-
The Journal of Extra-corporeal... Mar 2024The optimal timing for extracorporeal membrane oxygenation (ECMO) circuit change-out is crucial for the successful management of patients with severe cardiopulmonary... (Review)
Review
INTRODUCTION
The optimal timing for extracorporeal membrane oxygenation (ECMO) circuit change-out is crucial for the successful management of patients with severe cardiopulmonary failure. This comprehensive review examines the various factors that influence the timing of oxygenator replacement in the ECMO circuit. By considering these factors, clinicians can make informed decisions to ensure timely and effective change-out, enhancing patient outcomes and optimizing the delivery of ECMO therapy.
METHODOLOGY
A thorough search of relevant studies on ECMO circuits and oxygenator change-out was conducted using multiple scholarly databases and relevant keywords. Studies published between 2017 and 2023 were included, resulting in 40 studies that met the inclusion criteria.
DISCUSSION
Thrombosis within the membrane oxygenator and its impact on dysfunction were identified as significant contributors, highlighting the importance of monitoring coagulation parameters and gas exchange. Several factors, including fibrinogen levels, pre and post-membrane blood gases, plasma-free hemoglobin, D-dimers, platelet function, flows and pressures, and anticoagulation strategy, were found to be important considerations when determining the need for an oxygenator or circuit change-out. The involvement of a multidisciplinary team and thorough preparation were also highlighted as crucial aspects of this process.
CONCLUSION
In conclusion, managing circuit change-outs in ECMO therapy requires considering factors such as fibrinogen levels, blood gases, plasma-free hemoglobin, D-dimers, platelet function, flows, pressures, and anticoagulation strategy. Monitoring these parameters allows for early detection of issues, timely interventions, and optimized ECMO therapy. Standardized protocols, personalized anticoagulation approaches, and non-invasive monitoring techniques can improve the safety and effectiveness of circuit change-outs. Further research and collaboration are needed to advance ECMO management and enhance patient outcomes.
Topics: Humans; Extracorporeal Membrane Oxygenation; Oxygenators, Membrane; Anticoagulants; Hemoglobins; Gases
PubMed: 38488715
DOI: 10.1051/ject/2023047 -
The New Phytologist Sep 2019Photorespiration is frequently considered a wasteful and inefficient process. However, mutant analysis demonstrated that photorespiration is essential for recycling of... (Review)
Review
Photorespiration is frequently considered a wasteful and inefficient process. However, mutant analysis demonstrated that photorespiration is essential for recycling of 2-phosphoglycolate in C and C land plants, in algae, and even in cyanobacteria operating carboxysome-based carbon (C) concentrating mechanisms. Photorespiration links photosynthetic C assimilation with other metabolic processes, such as nitrogen and sulfur assimilation, as well as C metabolism, and it may contribute to balancing the redox poise between chloroplasts, peroxisomes, mitochondria and cytoplasm. The high degree of metabolic interdependencies and the pleiotropic phenotypes of photorespiratory mutants impedes the distinction between core and accessory functions. Newly developed synthetic bypasses of photorespiration, beyond holding potential for significant yield increases in C crops, will enable us to differentiate between essential and accessory functions of photorespiration.
Topics: Arabidopsis; Cell Respiration; Glycolates; Light; Nitrogen; Photochemical Processes
PubMed: 31032928
DOI: 10.1111/nph.15872 -
Frontiers in Immunology 2023Myeloid-derived suppressor cells (MDSCs) are a heterogeneous myeloid cell population and serve as a vital contributor to the tumor microenvironment. Reactive oxygen... (Review)
Review
Myeloid-derived suppressor cells (MDSCs) are a heterogeneous myeloid cell population and serve as a vital contributor to the tumor microenvironment. Reactive oxygen species (ROS) are byproducts of aerobic respiration and are involved in regulating normal biological activities and disease progression. MDSCs can produce ROS to fulfill their immunosuppressive activity and eliminate excessive ROS to survive comfily through the redox system. This review focuses on how MDSCs survive and function in high levels of ROS and summarizes immunotherapy targeting ROS in MDSCs. The distinctive role of ROS in MDSCs will inspire us to widely apply the blocked oxidative stress strategy in targeting MDSC therapy to future clinical therapeutics.
