Search

Background: Veno‐arterial extracorporeal membrane oxygenation (V‐A ECMO) is increasingly utilized in pediatric patients. Failure to recognize membrane oxygenator failure can lead to critical complications due to rapid deterioration of membrane oxygenator function. Therefore, identifying the predictors for membrane oxygenator exchange is crucial. However, risk factors for membrane oxygenator exchange in pediatric V‐A ECMO remain unclear; therefore, this study aimed to evaluate these risk factors. Methods: This retrospective cohort study enrolled all pediatric patients aged <18 years who received V‐A ECMO between August 2018 and July 2023 at a tertiary‐care pediatric hospital in Japan. The Cox proportional hazards model was used to evaluate the predictors of membrane oxygenator failure within 72 h after initiation. Results: During the study period, membrane oxygenator failure occurred in 18/55 (32.7%) children within 72 h; membrane oxygenator failure within 72 h occurred in 4/29 (13.8%) and 14/26 (53.8%) in the groups with ratio of blood flow divided by the blood flow limit of the membrane oxygenator (B/L) of <0.5 and ≥0.5, respectively (adjusted hazards ratio, 4.97 [95% confidence interval, 1.33–18.5]; p = 0.017). After adjusting for delta pressure of the oxygenator, an increase in body weight and aspartate aminotransferase levels were associated with an increase in early membrane oxygenator failure. Conclusions: This retrospective study demonstrated that a B/L ratio >0.5, an increase in body weight, and elevated aspartate aminotransferase were independent risk factors for early membrane oxygenator failure in pediatric V‐A ECMO. However, a prospective multicenter study with an appropriate sample size is warranted to mitigate potential bias, and enhance generalizability for further investigation of the association between a B/L ratio and early membrane oxygenator failure. [ABSTRACT FROM AUTHOR]

Blood clot formation inside the membrane oxygenator (MO) remains a risk in extracorporeal membrane oxygenation (ECMO). It is associated with thromboembolic complications and normally detectable only at an advanced stage. Established clinical monitoring techniques lack predictive capabilities, emphasizing the need for refinement in MO monitoring towards an early warning system. In this study, an MO was modified by integrating four sensor fibers in the middle of the hollow fiber mat bundle, allowing for bioimpedance measurement within the MO. The modified MO was perfused with human blood in an in vitro test circuit until fulminant clot formation. The optical analysis of clot residues on the extracted hollow fibers showed a clot deposition area of 51.88% ± 14.25%. This was detectable via an increased bioimpedance signal with a significant increase 5 min in advance to fulminant clot formation inside the MO, which was monitored by the clinical gold standard (pressure difference across the MO (dp-MO)). This study demonstrates the feasibility of detecting clot growth early and effectively by measuring bioimpedance within an MO using integrated sensor fibers. Thus, bioimpedance may even outperform the clinical gold standard of dp-MO as a monitoring method by providing earlier clot detection. [ABSTRACT FROM AUTHOR]

Introduction: The membrane oxygenator in extracorporeal circulation circuits is coated with acrylate-copolymer (ACP) or immobilized heparin (IHP) to enhance hemocompatibility. To evaluate the relative features of both coatings, we compared blood components circulated in the circuits with ACP-and IHP-coated membranes in vitro using whole human blood. Methods: Whole human blood was heparinized and circulated in two experimental circuits with an ACP-coated reservoir, tubes, and an ACP- or IHP-coated membrane. Platelet (PLT) counts and the amount of total protein (TP), complement component 3 (C3), and complement component 4 (C4) were measured at 0, 8, 16, 24, and 32 h in each experiment (n = 5). Results: The PLT count at 0-h circulation was lower in the IHP-coated than in the ACP-coated circuits (p = 0.034); however, no significant difference was observed at other time points. Reduction in TP at 8-h and 16-h circulation and in C3 at 32-h circulation was lesser in the ACP-coated than in the IHP-coated circuits (p = 0.004, 0.034, and 0.027, respectively); reduction in TP and C3 at other time points and C4 at each time point was not significantly different. There were significant interactions between coating type and circulation duration in the PLT, TP, and C3 transitions (p = 0.008, 0.020, and 0.043, respectively). Conclusions: Our findings suggest that ACP-coated membranes can prevent the initial drop in PLT count and C3 consumption over 32 h, whereas IHP-coated membranes could not prevent this drop in extracorporeal circulation. Therefore, ACP-coated membranes are suitable for short- and long-term extracorporeal life support. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Clinical & Cardiovascular Perfusion / Türk Klinik ve Kardiyovasküler Perfüzyon Dergisi is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Blood clot formation inside the membrane oxygenator (MO) remains a risk in extracorporeal membrane oxygenation (ECMO). It is associated with thromboembolic complications and normally detectable only at an advanced stage. Established clinical monitoring techniques lack predictive capabilities, emphasizing the need for refinement in MO monitoring towards an early warning system. In this study, an MO was modified by integrating four sensor fibers in the middle of the hollow fiber mat bundle, allowing for bioimpedance measurement within the MO. The modified MO was perfused with human blood in an in vitro test circuit until fulminant clot formation. The optical analysis of clot residues on the extracted hollow fibers showed a clot deposition area of 51.88% ± 14.25%. This was detectable via an increased bioimpedance signal with a significant increase 5 min in advance to fulminant clot formation inside the MO, which was monitored by the clinical gold standard (pressure difference across the MO (dp-MO)). This study demonstrates the feasibility of detecting clot growth early and effectively by measuring bioimpedance within an MO using integrated sensor fibers. Thus, bioimpedance may even outperform the clinical gold standard of dp-MO as a monitoring method by providing earlier clot detection.

