Extracorporeal membrane oxygenation-hemostatic complications

Acquired antithrombin deficiency in adult patients with postcardiotomy extracorporeal membrane oxygenation

IntroductionThis study aimed to investigate the relationship between acquired antithrombin deficiency in patients undergoing postcardiotomy extracorporeal membrane oxygenation (PC-ECMO) and thromboembolic or haemorrhagic events such as bleeding, peripheral arterial thromboembolism, and ischemic cerebrovascular events.MethodsThe study was designed as a single-center, prospective study and conducted at our hospital between November 2019 and June 2021. 50 patients who underwent ECMO due to postcardiotomy cardiogenic shock were included in the study. Antithrombin (AT) activity testing was performed immediately after ECMO placement and continued for 5 days. The total of haemorrhagic or thromboembolic events was defined as morbidity. The entire patient population was assessed daily for AT measurements according to morbidity status, and ROC analysis was applied to determine the cut-off point. The correlation between clinical outcomes and morbidities with antithrombin levels was analysed.ResultsIn our study, we identified a cut-off for AT levels on the first postoperative day. The risk of both bleeding (p = .006) and thromboembolism (p = .012) was significantly higher in patients below the 48.9% cut-off value. AT levels were compared with data on separation from PC-ECMO. The rate of separation from ECMO was 7.969 times higher in cases with AT levels above 51.8 on the third postoperative day and 5.6 times higher in cases with AT levels above 47.5 on the fourth postoperative day.ConclusionAcquired antithrombin deficiency may develop in adults undergoing PC-ECMO. In our study, we demonstrated that in patients with low antithrombin levels, the risk of bleeding and thromboembolism increased. Additionally, since AT levels were higher in survivors, this can be considered an indicator of severity. This study is the first prospective study related to determining target antithrombin levels in adult patients undergoing PC-ECMO.

Etiology of Leukemoid Reaction in Patients Undergoing Extracorporeal Membrane Oxygenation

INTRODUCTION

Nosocomial infections are frequent in patients receiving extracorporeal membrane oxygenation (ECMO). Leukemoid reaction, defined as >50,000 white blood cells (WBCs) per microliter, has been associated with infections in some populations. As ECMO is associated with significant inflammation activation between the patient's immune system and the circuit components, it is hypothesized that leukemoid reactions may have low specificity for identifying new infections in patients receiving ECMO.

MATERIALS AND METHODS

A retrospective cohort study was performed on all adult patients admitted to the Brooke Army Medical Center who received ECMO for greater than 72 hours between 2018 and 2022. Maximum WBCs were obtained for all charts. For those with leukemoid reaction, demographic information and clinical management was obtained. This study was determined to be exempt by Brooke Army Medical Center Institutional Review Board.

RESULTS

Among 182 patients receiving ECMO for greater than 72 hours, 15 (8%) developed a leukemoid reaction while on ECMO. The median (Interquartile range, IQR) WBC was 53.94 (50.98 to 62.55). Fourteen (93%) patients underwent an infectious evaluation. Patients had a median of 2 (IQR: 2 to 3) etiologies contributing to their leukemoid reaction. At the time of leukemoid reaction, 11 (73%) patients were receiving treatment for a known infection, 6 (40%) were found to have a new thrombus, and 4 (27%) were receiving glucocorticoids. Only 1 (7%) patient was found to have a new infection, an Acinetobacter baumannii bacteremia.

CONCLUSIONS

Leukemoid reactions occur infrequently in patients receiving ECMO and are generally multifactorial. In this cohort, leukemoid reactions rarely occurred in the setting of a new infection and suggest low utility to starting or broadening antimicrobials for these patients. Future studies identifying useful infectious markers are needed for patients receiving ECMO.

Clinical Relevance of Platelet-Leukocyte Aggregates and Platelet P-Selectin Expression During Venovenous Extracorporeal Membrane Oxygenation

Thrombosis continues to be a significant complication during venovenous extracorporeal membrane oxygenation (V-V ECMO). Platelet activation markers might serve as indicators of inflammation and thrombogenesis. The aim was to identify these markers in ECMO patients. Blood from 10 ECMO patients (before, during, after ECMO) and 11 healthy volunteers were collected to determine platelet-neutrophil-aggregates (PNAs), platelet-monocyte-aggregates (PMAs), fibrinogen-binding, and P-selectin-expression on platelets by flow cytometry. Critical illness was associated with significantly elevated levels of PNAs and PMAs, increased P-selectin expression, reduced fibrinogen-binding, and restricted activation of platelets. Although PNAs and PMAs decreased significantly within 2 hours after the initiation of ECMO and remained at those levels, ECMO did not affect basal P-selectin expression and fibrinogen-binding. These results correlated with coagulation activation. Platelet markers before ECMO were not indicators for an imminent system exchange and end of therapy. In conclusion, platelet dysfunction during ECMO was mainly attributed to the critical illness. Extracorporeal membrane oxygenation support strengthened the restricted response of platelets to exogenous agonists (P-selectin). Furthermore, a decrease in PNAs/PMAs after ECMO started identified a reduced inflammatory response. There was no correlation of analyzed platelet parameters with the incidence of thrombotic complications.

Evaluation of an aPTT guided versus a multimodal heparin monitoring approach in patients on extra corporeal membrane oxygenation: A retrospective cohort study

IntroductionBleeding and thrombotic complications are common in extracorporeal membrane oxygenation (ECMO) patients and are associated with increased mortality and morbidity. The optimal anticoagulation monitoring protocol in these patients is unknown. This study aims to compare the incidence of thrombotic and hemorrhagic complications before and after a protocol change. In addition, the association between hemostatic complications, coagulation tests and risk factors is evaluated.MethodsThis is a retrospective single center cohort study of adult ECMO patients. We collected demographics, ECMO parameters and coagulation test results. Outcomes of the aPTT guided and multimodal protocol, including aPTT, anti-Xa assay and rotational thromboelastometry were compared and the association between coagulation tests, risk factors and hemostatic complications was determined using a logistic regression analysis for repeated measurements.ResultsIn total, 250 patients were included, 138 in the aPTT protocol and 112 in the multimodal protocol. The incidence of thrombosis (aPTT: 14%; multimodal: 12%) and bleeding (aPTT: 36%; multimodal: 40%), did not significantly differ between protocols. In the aPTT guided protocol, the aPTT was associated with thrombosis (Odds Ratio [OR] 1.015; 95% confidence interval [CI] 1.004-1.027). In both protocols, surgical interventions were risk factors for bleeding and thrombotic complications (aPTT: OR 93.2, CI 39.9-217.6; multimodal OR 17.5, CI 6.5-46.9).DiscussionThe incidence of hemostatic complications was similar between both protocols and surgical interventions were a risk factor for hemostatic complications. Results from this study help to elucidate the role of coagulation tests and risk factors in predicting hemostatic complications in patients undergoing ECMO support.

Amniotic fluid embolism: A case-series

Amniotic fluid embolism (AFE) is a rare but potentially catastrophic pregnancy complication. This is a 10-year retrospective study on women with AFE from 2014 to 2023. Cases that met Clark's criteria or in whom a clinical diagnosis was made after exclusion of other causes were included. Information on clinical characteristics, treatment, complications and outcomes were collected and analysed. Four cases of AFE were identified. Two met Clark's criteria and presented with cardiac arrest requiring extracorporeal membrane oxygenation, of which one had cognitive and functional impairment. Two women had atypical AFE, one with disseminated intravascular coagulation (DIC)-type AFE who did not survive, and another who had paradoxical intracranial emboli from a patent foramen ovale, who had full recovery. All had coagulopathy and postpartum haemorrhage. Early recognition and initiation of cardiovascular support is crucial in AFE. DIC and haemorrhage should be treated aggressively. Survival and good outcomes of AFE are possible.

Current role of extracorporeal membrane oxygenation for the management of trauma patients: Indications and results

Extracorporeal membrane oxygenation (ECMO) has emerged as a vital circulatory life support measure for patients with critical cardiac or pulmonary conditions unresponsive to conventional therapies. ECMO allows blood to be extracted from a patient and introduced to a machine that oxygenates blood and removes carbon dioxide. This blood is then reintroduced into the patient’s circulatory system. This process makes ECMO essential for treating various medical conditions, both as a standalone therapy and as adjuvant therapy. Veno-venous (VV) ECMO primarily supports respiratory function and indicates respiratory distress. Simultaneously, veno-arterial (VA) ECMO provides hemodynamic and respiratory support and is suitable for cardiac-related complications. This study reviews recent literature to elucidate the evolving role of ECMO in trauma care, considering its procedural intricacies, indications, contraindications, and associated complications. Notably, the use of ECMO in trauma patients, particularly for acute respiratory distress syndrome and cardiogenic shock, has demonstrated promising outcomes despite challenges such as anticoagulation management and complications such as acute kidney injury, bleeding, thrombosis, and hemolysis. Some studies have shown that VV ECMO was associated with significantly higher survival rates than conventional mechanical ventilation, whereas other studies have reported that VA ECMO was associated with lower survival rates than VV ECMO. ECMO plays a critical role in managing trauma patients, particularly those with acute respiratory failure. Further research is necessary to explore the full potential of ECMO in trauma care. Clinicians should have a clear understanding of the indications and contraindications for the use of ECMO to maximize its benefits in treating trauma patients.

