Artificial organs最新文献

Introduction: Hyperphosphatemia is frequent in hemodialysis (HD) patients and associates with cardiovascular mortality. Parameters of online hemodiafiltration (OL-HDF) prescription influencing phosphate removal are poorly understood in real-world clinical settings.

Methods: We conducted a prospective observational study including chronic HD patients dialyzed at a single UK university hospital between December 2021 and July 2023. Phosphate removal was quantified from spent dialysate during a midweek session.

Results: Dialysate phosphate was measured during 161 dialysis sessions in 128 unique patients (19 on HD and 109 on OL-HDF), with mean age 63.3 ± 16.2 years and 77 (60.1%) men. Mean intra-dialytic phosphate removal was 25.6 ± 14.3 mmol per session. In multivariate analysis, pre-HD serum phosphate concentration, session time, and urea distribution volume (V) were positively associated with intradialytic phosphate removal. A significant interaction between session time and pre-HD serum phosphate concentration indicated that longer sessions provided greater benefit to patients with higher baseline phosphate levels. Conversely, dialysis modality (OL-HDF vs. HD) and substitution volume were not significantly associated with phosphate removal.

Conclusions: OL-HDF and substitution flow do not demonstrate a measurable beneficial impact on phosphate removal in a real-world setting. Session time, pre-HD serum phosphate concentration, and urea distribution volume (V) are the most relevant determinants of phosphate clearance in real-world clinical practice. Session duration emerges as the most effective modifiable factor for controlling phosphate burden in dialysis patients, particularly for those with higher pre-HD phosphate levels.

Background: Shear-induced hemolysis remains a major challenge in pediatric mechanical circulatory support (MCS), where hemolysis-related complications occur more frequently than in adults. Despite known hematologic differences between pediatric and adult blood, it is unclear whether pediatric red blood cells (RBCs) are intrinsically more susceptible to mechanical stress than those from adults. This study compared shear-induced hemolysis of pediatric and adult blood under identical conditions and assessed the predictive accuracy of established power-law hemolysis models.

Methods: This study investigated hemolysis of blood in 25 samples from 14 children aged 3-11 years. Repeated shear stress experiments were performed in a Couette shearing device by applying homogeneous, semi-sinusoidal shear stresses between 73 and 139 Pa for 20-80 repetitions. Hemolysis was quantified using the Harboe method and corrected for baseline and processing-related hemolysis. Results were compared to previously published adult data acquired using the same apparatus. Pediatric hemolysis was compared to adult results across defined shear-stress ranges, and two established power-law parameter sets were evaluated for predictive accuracy.

Results: Shear-induced hemolysis (IH) was assessed across mean shear stress amplitudes of 73-139 Pa. Across the full stress range, pediatric IH values (0.013%-0.395%) were lower than adult values (0.035%-0.532%). While no differences were observed at lower shear stresses (73-95 Pa and 95-117 Pa), pediatric samples showed a trend toward lower hemolysis at higher shear stresses (117-139 Pa). Of the two evaluated established parameter sets for power-laws from the literature, the parameter set C = 3.458 × 10-6, α = 0.2777 and β = 2.0639 demonstrated the best agreement within our investigated shear stress range.

Conclusion: Within the examined shear range, pediatric RBCs did not display increased sensitivity to mechanical stress compared to adult RBCs. These results suggest that increased hemolysis in pediatric MCS is more likely related to device design and device operating conditions than to an intrinsically higher susceptibility of pediatric blood. Due to the low availability of pediatric blood, adult blood appears suitable for initial hemolysis testing in pediatric device development, although larger pediatric cohorts will be necessary to refine hemolysis prediction models and to investigate additional blood damage mechanisms.

Background: Gastrointestinal bleeding is a common complication in continuous-flow left ventricular assist device (CF-LVAD) patients. Managing gastrointestinal bleeding often requires reducing or stopping anticoagulation, potentially increasing the risk of thromboembolic events. This study aimed to evaluate thromboembolic events in CF-LVAD recipients.

Methods: We analyzed data from our institutional Intermacs database from January 2008 to December 2023. The cohort included both primary implants and pump exchanges. Thromboembolic events were defined as ischemic stroke, transient ischemic attack, or pump thrombosis (excluding pre-gastrointestinal bleeding ones). Multivariable logistic regression was used to evaluate gastrointestinal bleeding as a risk factor for thromboembolic events.

Results: Among 1075 CF-LVAD implants, the median age was 58.5 years (IQR 50.0-65.7), with 79.8% male. Most patients (80.6%) had an Intermacs profile ≤ 3. Gastrointestinal bleeding occurred in 32.2%, among whom thromboembolic events occurred in 26.3%. Median time from gastrointestinal bleeding to thromboembolic events was 12.7 months (IQR 4.0-24.5). Gastrointestinal bleeding increased the risk of thromboembolic events by 52% (OR 1.52, p = 0.018). Additionally, among all CF-LVAD implants, patients aged ≥ 50 years had a 66% higher risk (p = 0.024), and Black patients had twice the risk compared to non-Black patients (p < 0.001). Axial-flow (OR 3.9) and partial magnetically levitated centrifugal-flow LVADs (OR 3.5) were associated with significantly higher thromboembolic risk compared to fully magnetically levitated centrifugal-flow devices (p < 0.001).

