Hemolysis Index Research Articles

Improving the hemocompatibility of centrifugal mechanical circulatory support devices at low flow rates.

An innovative solution has been recently proposed for the treatment of heart failure with preserved ejection fraction (HFpEF), using a centrifugal mechanical circulatory support (MCS) device. We sought firstly to assess the hemocompatibility of the proposed device. HFpEF treatment requires the blood pump to operate at low blood flow rate (0.05-0.5 L/min). Given high blood trauma expected in these conditions, we sought secondly to investigate design improvements in order to reduce this risk. Computational fluid dynamics was used to analyze the blood fluid filled within the centrifugal pump and to estimate the blood trauma due to its operation. This assessment is based on the computation of integrated quantities such as the hemolysis index and the turbulent dissipation energy. The hemolysis index associated with the present device is comparable to the figures from HVAD. With the proposed pump, for instance, an index of 0.0036 is obtained at 1 L/min and 3000 rpm. Using thinner blades for the impeller allows a 12% reduction of the hemolysis index in average, while reducing its diameter leads to an index 2.8 folds lower at 0.5 L/min. The present investigation shows the promising hemocompatibility of our centrifugal pump. Concerns about very high hemolysis generated at low flow rates could be overcome by reducing the impeller diameter. Experimental validations are planned to support our findings.

Fabrication and evaluation of four combinations of pullulan-based biopolymeric, microporous scaffolds impregnated with peppermint oil for management of partial thickness burn wounds and accelerated tissue regeneration

Burn injuries are common in both civilian and military settings and cause severe morbidity and mortality. The present study aimed to develop microporous bioactive scaffolds from the natural polysaccharide, pullulan, combined individually with Gelatin (Gel)/ Alginate (Alg)/ Chitosan (Ch)/ Carboxy-methyl cellulose (CMC), and crosslinked with glutaraldehyde to form a polymeric network. The objective was to evaluate and compare their efficacy in healing second degree partial-thickness burn wounds. The scaffolds were also impregnated with peppermint oil (PEO) to provide potential analgesic and cooling effects. Scaffolds were characterized using FTIR, TGA and SEM analysis to understand the intra-and intermolecular interactions and morphological characteristics. In vitro parameters like fluid uptake ability, biodegradation and hemolytic index were also assessed. Biocompatibility studies, including cell adhesion, migration and proliferation, were conducted using L929 mouse fibroblast cell lines. The in vivo efficacy was evaluated in Sprague Dawley rats inflicted with second degree burns to assess and compare wound retraction across different experimental groups. Histology, immunohistochemistry along with gram and picrosirius staining studies were also performed. The average pore size of all biopolymeric scaffold combinations ranged between 25.6-298μm. All four test combinations were non-hemolytic, with hemolytic indices between 0.3-2.9. Wound retraction studies in rats clearly indicated that among the four test combinations studied, Pu/Gel/PEO scaffold not only reduced local inflammation faster but also accelerated dermal regeneration in comparison to positive control as well as other test combinations (viz., Pu/Alg/PEO, Pu/Ch/PEO, and Pu/CMC/PEO). Immunohistochemistry results corroborated animal efficacy findings and demonstrated enhanced expression level of epidermal growth factor and fibroblast growth factor-2 in Pu/Gel/PEO scaffold treated group. Picrosirius staining also revealed enhanced collagen deposition in Pu/Gel/PEO scaffold treated group. The study findings suggest that biopolymeric scaffolds made from pullulan combined with gelatin and PEO (Pu/Gel/PEO) could serve as a promising substrate for skin regeneration template for second degree burns.

Effect of Blade Thickness on Hemodynamics and Hemolysis: A Case Study of Pediatric Centrifugal Blood Pumps.

Blood pumps have become popular whether for use as an implantable ventricular assist device or as extracorporeal membrane oxygenation. The quality of these pumps is assessed according to their ability to reduce the risk of blood damage thanks to an optimal choice of their geometric and operating properties. Lack of the research focused on the geometrical optimization of impellers has prompted this study. This study evaluated a computational and experimental analysis comparing the hemolytic performance of three centrifugal pumps. For this purpose, methods of Eulerian and Lagrangian are respectively used for hemodynamic and hemocompatibility investigations. Referring to the pediatric demands, these pumps function under clinically applicable pressure-flow conditions: 1 l/min of blood flow and a pressure differential of 60 mm Hg. These three pumps all use the same volute, but their impellers differ in terms of blade thickness. The objective is to examine how surface area affects the generation of hemolysis. In silico simulations were employed for both of the following tasks: first, identifying the distributions of velocities, pressures, and shear stresses; second, applying the Lagrangian approach to estimate the hemolysis index. Results showed the importance of the flow passage and the surface of the clearance on the hemocompatibility of the pumps. However, it was observed that there is not a linear effect of the blade thickness on the shear stress or index of hemolysis. Additionally, this work can provide information to develop an optimal design of a more hemocompatible blood pump.