Surface Modification of Poly(dimethylsiloxane) Blood Flow Chambers with a Poly(ethylene glycol) Conjugate and Factor XII Inhibitor

This study is focused on the application of a dual surface coating on poly(dimethylsiloxane) (PDMS) flow chambers, which aims to inhibit the contact activation pathway of coagulation. Polyethylene glycol (PEG) is a commonly used biocompatible molecule due to its hydrophilic nature and capacity to reduce protein adsorption. Corn trypsin inhibitor (CTI) is a selective inhibitor of Factor XII, which is the initial factor responsible for activating the intrinsic pathway of coagulation. By sequentially applying these two coatings to PDMS substrates, we expect the PEG-CTI coating to decrease blood clot formation and reduce fibrinogen deposition on surfaces compared to uncoated surfaces. Our results indicate that the PEG-CTI coating was successful in significantly reducing both cell adsorption and fibrinogen deposition to the surfaces of PDMS flow chambers. This study is a step toward applying PEG-CTI surface coatings to PDMS microfluidic artificial lungs, in which the surface interaction between the PDMS lungs and blood is a critical issue that must be mitigated to realize the full potential of this exciting therapeutic tool.

Anticoagulation Monitoring Strategies During Extracorporeal Membrane Oxygenation (ECMO) Therapy - Differences Between Simultaneously Obtained Coagulation Tests: A Retrospective Single-Center Cohort Study

INTRODUCTION

During extracorporeal membrane oxygenation (ECMO) systemic anticoagulation with unfractionated heparin (UFH) is standard-of-care. However, there is uncertainty regarding optimal anticoagulation monitoring strategies.

METHODS

We retrospectively investigated venovenous and venoarterial ECMO patients at the medical ICUs at the Medical University of Graz, Austria. We analyzed the correlation and concordance of R-time in thromboelastography (TEG), activated partial thromboplastin time (aPTT), and anti-Xa activity. The proportion within target range, the association of coagulation parameters above or below target range (aPTT 54-72 s; equals 1.5-2× upper limit of normal (ULN), anti-Xa activity 0.2-0.5 U/mL, and R-time in assays without heparinase 675-900 s; equals 1.5-2× ULN) with mortality, bleeding events and thrombotic complications were investigated.

RESULTS

We analyzed 671 clusters of simultaneously performed coagulation tests in 85 ECMO cases that fulfilled inclusion criteria. Median age of patients was 57 years and 32% were female. There were poor correlations between the three coagulation tests and the proportion of discordance was 46%. Within the target range were 21% of R-time, 15% of aPTT, and 44% of anti-Xa activity measurements. Singular and multiple bleeding events occurred in 25 and 32 patients, respectively. The most common bleeding locations were catheter and cannula insertion sites followed by pulmonary hemorrhage. In VA-ECMO, anti-Xa activity was associated (OR 1.03 [1.01-1.06], p = 0.005) and correlated with bleeding events (spearman rho 0.49, p = 0.002; point biserial 0.49, p = 0.001). aPTT level below target range was associated with reduced mortality (OR 0.98 [0.97-0.99], p = 0.024). Thrombotic events occurred in six patients with no association of coagulation tests.

CONCLUSION

There was a high rate of discordance and poor correlation between aPTT, anti-Xa activity and R-time in TEG in ECMO patients. We found high rates of bleeding events and in VA-ECMO an association with elevated anti-Xa activity levels.

Fibrinogen levels and bleeding risk in adult extracorporeal cardiopulmonary resuscitation: multicenter observational study subanalysis

•Hypofibrinogenemia frequently occurs in extracorporeal cardiopulmonary resuscitation (ECPR) and may heighten bleeding risk. This subanalysis of a multicenter observational study (SAVE-J II) included 2,100 adult patients receiving ECPR after out-of-hospital cardiac arrest at 36 facilities in Japan.•Overall, 7.5% of patients experienced non-cannulation hemorrhagic complications, and those with fibrinogen levels below 140 mg/dL at ECPR initiation faced significantly higher bleeding risk. These findings underscore the importance of monitoring and managing fibrinogen levels in ECPR to mitigate hemorrhagic events and improve patient outcomes.

Improved Results Over Time With Bridge-to-Lung Transplantation: A 10-Year Experience of a Single High-Volume Center

When donor scarcity limits timely lung transplantation (LTx), extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation (BTT) can prolong survival and delay deconditioning until the donor lungs become available. We reviewed 10-year BTT experiences of a single high-volume center, where 99 (59%) were on ECMO BTT among 169 eligible adult LTx cases. Both 28-day and 2-year survivals did not differ between BTT and non-BTT. The BTT data was then divided into two periods, delineated by the most recent 3 years. The clinical outcomes of the earlier period ("Period 1") and the later period ("Period 2") were compared, and mortality within 28 days of LTx was significantly lower in Period 2 (n = 1, 1.7%) than in Period 1 (n = 6, 14.6%, p < 0.01). Improved survival was observed in the subgroup with BTT duration of 14 days or more. Taken together, more experiences in BTT and improved competence may contribute to better survival after LTx, especially in patients receiving ECMO for 14 days or more.

Prospective Randomized Pilot Study Comparing Bivalirudin Versus Heparin in Neonatal and Pediatric Extracorporeal Membrane Oxygenation

OBJECTIVES

To test feasibility of a randomized controlled trial (RCT) with an endpoint of time at goal anticoagulation in children on extracorporeal membrane oxygenation (ECMO) randomized to receive bivalirudin vs. unfractionated heparin.

DESIGN

Open-label pilot RCT (NCT03318393) carried out 2018-2021.

SETTING

Single-center quaternary U.S. pediatric hospital.

PATIENTS

Children 0 days to younger than 18 years old supported with ECMO in the PICU or cardiovascular ICU.

INTERVENTIONS

Randomization to bivalirudin vs. unfractionated heparin while on ECMO.

MEASUREMENTS AND MAIN RESULTS

Sixteen patients were randomized to bivalirudin, and 14 patients were randomized to heparin. There was no difference in the primary outcome, time spent at goal anticoagulation, for patients randomized to bivalirudin compared with those randomized to heparin. While hemorrhagic complications were similar between study groups, thrombotic complications were higher with six of 16 patients in the bivalirudin group having one or more circuit changes compared with 0 of 14 patients in heparin group (mean difference, 37.5% [95% CI, 8.7-61.4%]; p = 0.02). Patients in the bivalirudin group received less packed RBC transfusions vs. those receiving heparin (median [interquartile range], 6.3 mL/kg/d [2.5-8.4 mL/kg/d] vs. 12.2 mL/kg/d [5.5-14.5 mL/kg/d]; p = 0.02).

CONCLUSIONS

In this single-center pilot RCT carried out 2018-2021, we found that the test of anticoagulation therapy of bivalirudin vs. heparin during ECMO was feasible. Larger multicenter studies are required to further assess the safety and efficacy of bivalirudin for pediatric ECMO.

What's the optimal temperature control strategy in patients receiving ECPR after cardiac arrest? A network meta-analysis

BACKGROUND

The optimal temperature control strategy in extracorporeal cardiopulmonary resuscitation (ECPR) patients is unknown, and several trials have reported conflicting results regarding its effectiveness. We aimed to conduct a systemic review and network meta-analysis (NMA) to assess the efficacy of temperature control in ECPR patients.

METHODS

Database searching of studies reporting data on temperature control strategy during ECPR in MEDLINE, EMBASE, Scopus, and Cochrane Library was performed. Primary outcomes were overall survival and neurological outcome. Pairwise meta-analysis and Bayesian NMA were performed on studies comparing outcomes among groups of moderate hypothermia (32-34 °C), mild hypothermia (34.1-36 °C) and normothermia (36.1-37.5 °C).

RESULTS

Nineteen retrospective studies were included (5622 patients). Statistically significant differences in good neurological outcome were observed in the direct comparison of moderate hypothermia and mild hypothermia (OR, 1.73; 95 % CI: 1.07-2.81) as well as moderate hypothermia and normothermia (OR, 2.14; 95 % CI: 1.24-3.67), but no significant differences were found in the NMA result. There was no difference in either survival outcome or the incidence of bleeding complications among any groups according to direct or indirect analysis.

CONCLUSIONS

Direct evidence suggests that moderate hypothermia might be associated with improved neurological outcomes in ECPR patients. However, no significant differences in survival outcomes were observed in either the direct or NMA results. Given the lower level of the evidence, interpretation should be made with caution.