Conclusions: Thromboembolic events remain a major risk in CF-LVAD patients. Gastrointestinal bleeding significantly increases thromboembolic risk. Higher risk was also seen in patients aged ≥ 50 years, Black patients, and those with older CF-LVAD models.

Backround: The membrane oxygenator is a critical component of extracorporeal circulation (ECC), whose performance directly depends on its structural architecture. Differences in fiber geometry and winding patterns lead to variable hemodynamic pressure conditions. The resulting pressure drop Delta p (Δp) across the oxygenator module is a decisive indicator for system load and the risk of blood trauma. The aim of this study is the comparative analysis of the Δp of three commercial oxygenators: Medtronic Affinity Fusion, Eurosets A.L. ONE Plus, and LivaNova Inspire 8F, calculated from the difference between inlet and outlet pressure.

Methods: This prospective observational study included 60 patients divided into three groups of 20 patients each, based on the type of oxygenator used in their perfusion circuit.

Results: The results of the study show that the Δp value was significantly higher for the Inspire 8F compared to the Affinity Fusion and A.L. ONE Plus oxygenators. Between measurement points T2 and T11, the highest Δp was 116 ± 56 mmHg for the Medtronic group, 123 ± 26 mmHg for the Eurosets group, and 168 ± 33 mmHg for the Inspire 8F group. No significant differences in Δp were observed between the Affinity Fusion and the A.L. ONE Plus at any measurement point.

Conclusion: The results of the study show that the Inspire has the highest Δp of all the oxygenators examined in this study. In addition to potential influencing factors, the value is also dependent on the internal structure and the surface properties of the oxygenators. However, the present study does not help to clarify the effects of the pressure before and after the oxygenator or the Δp itself on hemolysis and subsequent clinical parameters associated with the use of different commercially available oxygenators.

Background: Three-dimensional (3D) hepatocyte spheroids better recapitulate liver microenvironments than monolayers, but robust, high-throughput viability assessment remains challenging because of diffusion limits and stain penetration.

Objective: To evaluate a simple imaging-based approach that quantifies spheroid viability by measuring acridine orange (AO) and propidium iodide (PI) fluorescence and computing a PI brightness-to-area ratio.

Methods: Rat hepatocyte spheroids were formed on a rocker, stained with AO/PI, and imaged on an inverted fluorescence microscope with fixed exposure settings. We prepared mixtures representing nominal 0%, 30%, 50%, 70%, and 100% viable spheroids and analyzed the relationship between viability and the PI brightness-to-area ratio. Statistical analyses included one-way ANOVA with Tukey's HSD and simple linear regression with diagnostic checks. A urea/DNA functional assay as well as a small blinded study both served as an orthogonal validation.

Results: The PI brightness-to-area ratio decreased with increasing percent viable cells (Pearson r = -0.99; R² = 0.98; p = 1.81 × 10^-4). Residuals were approximately normal and homoscedastic. Urea/DNA strongly and positively correlated with viability (r = 1.00; p = 1.10 × 10^-4; R² = 1.00) with regression equation: y = 9.049444 × 10^-6 x + 3.036814 × 10^-5. All blinded studies were within 10% of established viability; average difference between mean observer estimates and ground truth was +1.7 percentage points (range -3.7 to +10).

Conclusions: A fixed-setting AO/PI imaging workflow yields a rapid, accessible proxy for hepatocyte spheroid viability that correlates with a functional readout. This approach is well-suited to high-throughput screening and method optimization.

Background: With the rising demand for platelet products, the use of apheresis-derived single donor platelets (SDPs) has grown substantially. While plateletpheresis is generally considered safe, it is not devoid of complications.

Materials and methods: This retrospective descriptive study reviews three adverse events that occurred during SDP collection at a transfusion medicine department. Root cause analysis (RCA) was employed using tools such as the 5 "Whys" technique and the Ishikawa (Fishbone) Diagram to identify underlying causes and propose preventive strategies.

Case details: In the first incident, a first-time donor experienced vasovagal symptoms triggered by a visible blood leak from the apheresis kit. The second incident involved a centrifuge alarm and mid-procedure halt due to blood spillage caused by improper kit installation. The third incident was identified post-procedure when the platelet concentrate was found contaminated with red blood cells from a manufacturing defect. All donors recovered without lasting health effects; however, such technical or procedural failures can erode donor confidence, reduce willingness for repeat donations, and impact retention of valuable apheresis donors.

Conclusion: The events in this case series highlight that adverse outcomes can stem from both equipment-related faults and human errors. Strengthening the voluntary apheresis donor base in India requires prioritizing donor safety, ensuring positive donation experiences, comprehensive staff training, adherence to standard operating procedures (SOPs), and fostering a supportive, trust-based environment.

