Extracorporeal Membrane Oxygenation Oxygenator Research Articles

The effect of excessive gas to blood ratios in an ECMO oxygenator.

Oxygenators for paediatric Extracorporeal Membrane Oxygenation (ECMO) are required to operate over a wide range of flow rates, in a patient group ranging from neonates through to fully grown adolescents. ECMO oxygenators typically have a manufacturer's stated maximum gas: blood flow rate (GBFR) ratio of 2:1, however, many patients require greater ratios than this for adequate CO2 removal. Mismatches in GBFR in theory could result in high gas phase pressures. These increased pressures in theory could cause the formation of gross gaseous microemboli (GME) placing the child at higher risk of neurological injury. We evaluated 6 paediatric and 6 adult A.L.ONE™ ECMO oxygenators and assessed their gas phase pressures and GME release, in an ex vivo setting, in GBFR ratios up to greater than 2, across a range of gas flow (1L - 10L/min) rates with a fraction of inspired oxygen (FiO2) content of 50% and 100%. There were no increases above 10mmHg observed in gas phase pressures in GBFR >= 2:1 in either adult or paediatric oxygenators. Laboratory examination of GME activity demonstrated a small increase in post-membrane GME release over the study period. GME release was unaffected by FiO2 setting or gas flow rate, with a maximum volume of < 6µL in both paediatric and adult oxygenators. In an ex vivo setting, increasing GBFR above 2:1 in a paediatric oxygenator, and to a GBFR of 2:1 in an adult oxygenator did not significantly increase gas phase pressures, and no oxygenator membrane rupture was observed. There were no associations between gas flow rates and GME production.

No Sequestration of Commonly Used Anti-Infectives in the Extracorporeal Membrane Oxygenation (ECMO) Circuit-An Ex Vivo Study.

Patients undergoing extracorporeal membrane oxygenation (ECMO) often require therapy with anti-infective drugs. The pharmacokinetics of these drugs may be altered during ECMO treatment due to pathophysiological changes in the drug metabolism of the critically ill and/or the ECMO therapy itself. This study investigates the latter aspect for commonly used anti-infective drugs in an ex vivo setting. A fully functional ECMO device circulated an albumin-electrolyte solution through the ECMO tubes and oxygenator. The antibiotic agents cefazolin, cefuroxim, cefepime, cefiderocol, linezolid and daptomycin and the antifungal agent anidulafungin were added. Blood samples were taken over a period of four hours and drug concentrations were measured via high-pressure liquid chromatography (HPLC) with UV detection. Subsequently, the study analyzed the time course of anti-infective concentrations. The results showed no significant changes in the concentration of any tested anti-infectives throughout the study period. This ex vivo study demonstrates that the ECMO device itself has no impact on the concentration of commonly used anti-infectives. These findings suggest that ECMO therapy does not contribute to alterations in the concentrations of anti-infective medications in severely ill patients.

Exploring the Nexus: Gaseous Micro-embolic Activity and Pressure Drop on ALONE ECMO Oxygenator

AbstractThe role of inlet and outlet oxygenator pressure know as pressure drop (ΔP) in the elimination of the gaseous micro-emboli activity (GMEA) remains obscured during Extracorporeal Membrane Oxygenation (ECMO) and Minimally Invasive Extracorporeal Circulation (MiECC). There is conflicting literature on the role of pressure drop in oxygenators as well as on oxygenating performance, fluid dynamics and in the role of gaseous micro-embolic activity elimination. We analyzed 14 procedures, 10 MiECC with polypropylene fibers ALONE AF oxygenator and 4 ECMO with polymethylpentene Alone ECMO Oxygenator (Eurosets, SRL, Medolla,Italy), in the central and peripheral cannulation configuration, respectively, through the use of GAMPT BCC300 for air gas micro-emboli (GME) in relation to the ΔP of Oxygenator and incidence of cavitation. The groups of MiECC, Central Cannulation VS Peripheral Cannulation reported: mean values for cavitation n° of bubbles was 330 ± 12 vs 80 ± 13; 1.5 vs 0% reported a diameter &gt; 500 μm; GME volume was 1.51 ± 0.2 vs 0.121 ± 0.2 (μL) in the arterial line, the mean ΔP of oxygenator reported was 89 ± 11 vs 130 ± 29 mmHg. The groups of ECMO, Central Cannulation VS Peripheral Cannulation reported: mean values for cavitation n° of bubbles was 470 ± 12 vs 140 ± 17; 2.1 vs 0% reported a diameter &gt; 500 μm; GME volume was 2.5 ± 0.5 vs 0.355 ± 0.7 (μL) in the arterial line, the mean ΔP of oxygenator reported was 88 ± 15vs 150 ± 23 mmHg. In this report, patients with low pressure drop in the oxygenator reported a statistically significant increase in GMEA in the arterial line of the circuit for each cavitation phenomenon, compared to the group with high pressure drop in the oxygenator who reported a reduced GMEA. In this report, oxygenators with higher pressure drops demonstrated a significant reduction of GMEA, however, further studies are needed to confirm these results.