Vascular Complications After Venoarterial Extracorporeal Membrane Oxygenation Support: A CT Study

OBJECTIVES

Vascular complications after venoarterial extracorporeal membrane oxygenation (ECMO) remains poorly studied, although they may highly impact patient management after ECMO removal. Our aim was to assess their frequency, predictors, and management.

DESIGN

Retrospective, observational cohort study.

SETTING

Two ICUs from a tertiary referral academic hospital.

PATIENTS

Adult patients who were successfully weaned from venoarterial ECMO between January 2021 and January 2022.

INTERVENTIONS

None.

PRIMARY OUTCOME

Vascular complications frequency related to ECMO cannula.

MEASUREMENTS AND MAIN RESULTS

A total of 288 patients were implanted with venoarterial ECMO during the inclusion period. One hundred ninety-four patients were successfully weaned, and 109 underwent a CT examination to assess for vascular complications until 4 days after the weaning procedure. The median age of the cohort was 58 years (interquartile range [IQR], 46-64 yr), with a median duration of ECMO support of 7 days (IQR, 5-12 d). Vascular complications were observed in 88 patients (81%). The most frequent complication was thrombosis, either cannula-associated deep vein thrombosis (CaDVT) ( n = 63, 58%) or arterial thrombosis ( n = 36, 33%). Nonthrombotic arterial complications were observed in 48 patients (44%), with 35 (31%) presenting with bleeding. The most common site of CaDVT was the inferior vena cava, occurring in 33 (50%) of cases, with 20% of patients presenting with pulmonary embolism. There was no association between thrombotic complications and ECMO duration, anticoagulation level, or ECMO rotation flow. CT scans influenced management in 83% of patients. In-hospital mortality was 17% regardless of vascular complications.

CONCLUSIONS

Vascular complications related to venoarterial ECMO cannula are common after ECMO implantation. CT allows early detection of complications after weaning and impacts patient management. Patients should be routinely screened for vascular complications by CT after decannulation.

Markers of Endothelial Injury in Extracorporeal Membrane Oxygenation: A New Risk Assessment Method

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) has become more widely used in recent years. However, ECMO remains a resource-intensive modality, and identifying patients most likely to benefit from it can be a complex task. Few methods exist to help risk stratify potential ECMO patients. Syndecan-1 (SDC-1) and soluble thrombomodulin (sTM) are markers of endothelial dysfunction and are used as a sign of disease severity in various forms of trauma. Our study aims to evaluate the association between precannulation levels of SDC-1 and sTM with mortality, current scoring systems, and their ability to predict mortality on ECMO.

METHODS

Patients initiated on venoarterial ECMO were retrospectively analyzed. Clinical data were collected, and precannulation Acute Physiology and Chronic Health Evaluation scores were calculated. Blood samples from precannulation collection were assayed for SDC-1 and sTM by enzyme linked immunosorbent assay. The primary outcome was mortality on ECMO.

RESULTS

Thirty-four patients were included in the analysis. Most were male (76.5%), with a median age of 61.5 y and body mass index of 28.2. Overall mortality was 61.7%. sTM was significantly higher in patients who died on venoarterial ECMO compared to those who lived. Pre-SDC-1 level of ≥951 ng/mL is marginally predictive of a higher mortality risk (area under the receiver operating characteristic curve 0.70; P = 0.070). Pre-sTM levels of ≥5348 pg/mL predicted mortality (area under the receiver operating characteristic curve 0.89; P = 0.003).

CONCLUSIONS

SDC-1 and sTM are associated with a higher mortality risk in patients on ECMO. These biomarkers may be a valuable addition to current scoring systems. Furthermore, more work should focus on characterizing the effects of cardiogenic shock on the endothelium.

Association of Activated Clotting Time-Guided Anticoagulation with Complications during Extracorporeal Membrane Oxygenation Support: A Systematic Review and Meta-Analysis

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) requires systemic anticoagulation to reduce the risk of thromboembolic events. Despite its historic role, activated clotting time (ACT) remains a widely used heparin monitoring method. Systematic evidence on the association of ACT-guided monitoring with hemorrhagic or thromboembolic complications does not exist.

DESIGN

Systematic literature review and meta-analysis (Scopus and PubMed, July 2023).

SETTING

All cohort studies.

PARTICIPANTS

Patients receiving ECMO support.

INTERVENTION

Anticoagulation monitoring with ACT.

MEASUREMENTS AND MAIN RESULTS

We identified 3,177 publications, with 8 studies reporting the average ACT values for patients with and without bleeding. Meta-analysis revealed no significant difference in the compared groups (SMD = 0.69; 95% CI -0.05 to 1.43, p = 0.069; I2 = 87.4%). Three studies (n = 117 patients) reported on the average ACT values for patients with thrombosis, without significant differences in ACT between patients with and without thrombosis (SMD = 0.47; 95% CI -0.50 to 1.44, p = 0.342; I2 = 81.1%).

CONCLUSIONS

Even though ACT is a widely used heparin monitoring tool, the evidence on its association with hemorrhagic or thromboembolic events is still controversial and limited. Further studies are essential to elucidate the role of ACT in anticoagulation monitoring during ECMO support.

Anticoagulation Management for Veno-Venous ECMO in COVID-19 Patients: Argatroban as Rescue Therapy in Heparin-Associated Thrombocytopenia

Background/Objectives: Extracorporeal membrane oxygenation (ECMO) has been widely used as a life support technique in COVID-19 acute respiratory distress syndrome (ARDS). The use of anticoagulation during ECMO support remains a topic of debate. The primary aim of this study is to demonstrate the safety and efficacy of using argatroban as an anticoagulant instead of heparin in patients with heparin-associated thrombocytopenia. Methods: 40 patients were enrolled and initially treated with unfractionated heparin for anticoagulation during ECMO, composing the UFH group. Twenty-one of these patients experienced a drop in platelet count to below 100,000 cells/mm3 and, after testing negative for IgG anti-PF4/heparin, the anticoagulation was switched to argatroban, composing the ARG group. Hemorrhagic events were recorded along with blood chemistry parameters. Results: Bleedings were significantly more frequent in the UFH group than in ARG group (58/579 days vs. 21/357 days, p = 0.041). No significant differences were observed in hemorrhagic episodes for each bleeding site, except for tracheal stoma (14 vs. 1, p = 0.011). No differences in activated partial thromboplastin time (aPTT) values were found between the two groups (aPTT 42.65 s vs. 44.70 s, p = 0.443). Linear regression analysis revealed that the platelet count on day 5 was correlated with the initial platelet count but not with the type of anticoagulant used (p = 0.001, CI 0.55, 0.69 and p = 0.078). Linear regression analysis in both groups showed a correlation between the duration of ECMO support and intensive care unit stay for the median aPTT and median platelet count. Furthermore, no major systemic thrombotic events or circuit clotting were observed in this patient cohort. Conclusions: Argatroban seems to be safe in patients with persistent heparin-associated thrombocytopenia undergoing ECMO.

The early decline in platelet count is associated with increased adverse outcomes in non heparin-induced thrombocytopenia pediatric patients undergoing VA-ECMO

INTRODUCTION

The impact of non heparin-induced thrombocytopenia on the clinical outcomes for pediatric cardiac surgery patients who required veno-arterial extracorporeal membrane support (VA-ECMO) for failure to wean from cardiopulmonary bypass (CPB) is uncertain. This study aimed to investigate the relationship between thrombocytopenia and prognosis in these patients.

METHODS

This retrospective study enrolled 96 pediatric patients (age < 18) who received VA-ECMO directly transitioned from CPB at Fuwai Hospital from January 2010 to June 2020. The association between relative decrease in platelet count (△PLT) post-ECMO 24 h and clinical outcomes was explored.

RESULTS

There were significant differences in Post-ECMO 24 h platelet counts, platelet count nadir, and duration of platelet decline between the survivors and non-survivors in CPB-ECMO groups. A positive correlation was found between △PLT post-ECMO 24 h and plasma-free hemoglobin (pFHb) (p = .014, r = 0.305), peak serum creatinine (p = .016, r = 0.299), peak AST (p = .014, r = 0.302), duration of platelet transfusion (p = .032, r = 0.270),The △PLT post-ECMO 24 h had predictive value on in-hospital mortality [(p < .001, AUROC = 0.781 (95% CI: 0.670-0.892)], massive bleeding (p = .001, AUROC 95% CI: 0.627-0.870), hemolysis (p = .046, AUROC 95% CI: 0.510-0.780), and nosocomial infection (p = .020, AUROC 95% CI: 0.536-0.801). Multivariate logistic regression showed that △PLT post-ECMO 24 h was associated with in-hospital mortality and hemolysis.

CONCLUSIONS

The relative early decrease in platelet count 24 h following transition to ECMO is associated with increased patient mortality, and is positively associated with adverse outcomes in pediatric cardiac surgery patients transferred from CPB to ECMO. Moreover, this decline rate can predict in-hospital survival, major bleeding, hemolysis, and hospital-acquired infections.

Prediction of Thrombus Formation within an Oxygenator via Bioimpedance Analysis

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.