The occurrence of thrombus formation within an extracorporeal membrane oxygenator is a common complication during extracorporeal membrane oxygenation therapy and can rapidly result in a life-threatening situation due to arterial thromboembolism, causing stroke, pulmonary embolism, and limb ischemia in the patient. The standard clinical practice is to monitor the pressure at the inlet and outlet of oxygenators, indicating fulminant, obstructive clot formation indicated by an increasing pressure difference (ΔP). However, smaller blood clots at early stages are not detectable. Therefore, there is an unmet need for sensors that can detect blood clots at an early stage to minimize the associated thromboembolic risks for patients. This study aimed to evaluate if forward scattered light (FSL) measurements can be used for early blood clot detection and if it is superior to the current clinical gold standard (pressure measurements). A miniaturized in vitro test circuit, including a custom-made test chamber, was used. Heparinized human whole blood was circulated through the test circuit until clot formation occurred. Four LEDs and four photodiodes were placed along the sidewall of the test chamber in different positions for FSL measurements. The pressure monitor was connected to the inlet and the outlet to detect changes in ΔP across the test chamber. Despite several modifications in the LED positions on the test chamber, the FSL measurements could not reliably detect a blood clot within the in vitro test circuit, although the pressure measurements used as the current clinical gold standard detected fulminant clot formation in 11 independent experiments. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Clot formation inside a membrane oxygenator (MO) due to blood-to-foreign surface interaction represents a frequent complication during extracorporeal membrane oxygenation. Since current standard monitoring methods of coagulation status inside the MO fail to detect clot formation at an early stage, reliable sensors for early clot detection are in demand to reduce associated complications and adverse events. Bioimpedance analysis offers a monitoring concept by integrating sensor fibers into the MO. Herein, the feasibility of clot detection via bioimpedance analysis is evaluated. A custom-made test chamber with integrated titanium fibers acting as sensors was perfused with heparinized human whole blood in an in vitro test circuit until clot formation occurred. The clot detection capability of bioimpedance analysis was directly compared to the pressure difference across the test chamber (ΔP-TC), analogous to the measurement across MOs (ΔP-MO), the clinical gold standard for clot detection. We found that bioimpedance measurement increased significantly 8 min prior to a significant increase in ΔP-TC, indicating fulminant clot formation. Experiments without clot formation resulted in a lack of increase in bioimpedance or ΔP-TC. This study shows that clot detection via bioimpedance analysis under flow conditions in a blood-perfused test chamber is generally feasible, thus paving the way for further investigation. [ABSTRACT FROM AUTHOR]

The occurrence of thrombus formation within an extracorporeal membrane oxygenator is a common complication during extracorporeal membrane oxygenation therapy and can rapidly result in a life-threatening situation due to arterial thromboembolism, causing stroke, pulmonary embolism, and limb ischemia in the patient. The standard clinical practice is to monitor the pressure at the inlet and outlet of oxygenators, indicating fulminant, obstructive clot formation indicated by an increasing pressure difference (ΔP). However, smaller blood clots at early stages are not detectable. Therefore, there is an unmet need for sensors that can detect blood clots at an early stage to minimize the associated thromboembolic risks for patients. This study aimed to evaluate if forward scattered light (FSL) measurements can be used for early blood clot detection and if it is superior to the current clinical gold standard (pressure measurements). A miniaturized in vitro test circuit, including a custom-made test chamber, was used. Heparinized human whole blood was circulated through the test circuit until clot formation occurred. Four LEDs and four photodiodes were placed along the sidewall of the test chamber in different positions for FSL measurements. The pressure monitor was connected to the inlet and the outlet to detect changes in ΔP across the test chamber. Despite several modifications in the LED positions on the test chamber, the FSL measurements could not reliably detect a blood clot within the in vitro test circuit, although the pressure measurements used as the current clinical gold standard detected fulminant clot formation in 11 independent experiments.

