The History of Extracorporeal Membrane Oxygenation and the Development of Extracorporeal Membrane Oxygenation Anticoagulation.

Extracorporeal membrane oxygenation (ECMO) was first started for humans in early 1970s by Robert Bartlett. Since its inception, there have been numerous challenges with extracorporeal circulation, such as coagulation and platelet activation, followed by consumption of coagulation factors and platelets, and biocompatibility of tubing, pump, and oxygenator. Unfractionated heparin (heparin hereafter) has historically been the defacto anticoagulant until recently. Also, coagulation monitoring was mainly based on bedside activated clotting time and activated partial thromboplastin time. In the past 50 years, the technology of ECMO has advanced tremendously, and thus, the survival rate has improved significantly. The indication for ECMO has also expanded. Among these are clinical conditions such as postcardiopulmonary bypass, sepsis, ECMO cardiopulmonary resuscitation, and even severe coronavirus disease 2019 (COVID-19). Not surprisingly, the number of ECMO cases has increased according to the Extracorporeal Life Support Organization Registry and prolonged ECMO support has become more prevalent. It is not uncommon for patients with COVID-19 to be on ECMO support for more than 1 year until recovery or lung transplant. With that being said, complications of bleeding, thrombosis, clot formation in the circuit, and intravascular hemolysis still remain and continue to be major challenges. Here, several clinical ECMO experts, including the "Father of ECMO"-Dr. Robert Bartlett, describe the history and advances of ECMO.

Comparison of Platelet Mass Index to Platelet Count as Transfusion Trigger in Neonatal Extracorporeal Membrane Oxygenation.

BACKGROUND: Platelet transfusions are routinely administered to neonates in intensive care units when there are concerns of bleeding, including high-risk situations like Extracorporeal Membrane Oxygenation (ECMO). Most platelets in ICUs are transfused prophylactically for thrombocytopenia based solely on the platelet count. Platelet Mass Index (PMI) has been proposed as an alternative to platelet count (PC) as a transfusion trigger. The objective of this study was to determine the relationship between PMI and platelet-specific maximal clot firmness (PMCF) in Rotational thromboelastometry (ROTEM), which gives an indication of platelet contribution to clot firmness and to investigate whether PMI may be a better choice as a trigger for platelet transfusions than PC. METHODS: Retrospective review of medical records of neonates with congenital heart disease placed on ECMO support in the cardiovascular intensive care unit (CVICU) from 2015 to 2018 was conducted. Platelet count (PC), platelet mean volume (PMV), ROTEM parameters along with demographic data including gestation age, birth weight, gender and survival were collected. Mixed effects linear models with a first order autoregressive covariance structure were used to assess the associations of PMI, PC, and MPV against PMCF. In addition, generalized estimating equations with a first order auto-regressive covariance structure were used to compare odds of transfusion using PC versus PMI triggers. RESULTS: A total of 92 tests on consecutive days were obtained for 12 ECMO patients (5 male, GA = 38.1 ± 1.6 weeks, BW = 3.1 ± 0.4 kgs, mean ± SD). A variation of 40.1% in PMCF was explained by platelet count (p < 0.001) while 38.5% of the variation in PMCF was explained by PMI (p < 0.001). If the platelet transfusion trigger was PC < 100 x 103 platelets/µL vs. PMI < 800. Using the PC trigger yielded significantly higher odds of transfusion compared to the PMI trigger (odds ratio = 1.31, 95% confidence interval: 1.18 - 1.45, p < 0.001). CONCLUSIONS: While our study failed to demonstrate a superior correlation of PMI with PMCF than PC, our study did reveal that using PMI as transfusion trigger would result in significantly less platelet transfusions, when compared with the current practice of using PC as a trigger.

Massive Transfusion Protocols in Obstetric Hemorrhage: Theory versus Reality.