The true incidence and risk factors of hemolysis in patients with Impella CP placement

Abstract Background The Impella, a micro axial-flow pump, is effective in treating cardiogenic shock. However, compared to other mechanical circulatory support devices, its high pump speeds can result in complications like hemolysis and subsequent renal failure. Previous reports have defined hemolysis based on the elevation of LDH levels or the presence of hemoglobinuria, but this approach may underestimate its occurrence. Hemolysis is commonly assessed using the hemolysis index, which is calculated through biochemical auto-analysis based on the absorbance measure of the red color change. However, since the hemolysis index is not highly sensitive, it is recommended to measure plasma free hemoglobin (PFHb) for accurate diagnosis of hemolysis. Purpose The aim of this single-center retrospective cohort study is to investigate the frequency of hemolysis in Impella CP using PFHb measurements and its association with the Impella support level. Methods Between December 2019 and June 2023, we included 116 patients who had the Impella CP device implanted at our hospital. For these patients, PFHb was measured twice daily during the Impella placement period (up to 13 days). A PFHb value of 0.06 or higher was considered indicative of hemolysis, at which point a haptoglobin preparation of 4000 units was administered. Separately, the hemolysis index was defined as hemolysis at a level of 41 mg/dL. We investigated the relationship between daily Impella settings, PFHb, and hemolysis index for each patient. Results The average age was 70 ± 13 years. 59% underwent ECPELLA, and 15% were introduced to renal replacement therapy (RTT) due to severe renal failure. During Impella placement, hemolysis was diagnosed in 33% of patients based on PFHb, while only 18% were diagnosed with hemolysis according to the hemolysis index. Upon separate analysis for Impella and ECPELLA during the initial three days, the support levels of Impella were significantly higher in the Impella group on Days 1 and 2, with no significant difference noted on Day 3. Moreover, PFHb levels were significantly higher in the Impella group on Day 1, while on Day 3, the levels were higher in the ECPELLA group. Patients on RRT had significantly higher max PFHb levels than those not on RRT (0.19 vs. 0.06 g/dL; p < 0.001). Next, we investigated the relationship between PFHb levels and Impella support levels in patients with either Impella or ECPELLA over 711 data points. Dividing Impella support into low (P1-3), middle (P4-6), and high (P7-9) categories, PFHb values were significantly higher at high P levels compared to low and middle P levels. Similar results were observed for both Impella and ECPELLA. Conclusion There is a possibility of underestimating hemolysis associated with Impella if PFHb measurement is not performed. Hemolysis showed a significant correlation with higher P levels (P7 and above) for both Impella and ECPELLA.

Comparison of a two-step Tempus600 hub solution single-tube vs. container-based, one-step pneumatic transport system.

Efficient and timely transportation of clinical samples is pivotal to ensure accurate diagnoses and effective patient care. During the transportation process, preservation of sample integrity is crucial to avoid pre-analytical aberrations on laboratory results. Here, we present a comparative analysis between a two-step Tempus600 hub solution single-tube and a one-step, container-based pneumatic transport system (PTS) from Airco, for the in-house transportation of blood samples. Ten blood samples from healthy volunteers were split in 10 mL collection tubes filled at full or half capacity for transportation with the two PTS (about 250 m). To compare the impact of transportation, markers of hemolysis such as lactate dehydrogenase (LDH), potassium (K+), and the hemolysis index (HI), were determined. Additionally, differences in HI in routine samples and repeated transportation was investigated. To assess and compare the mechanistic impact profiles, we recorded the acceleration profiles of the two PTS using a shock data logger. Transportation using the Tempus600 hub solution resulted in 49 and 46 % higher HI with samples filled to total or half capacity, respectively. Routine samples transported with the Tempus600 hub solution showed a higher median HI by 23 and 33 %. Additionally, shock logger analysis showed an elevated amount of shocks (6.5 fold) and shock intensities (1.8 fold). The Tempus600 hub solution caused an increased number of unreportable LDH or K+ results based on the hemolysis index. However, it was only statistically significant for LDH (p<0.01 and p<0.08)- while the comparisons for K+ were not statistically significant (p<0.28 and p<0.56).