Abstract Background Extracorporeal membrane oxygenation (ECMO) has gained widespread acceptance for the treatment of critically ill patients suffering from cardiac and/or respiratory failure. Various animal models have been developed to investigate the adverse effects induced by ECMO. Different membrane oxygenators have been used with varying priming volumes and membrane surfaces (Micro-1, small animal membrane oxygenator (SAMO)). Methods Sixteen male Lewis rats (350–400 g) were randomly assigned to receive ECMO with Micro-1 or SAMO (n = 8, respectively). Venoarterial ECMO was established after cannulation of the femoral artery and the jugular vein. The cardiac output was measured using a left-ventricular conductance catheter. The oxygen fraction of the ECMO was set to 1.0, 0.75, 0.5 and 0.21 after a stabilisation period of 15 min. Further, arterial blood gas analyses were performed at baseline, and during the first hour every 15 min after commencing the ECMO, and subsequently every 30 min. Dilutional anaemia was calculated using haemoglobin concentration at baseline, and 15 min after the start of ECMO therapy. Moreover, inflammation was determined by measuring tumour necrosis factor alpha, interleukin-6 and -10 at baseline and every 30 min. Results Animals of the Micro-1 group showed a significantly lower dilutional anaemia (ΔHaemoglobin t0 – t0.25: SAMO 6.3 [5.6–7.5] g/dl vs. Micro-1 5.6 [4.6–5.8] g/dl; p = 0.028). Further, significantly higher oxygen partial pressure was measured in the SAMO group, at an oxygen fraction of 0.75, 0.5 and 0.21 (380 [356–388] vs. 314 [263–352] mmHg, p = 0.002; 267 [249–273] mmHg vs. 197 [140–222] mmHg, p = 0.002; 87 [82–106] mmHg vs. 76 [60–79] mmHg, p = 0.021, respectively). However, no differences were found regarding the oxygen fraction of 1.0, in terms of carbon-dioxide partial pressure and cardiac output. Moreover, in the Micro-1 group tumour necrosis factor alpha was increased after 60 min and interleukin-6 after 120 min. Conclusion While the dilutional anaemia was increased after commencing the ECMO, the oxygenation was augmented in the SAMO group. The inflammatory response was elevated in the Micro-1 group.

Clot formation inside a membrane oxygenator (MO) due to blood-to-foreign surface interaction represents a frequent complication during extracorporeal membrane oxygenation. Since current standard monitoring methods of coagulation status inside the MO fail to detect clot formation at an early stage, reliable sensors for early clot detection are in demand to reduce associated complications and adverse events. Bioimpedance analysis offers a monitoring concept by integrating sensor fibers into the MO. Herein, the feasibility of clot detection via bioimpedance analysis is evaluated. A custom-made test chamber with integrated titanium fibers acting as sensors was perfused with heparinized human whole blood in an in vitro test circuit until clot formation occurred. The clot detection capability of bioimpedance analysis was directly compared to the pressure difference across the test chamber (ΔP-TC), analogous to the measurement across MOs (ΔP-MO), the clinical gold standard for clot detection. We found that bioimpedance measurement increased significantly 8 min prior to a significant increase in ΔP-TC, indicating fulminant clot formation. Experiments without clot formation resulted in a lack of increase in bioimpedance or ΔP-TC. This study shows that clot detection via bioimpedance analysis under flow conditions in a blood-perfused test chamber is generally feasible, thus paving the way for further investigation.

Extracorporeal blood oxygenation has become an alternative to supply O2 and remove CO2 from the bloodstream, especially when mechanical ventilation provides insufficient oxygenation. The use of a membrane oxygenator offers the advantage of lower airway pressure than a mechanical ventilator to deliver oxygen to the patient's blood. However, research and development are still needed to find appropriate membrane materials, module configuration, and to optimize hydrodynamic conditions for achieving high efficient gas transfer and excellent biocompatibility of the membrane oxygenator. This review aims to provide a comprehensive description of the basic principle of the membrane oxygenator and its development. It also discusses the role and challenges in the use of membrane oxygenators for extracorporeal oxygenation on respiratory and cardiac failure patients. [ABSTRACT FROM AUTHOR]

The modification of membrane oxygenators to minimize protein adsorption onto the surface is often accompanied by the loss of membrane performance. This study aims to explore polyethersulfone (PES) as a new material for membrane oxygenator applications and to assess its potentials. Accordingly, different modification techniques are applied to improve surface properties of PES membranes. To achieve this goal, two separate modification methods including incorporation of TiO2 into the membrane matrix as well as grafting polyethylene glycol (PEG) through oxygen plasma treatment are developed and the effects are examined. The results reveal that protein adsorption to the nanocomposite membrane containing 0.50 wt. % TiO2 and the grafted membrane decreased by 47 and 31%, respectively. In terms of performance, permeability and oxygen transfer rate of all modified membranes exceeded 808 GPU and 2.7 × 10−4 mol·m−2·s−1, respectively. Contact angle analysis revealed signs of hydrophilicity enhancement of membranes after modifications. The findings suggest that upon proper modifications, membranes based on PES could be considered as promising candidates for membrane oxygenator applications and deserves further investigations. [ABSTRACT FROM AUTHOR]

Chronic respiratory diseases are the third most frequent cause of death worldwide. However, the limited availability of transplantable organs led to an increased research effort in artificial lung systems. Current artificial lung systems use hollow fibre membrane-based oxygenators. Historic oxygenators using a direct liquid-gas or liquid-liquid interface outperformed todays hollow-fibre technology in terms of gas-transfer. However, these approaches were no longer pursued due to risk of embolization by gas or liquid droplet formation in the blood stream. The herein presented approach of a membrane-supported liquid-liquid oxygenator combines todays hollow-fibre technology with historic liquid-liquid approaches to achieve a stable interface without the risk of embolization but with the advantages of a higher gas-transfer and a decreasing foreign membrane surface of the oxygenator. Perfluoro- n -hexane was chosen as a hemocompatible carrier fluid for the presented liquid-liquid approach. In the proof-of-principle oxygenator, O2 and CO2 gas-transfers were measured to be 1.83 mmol O2 and 1.34 mmol CO2 , respectively. No Perfluoro- n -hexane droplets were detected in the blood after the experiment. This study demonstrates the proof of principle of a new membrane-supported liquid-liquid oxygenator. [Display omitted] • An approach for efficient simulation of liquid-liquid oxygenation by using a hollow fibre membrane is presented. • Liquid-liquid interaction between Perfluorocarbon liquid and blood was successfully investigated. • Washout of droplets into the bloodstream was prevented. [ABSTRACT FROM AUTHOR]