Extracorporeal membrane oxygenation (ECMO) is a life-saving intervention for patients with severe cardiac and respiratory failure. However, it carries risks of complications such as thromboembolism and bleeding. Clinical monitoring requires diagnostic imaging, but challenges arise due to the complexity of care and patient transport. Contrast-enhanced computed tomography (CT) is vital in diagnosing ECMO-related complications yet it poses challenges due to hemodynamic peculiarities, especially in peripheral veno-arterial (VA ECMO), where the interaction between forward cardiac output and retrograde ECMO return may lead to flow-related artifacts in contrast distribution. Advancements in non-invasive diagnostic tools, such as transesophageal echocardiography (TEE) and bedside neuroimaging, are key to managing ECMO patients. TEE helps detect the watershed area in VA ECMO to optimize flow adjustments, while new bedside neuroimaging techniques, such as low-field magnetic resonance imaging (MRI), avoid the risk of transporting ECMO patients to radiology and improve the early detection of cerebral events. Electrical impedance tomography may also allow the bedside evaluation of patients with ARDS undergoing veno-venous (VV ECMO). Despite their enormous potential, advanced bedside diagnostic systems are not yet routine in clinical practice but represent a promising area for development. This review explores current strategies and potential advancements in optimizing diagnostic imaging protocols and non-invasive techniques, focusing on contrast-enhanced CT, bedside echocardiography, and neuroradiology.

Background: Acute respiratory failure after cardiac surgery is an uncommon complication, affecting morbidity and mortality. In these patients, respiratory extracorporeal membrane oxygenation (ECMO) support may be beneficial, as it may help reduce pulmonary vasoconstriction and the impact of respiratory pressures on the heart. Nevertheless, literature reports of postcardiotomy veno-venous (V-V) ECMO use are sporadic.

Methods: This retrospective, multicenter cohort study analyzes data from the PELS-1 registry, focusing on adult patients who required V-V ECMO following cardiac surgery. PELS-1 was conducted across 34 cardiac surgery centers in 16 countries from 2000 to 2020.

Results: The study included 24 patients who received V-V ECMO over a total of 2163 patients requiring postocardiotomy extracorporeal support (1.1%). The median age was 64[50-69] years, and 16/24 (67%) were male. Median Euroscore II was 6.2[3.1-19.6]. Most patients required prolonged cardiopulmonary bypass (CPB) time (208[110-350] min). V-V ECMO was initiated in the ICU in 21 patients (87.5%) after a median of 5 [2-12] days postoperatively. ECMO support rapidly normalized gas exchange and lactate levels. However, complications were frequent: bleeding (10/22, 45.5%), acute kidney injury (10/24, 41.7%), pneumonia (10/24, 41.7%), and arrhythmias (7/24, 29.2%) were the most frequent ones. In-hospital mortality was high, with only 21.7% discharged alive. One-year survival was 12.5%.

Conclusions: Reported outcomes of patients receiving V-V ECMO after cardiac surgery are poor, despite effective correction of gas exchange. Early recognition of isolated respiratory failure and careful patient selection should be promoted. Further research is needed to optimize management in this high-risk population.

Background: In the last decades, various extracorporeal liver support systems were developed for hepatic failure with hyperbilirubinemia with the aim to clear the blood from protein-bound toxic molecules. Open albumin dialysis (OPAL) is a complex and expensive system that requires addition of human albumin. Plasma adsorption perfusion (PAP) using the anion exchange resin adsorber, BR-350, is an alternative liver support method that does not need additional blood products and is more cost-effective and less time-consuming.

Methods: At the University Hospital Essen, PAP using BR-350 was performed in a cohort of 9 patients with a mean of 6 sessions per patient. In a retrospective analysis, we compared the detoxification ability of PAP with that of the OPAL system conducted among 24 patients and with standard medical treatment (SMT) including hemodialysis that was performed among 24 patients. In addition, the technical effectiveness of a single session of PAP with BR-350 was compared with OPAL among 12 patients who were treated with both methods in a crossover design.

Results: The first single session (30.7.3 ± 13.5 mg/dL to 25.8 ± 13.4 mg/dL, p = 0.02) and the complete therapy (30.7 ± 13.5 mg/dL to 16.2 ± 6.3 mg/dL, p = 0.004) with PAP using BR-350 resulted in a statistically significant decrease of bilirubin concentrations. The median relative reduction of bilirubin achieved at the end of liver support treatment was comparable between PAP and OPAL (47% vs. 40%, p = 0.29). PAP was associated with a higher bilirubin reduction than the SMT plus dialysis (47% vs. -30%, p = 0.0001). The crossover comparison between the single session of PAP using BR-350 and OPAL revealed similar mean relative reduction rates of bilirubin (11% vs. 10%, p = 0.81). The single session of OPAL was associated with a more pronounced decrease of alkaline phosphatase, gamma-glutamyltransferase, hemoglobin, platelets, and leucocytes compared to PAP.

Conclusions: Both studied methods had comparable efficacy in reducing bilirubin in our studied patients in contrast to the retrospective control group. Since other substrates may also be relevant in treating liver failure, more studies are required. Patients with concomitant renal failure benefit from OPAL, whereas PAP might be more eligible for patients with a high risk of bleeding.