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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 -
American Journal of Physiology. Heart... Oct 2023Cardiovascular regulation of tissue oxygenation is generally viewed as an anti-drop process that prevents tissue oxygen concentration from falling below some minimum. I...
Cardiovascular regulation of tissue oxygenation is generally viewed as an anti-drop process that prevents tissue oxygen concentration from falling below some minimum. I propose that cardiovascular regulation is predominately an anti-rise process designed to downregulate oxygen delivery. This maintains an evolutionarily conserved, reduced intracellular environment to prevent oxidation of redox-sensitive regulatory protein thiols. A number of points support this hypothesis. First, oxygen is the only nutrient with a positive, fourfold diffusion gradient from the environment to systemic tissues, minimizing the likelihood that oxygen delivery is limited. Second, hemoglobin (Hb) retains oxygen unless offloading is absolutely necessary. The allosteric properties of Hb keep oxygen tightly bound until absolutely needed, and the Bohr shift, which favors offloading, is only transient and lost when metabolism is restored. Third, a myoglobin-like Hb (xHb) would offload all of its oxygen and could easily have evolved, but it did not. Fourth, oxygen-sensitive vasoconstrictors and hyperoxic-rarefaction prevent acute and chronic over perfusion. Fifth, Fåhraeus and Fåhraeus-Lindqvist effects reduce capillary hematocrit to minimize microcirculatory oxygen content. Sixth, venous blood remains 75% saturated, wasting 75% of cardiac output were an oxygen reserve not needed. Finally, xHb-containing red blood cells could be considerably smaller and thereby decrease Fåhraeus and Fåhraeus-Lindqvist effects and cardiac load. In summary, the capacity of the cardiovascular system to deliver oxygen to the tissues generally exceeds demand, and although maintenance of an oxygen delivery reserve is important, it is more important to prevent excess oxygen delivery.
Topics: Humans; Microcirculation; Erythrocytes; Heart; Cachexia; Oxygen
PubMed: 37624098
DOI: 10.1152/ajpheart.00449.2023 -
Burns : Journal of the International... Dec 2023Carbon monoxide (CO) is an odorless and colorless gas that can lead to fulminant and life-threatening intoxications. Besides an early diagnosis, an appropriate treatment... (Review)
Review
Carbon monoxide (CO) is an odorless and colorless gas that can lead to fulminant and life-threatening intoxications. Besides an early diagnosis, an appropriate treatment of the intoxication is important. In this context the reduction of CO concentration in blood and tissues is crucial revealing hyperbaric oxygen treatment (HBO) as a highly promising tool. However, the benefit of HBO in CO intoxications is still considered controversial. In this review, we discuss the evidence of the role of HBO treatment in isolated CO intoxication.
Topics: Humans; Oxygen; Carbon Monoxide Poisoning; Hyperbaric Oxygenation; Burns
PubMed: 37821285
DOI: 10.1016/j.burns.2023.06.007 -
Cell Biochemistry and Function Mar 2024Eukaryotic cells utilize oxygen for different functions of cell organelles owing to cellular survival. A balanced oxygen homeostasis is an essential requirement to... (Review)
Review
Eukaryotic cells utilize oxygen for different functions of cell organelles owing to cellular survival. A balanced oxygen homeostasis is an essential requirement to maintain the regulation of normal cellular systems. Any changes in the oxygen level are stressful and can alter the expression of different homeostasis regulatory genes and proteins. Lack of oxygen or hypoxia results in oxidative stress and formation of hypoxia inducible factors (HIF) and reactive oxygen species (ROS). Substantial cellular damages due to hypoxia have been reported to play a major role in various pathological conditions. There are different studies which demonstrated that the functions of cellular system are disrupted by hypoxia. Currently, study on cellular effects following hypoxia is an important field of research as it not only helps to decipher different signaling pathway modulation, but also helps to explore novel therapeutic strategies. On the basis of the beneficial effect of hypoxia preconditioning of cellular organelles, many therapeutic investigations are ongoing as a promising disease management strategy in near future. Hence, the present review discusses about the effects of hypoxia on different cellular organelles, mechanisms and their involvement in the progression of different diseases.
Topics: Humans; Hypoxia; Reactive Oxygen Species; Oxygen; Oxidative Stress; Signal Transduction; Cell Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit
PubMed: 38379257
DOI: 10.1002/cbf.3940 -
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 -
Respiratory Physiology & Neurobiology Sep 2023
Topics: Humans; Hypoxia; Oximetry; Oxygen; Altitude
PubMed: 37406841
DOI: 10.1016/j.resp.2023.104111 -
Proceedings of the National Academy of... Aug 2023Traditionally, nuclear spin is not considered to affect biological processes. Recently, this has changed as isotopic fractionation that deviates from classical mass...
Traditionally, nuclear spin is not considered to affect biological processes. Recently, this has changed as isotopic fractionation that deviates from classical mass dependence was reported both in vitro and in vivo. In these cases, the isotopic effect correlates with the nuclear magnetic spin. Here, we show nuclear spin effects using stable oxygen isotopes (O, O, and O) in two separate setups: an artificial dioxygen production system and biological aquaporin channels in cells. We observe that oxygen dynamics in chiral environments (in particular its transport) depend on nuclear spin, suggesting future applications for controlled isotope separation to be used, for instance, in NMR. To demonstrate the mechanism behind our findings, we formulate theoretical models based on a nuclear-spin-enhanced switch between electronic spin states. Accounting for the role of nuclear spin in biology can provide insights into the role of quantum effects in living systems and help inspire the development of future biotechnology solutions.