Extracorporeal membrane oxygenation (ECMO) is a respiratory or cardiac life support consisting of a vascular access cannula, a blood pump, and an artificial lung that removes carbon dioxide and adds oxygen. Venovenous ECMO is typically used for various forms of critical respiratory failure including severe pneumonia due to the new coronavirus, whereas venoarterial (VA) ECMO sees greater utilization in the patient with heart failure such as cardiac arrest or other clinical states in which cardiac dysfunction is a significant component of illness. The transference of gases occurs due to diffusion across the hollow fiber membranes packed in the module of the oxygenator. Emergence of microporous membrane tremendously enhanced gas diffusion, and currently microporous membrane with a dense layer on the blood-contacting surface is widely used for longer period of usage over weeks. As the usage period for respiratory failure is getting longer, development of more durable ECMO system is required in the future. [ABSTRACT FROM AUTHOR]

The Mortality in Cardiac Surgery Randomized Controlled Trial of Volatile Anesthetics (MYRIAD) demonstrated that cardiac surgery with either volatile anesthesia or intravenous anesthesia techniques can be comparable with respect to morbidity and mortality. Maintaining anesthesia during cardiopulmonary bypass (CPB) with either approach requires appreciation of the nuances that are unique to each. This narrative review addresses these technical challenges and other considerations. [ABSTRACT FROM AUTHOR]

In this study, a commercial polyimide is examined in the capacity of membrane oxygenator. The effects of polymer concentration, cosolvent, and nonsolvent additives in dope solution on the performance and morphology of membranes are investigated. In order to improve the performance, surface modification is carried out by using plasma‐enhanced chemical vapor deposition. The obtained results reveal that CO2 permeance decreased from 495 to 78 GPU upon increasing Matrimid concentration at constant tetrahydrofuran (THF) and ethanol (EtOH) concentrations. It was also found that increasing nonsolvent concentration as well as decreasing cosolvent concentration in dope led to increase in membrane gas permeance. According to morphological characterizations, increase in polymer concentration resulted in transformation of membranes from porous into spongy like microstructure with formation of a denser skin layer. In addition, membrane porosity and mean pore size reduced by increasing THF and decreasing EtOH concentrations. On the other hand, plasma treatment successfully introduced fluorine groups onto the membrane surface which promoted biocompatibility of the membranes. Energy‐dispersive X‐ray spectroscopy results revealed that fluorination of membrane surface was attained up to 23% and contact angle of membrane enhanced up to 120°. Membrane permeance was also increased slightly upon modification. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48824. [ABSTRACT FROM AUTHOR]

Background: Extracorporeal membrane oxygenation (ECMO) has gained widespread acceptance for the treatment of critically ill patients suffering from cardiac and/or respiratory failure. Various animal models have been developed to investigate the adverse effects induced by ECMO. Different membrane oxygenators have been used with varying priming volumes and membrane surfaces (Micro-1, small animal membrane oxygenator (SAMO)).Methods: Sixteen male Lewis rats (350-400 g) were randomly assigned to receive ECMO with Micro-1 or SAMO (n = 8, respectively). Venoarterial ECMO was established after cannulation of the femoral artery and the jugular vein. The cardiac output was measured using a left-ventricular conductance catheter. The oxygen fraction of the ECMO was set to 1.0, 0.75, 0.5 and 0.21 after a stabilisation period of 15 min. Further, arterial blood gas analyses were performed at baseline, and during the first hour every 15 min after commencing the ECMO, and subsequently every 30 min. Dilutional anaemia was calculated using haemoglobin concentration at baseline, and 15 min after the start of ECMO therapy. Moreover, inflammation was determined by measuring tumour necrosis factor alpha, interleukin-6 and -10 at baseline and every 30 min.Results: Animals of the Micro-1 group showed a significantly lower dilutional anaemia (ΔHaemoglobin t0 - t0.25: SAMO 6.3 [5.6-7.5] g/dl vs. Micro-1 5.6 [4.6-5.8] g/dl; p = 0.028). Further, significantly higher oxygen partial pressure was measured in the SAMO group, at an oxygen fraction of 0.75, 0.5 and 0.21 (380 [356-388] vs. 314 [263-352] mmHg, p = 0.002; 267 [249-273] mmHg vs. 197 [140-222] mmHg, p = 0.002; 87 [82-106] mmHg vs. 76 [60-79] mmHg, p = 0.021, respectively). However, no differences were found regarding the oxygen fraction of 1.0, in terms of carbon-dioxide partial pressure and cardiac output. Moreover, in the Micro-1 group tumour necrosis factor alpha was increased after 60 min and interleukin-6 after 120 min.Conclusion: While the dilutional anaemia was increased after commencing the ECMO, the oxygenation was augmented in the SAMO group. The inflammatory response was elevated in the Micro-1 group. [ABSTRACT FROM AUTHOR]