Cherry-Red Plasma Unraveling the Impact of PV-10 on Chemistry Assays

Abstract Background The accuracy of clinical laboratory measurements can be compromised by laboratory test interferences. PV-10 (Rose Bengal), a chemotherapy medication used in the treatment of metastatic melanoma, was observed to cause a cherry-red discoloration in plasma. This plasma color change, resembling hemolysis, raises serious concerns about potential interference in clinical laboratory tests. Our study focused on understanding the potential interference of PV-10, particularly the impact on the hemolysis index (H index) and various chemistry assays to ensure result accuracy in cancer treatment. Methods To investigate the potential interference of PV-10, pooled normal and high baseline bilirubin plasma samples were spiked with a gradient of PV-10 concentrations (0 to 22 µg/100µL). Samples were analyzed on Roche Cobas 8000 analyzer with H index and all the chemistry assays measured. Results The presence of PV-10 in plasma significantly increased the H index, in a dose-dependent manner. Specifically, the H index increased from 14 (control plasma) to 2643 at the highest PV-10 concentration (22 µg/100µL) in pooled plasma. Among all chemistry assays, most of them were not affected by PV-10. However, certain assays like IRON have dose dependent increase with PV-10 concentration. CHO2A (Total Cholesterol), TP (Total Protein), and TRIG (Triglycerides) have shown a consistent increase trend. In contrast, the DBILI values decreased with increasing PV-10 concentrations, from 6.7 mg/dL to 0.2 mg/dL. TBIL levels also demonstrated a gradual decline from 9.6 mg/dL to 8.4 mg/dL as PV-10 concentration increased in pooled high baseline bilirubin plasma. Conclusion This study provides insights into the potential interference of PV-10 in clinical chemistry assays. The elevated H index by PV-10 is not attributed to hemolysis. It is imperative for both laboratory professionals and care providers to recognize the implications of PV-10-induced plasma discoloration and its potential interference in laboratory tests.

Anatomical compatibility of a novel total artificial heart-An in-silico study.

ShuttlePump is a novel total artificial heart (TAH) recently introduced to potentially overcome the limitations associated with the current state-of-the-art mechanical circulatory support devices intended for adults. In this study, we adapted the outflow cannulation of the previously established ShuttlePump TAH and evaluated the anatomical compatibility using the virtual implantation technique. We retrospectively assessed the anatomical compatibility of the ShuttlePump using virtual implantation techniques within 3D-reconstructed anatomies of adult heart failure patients. Additionally, we examined the impact of outflow cannula modification on the hemocompatibility of the ShuttlePump through computational fluid dynamic simulations. A successful virtual implantation in 9/11 patients was achieved. However, in 2 patients, pump interaction with the thoracic cage was observed and considered unsuccessful virtual implantation. A strong correlation (r <-0.78) observed between the measured anatomical parameters and the ShuttlePump volume exceeding pericardium highlights the importance of these measurements apart from body surface area. The numerical simulation revealed that the angled outflow cannulation resulted in a maximum pressure drop of 1.8 mmHg higher than that of the straight outflow cannulation. With comparable hemolysis index, the shear stress thresholds of angled outflow differ marginally (<5%) from the established pump model. Similar washout behavior between the pump models indicate that the curvature did not introduce stagnation zone. This study demonstrates the anatomic compatibility of the ShuttlePump in patients with biventricular failure, which was achieved by optimizing the outflow cannulation without compromising hemocompatibility. Nevertheless, clinical validation is critical to ensure the clinical applicability of these findings.

B-127 The Effect of Hemolysis on Potassium Measurement in a Community Setting: The Marching Error