OBJECTIVE: Massive transfusion protocols are widely implemented in obstetrical practice in case of severe hemorrhage; however, different recommendations exist regarding the appropriate ratios of blood product components to be transfused. We report our extensive experience with massive component transfusion in a referral center in which the standard massive transfusion protocol is modified by ongoing clinical and laboratory evaluation. STUDY DESIGN: A retrospective chart review of all patients who had massive transfusion protocol activation in a level 4 referral center for obstetrical practice was performed from January 2014 to January 2020. Data collected included the etiology of obstetrical hemorrhage, number of blood products of each type transfused, crystalloid infusion, and several indices of maternal morbidity and mortality. Data are presented with descriptive statistics. RESULTS: A total of 62 patients had massive transfusion protocol activation, of which 97% received blood products. Uterine atony was found to be the most common etiology for massive hemorrhage (34%), followed by placenta accreta spectrum (32%). The mean estimated blood loss was 1,945 mL. A mean of 6.5 units of packed red blood cells, 14.8 units of fresh frozen plasma and cryoprecipitate, and 8.3 units of platelets were transfused per patient. No maternal deaths were seen. CONCLUSION: The ratios of transfused packed red blood cell to fresh frozen plasma/cryoprecipitate and of packed red blood cell to platelet units varied significantly from the fixed initial infusion ratio called for by our massive transfusion protocol resulting in universally favorable maternal outcomes. When rapid laboratory evaluation of hematologic and clotting parameters is available, careful use of this information may facilitate safe modification of an initial fixed transfusion ratio based on etiology of the hemorrhage and individual patient response. KEY POINTS: · Massive transfusion protocols in obstetrics follow fixed ratios of blood products.. · Actual usage of blood components is different than the standardized protocols.. · We recommend to modify the initial fixed transfusion ratio according to clinical response..

Convalescent plasma in hospitalized pediatric and obstetric coronavirus disease 2019 (COVID-19) patients.

BACKGROUND: Published data on coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) use in children and obstetric patients are limited. We describe a single-center experience of hospitalized patients who received CCP for acute COVID-19. METHODS: A retrospective review of children 0-18-years-old and pregnant patients hospitalized with laboratory-confirmed acute COVID-19 who received CCP from March 1, 2020 to March 1, 2021 was performed. Clinical and laboratory data were collected to assess the safety of CCP administration. Antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were measured in the CCP products and in patients before transfusion and at various time points post-transfusion. Correlation between the administered SARS-CoV-2 administered versus the SARS-CoV-2 anti-spike immunoglobulin response in patient serum was assessed. RESULTS: Twenty-two children and ten obstetric patients were eligible. Twelve pediatric and eight obstetric patients had moderate disease and ten pediatric and two obstetric patients had severe disease. Five pediatric patients died. Eighteen of 37 (48.6%) CCP titers that were measured met US Food and Drug Administration (FDA) criteria for high immunoglobulin G (IgG) antibody titer. There were no complications with transfusion. High-titer CCP showed a positive correlation with rise in patient total immunoglobulin levels only in obstetric patients but not in pediatric patients. Among pediatric patients, the median serum antibody level increased over time after transfusion. CONCLUSIONS: Coronavirus 2019 convalescent plasma was administered safely to our patients. Our study suggested that CCP did not interfere with endogenous antibody production. The antibody titer of CCP correlated with post-transfusion response only in obstetric patients. Randomized trials in pediatric and obstetric patients are needed to further understand how to dose CCP and evaluate efficacy.

Novel Coagulation Test Detects Anticoagulation Resistance and Is Associated With Thrombotic Events in Pediatric Patients Requiring Extracorporeal Membrane Oxygenation.

Bivalirudin, an IV direct thrombin inhibitor, and unfractionated heparin (UFH) are frequently used anticoagulants in the pediatric critical care setting. An accurate, specific, point-of-care test to quantify and detect anticoagulation resistance is not currently available. This study evaluates the ability of a rapid (< 10 min), micro-volume (< 50 uL) coagulation test to detect and quantify the anticoagulation effect of bivalirudin and UFH using a functional, clot time endpoint in pediatric critical care patients. DESIGN: Single-site retrospective laboratory sample analysis and chart review. SETTING: A 105-bed pediatric and cardiac ICUs delivering extracorporeal membrane oxygenation. SUBJECTS: Forty-one citrated, frozen, biobanked plasma specimens comprising 21 with bivalirudin and 20 with UFH from 15 anticoagulated pediatric patients were analyzed. Thirteen patients were on extracorporeal membrane oxygenation, one had a submassive pulmonary embolism, and one was on a left ventricular assist device. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: A Clotting Time Score (CTS) was derived on each sample. The CTS detected patients that had developed a pathologic clotting event with 100% sensitivity and 82% specificity compared with prothrombin time with 25% sensitivity/76% specificity and activated partial thromboplastin time with 0% sensitivity/0% specificity. Additionally, the CTS detected subtherapeutic anticoagulation in response to UFH in patients that were clinically determined to be UFH resistant requiring alternative anticoagulation with bivalirudin. CONCLUSIONS: The CTS appears to be a clinically valuable indicator of coagulation status in patients treated with either UFH or bivalirudin. Results outside of the therapeutic range due to inadequate dosing or anticoagulation resistance appeared to be associated with clot formation. CTS testing may reduce the risk of anticoagulation-related complications via the rapid identification of patients at high risk for pathologic thrombotic events.