Purpose: To report a technique of global cerebral embolic protection (CEP) designed for use during thoracic endovascular aortic repair (TEVAR). Technique: Arterial cannulas are inserted percutaneously in the right axillary artery (12-F) and left common carotid artery (LCCA; 10-F) to provide normothermic antegrade cerebral perfusion during TEVAR with neuromonitoring. Inferior vena cava blood is drawn using a 19-F femoral cannula, filtered, oxygenated, and delivered through independent roller pumps to the arterial cannulas. Static CEP is obtained by balloon occlusion of the 3 aortic arch branches proximally, resulting in complete separation of aortic and cerebral blood flow; static CEP is used during aortic endograft delivery and deployment. Dynamic CEP, obtained by creating flow reversal in the innominate artery and proximal LCCA, is used at all other times. Successful use of this CEP technique is illustrated in a patient with shaggy aorta undergoing fenestrated total arch TEVAR. Conclusion: Percutaneous normothermic bilateral antegrade cerebral perfusion provides effective CEP during TEVAR. [ABSTRACT FROM AUTHOR]

Currently, hollow fiber membranes are the standard technology for extracorporeal membrane oxygenators. Apart from the inevitable contact of the circulating blood with the artificial material, a suboptimal flow distribution within the oxygenator favors thrombus formation which leads to a rapid loss of gas exchange capacity. The current advancement in additive manufacturing allows the design of three-dimensional membrane-structures, based on triply periodic minimal surfaces (TPMS). One of their unique advantages is local geometry variation to manipulate the flow distribution. But how this anisotropy influences the overall device performance is non-trivial and requires numerical simulation. The aim of this study was to develop a reduced order model (ROM) that is able to efficiently predict three-dimensional flow distribution and gas transfer inside TPMS-structures. We performed a parametric study using a validated micro scale computational fluid dynamics (CFD) model. Afterwards, two different modeling approaches of Sherwood-correlations and artificial neural networks (NN) were compared to characterize flow and mass transfer from the simulated data. To create the ROM, the NN modeling strategy was then implemented into a porous medium CFD model. The developed ROM was also validated. Finally, an anisotropic TPMS-membrane-structure was compared numerically with an isotropic predicate. The NN fitting strategy showed superior accuracy over the Sherwood-correlations for characterizing mass transfer in TPMS-structures. With the ROM, the gas transfer rates of oxygen and carbon dioxide from the micro CFD model could be predicted within relative root mean squared errors (RRMSE) of 2.7% and 5.1%. The pressure drop in the experiments was predicted with an RRMSE accuracy of 7.6%. In comparison with the isotropic TPMS-structure, the anisotropic structure showed a homogenized flow distribution and increased gas transfer rates of 4% to 5% for oxygen and 2.3% to 7.4% for carbon dioxide at the simulated flow rates. • Approach for efficient simulation of anisotropic membrane-structures is presented. • Oxygen transport in blood accurately characterized using neural networks. • Prediction of gas transfer rates and pressure drops within 8% relative accuracy. • Anisotropic membrane-structures offer homogenized flow and increased mass transfer. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to provide an alternative treatment option to lung transplantation for patients with end-stage lung disease, we aim for the development of an implantable biohybrid lung (BHL), based on hollow fiber membrane (HFM) technology used in extracorporeal membrane oxygenators. Complete hemocompatibility of all blood contacting surfaces is crucial for long-lasting BHL durability and can be achieved by their endothelialization. Autologous endothelial cells (ECs) would be the ideal cell source, but their limited proliferation potential excludes them for this purpose. As induced pluripotent stem cell-derived ECs enable the generation of a large number of ECs, we assessed and compared their capacity to form a viable and confluent monolayer on HFM, while indicating physiologic EC-specific anti-thrombogenic and anti-inflammatory properties. ECs were generated from three different human iPSC lines, and seeded onto fibronectin-coated poly-4-methyl-1-pentene (PMP) HFM. Following phenotypical characterization, ECs were analyzed for their thrombogenic and inflammatory behavior with or without TNFα induction, using FACS and qRT-PCR. Complementary, leukocyte- and platelet adhesion assays were carried out. The capacity of the iPSC-ECs to reendothelialize cell-free monolayer areas was assessed in a scratch assay. ECs sourced from umbilical cord blood (hCBECs) were used as control. iPSC-derived ECs formed confluent monolayers on the HFM and showed the typical EC-phenotype by expression of VE-cadherin and collagen-IV. A low protein and gene expression level of E-selectin and tissue factor was detected for all iPSC-ECs and the hCBECs, while a strong upregulation of these markers was noted upon stimulation with TNFα. This was in line with the physiological and strong induction of leukocyte adhesion detected after treatment with TNFα, iPSC-EC and hCBEC monolayers were capable of reducing thrombocyte adhesion and repopulating scratched areas. iPSCs offer the possibility to provide patient-specific ECs in abundant numbers needed to cover all blood contacting surfaces of the BHL with a viable, non-thrombogenic and non-inflammatory monolayer. iPSC-EC clones can differ in terms of their reendothelialization rate, and pro-inflammatory response. However, a less profound inflammatory response may even be advantageous for BHL application. With the proven ability of the seeded iPSC-ECs to reduce thrombocyte adhesion, we expect that thrombotic events that could lead to BHL occlusion can be avoided, and thus, justifies further studies on enabling BHL long-term application.