Abstract Background Potassium is one of the most sensitive analytes to in-vitro hemolysis. To detect this error, modern clinical chemistry analyzers calculate the hemolysis index (HI) to estimate the degree of specimen hemolysis. Recently, Roche Diagnostics lowered the acceptable potassium HI limit from 100 to 20 and recommended laboratories avoid using specimens with an HI&amp;gt;20. The goal of this study was to determine a clinically acceptable HI cut-off for potassium at our community reference laboratory, relying on patient data from routine laboratory operation. Methods Plasma venous potassium, sodium, and HI test results from community patients measured on Roche cobas 8000 ISE and c701 modules between September 2022 to December 2023 were extracted from the Roche Infinity Middleware (n=1,101,897). Data was divided into groups based on HI which ranged from 0 to 300. The sample pool with the lowest level of hemolysis (HI≤10) was defined as the base group. Mean and standard deviation of potassium for each HI group was calculated and the difference in the mean between each group compared to the base group was calculated as both absolute and percent ΔK. Percent changes in critical values for both potassium and sodium as a function of hemolysis were calculated for each HI group. Measurement uncertainty (MU) for potassium was calculated using a top-down approach. Data were analyzed in Rstudio and Microsoft Excel. Results The vast majority of potassium specimens (83.8%) were stratified into the HI base group (HI ≤10) and 96.8 % had an HI ≤ 20, the cut-off recommended by Roche. The mean potassium level for each HI group increased as the degree of hemolysis in the specimens became more elevated. A MU-derived analytically significant shift of ΔK&amp;gt;0.1 mmol/L was observed for the bin HI 21-30. Depending on the employed total allowable error limit, clinically significant shifts in mean potassium levels were observed at HI bin 41-50 (RCPA: ΔK&amp;gt;0.2 mmol/L) or HI bin 101-150 (EFLM-derived reference change value: ΔK&amp;gt;10.1% and CLIA: ΔK&amp;gt;0.5mmol/L. The shift in patient potassium values seen as HI increased led to a change in critical results reporting frequencies. In the base group (HI≤10), 0.06% and 0.07% of results had low (&amp;lt;2.6 mmol/L) or high (&amp;gt;6.2 mmol/L) critical potassium values, respectively. When HI was 101-300, 0.00 and 15.7% of results had low or high critical potassium values. A similar comparison performed with sodium did not show the same shift in reported critical values. Linear regression of ΔK plotted vs HI produced the equation ΔK=0.0051xHI, validating the equation of Martinez-Morillo and Alvarez published previously using paired hemolyzed/non-hemolyzed potassium laboratory data. Conclusions In community patients, in-vitro hemolysis produced analytically significant errors at an HI of 20. Clinically significant errors occurred between an HI of 40-100. Past HI 100, mean ΔKs of 0.5-1.20 mmol/L were seen in our population. This shift in patient values as a function of hemolysis led to a change in critical result reporting, suggesting the generation of both factious critically high potassium results and the masking of critically low potassium results in our patient population.

A-105 Cherry-red plasma: unraveling the impact of PV-10 on chemistry assays

Abstract Background The accuracy of clinical laboratory measurements can be compromised by laboratory test interferences. PV-10 (Rose Bengal), a chemotherapy medication used in the treatment of metastatic melanoma, was observed to cause a cherry-red discoloration in plasma. This plasma color change, resembling hemolysis, raises serious concerns about potential interference in clinical laboratory tests. Our study focused on understanding the potential interference of PV-10, particularly the impact on the hemolysis index (H index) and various chemistry assays to ensure result accuracy in cancer treatment. Methods To investigate the potential interference of PV-10, pooled normal and high baseline bilirubin plasma samples were spiked with a gradient of PV-10 concentrations (0 to 22 µg/100µL). Samples were analyzed on Roche Cobas 8000 analyzer with H index and all the chemistry assays measured. Results The presence of PV-10 in plasma significantly increased the H index, in a dose-dependent manner. Specifically, the H index increased from 14 (control plasma) to 2643 at the highest PV-10 concentration (22 µg/100µL) in pooled plasma. Among all chemistry assays, most of them were not affected by PV-10. However, certain assays like IRON have dose dependent increase with PV-10 concentration. CHO2A (Total Cholesterol), TP (Total Protein), and TRIG (Triglycerides) have shown a consistent increase trend. In contrast, the DBILI values decreased with increasing PV-10 concentrations, from 6.7 mg/dL to 0.2 mg/dL. TBIL levels also demonstrated a gradual decline from 9.6 mg/dL to 8.4 mg/dL as PV-10 concentration increased in pooled high baseline bilirubin plasma. Conclusions This study provides insights into the potential interference of PV-10 in clinical chemistry assays. The elevated H index by PV-10 is not attributed to hemolysis. It is imperative for both laboratory professionals and care providers to recognize the implications of PV-10-induced plasma discoloration and its potential interference in laboratory tests.