Topics: Reactive Oxygen Species; Myeloid-Derived Suppressor Cells; Myeloid Cells; Oxidative Stress; Cell Respiration
PubMed: 37646034
DOI: 10.3389/fimmu.2023.1226443 -
Free Radical Biology & Medicine Aug 2019Metabolic processes in cells and chemical processes in the environment are fundamentally intertwined and have evolved in concert for most of Earth's existence. Here I... (Review)
Review
Metabolic processes in cells and chemical processes in the environment are fundamentally intertwined and have evolved in concert for most of Earth's existence. Here I argue that intrinsic properties of cellular metabolism imposed central constraints on the historical trajectories of biopsheric productivity and atmospheric oxygenation. Photosynthesis depends on iron, but iron is highly insoluble under the aerobic conditions produced by oxygenic photosynthesis. These counteracting constraints led to two major stages of Earth oxygenation. After a cyanobacteria-driven biospheric expansion near the Archean-Proterozoic boundary, productivity remained largely restricted to continental boundaries and shallow aquatic environments where weathering inputs made iron more accessible. The anoxic deep open ocean was rich in free iron during the Proterozoic, but this iron was largely inaccessible, partly because an otherwise nutrient-poor ocean was limiting to photosynthesis, but also because a photosynthetic expansion would have quenched its own iron supply. Near the Proterozoic-Phanerozoic boundary, bioenergetics innovations allowed eukaryotic photosynthesis to overcome these interconnected negative feedbacks and begin expanding into the deep open oceans and onto the continents, where nutrients are inherently harder to come by. Key insights into what drove the ecological rise of eukaryotic photosynthesis emerge from analyses of marine Synechococcus and Prochlorococcus, abundant marine picocyanobacteria whose ancestors colonized the oceans in the Neoproterozoic. The reconstructed evolution of this group reveals a sequence of innovations that ultimately produced a form of photosynthesis in Prochlorococcus that is more like that of green plant cells than other cyanobacteria. Innovations increased the energy flux of cells, thereby enhancing their ability to acquire sparse nutrients, and as by-product also increased the production of organic carbon waste. Some of these organic waste products had the ability to chelate iron and make it bioavailable, thereby indirectly pushing the oceans through a transition from an anoxic state rich in free iron to an oxygenated state with organic carbon-bound iron. Resulting conditions (and parallel processes on the continents) in turn led to a series of positive feedbacks that increased the availability of other nutrients, thereby promoting the rise of a globally productive biosphere. In addition to the occurrence of major biospheric expansions, the several hundred million-year periods around the Archean-Proterozoic and Proterozoic-Phanerozoic boundaries share a number of other parallels. Both epochs have also been linked to major carbon cycle perturbations and global glaciations, as well as changes in the nature of plate tectonics and increases in continental exposure and weathering. This suggests the dynamics of life and Earth are intimately intertwined across many levels and that general principles governed transitions in these coupled dynamics at both times in Earth history.
Topics: Biological Evolution; Cyanobacteria; Eukaryota; Iron; Oceans and Seas; Oxygen; Photosynthesis
PubMed: 31082508
DOI: 10.1016/j.freeradbiomed.2019.05.004 -
Acta Biomaterialia Oct 2022The artificial lung (AL) technology is one of the membrane-based artificial organs that partly augments lung functions, i.e. blood oxygenation and CO removal. It is... (Review)
Review
The artificial lung (AL) technology is one of the membrane-based artificial organs that partly augments lung functions, i.e. blood oxygenation and CO removal. It is generally employed as an extracorporeal membrane oxygenation (ECMO) device to treat acute and chronic lung-failure patients, and the recent outbreak of the COVID-19 pandemic has re-emphasized the importance of this technology. The principal component in AL is the polymeric membrane oxygenator that facilitates the O/CO exchange with the blood. Despite the considerable improvement in anti-thrombogenic biomaterials in other applications (e.g., stents), AL research has not advanced at the same rate. This is partly because AL research requires interdisciplinary knowledge in biomaterials and membrane technology. Some of the promising biomaterials with reasonable hemocompatibility - such as emerging fluoropolymers of extremely low surface