Multimodality Quantification of Thrombus Deposition in Extracorporeal Membrane Oxygenation (ECMO); Correlating Oxygenator Computed Tomography Imaging, Electron Microscopy and Histology to Clinical Outcomes

Introduction: Extracorporeal membrane oxygenation (ECMO) is essential for supporting cardiopulmonary function in critically ill patients, However, ECMO incurs thrombogenic risks due to activation of coagulation factors and blood cells by the biomaterial surfaces. This leads to complications such as frequent device replacement and systemic embolization despite the use of anticoagulation, suggesting additional mechanisms contribute to medical device-associated thrombosis. We propose that the geometry of the ECMO oxygenator significantly influences the structure and extent of clot formation and stability. To investigate this, we employed quantitative imaging and histologic techniques for a high-resolution, three-dimensional analysis of clot morphology in ECMO components, aiming to enhance our understanding of clot formation mechanisms, correlate these observations to clinical outcomes, and develop effective mitigation strategies. Methods: We developed a prospective study in which patients consented to the collection of blood samples, used ECMO components, and collection of relevant clinical variables. Computed tomography (CT) images were acquired using an Inveon microCT. H&amp;E stains, scanning electron microscopy (SEM), and CT images were processed through the Dragonfly software to accomplish a 3D visualization and analysis of clot composition. Clinical demographics and ECMO characteristics were recorded for each patient. Results: Digital photographs of used oxygenators are displayed in figure (A). Through CT scans, we quantified clot formation of distinct densities across the layers of the ECMO oxygenator (D). The results were able to quantify intraoxygenator thrombosis with high fidelity (27.65%, 14.56%, and 26.35% of the available membrane area was thrombosed across three representative oxygenators). Using a frontal CT scan to investigate clot formation identified five layers of varying structures across the intended path of blood flow (B). Clot formation was observed in layer 4 and layer 5, in which thrombosis occluded up to 12.2% of the layer on average. The overall ranking of clot formation under hemodynamic performance changes for all five layers was as follows: layer 5 &amp;gt; layer 4 &amp;gt; layer 1 = layer 2 &amp;gt;&amp;gt; layer 3. The use of anticoagulation at the time of ECMO decannulation significantly reduced the content of clot formation (P&amp;lt;0.0001). We then correlated digital biomarkers from imaging with thrombus composition. Detailed histological examination (HE) and SEM was undertaken on dismantled oxygenators (B &amp; C). We focused on thrombi at the interfaces and within the hollow fibers of the oxygenator. SEM and HE staining illustrated increased thickness, length, and density of fibrin structures in the thrombi from layer 5 to layer 4, whereas the numbers of platelets and cells decreased. Overall, layer 5 exhibited the most diverse types of thrombi, including blood cell-rich, platelet-rich, and fibrin-rich clots. We also observed aligned clots and significant clot formation in the hollow fiber area of layer 4, reflecting the geometry of the specific layer. Discussion: This pilot study examined the potential for imaging-based modalities to evaluate device associated thrombosis ex vivo, correlating these imaging findings to direct observations of thrombus composition and location. This methodology provides a platform to investigate ECMO device failure, identifying the key locations within select oxygenators where local device modification may be of most benefit. Future research will prioritize designing membrane oxygenator properties to minimize thrombus deposition, and will allow us to incorporate the use of serial imaging endpoints in future clinical trials evaluating medical device-associated thrombosis.

Surface Modification of Oxygenator Fibers with a Catalytically Active Metal-Organic Framework to Generate Nitric Oxide: An Ex Vivo Pilot Study.