A-098 Reducing Hemolyzed Specimen Rejection for Aspartate Aminotransferase (AST): A Quality Improvement Initiative to Further Optimize Concentration-Specific H-index Thresholds

Abstract Background Serum aspartate aminotransferase (AST) is a commonly ordered test useful for diagnosing and monitoring hepatocellular damage. The hemolysis (H) index interference threshold for the Roche Cobas AST reagent is H=20, which is the lowest of all tests on Roche chemistry platforms (Cobas c701, c502, and e801). Previous optimization studies supported the implementation of an AST concentration-specific tiered hemolysis interference threshold schema: AST&amp;lt;100 U/L (H=50), AST=100-200 U/L (H=100), AST=201-300 U/L (H=200) and AST&amp;gt;301 U/L (H=500). This schema significantly reduced redraws; however, a significant number of rejected samples were noted to have AST results within the reference interval (RI). The aim of this study was to establish an H-index threshold for samples with AST results within the RI. Methods Twelve pools of residual serum samples were created with AST concentrations ranging from 17-66 U/L. Each pool was split into 2 aliquots, receiving either 10% of a lab-produced hemolysate solution generating H-indices from 62-508 or 10% of a 0.9% saline control. Aliquots were mixed in equal portions to create a series of 5 samples with increasing hemolysis according to CLSI guideline EP-07 and analyzed in EP Evaluator. Median(interquartile range (IQR)) H-index thresholds were calculated for error limits beginning at +5 U/L and increasing incrementally (+1 U/L) to +10 U/L. Clinical cases with an H-index slightly above the hemolysis interference threshold (50≤H≤70) and results within the RIs (Male:8-48U/L; Female:8-43U/L) were reviewed by the Chemistry Resident/Fellow on-call (n=68) over a period of 8 months. Results were released with a comment if risk of clinical misinterpretation due to a falsely elevated result was low. Previous, non-hemolyzed AST results were compared within 45 days, if available, by paired-Wilcoxon test (Graphpad Prism). Results The median(range) of initial AST results in the serum pools was 20(17-66) U/L. The calculated H-index thresholds (median(IQR)) using error limits of +5, +6, +7, +8, +9, +10 U/L were 49(43-53), 56(52-63), 66(61-78), 78(72-81), 91(84-91) and 101 (96-107), respectively. All slightly hemolyzed AST results (50≤H≤70) within the RI were released with a comment upon chart review. Previously reported AST values (n=23) were compared to current (hemolyzed) concentrations and found to be statistically significantly increased relative to previous results from the same patient (median(range) difference: 3.7(-3.6-11)U/L, p=0.009). However, the median difference was &amp;lt;5U/L or 10%, the laboratory’s criteria used to define a clinically significant difference. Conclusions A median H-index limit of up to 100 can be applied to samples when AST is within the RI. The risk of misinterpretation for results with mild-moderate hemolysis was low in the cases reviewed. Sample rejection rates and reporting delays can be diminished by implementing this practice. Interpretation can be further enhanced by appending the following comment to hemolyzed samples: “Specimen was received with hemolysis slightly above the accepted threshold. This degree of hemolysis is associated with a false increase of approximately 5-10 U/L. Interpret in conjunction with other laboratory and clinical findings.”

A-345 Effect of Hemolysis on Routine Blood Gas Analytes

Abstract Background Hemolysis is a major pre-analytical concern for most laboratory analytes. Detection of hemolysis and mitigation efforts are especially important for analytes, such as potassium, with high intracellular concentrations. Routine serum and plasma chemistry tests are performed on analyzers with the capacity to detect and measure the degree of hemolysis. However, for whole blood chemistries and blood gas measurements, the instruments utilized lack this capacity. The aim of this study was to evaluate the effect of hemolysis on whole blood and blood gas analytes and to compare visual assessments of hemolysis to measured hemolysis indices (H-index). Methods Remnant whole blood samples were split into two portions and each portion was aspirated and dispensed through a syringe one or more times. For the mock portion, only the syringe was used, while the hemolyzed portion had a needle affixed to the end of the syringe. The needle provided shear stress on the red blood cells to induce hemolysis, while the mock procedure was used to assess the impact of aspirating/dispensing on the sample in the absence of hemolysis. Each portion was then analyzed on a Radiometer ABL800 series instrument, spun down, and the H-index of the plasma portion was measured on a Roche cobas 8000 instrument. Medical technologists recorded their visual assessment of the specimens, with two technologists agreeing to the categorization of the specimen as either slightly, moderately, or severely hemolyzed. Degree of hemolysis was categorized by the delta (hemolyzed - mock) of the measured H-index: slight hemolysis was defined as an H-index delta of &amp;lt;100, moderate as 100-500 and severe as &amp;gt;500. Results The effect of hemolysis, with H-indices ranging from 2 to 3861, on 13 routine blood gas analytes was studied for 85 whole blood specimens. Hemolysis had little effect on metabolites, as percent bias was within ±3% at all levels of hemolysis for glucose, creatinine, and lactate. Similarly, most cooximetry components were minimally affected, with total hemoglobin, oxyhemoglobin, carboxyhemoglobin, and oxygen saturation within ±5% bias at all levels of hemolysis. Methemoglobin had a larger overall negative bias, with slight, moderate, and severe hemolysis levels yielding percent biases of -6.6, -12.3, and -13.3%, respectively. As expected, potassium displayed a significant positive bias with increasing hemolysis, with a generally linear trend. At moderate levels of hemolysis, the average potassium bias was 24.0% and at severe levels, over 100%. Sodium and ionized calcium also displayed overall linear trends but with a negative bias. At slight, moderate, and severe levels of hemolysis, sodium had a -0.56, -1.10, and -3.96% bias, and ionized calcium had a -2.99, -5.65, and -15.5% bias respectively. Conclusions Hemolysis can falsely increase or decrease a range of blood gas analytes and lead to misinterpretation of results and adversely affect clinical decision-making. Therefore, equipping current blood gas analyzers with hemolysis detection capabilities is crucial to enable laboratories to mitigate this effect and ensure accurate results for patient care.