Discontinuation of Cardiac Devices at or Near an Adult Patient's End of Life

Advances in medical technology have begun to blur the lines between life and death as well as the lines between appropriate and inappropriate therapy. This review addresses the charged issue of the management of cardiac devices at or near the end of a patient's life, provides a summary of prior and current opinion with some historical context, and attempts to provide some modest guidance as to how to approach the various options to the patient's best advantage. Modalities to be addressed include indwelling electronic devices, the left ventricular assistance device, and extracorporeal mechanical oxygenation, and includes available outcome data as well as ethical analysis from a number of commentators. The expected further increase in technical sophistication of these devices is expected to render the various aspects of device deactivation more and more complex over the course of the next few years such that careful attention to and knowledge about this issue will continue to be more and more necessary.

"Reactive" Chemical Strategy to Attain Substrate Independent "Liquid-Like" Omniphobic Solid Anti-Biofouling Coatings

Covalent and defect-free surface-grafted solid lubricating chains that can impart 'liquid-like' slippery behavior have proven advantageous over lubricant infused and textured anti-wetting surfaces. Herein, the co-hydrolysis and co-condensation of a mixture of organosilanes followed by the epoxy-amine ring opening reaction at the interface results in a highly robust, transparent and 'liquid-like' solid slippery omniphobic coating (LL-OSC). The presence of the epoxy-terminated organosilane a) acts as a molecular spacer in between the low-surface energy, rigid fluorine terminated silane and b) provides 'reactive' epoxy groups for covalent binding to a pre-functionalized amine surface for potential applicability in droplet transport and manipulation, diagnostics etc. LL-OSC exhibits resistance to both solid and liquid abrasions such as sandpaper abrasions, prolonged UV irradiation, DI water and high temperature (30 days), submersion in chemically contaminated aqueous solutions. This is the first report of a hemocompatible solid slippery coating for inhibiting platelet adhesion, thus, paving way for blood-contacting medical device applications. Our LL-OSC exhibits remarkable cytocompatibility, repellence to plasma protein, cells and prevents biofilm formation. Additionally, the substrate independent LL-OSC can be applied onto metals and polymers. We envision that the reported durable, solid slippery coating will find widespread applicability in hospital settings, electronic devices etc.

Outcomes of extracorporeal membrane oxygenation cannulation strategy in lung transplantation: A retrospective cohort study

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) with different cannulation strategies is determined according to surgical position and patient condition. However, no cannulation guidelines have been proposed. This retrospective study assessed the outcomes of diverse ECMO cannulation strategies in patients undergoing lung transplantation (LTx).

METHODS

Data of patients undergoing intraoperative veno-arterial ECMO-assisted LTx were retrospectively collected from December 1st, 2015 to October 31st, 2021. Patients were classified into three groups based on the different cannulation strategies: femoral artery-femoral vein (F-F)-ECMO, axillary artery-femoral vein (A-F)-ECMO, and ascending aorta-femoral vein (AAO-F)-ECMO. The F-F-ECMO, A-F-ECMO, and AAO-F-ECMO groups comprised 34, 44, and 30 patients, respectively.

MAIN RESULTS

The AAO-F-ECMO group exhibited a significantly shorter duration of postoperative ECMO therapy (3 vs. 2 vs. 0 days, P < 0.01).the level of postoperative proBNP was lower on the third and seventh days (P < 0.001). AAO-F-ECMO patients had a significantly lower incidence of postoperative infections, heart failure, and bleeding (P < 0.05). Similar outcomes were observed in postoperative survival rates among the three groups (P > 0.05).

CONCLUSIONS

Ascending aorta-femoral vein ECMO can provide sufficient and effective aerobic blood to perfuse organs with fewer side effects than cannulation in the femoral artery-femoral vein or axillary artery-femoral vein.

Factor XII promotes the thromboinflammatory response in a rat model of venoarterial extracorporeal membrane oxygenation

BACKGROUND

Factor XII (FXII) is a multifunctional protease capable of activating thrombotic and inflammatory pathways. FXII has been linked to thrombosis in extracorporeal membrane oxygenation (ECMO), but the role of FXII in ECMO-induced inflammatory complications has not been studied. We used novel gene-targeted FXII- deficient rats to evaluate the role of FXII in ECMO-induced thromboinflammation.

METHODS

FXII-deficient (FXII-/-) Sprague-Dawley rats were generated using CRISPR/Cas9. A minimally invasive venoarterial (VA) ECMO model was used to compare wild-type (WT) and FXII-/- rats in 2 separate experimental cohorts: rats placed on ECMO without pharmacologic anticoagulation and rats anticoagulated with argatroban. Rats were maintained on ECMO for 1 hour or until circuit failure occurred. Comparisons were made with unchallenged rats and rats that underwent a sham surgical procedure without ECMO.

RESULTS

FXII-/- rats were maintained on ECMO without pharmacologic anticoagulation with low resistance throughout the 1-hour experiment. In contrast, WT rats placed on ECMO without anticoagulation developed thrombotic circuit failure within 10 minutes. Argatroban provided a means to maintain WT and FXII-/- rats on ECMO for the 1-hour time frame without thrombotic complications. Analyses of these rats demonstrated that ECMO resulted in increased neutrophil migration into the liver that was significantly blunted by FXII deficiency. ECMO also resulted in increases in high molecular weight kininogen cleavage and complement activation that were abrogated by genetic deletion of FXII.

CONCLUSIONS

FXII initiates hemostatic system activation and key inflammatory sequelae in ECMO, suggesting that therapies targeting FXII could limit both thromboembolism and inopportune inflammatory complications in this setting.

Membrane-based microfluidic systems for medical and biological applications

Microfluidic devices with integrated membranes that enable control of mass transport in constrained environments have shown considerable growth over the last decade. Membranes are a key component in several industrial processes such as chemical, pharmaceutical, biotechnological, food, and metallurgy separation processes as well as waste management applications, allowing for modular and compact systems. Moreover, the miniaturization of a process through microfluidic devices leads to process intensification together with reagents, waste and cost reduction, and energy and space savings. The combination of membrane technology and microfluidic devices allows therefore magnification of their respective advantages, providing more valuable solutions not only for industrial processes but also for reproducing biological processes. This review focuses on membrane-based microfluidic devices for biomedical science with an emphasis on microfluidic artificial organs and organs-on-chip. We provide the basic concepts of membrane technology and the laws governing mass transport. The role of the membrane in biomedical microfluidic devices, along with the required properties, available materials, and current challenges are summarized. We believe that the present review may be a starting point and a resource for researchers who aim to replicate a biological phenomenon on-chip by applying membrane technology, for moving forward the biomedical applications.

Evaluating the efficacy and safety of temporary mechanical circulatory support devices in acute cardiogenic shock: A subgroup-specific systematic review

OBJECTIVE

This systematic review aims to assess the comparative effectiveness and safety of temporary mechanical circulatory support (MCS) devices in various subgroups of patients with acute cardiogenic shock, providing insights for personalized clinical decision-making.

METHODS

We conducted a comprehensive search across major databases to identify studies that reported on the use of temporary MCS devices like TandemHeart, Impella, and VA-ECMO in acute cardiogenic shock. Special attention was given to subgroup analyses based on etiologies of shock, patient demographics, and comorbid conditions.

RESULTS

Our analysis revealed that while devices like TandemHeart and Impella offer significant hemodynamic support, their effectiveness and safety profiles vary across different patient subgroups. VA-ECMO demonstrated the highest flow rates and potential for mortality benefits but requires careful management due to associated risks. The lack of randomized controlled trials in specific patient subgroups highlights a gap in the current literature, underscoring the need for targeted research.

CONCLUSION

The review underscores the necessity of a personalized approach in selecting temporary MCS devices for patients with acute cardiogenic shock, guided by specific patient characteristics and clinical scenarios. Future research should focus on addressing the identified evidence gaps through well-designed studies that provide robust subgroup-specific data, enabling clinicians to optimize treatment strategies and improve patient outcomes in this critical care context.

Management of Extracorporeal Membrane Oxygenation Anticoagulation in the Perioperative Period: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To derive systematic review-informed, modified Delphi consensus regarding the management of children on extracorporeal membrane oxygenation (ECMO) undergoing invasive procedures or interventions developed by the Pediatric Anticoagulation on ECMO CollaborativE (PEACE) Consensus Conference.

DATA SOURCES

A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021.

STUDY SELECTION

ECMO anticoagulation and hemostasis management in the perioperative period and during procedures.

DATA EXTRACTION

Two authors reviewed all citations independently, with a third independent reviewer resolving any conflicts. Seventeen references were used for data extraction and informed recommendations. Evidence tables were constructed using a standardized data extraction form.

DATA SYNTHESIS

Risk of bias was assessed using the Quality in Prognosis Studies tool. The evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation system. Forty-eight experts met over 2 years to develop evidence-based recommendations and, when evidence was lacking, expert-based consensus statements for the management of bleeding and thrombotic complications in pediatric ECMO patients. A web-based modified Delphi process was used to build consensus via the Research And Development/University of California Appropriateness Method. Consensus was defined as greater than 80% agreement. Four good practice statements, 7 recommendations, and 18 consensus statements are presented.