Coating all portions of an extracorporeal membrane oxygenation (ECMO) circuit with materials exhibiting inherent, permanent antithrombotic properties is an essential step to prevent thrombus-induced complications. However, developing antithrombotic coatings for oxygenator fibers within membrane oxygenators of ECMO systems has proven challenging. We have used polydopamine (PDA) to coat oxygenator fibers and immobilize a Cu-based metal-organic framework (MOF) on the surface to act as a nitric oxide (NO) catalyst. Importantly, the PDA/MOF coating will produce NO indefinitely from endogenous S-nitrosothiols and it has not previously been applied to ECMO oxygenator fibers.

Long-term ECMO, efficiency and performance of EUROSETS adult A.L.ONE ECMO oxygenator

BackgroundThe management of the oxygenator can be prolonged in the long-term procedures especially during extracorporeal membrane oxygenation (ECMO) for bridge to transplant or bridge to recovery. Long-term use often involves an overrun of the time of use with respect to certification of the oxygenating module of 14 days, for the maintenance of performance and efficiency of the oxygenator. The evaluation of the long-term oxygenator efficiency is complex and depends on the: patient pathology, ECMO configuration, the management of coagulation and anticoagulation, materials selection and circuit components, the structure, design and performance of the oxygenator. In this context we investgated the long-term performance of the A.L.ONE Eurosets ECMO oxygenator in relation to the parameters prodromal to replacement.MethodsWe retrospectively collected eight years data from Anthea Hospital GVM Care & Research, Bari, Italy on the long-term use exceeding 14 days of Eurosets A.L.ONE ECMO Adult oxygenator in Polymetylpentene fiber, for ECMO procedures, including the procedures: Veno Arterial (VA) ECMO post-cardiotomy or not, veno-venous (VV) ECMO. The primary end points were the evaluation of Gas Transfer: oxygen partial pressure (PO2) post oxygenator, Carbon dioxide partial pressure (PCO2) post oxygenator, the oxygen transfer across the oxygenator membrane V′O2, differential CO2 content across oxygenator; Pressure monitoring: oxygenator pressure Drop in relation to Blood flow rate (BFR) (ΔP); Hematologic values: Hemoglobin, Fibrinogen, Platelets, aPTT, D-Dimer, LDH.ResultsNine VA ECMO patients who used the oxygenator for 18.5 days and two VV ECMO patients who used the oxygenators for 17.2 days on the seventeenth days reported average values PaO2 (267 ± 29 mmHg); PaCO2 (34 ± 4 mmHg) with gas blender values set to 3.8 ± 0.6 L/min of air and a FiO2 of 78 ± 5%; the transfer across the oxygenator membrane V′O2 was 189 ± 43 (ml/min/m2). The mean peak of partial pressure of carbon dioxide from the gas exhaust of oxygenator (PECO2) was 38 ± 4 mmHg; differential CO2 across the oxygenator “pre-oxygenator PCO2–post-oxygenator PCO2” (18 ± 6 mmHg); the mean blood flow rate (BFR) 4.5 ± 0.6 (L/minute); the pump revolution per minutes mean maximum rate was 4254 ± 345 (RPM); the mean pressure drop (ΔP) was 76 ± 12 mmHg; the mean peak of d-dimers (DDs) was 23.6 ± 0.8 mg / dL; the mean peak of LDH was 230 ± 55 (mg/dl); fibrinogen mean peak 223 ± 40 (mg/dl).ConclusionsThe performance of the Eurosets A.L.ONE ECMO Adult polymethylpentene fiber oxygenator in our experience has proven efficiency in terms of O2 uptake and CO2 removal, blood fluid dynamics, metabolic compensation and heat exchange in the long-term treatment. The device was safe without iatrogenic problems over a period of 14 days in the patients undergoing ECMO VA and in all patients undergoing VV ECMO with continuous administration of anticoagulation therapy.

Extracorporeal membrane oxygenation and Extracorporeal Membrane Oxygenation Cardiopulmonary Resusciation (ECPR) research priorities in Australia: A clinician survey