Introduction: To understand the behavior of platelet volume indices and the von Willebrand factor (VWF), in vitro experiments using whole human blood were performed with extracorporeal circulation (ECC) circuits, including membrane oxygenators coated with acrylate copolymer (ACP) or immobilized heparin (IHP)., Methods: Heparinized blood was circulated through two distinct experimental circuits: an ACP-coated reservoir and tubes, as well as membranes coated with either ACP or IHP (comprising five pieces of each type). The platelet distribution width, mean platelet volume (MPV), platelet large cell ratio (P-LCR), VWF quantity (VWFQ), and VWF activity (VWFA) were measured at 0, 8, 16, 24, and 32 h in each experiment. A two-way analysis of variance (ANOVA) was performed to determine whether the coating type or circulation duration affected the transition of each measurement., Results: Two-way ANOVA indicated that the transitions of MPV, P-LCR, and VWFA were significantly affected by the circulation duration ( p  = 0.030, 0.001, and <0.001, respectively) and that the transitions of VWFQ and VWFA were significantly affected by the coating type ( p  = 0.022 and 0.006, respectively). Factor interactions between the coating type and circulation duration were not observed for each transition ( p  > 0.05)., Conclusions: Our findings suggest that P-LCR is a good index for platelet activation in blood-circulating ECC and that VWFA and VWFQ are significantly attenuated in blood-circulating ECC with ACP-coated membranes, indicating the advantage of IHP coating regarding platelet activation., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The oxygenation membrane, a core material of extracorporeal membrane oxygenation (ECMO), is facing challenges in balancing anti-plasma leakage, gas exchange efficiency, and hemocompatibility. Here, inspired by the asymmetric structural features of alveolus pulmonalis, a novel triple-functional membrane for blood oxygenation with a Janus architecture is proposed, which is composed of a hydrophobic polydimethylsiloxane (PDMS) layer to prevent plasma leakage, an ultrathin polyamide layer to enhance gas exchange efficiency with a CO 2 :O 2 permeance ratio of ≈10.7, and a hydrophilic polyzwitterionic layer to improve the hemocompatibility. During the simulated ECMO process, the Janus oxygenation membrane exhibits excellent performance in terms of thrombus formation and plasma leakage prevention, as well as adequate O 2 transfer rate (17.8 mL min -1 m -2 ) and CO 2 transfer rate (70.1 mL min -1 m -2 ), in comparison to the reported oxygenation membranes. This work presents novel concepts for the advancement of oxygenation membranes and demonstrates the application potential of the asymmetric triple-functional Janus oxygenation membrane in ECMO., (© 2023 Wiley-VCH GmbH.)

Oxygenation membranes operate as indirectly contacting barriers between blood and gas in extracorporeal membrane oxygenation (ECMO), improving oxygenation and removing carbon dioxide from blood. However, the low gas exchange efficiency of the current poly (4-methyl-1-pentene) (PMP) artificial lung membrane results in a high prime volume. Facilitated transport membrane is a fascinating strategy to construct high-performance membranes for blood-gas exchange. This study put forward hybrid strategy by using metal-covalent organic frameworks (MCOFs) to construct facilitated transport membrane of PMP flat membranes and hollow fiber membranes (HFMs) via thermally induced phase separation (TIPS) to achieve facilitated blood-gas exchange. Cu-TAPB-COF nanosheets (CuCON) with framework structure and abundant active metal sites were synthetized and introduced into PMP to construct hybrid oxygenation membranes, reducing the resistance of gas exchange channels and ensuring the high affinity toward CO 2 and O 2. Cu+ and benzene rings existed in aromatic skeleton as well as the tunable structure, that could ensure the stability of MCOF and the uniform distribution of facilitated transport sites. The prepared PMP-CuCON-1 HFMs exhibited O 2 and CO 2 exchange rate of ∼467.5 ml min−1 m−2 and ∼309.1 ml min−1 m−2 in blood gas exchange process, which was 143.1% and 261.3% higher than the commercial PMP HFM, respectively. Asymmetric structure ensured resistance to plasma leakage for more than two weeks, and Cu+ kept stable in CuCON and hybrid membranes. The hybrid membrane exhibited superior blood-gas exchange performance and good hemocompatibility, possessing great potential for application. [Display omitted] • PMP-CuCON membranes were fabricated for facilitated blood-gas transport. • PMP-CuCON hollow fiber oxygenation membranes with superior performance were prepared. • Multiple facilitated transport sites and mass transfer channels were introduced via CuCON. • The membrane shows enhancing gas permeance and long-term stability. [ABSTRACT FROM AUTHOR]