CONCLUSIONS

Although agreement among experts was strong, important future research is required in this population for evidence-informed recommendations.

Heparin-induced thrombocytopenia in extracorporeal membrane oxygenation-supported patients: a systematic review and meta-analysis

BACKGROUND

In recent years, extracorporeal membrane oxygenation (ECMO) has been increasingly used in critically ill patients with respiratory or cardiac failure. Heparin is usually used as anticoagulation therapy during ECMO support. However, heparin-induced thrombocytopenia (HIT) in ECMO-supported patients, which results in considerable morbidity and mortality, has not yet been well described. This meta-analysis and systematic review aimed to thoroughly report the incidence of HIT on ECMO, as well as the characteristics and outcomes of HIT patients.

METHODS

We searched the PubMed, Embase, Cochrane Library, and Scopus databases for studies investigating HIT in adult patients supported by ECMO. All studies conforming to the inclusion criteria were screened from 1975 to August 2023. Nineteen studies from a total of 1,625 abstracts were selected. The primary outcomes were the incidence of HIT and suspected HIT.

RESULTS

The pooled incidence of HIT in ECMO-supported patients was 4.2% (95% CI: 2.7-5.6; 18 studies). A total of 15.9% (95% CI: 9.0-22.8; 12 studies) of patients on ECMO were suspected of having HIT. Enzyme-linked immunosorbent assay (ELISA) is the most commonly used immunoassay. The median optical density (OD) of the ELISA in HIT-confirmed patients ranged from 1.08 to 2.10. In most studies, the serotonin release assay (SRA) was performed as a HIT-confirming test. According to the subgroup analysis, the pooled incidence of HIT in ECMO patients was 2.7% in studies whose diagnostic mode was functional assays, which is significantly lower than the incidence in studies in which the patients were diagnosed by immunoassay (14.5%). Argatroban was most commonly used as an alternative anticoagulation agent after the withdrawal of heparin. Among confirmed HIT patients, 45.5% (95% CI: 28.8-62.6) experienced thrombotic events, while 50.1% (95% CI: 24.9-75.4) experienced bleeding events. Overall, 46.6% (95% CI: 30.4-63.1) of patients on ECMO with HIT died.

CONCLUSION

According to our study, the pooled incidence of HIT in ECMO-supported patients is 4.2%, and it contributes to adverse outcomes. Inappropriate diagnostic methods can easily lead to misdiagnosis of HIT. Further research and development of diagnostic algorithms and laboratory assays are warranted.

Differences in Treatment Outcomes According to the Insertion Method Used in Extracorporeal Cardiopulmonary Resuscitation: A Single-Center Experience

Background

Venoarterial extracorporeal membrane oxygenation (ECMO) is a key treatment method used with patients in cardiac arrest who do not respond to medical treatment. A critical step in initiating therapy is the insertion of ECMO cannulas. Peripheral ECMO cannulation methods have been preferred for extracorporeal cardiopulmonary resuscitation (ECPR).

Methods

Patients who underwent ECPR at Daegu Catholic University Medical Center between January 2017 and May 2023 were included in this study. We analyzed the impact of 2 different peripheral cannulation strategies (surgical cutdown vs. percutaneous cannulation) on various factors, including survival rate.

Results

Among the 99 patients included in this study, 66 underwent surgical cutdown, and 33 underwent percutaneous insertion. The survival to discharge rates were 36.4% for the surgical cutdown group and 30.3% for the percutaneous group (p=0.708). The ECMO insertion times were 21.3 minutes for the surgical cutdown group and 10.3 minutes for the percutaneous group (p<0.001). The factors associated with overall mortality included a shorter low-flow time (hazard ratio [HR], 1.045; 95% confidence interval [CI], 1.019-1.071; p=0.001) and whether return of spontaneous circulation was achieved (HR, 0.317; 95% CI, 0.127-0.787; p=0.013). Low-flow time was defined as the time from the start of cardiopulmonary resuscitation to the completion of ECMO cannula insertion.

Conclusion

No statistically significant difference in in-hospital mortality was observed between the surgical and percutaneous groups. However, regardless of the chosen cannulation strategy, reducing ECMO cannulation time was beneficial, as a shorter low-flow time was associated with significant benefits in terms of survival.

Lung biopsies in infants and children in critical care situation

INTRODUCTION

Lung biopsy is considered as the last step investigation for diagnosing lung diseases; however, its indication must be carefully balanced with its invasiveness. The present study aims to evaluate the diagnostic yield of lung biopsy in critically ill patients hospitalized in the pediatric intensive care unit (ICU).

MATERIAL AND METHODS

Children who underwent a lung biopsy in the ICU between 1995 and 2022 were included. Biopsies performed in the operating room and post-mortem biopsies were excluded.

RESULTS

Thirty-one patients were included, with a median age of 18 days (2 days to 10.8 years); 21 (67.7%) were newborns. All patients required invasive mechanical ventilation, 26 (89.7%) had a pulmonary hypertension, and 22 (70.9%) were placed under extracorporeal membrane oxygenation (ECMO). The lung biopsy led to a diagnosis in 81% of the patients. The diagnostic reliability seemed to decrease with age (95% in newborns, 71% in 1 month to 2 years and 0/3 patients aged over 2 years old). Diffuse developmental disorders of the lung accounted for 15 (49%) patients, primarily alveolar capillary dysplasia, followed by surfactant disorders in 5 (16%) patients. Complications occurred in 9/31 (29%) patients including eight under ECMO, with massive hemorrhages in seven cases.

DISCUSSION AND CONCLUSION

In critical situations, lung biopsy should be performed. Lung biopsy is a reliable diagnostic procedure for neonates in critical situation when a diffuse developmental disorder of the lung is suspected. The majority of lung biopsy complication was associated with the use of ECMO. The prospective evaluation of the complications of such procedure under ECMO, and particularly over 10 days of ECMO and in children over 2-year-old remains to be ascertained.

Multi-Method Investigation of Blood Damage Induced By Blood Pumps in Different Clinical Support Modes

To investigate the effects of blood pumps operated in different modes on nonphysiologic flow patterns, cell and protein function, and the risk of bleeding, thrombosis, and hemolysis, an extracorporeal blood pump (CentriMag) was operated in three clinical modalities including heart failure (HF), venous-venous (V-V) extracorporeal membrane oxygenation (ECMO), and venous-arterial (V-A) ECMO. Computational fluid dynamics (CFD) methods and coupled hemolysis models as well as recently developed bleeding and thrombosis models associated with changes in platelet and von Willebrand factor (vWF) function were used to predict hydraulic performance and hemocompatibility. The V-A ECMO mode had the highest flow losses and shear stress levels, the V-V ECMO mode was intermediate, and the HF mode was the lowest. Different nonphysiologic flow patterns altered cell/protein morphology and function. The V-A ECMO mode resulted in the highest levels of platelet activation, receptor shedding, vWF unfolding, and high molecular weight multimers vWF (HMWM-vWF) degradation, leading to the lowest platelet adhesion and the highest vWF binding capacity, intermediate in the V-V ECMO mode, and opposite in the HF mode. The V-A ECMO mode resulted in the highest risk of bleeding, thrombosis, and hemolysis, with the V-V ECMO mode intermediate and the HF mode lowest. These findings are supported by published experimental or clinical statistics. Further studies found that secondary blood flow passages resulted in the highest risk of blood damage. Nonphysiologic blood flow patterns were strongly associated with cell and protein function changing, blood damage, and complications.

Analysis of adverse events related to extracorporeal membrane oxygenation from a nationwide database of patient-safety accidents in Japan

Although adverse events related to extracorporeal membrane oxygenation have been reported, epidemiological data on life-threatening events are insufficient to study the causes of such adverse events. Data from the Japan Council for Quality Health Care database were retrospectively analyzed. The adverse events extracted from this national database included events associated with extracorporeal membrane oxygenation reported between January 2010 and December 2021. We identified 178 adverse events related to extracorporeal membrane oxygenation. At least 41 (23%) and 47 (26%) accidents resulted in death and residual disability, respectively. The most common adverse events were cannula malposition (28%), decannulation (19%), and bleeding (15%). Among patients with cannula malposition, 38% did not undergo fluoroscopy-guided or ultrasound-guided cannulation, 54% required surgical treatment, and 18% required trans-arterial embolization. In this epidemiological study in Japan, 23% of the adverse events related to extracorporeal membrane oxygenation had fatal outcomes. Our findings suggest that a training system for cannulation techniques may be needed, and hospitals offering extracorporeal membrane oxygenation should perform emergency surgeries.