BackgroundThe use of extracorporeal membrane oxygenation (ECMO) for cardiorespiratory failure and during cardiopulmonary resuscitation has increased significantly and is resource intensive. High-quality evidence to guide management of patients on ECMO is limited. ObjectivesThe objective of this study was to determine the research priorities of clinicians for ECMO and Extracorporeal Membrane Oxygenation Cardiopulmonary Resusciation (ECPR) in Australia and New Zealand. MethodsA prospective, binational survey of clinicians was conducted in May 2022. ResultsThere were 133 respondents; 110 (84%) worked at an Australian ECMO centre; 28 (21%) were emergency, 45 (34%) were intensive care, and 41 (31%) were nursing clinicians. All aspects of ECMO care were identified by respondents as being important for further research; however, appropriate patient selection and determining long-term outcomes were ranked the highest. While most believed ECMO was efficacious, they felt that there was insufficient evidence to determine cost-effectiveness. There was uncertainty of the best model of ECPR provision. Equipoise exists for randomised studies into anticoagulation, blood product usage, and ECPR. ConclusionsThis survey found strong support amongst clinicians for further research into the optimal use of ECMO and ECPR and provides a frame work for prioritising future clinical trials and research agendas.

Specific features of antimicrobial therapy in patients with severe respiratory failure receiving veno-venous extracorporeal membrane oxygenation (ECMO)

In modern medicine, the extracorporeal membrane oxygenation (ECMO) is becoming increasingly common in the treatment of severe respiratory failure. The development of infectious complications in patients receiving ECMO often leads to an increase in the duration of the procedure and significantly increases the risk of death. Dosing of antimicrobials during ECMO remains uncertain and requires further research. Diagnosis of infectious complications during ECMO is a difficult and requires the development of diagnostic protocols and the use of routine microbiological studies. The use of antimicrobials during ECMO could be complicated due to decrease in effective plasma concentration. The adsorption of antibacterial drugs in the ECMO circuit and oxygenator, the use of infusion therapy, the development of hypoalbuminemia, as well as the high incidence of acute renal and hepatic dysfunction in critically ill patients lead to an inevitable change in the volume of distribution and clearance of antibacterial drugs. These conditions require an individual approach to the choice of antimicrobials and optimization of dosing regimens in critically ill patients receiving ECMO.

Isavuconazole plasma concentrations in critically ill patients during extracorporeal membrane oxygenation.

BackgroundIsavuconazole is an antifungal drug used for treatment of invasive fungal infections. Critically ill COVID-19 and influenza patients require extracorporeal membrane oxygenation (ECMO) in cases with severe acute respiratory distress syndrome and have risk factors for invasive pulmonary aspergillosis. Little is known about isavuconazole plasma concentrations during ECMO.ObjectivesTo determine isavuconazole plasma concentrations in seven patients treated with intravenous isavuconazole under ECMO and the influence of the ECMO circuit immediately after the first isavuconazole dose.MethodsCritically ill patients treated with isavuconazole (standard doses) and ECMO were included in this study. Sixty-four blood samples used for measurement of isavuconazole concentrations were collected at several timepoints starting 2 h after the first isavuconazole dose up to 168 h. An additional 27 blood samples were drawn from the inflow and outflow line of the membrane oxygenator to assess any potential isavuconazole clearance effect of the ECMO oxygenation device and the lines.ResultsMedian isavuconazole trough levels above 1 μg/mL (min. 0.83, max. 1.73) or 2 μg/mL (min. 0.84, max. 2.97) were achieved 24 h or 96 h after the first dose of isavuconazole. The isavuconazole plasma concentrations pre (inflow line) and post (outflow line) the membrane oxygenator were directly correlated (ρ = 0.987, R2 = 0.994, P < 0.001). Post membrane oxygenator isavuconazole concentrations were directly correlated to contemporaneous samples obtained from the arterial lines of patients (ρ = 0.942, R2 = 0.945, P < 0.001).ConclusionsIsavuconazole concentrations might be influenced by the higher volume of distribution due to ECMO therapy, but were not altered by the ECMO oxygenator and achieved median plasma concentrations >1 μg/mL 24 h after the first loading dose.

Indwelling Central Venous Catheters Drive Bloodstream Infection During Veno-venous Extracorporeal Membrane Oxygenation Support.