energy - must first be fabricated into membranes to exhibit effective gas exchange performance. As AL membranes must also demonstrate high hemocompatibility in tandem, it is essential to test the membranes using in-vitro hemocompatibility experiments before in-vivo test. Hence, it is vital to have a reliable in-vitro experimental protocol that can be reasonably correlated with the in-vivo results. However, current in-vitro AL studies are unsystematic to allow a consistent comparison with in-vivo results. More specifically, current literature on AL biomaterial in-vitro hemocompatibility data are not quantitatively comparable due to the use of unstandardized and unreliable protocols. Such a wide gap has been the main bottleneck in the improvement of AL research, preventing promising biomaterials from reaching clinical trials. This review summarizes the current state-of-the-art and status of AL technology from membrane researcher perspectives. Particularly, most of the reported in-vitro experiments to assess AL membrane hemocompatibility are compiled and critically compared to suggest the most reliable method suitable for AL biomaterial research. Also, a brief review of current approaches to improve AL hemocompatibility is summarized. STATEMENT OF SIGNIFICANCE: The importance of Artificial Lung (AL) technology has been re-emphasized in the time of the COVID-19 pandemic. The utmost bottleneck in the current AL technology is the poor hemocompatibility of the polymer membrane used for O/CO gas exchange, limiting its use in the long-term. Unfortunately, most of the in-vitro AL experiments are unsystematic, irreproducible, and unreliable. There are no standardized in-vitro hemocompatibility characterization protocols for quantitative comparison between AL biomaterials. In this review, we tackled this bottleneck by compiling the scattered in-vitro data and suggesting the most suitable experimental protocol to obtain reliable and comparable hemocompatibility results. To the best of our knowledge, this is the first review paper focusing on the hemocompatibility challenge of AL technology.
Topics: Biocompatible Materials; COVID-19; Carbon Dioxide; Humans; Lung; Membranes, Artificial; Oxygenators, Membrane; Pandemics; Polymers; Technology
PubMed: 36089235
DOI: 10.1016/j.actbio.2022.09.003 -
Brazilian Journal of Cardiovascular... Feb 2023Extracorporeal perfusion flow type requires further investigation. The aim of this study is to compare the effects of pulsatile and nonpulsatile flow on oxygenator... (Randomized Controlled Trial)
Randomized Controlled Trial
INTRODUCTION
Extracorporeal perfusion flow type requires further investigation. The aim of this study is to compare the effects of pulsatile and nonpulsatile flow on oxygenator fibers that were analyzed by scanning electron microscope (SEM) and to extensively study patients' coagulation profiles, inflammatory markers, and functional blood tests.
METHODS
Twelve patients who had open heart surgery were randomly divided into two groups; the nonpulsatile flow (group NP, six patients) and pulsatile flow (group P, six patients) groups. Both superficial view and axial sections of the oxygenator fiber samples were examined under SEM to compare the thickness of absorbed blood proteins and amount of blood cells on the surface of oxygenators. Platelet count, coagulation profile, and inflammatory predictors were also studied from the blood samples.
RESULTS
Fibrinogen levels after cardiopulmonary bypass were significantly lower in group NP (group P, 2.57±2.78 g/L; group NP; 2.39±0.70 g/L, P=0.03). Inflammatory biomarkers such as C-reactive protein, interleukin (IL)-6, IL-12, apelin, S100β, and tumor necrosis factor alpha were comparable in both groups. Axial sections of the oxygenator fiber samples had a mean thickness of 45.2 µm and 46.5 µm in groups P and NP, respectively, and this difference is statistically significant (P=0.006). Superficial view of the fiber samples showed obviously lower platelet, leukocyte, and erythrocyte levels in group P.
CONCLUSION
Our study demonstrated that both cellular elements and protein adsorption on oxygenator fibers are lower in the group P than in the group NP. Pulsatile perfusion has better biocompatibility on extracorporeal circulation when analyzed by SEM technique.
Topics: Humans; Oxygenators, Membrane; Pulsatile Flow; Electrons; Extracorporeal Circulation; Cardiopulmonary Bypass; Interleukin-6
PubMed: 35895987
DOI: 10.21470/1678-9741-2021-0519 -
ASAIO Journal (American Society For... Jul 2023Membrane oxygenator failure during venovenous (V-V) extracorporeal membrane oxygenation (ECMO) can lead to life-threatening hypoxia, high replacement costs, and may be...