Detecting Oxygenator Thrombosis in ECMO: A Review of Current Techniques and an Exploration of Future Directions

Extracorporeal membrane oxygenation (ECMO) is a life-support technique used to treat cardiac and pulmonary failure, including severe cases of COVID-19 (coronavirus disease 2019) involving acute respiratory distress syndrome. Blood clot formation in the circuit is one of the most common complications in ECMO, having potentially harmful and even fatal consequences. It is therefore essential to regularly monitor for clots within the circuit and take appropriate measures to prevent or treat them. A review of the various methods used by hospital units for detecting blood clots is presented. The benefits and limitations of each method are discussed, specifically concerning detecting blood clots in the oxygenator, as it is concluded that this is the most critical and challenging ECMO component to assess. We investigate the feasibility of solutions proposed in the surrounding literature and explore two areas that hold promise for future research: the analysis of small-scale pressure fluctuations in the circuit, and real-time imaging of the oxygenator. It is concluded that the current methods of detecting blood clots cannot reliably predict clot volume, and their inability to predict clot location puts patients at risk of thromboembolism. It is posited that a more in-depth analysis of pressure readings using machine learning could better provide this information, and that purpose-built imaging could allow for accurate, real-time clotting analysis in ECMO components.

Neuromonitoring of Pediatric and Adult Extracorporeal Membrane Oxygenation Patients: The Importance of Continuous Bedside Tools in Driving Neuroprotective Clinical Care

Extracorporeal membrane oxygenation (ECMO) is a form of temporary cardiopulmonary bypass for patients with acute respiratory or cardiac failure refractory to conventional therapy. Its usage has become increasingly widespread and while reported survival after ECMO has increased in the past 25 years, the incidence of neurological injury has not declined, leading to the pressing question of how to improve time-to-detection and diagnosis of neurological injury. The neurological status of patients on ECMO is clinically difficult to evaluate due to multiple factors including illness, sedation, and pharmacological paralysis. Thus, increasing attention has been focused on developing tools and techniques to measure and monitor the brain of ECMO patients to identify dynamic risk factors and monitor patients' neurophysiological state as a function in time. Such tools may guide neuroprotective interventions and thus prevent or mitigate brain injury. Current means to continuously monitor and prevent neurological injury in ECMO patients are rather limited; most techniques provide indirect or postinsult recognition of irreversible brain injury. This review will explore the indications, advantages, and disadvantages of standard-of-care, emerging, and investigational technologies for neurological monitoring on ECMO, focusing on bedside techniques that provide continuous assessment of neurological health.

Prevalence of FXII-Deficiency and Its Relevance to Monitoring Anticoagulation in Adults Receiving Extracorporeal Membrane Oxygenation

During extracorporeal membrane oxygenation (ECMO) blood is exposed to artificial surfaces, resulting in contact activation of the intrinsic coagulation pathway initiated by coagulation factor XII (FXII). Little is known about the prevalence of acquired FXII-deficiency, especially during ECMO. The primary outcome was the prevalence of acquired FXII-deficiency (FXII activity <60%) during ECMO. Secondary outcomes included differences in hemorrhagic/thromboembolic complications, doses of unfractionated heparin administered, and time points of anticoagulation within target ranges between patients with and without FXII-deficiency. Of 193 adults receiving ECMO therapy between 2013 and 2021, FXII testing was performed in 64 (33%) patients. Of these, 89% ( n = 57) had an acquired FXII-deficiency. Median complication-free intervals were not different between patients with and without acquired FXII-deficiency (bleeding: 28 days [6-145] vs. 12 days [11-not available], p = 0.85; thromboembolism: 16 days [8-54] vs. 13 days [3-15], p = 0.053). Patients with acquired FXII-deficiency received less heparin (16,554 IU/day vs. 25,839 IU/day; p = 0.009) and were less likely to be within aPTT-target ranges (23.1% [14.3%-36.4%] vs. 37.8% [33.7%-58.3%], p = 0.005). Acquired FXII-deficiency is common during ECMO and may affect monitoring of anticoagulation. The impact of FXII-activity on complications needs to be determined in future studies.

Left ventricular thrombosis caused cerebral embolism during venoarterial extracorporeal membrane oxygenation support: A case report

BACKGROUND

Venoarterial (VA) extracorporeal membrane oxygenation (ECMO), an effective short-term circulatory support method for refractory cardiogenic shock, is widely applied. However, retrospective analyses have shown that VA-ECMO-assisted cases were associated with a relatively high mortality rate of approximately 60%. Embolization in important organs caused by complications of left ventricular thrombosis (LVT) during VA-ECMO is also an important reason. Although the incidence of LVT during VA-ECMO is not high, the consequences of embolization are disastrous.

CASE SUMMARY

A 37-year-old female patient was admitted to hospital because of fever for 4 d and palpitations for 3 d. After excluding the diagnosis of coronary heart disease, we established a diagnosis of "clinically explosive myocarditis". The patient still had unstable hemodynamics after drug treatment supported by VA-ECMO, with heparin for anticoagulation. On day 4 of ECMO support, a left ventricular thrombus attached to the papillary muscle root of the mitral valve was found by transthoracic echocardiography. Left ventricular decompression was performed and ECMO was successfully removed, but the patient eventually died of multiple cerebral embolism.

CONCLUSION

LVT with high mobility during VA-ECMO may cause embolism in important organs. Therefore, a "wait and see" strategy should be avoided.

Mechanical Circulatory Support in Pediatric Myocarditis: Support Strategies and Outcomes in a Nationally Representative Cohort

Background

Myocarditis is a common cause of pediatric heart failure which may require mechanical circulatory support (MCS). The purpose of this study is to describe MCS strategies used in a nationwide cohort of pediatric patients with myocarditis, identify trends over time, and compare outcomes between MCS strategies.

Methods

This study utilized the Kids' Inpatient Database (KID), a national sample of administrative discharge data. KID admissions from 2003-2016 were queried using ICD-9/10 codes to identify those with a diagnosis of myocarditis. MCS outcomes were compared using logistic regression.

Results

Of 5,661 admissions for myocarditis, MCS was used in 424 (7.5%), comprised of extracorporeal membrane oxygenation (ECMO) in 312 (73.6%), including 32 (10.2%) instances of extracorporeal cardiopulmonary resuscitation (ECPR), temporary ventricular assist devices (tVAD) in 28 (6.6%), durable VAD (dVAD) in 42 (9.9%) and combination MCS in 42 (9.9%). MCS use increased over time (p=0.031), but MCS strategies did not significantly change. Mortality was high in the MCS group (28.3%). There was no difference in odds of death in the VAD only or combination MCS group compared to the non-ECPR ECMO group (p=0.07 and p=0.65, respectively).

Conclusion

MCS is used in 1 in 13 pediatric myocarditis cases, and MCS use is increasing over time with ECMO remaining the most frequently used modality. Mortality remains high in patients that receive MCS but does not differ between those receiving VAD or combination MCS as compared to non-ECPR ECMO on unadjusted analysis. Further prospective analysis is required to evaluate the relative effectiveness of MCS modalities in this disease.

Evaluation of Bivalirudin During Adult Extracorporeal Membrane Oxygenation: A Retrospective Characterization of Dosing, Efficacy and Bleeding

Objective: Although heparin is the current standard anticoagulant during venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO), factors including heparin-induced thrombocytopenia, heparin resistance and drug shortages necessitate alternative anticoagulants such as direct thrombin inhibitors. The aim was to characterize dosing, safety, and efficacy of bivalirudin during ECMO support. Methods: This retrospective single-center study included 24 adults on ECMO support who received ≥6 hours of bivalirudin. The primary endpoint was dose to first therapeutic activated partial thromboplastin time (aPTT). Secondary endpoints included evaluating dosing between ECMO modes, incidence of bleeding and thrombotic events, and time in therapeutic range (TTR). Results: The dose at time of first therapeutic aPTT was bivalirudin 0.05 [0.05-0.1] mg/kg/hour. Bivalirudin dosing requirements were lower in VAECMO compared to VV-ECMO patients and were not impacted by continuous venovenous hemofiltration. Time to therapeutic aPTT was 5.5 [2-13] hours for VA-ECMO and 4.5 [2-8.6] hours for VV-ECMO patients. During any mode of ECMO TTR was 58.3% [39.6-73.1]. Thrombotic events occurred in 3 (13%) patients and major bleeding occurred in 12 (50%) patients. Conclusions: Our findings demonstrated variable bivalirudin dosing requirements based on mode of ECMO and dosing modifications may not be required during CVVH. Factors including mode of ECMO, indication for bivalirudin and concomitant antiplatelet therapy may impact hematologic events. Application of this data can assist with developing a bivalirudin ECMO protocol which provides less variability in initial dosing and TTR.