Richard W Melchior,1 Steven W Sutton,2 William Harris,3 Heidi J Dalton4,5 1Department of Perfusion Services, The Children's Hospital of Philadelphia, Philadelphia, PA, 2Cardiovascular Support Services, Inc., Dallas, TX, 3Department of Perfusion Services, Ochsner Clinic Foundation, New Orleans, LA, 4Alaskan Native Tribal Health Consortium, Anchorage, AK, 5Department of Child Health, University of Arizona-College of Medicine, Phoenix, AZ, USAAbstract: The development of the membrane oxygenator for pediatric cardiopulmonary bypass has been an incorporation of ideology and technological advancements with contributions by many investigators throughout the past two centuries. With the pursuit of this technological achievement, the ability to care for mankind in the areas of cardiac surgery has been made possible. Heart disease can affect anyone within the general population, but one such segment that it can affect from inception includes children. Currently, congenital heart defects are the most common birth defects nationally and worldwide. A large meta-analysis study from 1930 to 2010 was conducted in review of published medical literature totaling 114 papers with a study population of 24,091,867 live births, and divulged a staggering incidence of congenital heart disease involving 164,396 subjects with diverse cardiac illnesses. The prevalence of these diseases increased from 0.6 per 1,000 live births from 1930–1934 to 9.1 per 1,000 live births after 1995. These data reveal an emphasis on a growing public health issue regarding congenital heart disease. This discovery displays a need for heightened awareness in the scientific and medical industrial community to accelerate investigative research on emerging cardiovascular devices in an effort to confront congenital anomalies. One such device that has evolved over the past several decades is the pediatric membrane oxygenator. The pediatric membrane oxygenator, in conjunction with the heart lung machine, assists in the repair of most congenital cardiac defects. Numerous children born with congenital heart disease with or without congestive heart failure have experienced improved clinical outcomes in quality of life, survival, and mortality as a result of the inclusion of this technology during their cardiac surgical procedure. The purpose of this review is to report a summary of the published medical and scientific literature related to development of the pediatric membrane oxygenator from its conceptual evolutionary stages to artificially supporting whole body perfusion in the modern pediatric cardiac surgical setting. Keywords: cardiovascular perfusion, pediatric cardiac surgery, extracorporeal technological advancement

This article developes a pediatric membrane oxygenator that is compact, high performance, and highly safe. This novel experimental approach, which imaging the inside of a membrane oxygenator during fluid perfusion using high-power X-ray CT, identifies air and blood retention in the local part of a membrane oxygenator. The cause of excessive pressure drop in a membrane oxygenator, which has been the most serious dysfunction in cardiovascular surgery and extracorporeal membrane oxygenation (ECMO), is the local retention of blood and air inside the oxygenator. Our designed blood flow channel for a membrane oxygenator has a circular channel and minimizes the boundary between laminated parts. The pressure drop in the blood flow channel is reduced, and the maximum gas transfer rates are increased by using this pediatric membrane oxygenator, as compared with the conventional oxygenator. Furthermore, it would be possible to reduce the incidents, which have occurred clinically, due to excessive pressure drop in the blood flow channel of the membrane oxygenator. The membrane oxygenator is said to be the “last stronghold” for patients with COVID-19 receiving ECMO treatment. Accordingly, the specification of our prototype is promising for low weight and pediatric patients.

Background. Improving oxygen delivery to challenging wound types has been shown to optimize and accelerate several key contributors to healing. This study aims to compare selective skin substitutes and primary dressings and evaluate their ability to transfer oxygen to the wound. Methods. Visual and quantitative methods were employed to measure gas and fluid movement across several skin substitutes, including a bilayer nylon and silicone dressing coated with porcine gelatin and aloe vera (CNS), a porous bovine collagen-glycosaminoglycan (GAG) matrix dressing coated with silicone (UBC), and a urethane biodegradable temporizing matrix (PFD). Results. Fluids did not move across solid silicone membranes or urethane foam while oxygen movement across solid silicone membranes was inversely proportional to the thickness of the membrane. Oxygen moved across the coated nylon and silicone dressing 5.63 times faster than across the bovine-GAG scaffold and 2.0 times faster than the biodegradable temporizing matrix of polyurethane. Conclusions. The coated nylon and silicone matrix functioned like a membrane oxygenator, potentially augmenting atmospheric oxygen delivery to healing wounds. [ABSTRACT FROM AUTHOR]

Oxygenation membranes in extracorporeal membrane oxygenation (ECMO) with excellent gas permeability, good hemocompatibility and durable resistance to plasma leakage is the key to achieve long-term and efficient blood oxygenation. This study put forward surface segregation strategy in thermally induced phase separation (TIPS) of poly (4-methyl-1-pentene) (PMP) membranes to realize the in-situ surface modification. Heterostructured PMP membranes with hydrophilic hemocompatible surface and hydrophobic body were obtained by migration of hydrophilic segments of the amphiphilic block copolymer Pluronic F127 to the surface in their preparation process. The hydrophilic surface could effectively improve hemocompatibility of membranes through hydration layer effect and steric hindrance effect, also reduce platelet adhesion significantly, and prolong the coagulation time of the four coagulation items within the normal physiological range of human body. When adding 10 wt% F127, the membrane exhibited an optimum CO 2 permeance of ∼11461 GPU and O 2 permeance of ∼13335 GPU, respectively, and an optimized blood oxygenation performance in vitro with O 2 flux of 122.9 ml min−1 m−2 and CO 2 flux of 129.2 ml min−1 m−2, and the asymmetric structure ensures resistance to plasma leakage for more than two months, that showed great application potential. Besides, preparation of hollow fiber membranes based on surface segregation was also explored, aiming to realize the enhanced performance and large-scale preparation of PMP oxygenation membranes. The membranes prepared in this work exhibited an outstanding performance when applied in blood oxygenation, showing great application potentials. [Display omitted] • PMP-F127 membranes were fabricated via surface segregation. • The membrane has a hemocompatible skin layer and an asymmetric support layer. • The membrane shows good gas permeability and long-term stability. • A large-scale PMP/F127-10 hollow fiber oxygenation membranes were prepared. [ABSTRACT FROM AUTHOR]

