology and transplantation. While great strides have been made to evaluate normothermic perfusion's impact on kidney graft viability and transplant success, future research into unified protocol, clinically relevant biomarkers, cost-utility analysis, and use with associated therapeutic and imaging modalities is paramount.

Patients with implantable left ventricular assist devices (LVAD) are at risk of ventricular arrhythmias but these may be hemodynamically tolerated. An electrocardiogram (ECG) is essential to determine whether an LVAD-supported patient is experiencing a ventricular arrhythmia. Access to 12 lead ECG is predominantly in healthcare facilities. Implantable LVAD also cause significant electromagnetic interference leading to artefacts on ECG. We report a patient on Heartmate 3 LVAD with a diagnostic quality 6 lead ECG obtained with an AliveCor device during an episode of sustained palpitations. The AliveCor device may be used for remote identification of ventricular arrhythmias in LVAD patients.