Blood stream infection (BSI) is a potentially lethal complication in patients receiving extracorporeal membrane oxygenation (ECMO). It may be particularly common in patients with veno-venous ECMO due to their long hospitalization in the intensive care unit. Given that these patients have concurrent indwelling central venous catheters (CVC), it is unclear whether the ECMO circuit, CVC, or both, contribute to BSI. This study evaluated the risk factors associated with BSI in patients receiving veno-venous ECMO in a single institution study of 61 patients from 2016 through 2019. All ECMO catheters and the circuit oxygenator fluid were aseptically collected and analyzed for microorganisms at the time of decannulation. New BSI was diagnosed in 15 (24.6%) patients and increased mortality by threefold. None of the ECMO catheters or oxygenator fluid were culture positive. BSI increased with CVC use of over 8 days and was significantly lowered when CVC were exchanged by day 8 compared with patients with exchanges at later points (15.0% vs. 42.8%, p = 0.02). Median length of CVC use in the BSI-negative and BSI-positive group were 6.3 ± 5.0 and 9.4 ± 5.1, respectively (p = 0.04). In summary, BSI is a potentially lethal complication in patients receiving ECMO. Indwelling CVC, not the ECMO circuitry, is the likely contributor for BSI, and exchanging CVC by day 8 can reduce the incidence of BSI.

Use of Carboxyhemoglobin as an Early Sign of Oxygenator Dysfunction in Patients Supported by Extracorporeal Membrane Oxygenation.

IntroductionPlasma free hemoglobin is the gold standard for monitoring hemolysis in extracorporeal membrane oxygenation (ECMO) but its routine use has some limitations. Carboxyhemoglobin (HbCO) is also a marker of intravascular hemolysis. We aimed to investigate HbCO as a marker of both hemolysis and oxygenator dysfunction in patients supported by ECMO.MethodsRetrospective analysis of patients on ECMO in an adult ICU in a tertiary hospital. HbCO was recorded every 6 h in the 48 h before and after oxygenator change in adult patients on ECMO support with an oxygenator dysfunction and replacement.ResultsThe investigation of 27 oxygenators replacements in 19 patients demonstrated that HbCO values progressively increased over time and then significantly decreased after oxygenator change. Median oxygenator lifespan was 14 days [interquartile range (IQR) 8–21] and there was no correlation between HbCO and oxygenator lifespan [Spearman coefficient 0.23 (p = 0.23)]. HbCO values at oxygenator change [HbCO median 2.7 (IQR 2.5–3.5)] were significantly higher than the HbCO values 1 week before [HbCO median 2.07 (IQR 1.86–2.8)] (p value < 0.001).ConclusionOur data highlight the potential role of HbCO as a novel marker for ECMO oxygenator dysfunction.

Effect of Platelet Transfusions on Extracorporeal Life Support Oxygenator's Function.

ObjectiveBleeding is a common complication of extracorporeal membrane oxygenation (ECMO), leading to increased mortality. Since one of its main complications is bleeding, platelet transfusions are frequently prescribed for children on ECMO. However, there is currently very little information on the effect of platelet transfusions on the function of the ECMO oxygenator. Our objective was to describe the effect of platelet transfusions on oxygenator function.MethodsIn this retrospective study, we included all children (<18 years) who received ECMO support in our pediatric intensive care unit (PICU) between January 2017 and December 2019. Oxygenator function, measured before and after platelet transfusion, was assessed by post-oxygenator PECMOO2 and the gradient in pre- post-oxygenator pressures (Delta Pressure).ResultsOver 3 years, we analyzed 235 platelet transfusions from 55 children who received ECMO support. Thirty-two (80%) of children were on veno-arterial ECMO and majority of them were peripherally cannulated. When looking at all transfusions, the post-transfusion change in delta-pressure was 0.1 mmHg (p = 0.69) and post-membrane PECMOO2 was 6 mmHg (p = 0.49). However, in the subgroup with the lowest quartile of pre-transfusion oxygenator function, the post-transfusion change in delta-pressure was −5.2 ± 2.7 mmHg (p < 0.001) and the post-transfusion change in PECMOO2 was −118 ± 49 (p < 0.001). The area under the ROC curve for the pre-transfusion delta-pressure and PECMOO2 to predict a worsening of the oxygenator function were 0.72 (95%CI 0.63–0.81) and 0.71 (95%CI 0.64–0.78), respectively. Using regression models, pre-transfusion delta-pressure and PECMOO2 were the only independent factors associated with oxygenator function worsening (p < 0.001).ConclusionOur study suggests that overall, platelet transfusions do not seem to impact the ECMO oxygenator’s function. However, in the subgroup of patients with the lowest pre-transfusion oxygenator function, platelet transfusions were independently associated with a worsening function. Future studies should investigate if this warrants adjustments of the anticoagulation strategy around the platelet transfusion, especially among patients with lower oxygenator function.