Background: There is no acceptable method of testing oxygen transfer performance in membrane oxygenators quickly and easily during cardiopulmonary bypass. Pre-clinical testing of oxygenators is performed under controlled situations in the laboratory, correlating oxygen transfer to blood flow using 100% oxygen. This laboratory method cannot be used clinically as oxygen transfer values vary significantly at each blood flow and the FiO2 is not kept at 1. Therefore, a formula was developed which corrects the existing FiO2 to attain a PaO2 of 150 mmHg: the corrected FiO2 at 150 mmHg. In graph form, this corrected FiO2 (x-axis) is correlated to the patient’s oxygen consumption levels (y-axis), which determines the membrane oxygenator oxygen transfer performance. Methods: Blood gas and hemodynamic parameters taken during cardiopulmonary bypass using the Medtronic Fusion were used to calculate the oxygen consumption (inlet conditions to the oxygenator) and the corrected FiO2 for a PaO2 of 150 mmHg. Validation of the formula “FiO2-PaO2/(Pb−pH2O)+0.21” was carried out by plotting the calculated values on a graph using PaO2 values between 145 to 155 mmHg and then, using the corrected FiO2 for PaO2s outside of this range. Results: All trend-lines correlated significantly to confirm that the Medtronic Fusion had an extrapolated oxygen transfer of 419 milliliters O2/min at an FiO2 of 1 to achieve a PaO2 of 150 mmHg. Conclusions: Use of the corrected FiO2 correlated to the oxygen transfer conditions of the membrane oxygenator can easily be used on a routine basis, providing valuable information clinically. When used by the manufacturer under laboratory conditions, further clinically relevant data is provided in terms of FiO2 and resultant PaO2s instead of the present limitations using blood flow. In this way, a clinically justifiable method has been developed to finally establish a standard in testing membrane oxygenator performance. [ABSTRACT FROM AUTHOR]

Device-induced thrombosis remains a major complication of extracorporeal life support (ECLS). To more thoroughly understand how blood components interact with the artificial surfaces of ECLS circuit components, assessment of clot deposition on these surfaces following clinical use is urgently needed. Scanning electron microscopy (SEM), which produces high-resolution images at nanoscale level, allows visualization and characterization of thrombotic deposits on ECLS circuitry. However, methodologies to increase the quantifiability of SEM analysis of ECLS circuit components have yet to be applied clinically. To address these issues, we developed a protocol to quantify clot deposition on ECLS membrane oxygenator gas transfer fiber sheets through digital and SEM imaging techniques. In this study, ECLS membrane oxygenator fiber sheets were obtained, fixed, and imaged after use. Following a standardized process, the percentage of clot deposition on both digital images and SEM images was quantified using ImageJ through blind reviews. The interrater reliability of quantitative analysis among reviewers was evaluated. Although this protocol focused on the analysis of ECLS membrane oxygenators, it is also adaptable to other components of the ECLS circuits such as catheters and tubing. Key features • Quantitative analysis of clot deposition using digital and scanning electron microscopy (SEM) techniques • High-resolution images at nanoscale level • Extracorporeal life support (ECLS) devices • Membrane oxygenators • Blood-contacting surfaces Graphical overview., Competing Interests: Competing interestsThere are no conflicts of interest., (©Copyright : © 2023 The Authors; This is an open access article under the CC BY-NC license.)

Extracorporeal membrane oxygenation (ECMO) is one of the most important supporting therapies for patients with severe cardiopulmonary failure, and the core component of ECMO is the membrane oxygenator. However, in clinical application, the membrane oxygenator faces a dilemma in balancing anticoagulation and hemorrhage risks, which restrains the service life of membrane oxygenator and affects patients' safety seriously. In this work, we introduce poly (1-vinyl-2-pyrrolidone) (PVP) and poly (acrylic acid) (PAA) into polyethersulfone (PES) membranes simply by in-situ crosslinking polymerization and nonsolvent induced phase separation (NIPS) method. All the modified membranes exhibit favorable hemocompatibility with prolonged activated partial thromboplastin time (APTT) (>10 s). Besides, the introduction of PAA can improve CO 2 and O 2 permeabilities simultaneously (increased by 36.57% and 30.86% at maximum, respectively, compared with pristine PES membrane). Finally, an ECMO-simulated gas-liquid contactor circulation device is designed, and the modified membranes show better oxygenation performance and CO 2 removal performance. The membrane modification and fabrication methods in this work are simple, low-cost, and easily industrialized. The work has practical guiding significance for the subsequent membrane research and application toward oxygenators. [Display omitted] • The membrane preparation method is easily industrialized and also suitable for hollow fiber membranes. • A normalized ECMO-simulated circulation device is built. • Better comprehensive properties of anticoagulation, antifouling and gas permeability are obtained for the modified membranes. [ABSTRACT FROM AUTHOR]