Membrane oxygenator failure during venovenous (V-V) extracorporeal membrane oxygenation (ECMO) can lead to life-threatening hypoxia, high replacement costs, and may be associated with a hyperfibrinolytic state and bleeding. The current understanding of the underlying mechanisms that drive this is limited. The primary aim of this study therefore is to investigate the hematological changes that occur before and after membrane oxygenator and circuit exchanges (ECMO circuit exchange) in patients with severe respiratory failure managed on V-V ECMO. We analyzed 100 consecutive V-V ECMO patients using linear mixed-effects modeling to evaluate hematological markers in the 72 hours before and 72 hours after ECMO circuit exchange. A total of 44 ECMO circuit exchanges occurred in 31 of 100 patients. The greatest change from baseline to peak were seen in plasma-free hemoglobin (42-fold increase p < 0.01) and the D-dimer:fibrinogen ratio (1.6-fold increase p = 0.03). Bilirubin, carboxyhemoglobin, D-dimer, fibrinogen, and platelets also showed statistically significant changes ( p < 0.01), whereas lactate dehydrogenase did not ( p = 0.93). Progressively deranged hematological markers normalize more than 72 hours after ECMO circuit exchange, with an associated reduction in membrane oxygenator resistance. This supports the biologic plausibility that ECMO circuit exchange may prevent further complications such as hyperfibrinolysis, membrane failure, and clinical bleeding.
Topics: Humans; Extracorporeal Membrane Oxygenation; Hemorrhage; Oxygenators, Membrane; Respiratory Insufficiency
PubMed: 37146593
DOI: 10.1097/MAT.0000000000001976 -
Pediatric Critical Care Medicine : a... Mar 2020To determine the oxygenator impact on alterations of ceftolozane/tazobactam in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch)...
OBJECTIVES
To determine the oxygenator impact on alterations of ceftolozane/tazobactam in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch) extracorporeal membrane oxygenation circuit including the Quadrox-i oxygenator (Maquet, Wayne, NJ).
DESIGN
A 1/4-inch and 3/8-inch, simulated closed-loop extracorporeal membrane oxygenation circuits were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. Additionally, 1/4-inch and 3/8-inch circuits were also prepared without an oxygenator in series. A one-time dose of ceftolozane/tazobactam was administered into the circuits and serial preoxygenator and postoxygenator concentrations were obtained at 5 minutes, 1, 2, 3, 4, 5, 6, and 24-hour time points. Ceftolozane/tazobactam was also maintained in a glass vial and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation SETTING:: A free-standing extracorporeal membrane oxygenation circuit.
PATIENTS
None.
INTERVENTIONS
Single-dose administration of ceftolozane/tazobactam into closed-loop extracorporeal membrane oxygenation circuits prepared with and without an oxygenator in series with serial preoxygenator, postoxygenator, and reference samples obtained for concentration determination over a 24-hour study period.
MEASUREMENTS AND MAIN RESULTS
For the 1/4-inch circuit, there was approximately 92% ceftolozane and 22-25% tazobactam loss with the oxygenator in series and 19-30% ceftolozane and 31-34% tazobactam loss without an oxygenator in series at 24 hours. For the 3/8-inch circuit, there was approximately 85% ceftolozane and 29% tazobactam loss with the oxygenator in series and 25-27% ceftolozane and 23-26% tazobactam loss without an oxygenator in series at 24 hours. The reference ceftolozane and tazobactam concentrations remained relatively constant during the entire study period demonstrating the drug loss in each size of the extracorporeal membrane oxygenation circuit with or without an oxygenator was not a result of spontaneous drug degradation.
CONCLUSIONS
This ex vivo investigation demonstrated substantial ceftolozane loss within an extracorporeal membrane oxygenation circuit with an oxygenator in series with both sizes of the Quadrox-i oxygenator at 24 hours and significant ceftolozane loss in the absence of an oxygenator. Tazobactam loss was similar regardless of the presence of an oxygenator. Further evaluations with multiple dose in vitro and in vivo investigations are needed before specific drug dosing recommendations can be made for clinical application with extracorporeal membrane oxygenation.