Inflammatory Progression in Patients Undergoing Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is identified as a novel therapeutic strategy that offers short-term support to the metabolism of the heart and lungs in humans. Recently, the clinical centers, which provide ECMO has increased rapidly worldwide. The indications for the use of ECMO in daily clinical practice were broadened dynamically. However, even with the widespread adoption of ECMO, it still remains significant morbidity and mortality, and the underlying mechanisms are still not elucidated. Notably, one of the vital complications during ECMO was proposed as the inflammatory progression within the extracorporeal circulation. via the development of inflammatory response, patients with ECMO may further suffer from systemic inflammatory response syndrome (SIRS), posing serious risks to human health. Recently, growing evidence confirmed that through exposure of blood into the ECMO circuit could lead to the stimulation of the immune system which also facilitated the inflammatory response and systemic impaired. In the current review, the pathological development of inflammatory progression in patients with ECMO is well-listed. Furthermore, the relationship between immune-related activation and the development of inflammation is also summarized, which may further help us to decide the therapeutic strategies in daily clinical practice.

Unravelling Surface Modification Strategies for Preventing Medical Device-Induced Thrombosis

The use of biomaterials in implanted medical devices remains hampered by platelet adhesion and blood coagulation. Thrombus formation is a prevalent cause of failure of these blood-contacting devices. Although systemic anticoagulant can be used to support materials and devices with poor blood compatibility, its negative effects such as an increased chance of bleeding, make materials with superior hemocompatibility extremely attractive, especially for long-term applications. This review examines blood-surface interactions, the pathogenesis of clotting on blood-contacting medical devices, popular surface modification techniques, mechanisms of action of anticoagulant coatings, and discusses future directions in biomaterial research for preventing thrombosis. In addition, this paper comprehensively reviews several novel methods that either entirely prevent interaction between material surfaces and blood components or regulate the reaction of the coagulation cascade, thrombocytes, and leukocytes.

Early extracorporeal membranous oxygenation and burn excision in severe burn and inhalation injury

Introduction

Extracorporeal membranous oxygenation (ECMO) as a salvage therapy for patients with severe acute respiratory distress syndrome (ARDS) has been described but experience is limited in burn cases. Few case reports detail the use of ECMO the setting of burn excision.

Case

Here, we describe a 40-year-old female found down in a house fire who presented with 30% total body surface area burns and severe inhalation injury resulting in ARDS. Veno-venous ECMO was initiated 12 h after injury, with a total ECMO run of 523 h. In that time, she underwent three tangential excisions with significant intraoperative and postoperative bleeding complications requiring in total 37 units of packed red blood cells, 8 pools of platelets, 24 units of fresh frozen plasma, and 1 unit of cryoprecipitate. The patient was successfully weaned from veno-venous ECMO. She required six subsequent excisions after her ECMO decannulation for both infection control and complete excision of her full-thickness burns. She was ultimately discharged to an inpatient rehabilitation facility.

Discussion

This report serves as the first detailed description of perioperative resuscitation on ECMO during burn excision and adds to the body of literature regarding ECMO support in the burned patient. This case specifically highlights the multidisciplinary care and resource demands of performing burn excision during ECMO as well as the associated bleeding complications of doing so. Further study is needed to define optimal timing, patient selection, and strategy for coagulopathy management and surgical care of the burn patient with ARDS treated with ECMO.

Lay Summary

Patients with severe burn injuries can have associated injuries to their lungs from both smoke and as a response to the stress a severe burn puts on the body. The injuries can be so severe that supportive machines can be needed that do the work of the lungs by adding oxygen to the blood, called extracorporeal membranous oxygenation (ECMO). These extreme measures are critical to supporting severe respiratory problems and have been incorporated into caring for burn patients with severely injured lungs. ECMO requires significant resources and has risks, including bleeding and clotting issues. Severely burned patients also need surgery to remove burned skin and decrease the stress placed on the body. Only a handful of cases have been described where burn surgery has been performed while a patient was on ECMO support. In our experience caring for a severely burned patient and performing multiple surgeries on ECMO, we encountered multiple bleeding complications secondary to the use of ECMO, resulting in large amounts of transfusion products needed. After one month, the patient's lungs recovered and ECMO was not needed. The patient survived to discharge from the hospital after completion of additional necessary burn surgeries. This report is the first to explain in detail the experience of performing burn excision on a patient on ECMO. We describe the resources and team members needed for success and believe further research must be done to best manage burn injuries while on ECMO.

Bilateral Femoral Cannulation Is Associated With Reduced Severe Limb Ischemia-Related Complications Compared With Unilateral Femoral Cannulation in Adult Peripheral Venoarterial Extracorporeal Membrane Oxygenation: Results From the Extracorporeal Life Support Registry

OBJECTIVES

Peripheral venoarterial extracorporeal membrane oxygenation (ECMO) with femoral access is obtained through unilateral or bilateral groin cannulation. Whether one cannulation strategy is associated with a lower risk for limb ischemia remains unknown. We aim to assess if one strategy is preferable.

DESIGN

A retrospective cohort study based on the Extracorporeal Life Support Organization registry.

SETTING

ECMO centers worldwide included in the Extracorporeal Life Support Organization registry.

PATIENTS

All adult patients (≥ 18 yr) who received peripheral venoarterial ECMO with femoral access and were included from 2014 to 2020.

INTERVENTIONS

Unilateral or bilateral femoral cannulation.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the occurrence of limb ischemia defined as a composite endpoint including the need for a distal perfusion cannula (DPC) after 6 hours from implantation, compartment syndrome/fasciotomy, amputation, revascularization, and thrombectomy. Secondary endpoints included bleeding at the peripheral cannulation site, need for vessel repair, vessel repair after decannulation, and in-hospital death. Propensity score matching was performed to account for confounders. Overall, 19,093 patients underwent peripheral venoarterial ECMO through unilateral ( n = 11,965) or bilateral ( n = 7,128) femoral cannulation. Limb ischemia requiring any intervention was not different between both groups (bilateral vs unilateral: odds ratio [OR], 0.92; 95% CI, 0.82-1.02). However, there was a lower rate of compartment syndrome/fasciotomy in the bilateral group (bilateral vs unilateral: OR, 0.80; 95% CI, 0.66-0.97). Bilateral cannulation was also associated with lower odds of cannulation site bleeding (bilateral vs unilateral: OR, 0.87; 95% CI, 0.76-0.99), vessel repair (bilateral vs unilateral: OR, 0.55; 95% CI, 0.38-0.79), and in-hospital mortality (bilateral vs unilateral: OR, 0.85; 95% CI, 0.81-0.91) compared with unilateral cannulation. These findings were unchanged after propensity matching.

CONCLUSIONS

This study showed no risk reduction for overall limb ischemia-related events requiring DPC after 6 hours when comparing bilateral to unilateral femoral cannulation in peripheral venoarterial ECMO. However, bilateral cannulation was associated with a reduced risk for compartment syndrome/fasciotomy, lower rates of bleeding and vessel repair during ECMO, and lower in-hospital mortality.

Acquired von Willebrand disease in children undergoing extracorporeal membrane oxygenation: a prospective observational study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) provides cardiopulmonary support for children with severe cardiac and/or pulmonary failure. The incidence of bleeding complications during ECMO support is high. Acquired von Willebrand disease (AVWD) might contribute to the development of bleeding complications.

OBJECTIVE

To study the incidence and longitudinal profile of AVWD during the first 14 days of ECMO support in children and to investigate the association between AVWD and bleeding complications.

METHODS

This prospective observational study included pediatric patients (0-17 years) receiving ECMO. Blood was sampled prior to and after ECMO start, daily and 12 to 24 hours after stopping ECMO. von Willebrand factor (VWF) parameters and multimer patterns were determined. Clinical data were collected for each patient. AVWD was defined as loss of high-molecular weight multimers (ie, decreased compared with baseline) or a VWF:collagen binding/VWF: antigen (Ag) ratio or VWF:activity/VWF:Ag ratio below 0.7.

RESULTS

All of 50 (100%) patients developed AVWD during ECMO. The VWF:collagen binding /VWF:Ag ratio, VWF:activity/VWF:Ag ratio, and high-molecular weight multimers decreased during the initial days and recovered to baseline level within 24 hours after stopping ECMO. The incidence and longitudinal profile of AVWD were similar in patients with and without major bleeding complications.

CONCLUSION

Children receiving ECMO support commonly develop AVWD. AVWD develops rapidly after ECMO initiation and recovers quickly after ECMO cessation. Importantly, AVWD appears to be independent of major bleeding.

Tranexamic Acid for Bleeding Management in Adult Patients on Extracorporeal Membrane Oxygenation

This study described the outcomes of patients receiving topical, nebulized, endobronchial, or systemic tranexamic acid (TXA) for bleeding events while on extracorporeal membrane oxygenation (ECMO). We performed a single-center case series including adult patients >18 years old supported on either venovenous (VV) or venoarterial (VA) ECMO from January 1, 2014, to April 21, 2021. The primary outcome was hemostatic control defined as a composite of initial cessation of therapeutic interventions to mitigate bleeding or resumption of anticoagulation if previously held. Secondary outcomes included changes in transfusion requirements and lysis at 30-minute (LY30) values, venous thromboembolism (VTE) events, and seizures. In total, 47 patients were included for full analysis. There were 19 patients with surgical bleeds, 18 patients with medical bleeds, and 10 patients with multiple bleeds. Overall, initial hemostatic control was achieved in 79%, 67%, and 90% of patients, respectively. Pre- and post-TXA transfusion requirements were not significantly different ( p = 0.2), although the intraindividual change in median LY30 was -5.1% compared with baseline (95% confidence interval [CI], -12.4% to -1.5%, p = 0.005). The occurrence of VTE and seizures was relatively low and similar among patient bleeding groups. Tranexamic acid provided initial hemostatic control in roughly three quarters of patients with bleeding events on ECMO and side effects were infrequent.