Pharmacokinetic profiles of antifungal drugs during extracorporeal membrane oxygenation life support

Extracorporeal membrane oxygenation (ECMO), a kind of life support technology that can replace lung and heart function, is widely used in critical respiratory and circulatory exhaustion. Because of the serious diseases and the use of interventional catheters, patients receiving ECMO life support are often administrated with broad-spectrum antimicrobial agents, which increase the risk of fungal infection. Fungal infection during ECMO can increase mortality. How to effectively control fungal infection is a thorny problem faced by clinicians. During the treatment of ECMO, the patient's physiological status, ECMO oxygenation membrane, circulation pipeline and other factors may change the pharmacokinetic profiles of antifungal drugs, thereby affect the clinical efficacy of drugs. This artical reviews the pharmacokinetic characteristics of antifungal drugs during ECMO support, in order to provide references for clinical antifungal treatment.

Exhaled Breath and Oxygenator Sweep Gas Propionaldehyde in Acute Respiratory Distress Syndrome

Background: Oxidative stress-induced lipid peroxidation (LPO) due to neutrophil-derived reactive oxygen species plays a key role in the early stage of the acute respiratory distress syndrome (ARDS). Monitoring of oxidative stress in this patient population is of great interest, and, ideally, this can be done noninvasively. Recently, propionaldehyde, a volatile chemical compound (VOC) released during LPO, was identified in the breath of lung transplant recipients as a marker of oxidative stress. The aim of the present study was to identify if markers of oxidative stress appear in the oxygenator outflow gas of patients with severe ARDS treated with veno-venous extracorporeal membrane oxygenation (ECMO). Methods: The present study included patients with severe ARDS treated with veno-venous ECMO. Concentrations of acetone, isoprene, and propionaldehyde were measured in inspiratory air, exhaled breath, and oxygenator inflow and outflow gas at corresponding time points. Ion-molecule reaction mass spectrometry was used to measure VOCs in a sequential order within the first 24 h and on day three after ECMO initiation. Results: Nine patients (5 female, 4 male; age = 42.1 ± 12.2 year) with ARDS and already established ECMO therapy (pre-ECMO PaO2/FiO2 = 44.0 ± 11.5 mmHg) were included into analysis. VOCs appeared in comparable amounts in breath and oxygenator outflow gas (acetone: 838 (422–7632) vs. 1114 (501–4916) ppbv; isoprene: 53.7 (19.5–244) vs. 48.7 (37.9–108) ppbv; propionaldehyde: 53.7 (32.1–82.2) vs. 42.9 (24.8–122) ppbv). Concentrations of acetone, isoprene, and propionaldehyde in breath and oxygenator outflow gas showed a parallel course with time. Conclusions: Acetone, isoprene, and propionaldehyde appear in breath and oxygenator outflow gas in comparable amounts. This allows for the measurement of these VOCs in a critically ill patient population via the ECMO oxygenator outflow gas without the need of ventilator circuit manipulation.

Surgical outcomes and complications of bedside tracheostomy in the ICU for patients on ECMO.

Extracorporeal membrane oxygenation (ECMO) is increasingly employed in the management of patients with severe cardiac and pulmonary dysfunction. Patients commonly require tracheostomy for ventilator liberation. Though bedside percutaneous tracheostomy is commonly performed, it has the potential for increased complications, both surgical and with the ECMO circuit. We examined surgical outcomes of bedside percutaneous tracheostomy in the ECMO population. Patients were identified from an institutional database for bedside procedures. Demographics and data on complications were recorded. Descriptive statistics were calculated. 37 patients on ECMO at the time of tracheostomy were identified. Median age and BMI were 43.2 and 28.0, respectively. 33 patients (89%) were on VV ECMO, and 4 (11%) were on VA ECMO. All were on anticoagulation prior to tracheostomy, which was held for 4 h before and after the procedure in all cases. There were no procedure-related deaths or airway losses. No patients experienced periprocedural clotting events of their ECMO circuit or oxygenator within 24 h. 3 patients (8%) required reintervention (re-exploration or bronchoscopy) for bleeding. Four other patients (10%) had minor bleeding controlled with packing. One patient had pneumomediastinum which resolved without intervention, and one had an occlusion of their tracheostomy which was treated with tracheostomy exchange. Bedside percutaneous tracheostomy is feasible for patients on ECMO. Further study is needed to determine specific risk factors for complications and means to mitigate these. Bedside percutaneous tracheostomy may be considered as part of the management of patients on ECMO to help facilitate liberation from mechanical support.