Hemolysis Index, Carboxyhemoglobin, and Methemoglobin for the Early Identification of Patients at Risk for Cardiac Surgery–Associated Acute Kidney Injury

Hemolysis is a contributor to CS-AKI. Biochemistry analyzers provide a hemolysis index to quantify in vitro hemolysis, a condition that can, for example, affect the accuracy of potassium concentration measurements. We aimed to assess whether the postoperative plasma level of the hemolysis index (HIpostoperative) could aid the early recognition of patients at risk for cardiac surgery-associated acute kidney injury (CS-AKI) and also to evaluate other hemolysis indicators: plasma carboxyhemoglobin (COHbpostoperative) and methemoglobin (MetHbpostoperative). One-year retrospective study. University hospital. Patients undergoing elective cardiac surgery. None. In 1090 patients, the median HIpostoperative was higher in patients who developed CS-AKI compared to patients who did not (11 mg/dL [interquartile range (IQR), 5-38 mg/dL] v 7 mg/dL [IQR, 3-16 mg/dL]; p < 0.001). HIpostoperative refined the early recognition of CS-AKI: the area under the precision-recall curve (AUPRC) for HIpostoperative was 37% (95% confidence interval [CI], 31%-42%), whereas the AUPRC associated with no discriminative power, equal to the prevalence of CS-AKI in the whole population, was 21%. Among the 611 patients with measurements for all 3 biomarkers, the AUPRC of HIpostoperative was higher than that of COHbpostoperative or MetHbpostoperative (+6.6% and +7.4% respectively; p < 0.0001 for both). Unlike COHbpostoperative or MetHbpostoperative, the incorporation of HIpostoperative into a model (trained on a sample then validated in another sample) of CS-AKI early recognition significantly enhanced its performance, with a +1.9% (95% CI, 1.6%-2.1%) increase in AUPRC (p < 0.0001). Elevated HIpostoperative represents an early alert signal for the development of CS-AKI. Our findings support the incorporation of HIpostoperative, a readily available biomarker, into predictive scores of CS-AKI.

Hemolysis analysis of centrifugal blood pump based on numerical simulation

Abstract The operation of blood pump will cause mechanical damage to red blood cells and lead to hemolysis. Based on this, CFD technology is used to simulate the three-dimensional flow field of centrifugal blood pump. According to the analysis of velocity field, pressure field and stress field; Based on the hemolysis power function model, the hemolysis performance of blood pump is predicted by Lagrange particle tracking method, and the impeller structure is adjusted to improve its flow performance and reduce the hemolysis index. The research results can provide a basis for the structural improvement and performance improvement of centrifugal heart pump.

Design Improvement for Interventional Blood Pumps Based on Flow Analysis

Abstract Interventional blood pumps serve as a crucial component for temporary mechanical circulatory support in the treatment of heart failure, specifically designed to improve blood circulation recovery and survival rate in patients undergoing treatment for acute cardiovascular diseases. This study aims to design a novel interventional blood pump with a focus on achieving exceptional hydraulic performance and superior blood compatibility based on numerical simulation, which considers the interactions between the blood pump and the upstream (drainage cannula) and downstream (aorta) flow fields, establishing a full-scale flow field analysis. For the numerical method, the Reynolds-Averaged Navier-Stokes (RANS) equations coupling with the k-ɛ turbulence model are solved. The result indicates that high shear stress exists around the leading and trailing edges of impeller blades and there is a jet at the outlet of impeller, and the blade leading and trailing edge, and the outlet of the impeller are the dominant regions for higher hemolysis occurrence. It is also noted that the presence of an interventional blood pump generates significant vortex structures within the aorta. To effectively reduce the hemolysis index, back-sweep concept is applied to this study also optimize the impeller’s leading edge. The analysis result confirms that the back swept leading edge of impeller blade helps improve the blood compatibility for interventional blood pumps.