Topics: Adolescent; Adult; Anti-Bacterial Agents; Cephalosporins; Child; Child, Preschool; Equipment Design; Extracorporeal Membrane Oxygenation; Humans; Infant; Infant, Newborn; Metabolic Clearance Rate; Oxygenators, Membrane; Tazobactam; Young Adult
PubMed: 31688715
DOI: 10.1097/PCC.0000000000002174 -
Perfusion Jan 2023A high-pressure excursion (HPE) is a sudden increase in oxygenator inlet pressure during cardiopulmonary bypass (CPB). The aims of this study were to identify factors... (Observational Study)
Observational Study
INTRODUCTION
A high-pressure excursion (HPE) is a sudden increase in oxygenator inlet pressure during cardiopulmonary bypass (CPB). The aims of this study were to identify factors associated with HPE, to describe a treatment protocol utilizing epoprostenol in severe cases, and to assess early outcome in HPE patients.
METHODS
Patients who underwent cardiac surgery with cardiopulmonary bypass at Sahlgrenska University Hospital 2016-2018 were included in a retrospective observational study. Pre- and post-operative data collected from electronic health records, local databases, and registries were compared between HPE and non-HPE patients. Factors associated with HPE were identified with logistic regression models.
RESULTS
In total, 2024 patients were analyzed, and 37 (1.8%) developed HPE. Large body surface area (adjusted Odds Ratio (aOR): 1.43 per 0.1 m; 95% confidence interval (CI): 1.16-1.76, p < 0.001), higher hematocrit during CPB (aOR: 1.20 per 1%; (1.09-1.33), p < 0.001), acute surgery (aOR: 2.98; (1.26-6.62), p = 0.018), and previous stroke (aOR: 2.93; (1.03-7.20), p = 0.027) were independently associated with HPE. HPE was treated with hemodilution ( = 29, 78.4%), and/or extra heparin ( = 23, 62.2%), and/or epoprostenol ( = 12, 32.4%). No oxygenator change-out was necessary. While there was no significant difference in 30-day mortality (2.7% vs 3.2%, p = 1.0), HPE was associated with a higher perioperative stroke rate (8.1% vs 1.8%, aOR 5.09 (1.17-15.57), p = 0.011).
CONCLUSIONS
Large body surface area, high hematocrit during CPB, previous stroke and acute surgery were independently associated with HPE. A treatment protocol including epoprostenol appears to be a safe option. Perioperative stroke rate was increased in HPE patients.
Topics: Humans; Cardiopulmonary Bypass; Epoprostenol; Oxygenators; Risk Factors; Stroke
PubMed: 34510993
DOI: 10.1177/02676591211043700 -
Current Opinion in Pharmacology Aug 2020Hypoxia is a major impediment to many foremost cancer treatments that require O for generation of tumoricidal reactive oxygen species. Liquid perfluorocarbons (PFCs) are... (Review)
Review
Hypoxia is a major impediment to many foremost cancer treatments that require O for generation of tumoricidal reactive oxygen species. Liquid perfluorocarbons (PFCs) are inert gas solvents that help alleviate this oxygen deficit situation. PFC nanoemulsions have demonstrated oxygen delivery to tissues. The lifetime of O in PFCs is considerably expanded. PFC nanodroplets extravasate and accumulate in tumors. Alternatively, PFCs stabilize injectable O microbubbles. On-demand local O delivery is facilitated by ultrasound. Liquid PFC nanodroplets that convert into microbubbles upon activation provide another shuttle for O-delivery. PFC nanocarriers can also be enriched with fluorescent dyes, radiopaque materials, photo(sono)sensitizers, loaded with chemotherapeutics, and fitted with targeting devices, or stimuli-responsive functions for image-guided theranostics. We review recent literature on PFC-based O carriers to enhance the efficacy of radiotherapy, photo(sono)dynamic therapy and chemotherapy. Of particular relevance to this series of reviews, PFC-based carriers may provide novel strategies to promote T-cell trafficking into tumors to improve immune responses.
Topics: Animals; Emulsions; Fluorocarbons; Humans; Microbubbles; Nanostructures; Neoplasms; Oxygen; Tumor Hypoxia
PubMed: 32979727
DOI: 10.1016/j.coph.2020.08.010