Extracorporeal Membrane Oxygenation for Coronavirus Disease 2019 in Shanghai, China.

Severe cases of coronavirus disease 2019 (COVID-19) cannot be adequately managed with mechanical ventilation alone. The role and outcome of extracorporeal membrane oxygenation (ECMO) in the management of COVID-19 is currently unclear. Eight COVID-19 patients have received ECMO support in Shanghai with seven with venovenous (VV) ECMO support and one veno arterial (VA) ECMO during cardiopulmonary resuscitation. As of March 25, 2020, four patients died (50% mortality), three patients (37.5%) were successfully weaned off ECMO after 22, 40, and 47 days support, respectively, but remain on mechanical ventilation. One patient is still on VV ECMO with mechanical ventilation. The partial pressure of oxygen/fractional of inspired oxygen ratio before ECMO initiation was between 54 and 76, and all were well below 100. The duration of mechanical ventilation before ECMO ranged from 4 to 21 days. Except the one emergent VA ECMO during cardiopulmonary resuscitation, other patients were on ECMO support for between 18 and 47 days. In conclusion, ensuring effective, timely, and safe ECMO support in COVID-19 is key to improving clinical outcomes. Extracorporeal membrane oxygenation support might be an integral part of the critical care provided for COVID-19 patients in centers with advanced ECMO expertise.

Influence of Extracorporeal Membrane Oxygenation Circuit on Nutritional Supplements

Background The main function of extracorporeal membrane oxygenation (ECMO) is to provide systemic perfusion and gas exchange for patients with severe, acute respiratory or cardiac illness. The ECMO system consists of blood pump and a membrane oxygenator. ECMO oxygenator fibers, blood pump and tubing may bind circulating compounds such as drugs and nutritional components during ECMO support. Any loss of vital nutrients due to adsorption to the ECMO circuits may lead to further nutritional debilitation in critical ill patients. Objective The purpose of study is to analyze the amount of nutritional supplements adsorbed to the ECMO circuit under controlled ex vivo conditions Methods Six identical ECMO circuits were primed with fresh human whole blood and maintained under physiological conditions at 36°C for 24 hours. A dose of nutritional supplement calculated for a 70 kg patient was added. 150 mL volume was drawn from priming bag for control samples and kept under similar conditions. Blood samples were obtained at predetermined time points and analyzed for concentrations of vitamins, minerals, lipids, and proteins. Statistical analyses were performed using mixed models with robust standard errors, which allows for repeated samples within each setup and incomplete data. Results No significant differences were found between the ECMO circuits and controls for any of the measured variables: cobalamin, folate, vitamin A, glucose, concentration of minerals, HDL cholesterol, LDL cholesterol, total cholesterol, triglycerides, and total proteins. There was an initial decrease and then and increase in the concentration of cobalamin and folate. Vitamin A concentrations decreased in both groups over time. There was a decrease in concentration of glucose and an increased concentration of lactate dehydrogenase over time in both groups. Conclusion There were no changes in the concentrations of nutritional supplements in an ex vivo ECMO circuit compared to control samples, indicating that parenteral nutrition can be given during ECMO support. However, the time span of this study was limited, and the design made it impossible to investigate any functional and structural changes over time in nutritional supplements which lead to diminished effects through the ECMO circuit.

The use of apnea test and brain death determination in patients on extracorporeal membrane oxygenation: A systematic review

ObjectiveTo review practices of brain death (BD) determination in patients on extracorporeal membrane oxygenation (ECMO). MethodsA systematic search was applied to PubMed and 6 electronic databases from inception to May 22, 2019. Studies reporting methods of BD assessment in adult patients (>18 years old) while on ECMO were included, after which data regarding BD assessment were extracted. ResultsTwenty-two studies (n = 177 patients) met the inclusion criteria. Eighty-eight patients (50%) in 19 studies underwent the apnea test (AT); most commonly through decreasing the ECMO sweep flow in 14 studies (n = 42, 48%), followed by providing CO2 through the ventilator in 2 studies (n = 6, 7%), and providing CO2 through the ECMO oxygenator in 1 study (n = 1, 1%). The details of the AT were not reported in 2 studies (n = 39, 44%). In 19 patients (22%), the AT was nonconfirmatory due to hemodynamic instability, hypoxia, insufficient CO2 rise, or unreliability of the AT. A total of 157 ancillary tests were performed, including electroencephalogram (62%), computed tomography angiography (22%), transcranial Doppler ultrasound (6%), cerebral blood flow nuclear study (5%), cerebral angiography (4%), and other (1%). Forty-seven patients (53% of patients with AT) with confirmatory AT still underwent additional ancillary for BD confirmation. Only 21 patients (12% of all patients) were declared brain-dead using confirmatory ATs alone without ancillary testing. ConclusionsPerforming AT for patients with ECMO was associated with high failure rate and hemodynamic complications. Our study highlights the variability in practice in regard to the AT and supports the use of ancillary tests to determine BD in patients on ECMO.