Transfusion in Neonatal Extracorporeal Membrane Oxygenation: A Best Practice Review

Extracorporeal Membrane Oxygenation (ECMO) is an important tool for managing critically ill neonates. Bleeding and thrombotic complications are common and significant. An understanding of ECMO physiology, its interactions with the unique neonatal hemostatic pathways, and appreciation for the distinctive risks and benefits of neonatal transfusion as it applies to ECMO are required. Currently, there is variability regarding transfusion practices, related to changing norms and a lack of high-quality literature and trials. This review provides an analysis of the neonatal ECMO transfusion literature and summarizes available best practice guidelines.

SARS-CoV-2-Infected Pregnant Woman Requiring 38 Days of Extracorporeal Membrane Oxygenation Experiences Rectal Ulcer Bleeding: A Case Report

Pregnancy has been shown to be associated with an adverse clinical course and symptomatic patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Extracorporeal membrane oxygenation (ECMO) is rarely used in pregnant or postpartum women with severe coronavirus disease 2019 (COVID-19). Here, we report the rare case of a pregnant woman diagnosed with SARS-CoV-2 infection placed on ECMO postpartum who subsequently received treatment for active rectal ulcer bleeding. Despite being placed on ECMO for 38 days and receiving a massive transfusion of 95 packs of red blood cells, she recovered and was discharged on hospital day 112. ECMO can be used in most patients with severe COVID-19, including pregnant patients, although potential coagulopathy complications must be considered.

Clinical relevance of cell-free DNA during venovenous extracorporeal membrane oxygenation

BACKGROUND

Thrombosis remains a critical complication during venovenous extracorporeal membrane oxygenation (VV ECMO). The involvement of neutrophil extracellular traps (NETs) in thrombogenesis has to be discussed. The aim was to verify NETs in the form of cell-free DNA (cfDNA) in the plasma of patients during ECMO.

METHODS

A fluorescent DNA-binding dye (QuantifFluor®, Promega) was used to detect cell-free DNA in plasma samples. cfDNA concentrations from volunteers (n = 21) and patients (n = 9) were compared and correlated with clinical/technical data before/during support, ECMO end and time of a system exchange.

RESULTS

Before ECMO, patients with a median (IQR) age of 59 (51/63) years, SOFA score of 11 (10/15), and ECMO run time of 9.0 (7.0/19.5) days presented significantly higher levels of cfDNA compared to volunteers (6.4 (5.8/7.9) ng/μL vs. 5.9 (5.4/6.3) ng/μL; p = 0.044). Within 2 days after ECMO start, cfDNA, inflammatory, and hemolysis parameters remained unchanged, while platelets decreased (p = 0.005). After ECMO removal at the end of therapy, cfDNA, inflammation, and coagulation data (except antithrombin III) remained unchanged. The renewal of a system resulted in known alterations in fibrinogen, d-dimers, and platelets, while cfDNA remained unchanged.

CONCLUSION

Detection of cfDNA in plasma of ECMO patients was not an indicator of acute and circuit-induced thrombogenesis.

Factors XI and XII in extracorporeal membrane oxygenation: longitudinal profile in children

Background

Extracorporeal membrane oxygenation (ECMO) is used in children with cardiopulmonary failure. While the majority of ECMO centers use unfractionated heparin, other anticoagulants, including factor XI and factor XII inhibitors are emerging, which may prove suitable for ECMO patients. However, before these anticoagulants can be applied in these patients, baseline data of FXI and FXII changes need to be acquired.

Objectives

This study aimed to describe the longitudinal profile of FXI and FXII antigenic levels and function before, during, and after ECMO in children.

Methods

This is a prospective observational study in neonatal and pediatric patients with ECMO (<18 years). All patients with venoarterial ECMO and with sufficient plasma volume collected before ECMO, on day 1 and day 3, and 24 hours postdecannulation were included. Antigenic levels and functional activity of FXI and FXII were determined in these samples. Longitudinal profiles of these values were created using a linear mixed model.

Results

Sixteen patients were included in this study. Mean FXI and FXII antigenic levels (U/mL) changed from 7.9 and 53.2 before ECMO to 6.0 and 34.5 on day 3 and they recovered to 8.8 and 39.4, respectively, after stopping ECMO. Function (%) of FXI and FXII decreased from 59.1 and 59.0 to 49.0 and 50.7 on day 3 and recovered to 66.0 and 54.4, respectively.

Conclusion

This study provides the first insights into changes of the contact pathway in children undergoing ECMO. FXI and FXII antigen and function change during ECMO. Results from this study can be used as starting point for future contact pathway anticoagulant studies in pediatric patients with ECMO.

Anti-Factor-Xa and Activated Partial Thromboplastin Time Concordance and Outcomes in Adults Undergoing Extracorporeal Membrane Oxygenation: A Secondary Analysis of the Pilot Low-Dose Heparin in Critically Ill Patients Undergoing Extracorporeal Membrane Oxygenation Randomized Trial

OBJECTIVES

To determine the concordance between activated partial thromboplastin time (aPTT) and anti-factor-Xa (anti-Xa) in adults undergoing extracorporeal membrane oxygenation (ECMO) and to identify the factors associated with discordant paired aPTT/anti-Xa.

DESIGN

Pre-planned secondary analysis of the Low-Dose Heparin in Critically Ill Patients Undergoing Extracorporeal Membrane Oxygenation pilot randomized unblinded, parallel-group controlled trial.

SETTING

Two ICUs in two university hospitals.

PATIENTS

Thirty-two critically ill patients who underwent ECMO and who had at least one paired aPTT and anti-Xa assay performed at the same time.

INTERVENTIONS

We analyzed the concordance between aPTT and anti-Xa and identified factors associated with discordant paired aPTT/anti-Xa based on their respective therapeutic ranges. We also compared biological parameters between heparin resistance episode and no heparin resistance.

MEASUREMENTS AND MAIN RESULTS

Of the 32 patients who were included in this study, 24 (75%) had at least one discordant paired aPTT/anti-Xa. Of the 581 paired aPTT/anti-Xa that were analyzed, 202 were discordant. The aPTT was relatively lower than anti-Xa in 66 cases (32.7%) or relatively higher than anti-Xa in 136 cases (67.3%). Thirty-three heparin resistance episodes were identified in six patients (19%).

CONCLUSIONS

In these critically ill patients undergoing ECMO, one third of paired aPTT/anti-Xa measures was discordant. Coagulopathy and heparin resistance might be the reasons for discordance. Our results support the potential importance of routinely monitoring both tests in this setting.

Anticoagulation with Intravenous Direct Thrombin Inhibitors in Pediatric Extracorporeal Membrane Oxygenation: A Systematic Review of the Literature

Although intravenous (IV) direct thrombin inhibitors (DTI) have gained interest in pediatric extracorporeal membrane oxygenation (ECMO), dosing and safety information is limited. The objective of this systematic review was to characterize DTI types, dosing, monitoring, and outcomes (bleeding and thromboembolic) in pediatric ECMO patients managed with IV DTIs. We conducted searches of MEDLINE (Ovid) and Embase (Elsevier) from inception through December 2022. Case reports, retrospective studies, and prospective studies providing per-patients or summary data for patient(s) <18 years of age receiving IV DTI for ECMO anticoagulation were included. Study selection and data extraction were conducted independently by two reviewers. A total of 28 studies: 14 case reports, 13 retrospective studies, and 1 prospective study were included, totaling 329 patients. Bivalirudin was utilized in 318 (96.7%), argatroban in 9 (2.7%), and lepirudin in 2 (0.6%) patients. Infusion dosing included: bivalirudin 0.14 ± 0.37 mg/kg/h, argatroban 0.69 ± 0.73 µg/kg/min, lepirudin 0.14 ± 0.02 mg/kg/h. Laboratory monitoring tests utilized were the activated clotting time, activated partial thromboplastin time (aPTT), diluted thrombin time, and thromboelastography measures. The aPTT was utilized in most patients (95%). Thromboembolism, bleeding, or death were observed in 17%, 17%, and 23% of bivalirudin, argatroban, and lepirudin patients, respectively. Bivalirudin appears to be the most frequently used DTI in pediatric ECMO. Dosing and laboratory monitoring varied, and bleeding and thromboembolic events were reported in 17% of patients. Prospective studies are warranted to establish dosing, monitoring, safety, and efficacy of bivalirudin and other IV DTI in pediatric ECMO.