Topics: Oxygen Isotopes; Oxygen; Biological Phenomena
PubMed: 37523549
DOI: 10.1073/pnas.2300828120 -
Neurochemical Research Jul 2024Lactate has received attention as a potential therapeutic intervention for brain diseases, particularly those including energy deficit, exacerbated inflammation, and...
Lactate has received attention as a potential therapeutic intervention for brain diseases, particularly those including energy deficit, exacerbated inflammation, and disrupted redox status, such as cerebral ischemia. However, lactate roles in metabolic or signaling pathways in neural cells remain elusive in the hypoxic and ischemic contexts. Here, we tested the effects of lactate on the survival of a microglial (BV-2) and a neuronal (SH-SY5Y) cell lines during oxygen and glucose deprivation (OGD) or OGD followed by reoxygenation (OGD/R). Lactate signaling was studied by using 3,5-DHBA, an exogenous agonist of lactate receptor GPR81. Inhibition of lactate dehydrogenase (LDH) or monocarboxylate transporters (MCT), using oxamate or 4-CIN, respectively, was performed to evaluate the impact of lactate metabolization and transport on cell viability. The OGD lasted 6 h and the reoxygenation lasted 24 h following OGD (OGD/R). Cell viability, extracellular lactate concentrations, microglial intracellular pH and TNF-ɑ release, and neurite elongation were evaluated. Lactate or 3,5-DHBA treatment during OGD increased microglial survival during reoxygenation. Inhibition of lactate metabolism and transport impaired microglial and neuronal viability. OGD led to intracellular acidification in BV-2 cells, and reoxygenation increased the release of TNF-ɑ, which was reverted by lactate and 3,5-DHBA treatment. Our results suggest that lactate plays a dual role in OGD, acting as a metabolic and a signaling molecule in BV-2 and SH-SY5Y cells. Lactate metabolism and transport are vital for cell survival during OGD. Moreover, lactate treatment and GPR81 activation during OGD promote long-term adaptations that potentially protect cells against secondary cell death during reoxygenation.
Topics: Microglia; Glucose; Humans; Neurons; Oxygen; Lactic Acid; Cell Survival; Animals; Mice; Neuroprotective Agents; Cell Hypoxia; Tumor Necrosis Factor-alpha; Receptors, G-Protein-Coupled; Cell Line, Tumor; Cell Line; Monocarboxylic Acid Transporters
PubMed: 38551797
DOI: 10.1007/s11064-024-04135-7 -
Cellular and Molecular Neurobiology Jul 2023Normoxia is defined as an oxygen concentration of 20.9%, as in room air, whereas hypoxia refers to any oxygen concentration less than this. Any physiological oxygen... (Review)
Review
Normoxia is defined as an oxygen concentration of 20.9%, as in room air, whereas hypoxia refers to any oxygen concentration less than this. Any physiological oxygen deficiency or tissue oxygen deficiency relative to demand is called hypoxia. Neural stem cells (NSCs) are multipotent stem cells that can differentiate into multiple cell lines such as neurons, oligodendrocytes, and astrocytes. Under hypoxic conditions, the apoptosis rate of NSCs increases remarkably in vitro or in vivo. However, some hypoxia promotes the proliferation and differentiation of NSCs. The difference is related to the oxygen concentration, the duration of hypoxia, the hypoxia tolerance threshold of the NSCs, and the tissue source of the NSCs. The main mechanism of hypoxia-induced proliferation and differentiation involves an increase in cyclin and erythropoietin concentrations, and hypoxia-inducible factors play a key role. Multiple molecular pathways are activated during hypoxia, including Notch, Wnt/β-catenin, PI3K/Akt, and altered microRNA expression. In addition, we review the protective effect of exogenous NSCs transplantation on ischemic or anoxic organs, the therapeutic potential of hypoxic preconditioning on exogenous NSCs and clinical application of NSCs.
Topics: Humans; Phosphatidylinositol 3-Kinases; Cell Proliferation; Neural Stem Cells; Cell Differentiation; Hypoxia; Cell Hypoxia; Oxygen; Cells, Cultured
PubMed: 36308642
DOI: 10.1007/s10571-022-01293-6 -
The EMBO Journal Jun 2024The in vitro oxygen microenvironment profoundly affects the capacity of cell cultures to model physiological and pathophysiological states. Cell culture is often...
The in vitro oxygen microenvironment profoundly affects the capacity of cell cultures to model physiological and pathophysiological states. Cell culture is often considered to be hyperoxic, but pericellular oxygen levels, which are affected by oxygen diffusivity and consumption, are rarely reported. Here, we provide evidence that several cell types in culture actually experience local hypoxia, with important implications for cell metabolism and function. We focused initially on adipocytes, as adipose tissue hypoxia is frequently observed in obesity and precedes diminished adipocyte function. Under standard conditions, cultured adipocytes are highly glycolytic and exhibit a transcriptional profile indicative of physiological hypoxia. Increasing pericellular oxygen diverted glucose flux toward mitochondria, lowered HIF1α activity, and resulted in widespread transcriptional rewiring. Functionally, adipocytes increased adipokine secretion and sensitivity to insulin and lipolytic stimuli, recapitulating a healthier adipocyte model. The functional benefits of increasing pericellular oxygen were also observed in macrophages, hPSC-derived hepatocytes and cardiac organoids. Our findings demonstrate that oxygen is limiting in many terminally-differentiated cell types, and that considering pericellular oxygen improves the quality, reproducibility and translatability of culture models.
Topics: Oxygen; Adipocytes; Humans; Cell Differentiation; Cell Culture Techniques; Animals; Glycolysis; Hepatocytes; Cell Hypoxia; Mitochondria; Mice; Hypoxia-Inducible Factor 1, alpha Subunit; Cells, Cultured; Glucose; Macrophages
PubMed: 38580776
DOI: 10.1038/s44318-024-00084-7