Outcomes among Patients Treated with Renal Replacement Therapy during Extracorporeal Membrane Oxygenation: A Single-Center Retrospective Study

Background: Extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) are modalities used in critically ill patients suffering organ failure and metabolic derangements. Although the effects of CRRT have been extensively studied, the impact of simultaneous CRRT and ECMO is less well described. The purpose of this study is to evaluate the incidence and the impact of CRRT on outcomes of patients receiving ECMO. Methods: A single center, retrospective chart review was conducted for patients receiving ECMO therapy over a 6-year period. Patients who underwent combined ECMO and CRRT were compared to those who underwent ECMO alone. Intergroup ­statistical comparisons were performed using Wilcoxon/Kruskal-Wallis and chi-square tests. Logistic regression was performed to identify independent risk factors for mortality. Results: The demographic and clinical data of 92 patients who underwent ECMO at our center were reviewed including primary diagnosis, indications for and mode of ECMO support, illness severity, oxygenation index, vasopressor requirement, and presence of acute kidney injury. In those patients that required ECMO with CRRT, we reviewed urine output prior to initiation, modality used, prescribed dose, net fluid balance after 72 h, requirement of renal replacement therapy (RRT) at discharge, and use of diuretics prior to RRT initiation. Our primary endpoint was survival to hospital discharge. During the study period, 48 patients required the combination of ECMO with CRRT. Twenty-nine of these patients survived to hospital discharge. Of the 29 survivors, 6 were dialysis dependent at hospital discharge. The mortality rate was 39.5% with combined ECMO/CRRT compared to 31.4% among those receiving ECMO alone (p = 0.074). Of those receiving combined therapy, nonsurvivors were more likely to have a significantly positive net fluid balance at 72 h (p = 0.001). A multivariate linear regression analysis showed net positive fluid balance and increased age were independently associated with mortality. Conclusions: Use of CRRT is prevalent among patients undergoing ECMO, with over 50% of our patient population receiving combination therapy. Fluid balance appears to be an important variable associated with outcomes in this cohort. Rates of renal recovery and overall survival were higher compared to previously published reports among those requiring combined ECMO/CRRT.

First Experience with Extracorporeal Membrane Oxygenation in Iran, under Difficult Conditions

Background: Extracorporeal membrane oxygenation (ECMO) provides hemodynamic and oxygenation support in critical conditions. The commencement of this modality in Iran coincided with severe economic constraints across Iran. Methods: This retrospective study was performed in Masih Daneshvari Medical Center from 2010 to 2015, during which period, sanction-related limitations in the import of equipment prompted us to integrate a Medtronic or Stöckert head pump console into a Maquet ECMO Oxygenator so as to sustain the ECMO program. Comparisons were performed between successful and unsuccessful ECMO procedures and survivors. Factors associated with unsuccessful ECMO were evaluated with a multivariate logistic regression. Results: Thirty-three (68.8%) patients were male and 15 (31.2%) were female. The mean age of the patients was 35±16.6 years. Thirty-seven (77.1%) patients were weaned off ECMO successfully; the rate was higher than that in previous studies. Totally, 35.4% of the study population survived to hospital discharge. The most common cause of death in all the ECMO patients who were successfully weaned was sepsis. The most common cause of death in the patients who underwent unsuccessful ECMO was multisystem organ failure. The mean ECMO support time was 53.37±46.26 hours. The patients who were alive at discharge were significantly younger (25.5±14.5 vs. 40.2±15.5 y; P=0.002) and had a significantly lower ECMO duration (24 [25-75% interquartile: 18.5-36] vs. 48 [25-75% interquartile: 24-72] h; P=0.044) than the non-survivors. Conclusion: An assembly of ECMO components from different companies could be done safely, at least for a short period of time.