The effects of time and anticoagulant type on hematologic values in cockatiels (Nymphicus hollandicus)

BackgroundAvian hematologic characteristics complicate evaluation; therefore, complete blood cell counts require manual analysis for best accuracy. Furthermore, the quality of samples may be affected by prolonged shipment. MethodsBlood was collected from the right jugular vein of twenty-four, 7-year-old (14 male, 10 female), wild-type cockatiels (Nymphicus hollandicus). Smears were prepared using fresh, untreated blood. The remainder was divided into dipotassium ethylenediaminetetraacetic acid (EDTA) and lithium heparin microtainers. A hematocrit tube and blood smear were prepared at baseline, 24, 48, and 72 hours after venipuncture. Packed cell volume (PCV), total solids (TS), estimated white blood cell (WBC) count, WBC differential (heterophils, lymphocytes, monocytes, eosinophils, basophils), hemolysis index (HI), and preparation quality were assessed and compared to baseline. After log transformation, the effects of anticoagulants across time points were compared. ResultsHeparinized samples had significant differences in WBC, heterophil, and lymphocyte counts at 48 hours, and PCV and TS at 72 hours compared to baseline. There was a positive proportional bias in PCV and TS from EDTA anticoagulant samples at 24, 48, and 72 hours, and from heparinized samples at 48 and 72 hours compared to baseline. The EDTA samples had increased PCV and TS compared to heparin at all time points, and higher WBC and heterophil counts at 48 hours compared to baseline. A type II methodological error cannot be excluded. ConclusionThese results suggest that the anticoagulant used and time spent in anticoagulant alters hematologic values in cockatiels, which may have significant clinical implications. The importance of sample processing within 24 hours and anticoagulant-specific reference intervals for hematologic variables should be considered.

Optimization of a centrifugal blood pump in terms of hemolysis index and hydraulic efficiency

Optimization of a centrifugal blood pump in terms of hemolysis index and hydraulic efficiency

Verifying the nonreporting hemolysis index for potassium, phosphate, magnesium, AST, LDH, iron, CA 19-9, and vitamin D, using Beckman Coulter AU5800 and DxI800 automated analyzers.

Hemolysis is a common reason for nonreporting results in biochemistry and is measured using the hemolysis index (HI), with nonreporting limits set for analytes by manufacturers. To verify the nonreporting HI limit for potassium, phosphate, magnesium, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), iron, CA19-9, and vitamin D on the Beckman Coulter AU5800/DxI800 analyzers. Hemolysate was created from EDTA-lined tubes of whole blood using an osmotic shock procedure. The hemolysate underwent serial dilutions with saline and was spiked in paired serum. The delta changes in HI and analyte concentration were measured, assessed using regression analysis, and compared against calculated reference change values. A linear relationship between increasing HI and increasing analyte concentration (R2 > 0.9) was observed for potassium (y = 0.8864x), phosphate (y = 0.1079x), magnesium (y = 0.0678x), AST (y = 29.035x), and LDH (y = 350x). Increasing HI values did not have a linear effect on iron (y = -0.2544x), CA19-9 (y = 2.7019x), or vitamin D (y = 8.036x) concentrations. The results from this experiment support increasing the HI nonreporting limit to 100 mg/dL for potassium; 200 mg/dL for magnesium; and 300 mg/dL for phosphate, CA19-9, and vitamin D. The iron assay is not affected by hemolysis as high as 500 mg/dL. The current HI nonreporting limit of 50 mg/dL is appropriate for LDH.

Development of an equation to predict delta bilirubin levels using machine learning

ObjectiveDelta bilirubin (albumin-covalently bound bilirubin) may provide important clinical utility in identifying impaired hepatic excretion of conjugated bilirubin, but it cannot be measured in real-time for diagnostic purposes in clinical laboratories. MethodsA total of 210 samples were collected, and their delta bilirubin levels were measured four times using high-performance liquid chromatography. Data collected included age, sex, diagnosis code, delta bilirubin, total bilirubin, direct bilirubin, total protein, albumin, globulin, aspartate aminotransferase, alanine transaminase, alkaline phosphatase, gamma-glutamyl transferase, lactate dehydrogenase, hemoglobin, serum hemolysis value, hemolysis index, icterus value (Iv), icterus index (Ii), lipemia value (Lv), and lipemia index. To conduct feature selection and identify the optimal combination of variables, linear regression machine learning was performed 1,000 times. ResultsThe selected variables were total bilirubin, direct bilirubin, total protein, albumin, hemoglobin, Iv, Ii, and Lv. The best predictive performance for high delta bilirubin concentrations was achieved with the combination of albumin-direct bilirubin-hemoglobin-Iv-Lv. The final equation composed of these variables was as follows: delta bilirubin = 0.35 × Iv + 0.05 × Lv − 0.23 × direct bilirubin − 0.05 × hemoglobin − 0.04 × albumin + 0.10. ConclusionThe equation established in this study is practical and can be easily applied in real-time in clinical laboratories.

Stability of adrenocorticotropic hormone in whole blood samples: effects of storage conditions.

Adrenocorticotropic hormone (ACTH) is a peptide secreted by pituitary gland that plays an important role in regulating cortisol secretion. Its determination is difficult because of instability in whole blood. Several factors that influence ACTH stability in blood before analysis have been identified: temperature, hemolysis, time to centrifugation and presence of protease inhibitors. Published results on ACTH whole blood stability seem contradictory. We performed a stability study in 10 healthy volunteers. Three different conditions were tested: ethylenediaminetetraacetic acid (EDTA) at 4 °C, EDTA + aprotinin at 4 °C, EDTA + aprotinin at room temperature. Stability was evaluated for 8 hours. Adrenocorticotropic hormone measurements and hemolysis index were performed respectively on Cobas e602 and c701 (Roche Diagnostics, Mannheim, Germany). We compared percentage deviations with total change limit using a threshold of 7.5%. We showed that ACTH is stable 8 hours with EDTA at 4 °C, 4 hours with EDTA + aprotinin at 4 °C and 2 hours with EDTA + aprotinin at 22 °C. Aprotinin does not appear to give ACTH greater stability but can be used without exceeding 4 hours at 4 °C. Refrigerated pouch transport also seems to be more appropriate for ACTH in whole blood.

Synthesis and bio-medical applications of multifunctional phosphorester cyclic amide anchored sterculia network

The main focus of the present research is to design network hydrogels derived from natural polymers to promote a sustainable future. Multifunctional hydrogels were prepared by combining sterculia gum (SG), phosphorester -cyclic amide polymers for bio-medical applications including drug delivery (DD). The antibiotic drug ceftriaxone was incorporated into hydrogels to enhance wound healing potential. The surface morphology of copolymers was investigated by using FESEM and AFM techniques. FTIR and 13C NMR spectroscopic techniques provided insight into the formation of network structures. In FTIR analysis, distinctive bands were identified: at 1649 cm−1 attributed to CO stretching of the cyclic amide of PVP, at 1147 cm−1 and 974 cm−1 representing PO stretching and P-O-C of poly(BMEP), respectively. In the 13C NMR spectrum, a prominent peak at 63.272 ppm revealed the presence of (O-CH2) linkage of poly(BMEP). XRD demonstrated amorphous characteristics of hydrogels. The interactions of copolymer with blood, bio-membrane and encapsulated drug illustrated their biocompatibility, bio-adhesion and controlled DD properties. The dressings expressed a hemolytic index value of 2.58 ± 0.03 %. The hydrogels exhibited mucoadhesive character, revealed from the adhesion force of 50.0 ± 5 mN needed to separate polymer dressing from the mucosa. Dressings exhibited antioxidant properties and displayed 33.73 ± 0.3 % radical scavenging in the DPPH assay. Protein adsorption test of copolymer illustrated 9.48 ± 0.970 % of albumin adsorption. The tensile strength of the dressing was found 0.54 ± 0.03 N mm−2 while the burst strength 9.92 ± 0.27 N was observed. The sustained release of the drug was provided by supra-molecular interactions. Drug release followed a non-Fickian diffusion mechanism and the release profile was best described by the Higuchi kinetic model. Additionally, hydrogel dressings revealed permeability to H2O vapors and O2 and antimicrobial activity. These findings suggest the suitability of sterculia gum-based hydrogels for DD uses.