Transfusion-Associated Adverse Events: A Case Report of Nurse Hemovigilance and Recognition of Respiratory Distress.

Although blood transfusions are considered a potentially life-saving therapy, noninfectious and infectious adverse events can lead to significant morbidities and even mortality. Vital signs and visual observation of patients during blood transfusions are thoroughly taught in nursing school. Updated terms of hemovigilance and transfusion-associated adverse events ( TAAEs ) are presented through this case study. A patient with factor V deficiency, which requires chronic plasma transfusions, experienced 2 types of TAAEs, anaphylaxis and transfusion-associated circulatory overload. The patient's history and TAAEs are presented and discussed to provide evidence for the importance of vigilant bedside surveillance. Early identification of TAAEs may prevent unnecessary morbidity and/or mortality. The primary nursing functions and responsibilities are presented with algorithmic supplementation to facilitate better understanding of best practice. Ongoing assessment of hemovigilance practices is indicated to ascertain which monitoring tools can lead to optimal patient care.

Blood transfusion is associated with increased mortality for neonates with congenital diaphragmatic hernia on extracorporeal membrane oxygenation support.

BACKGROUND AND OBJECTIVES: Blood transfusion is frequently needed to maintain adequate haemostasis and improve oxygenation for patients treated with extracorporeal membrane oxygenation (ECMO). It is more so for neonates with immature coagulation systems who require surgical intervention such as congenital diaphragmatic hernia (CDH) repair. There is growing evidence suggesting an association between blood transfusions and increased mortality. The aim of this study is to evaluate the association of blood transfusions during the peri-operative period of CDH repair, among other clinical parameters, with mortality in neonates undergoing on-ECMO CDH repair. MATERIALS AND METHODS: We performed a single centre retrospective chart review of all neonates with CDH undergoing on-ECMO surgical repair from January 2010 to December 2020. Logistic regression was used to investigate associations with survival status. RESULTS: Sixty-two patients met the inclusion criteria. Platelet transfusions (odds ratio [OR] 1.42, 95% confidence interval [CI]: 1.06-1.90) in the post-operative period and ECMO duration (OR 1.17, 95% CI: 1.05-1.30) were associated with increased mortality. Major bleeding complications had the strongest association with mortality (OR 10.98, 95% CI: 3.27-36.91). Gestational age, birth weight, Apgar scores, sex, blood type, right versus left CDH, venovenous versus venoarterial ECMO and duration of ECMO before CDH repair and circuit change after adjusting for ECMO duration were not significantly associated with survival. CONCLUSION: Platelet transfusion in the post-operative period and major bleeding are associated with increased mortality in CDH neonates with surgical repair. The data suggest a need to develop robust plans for monitoring and preventing coagulation aberrancies during neonatal ECMO support.

Bivalirudin or Unfractionated Heparin for Anticoagulation in Pediatric Patients on Continuous Flow Ventricular Assist Device Support: Single-Center Retrospective Cohort Study.

OBJECTIVES: Bivalirudin is a direct thrombin inhibitor that is being increasingly used for anticoagulation in children after ventricular assist device (VAD) implantation. While the data on bivalirudin use in pulsatile flow VADs are growing, reports on its use in patients on continuous flow (CF) VAD as well as comparisons of associated outcomes with unfractionated heparin (UFH) remain limited. DESIGN: Retrospective cohort study. SETTING: Single tertiary-quaternary referral center. PATIENTS: All patients less than 21 years old on CF-VAD support who received bivalirudin or UFH for anticoagulation between the years 2016 and 2020. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Clinical characteristics compared between the cohorts included time to target range of anticoagulation, markers of hemolysis, and prevalence of hemocompatibility-related adverse events such as major hemorrhagic complications, ischemic stroke, and pump thrombosis. In 42 unique patients (41 HeartWare HVAD [Medtronic, Minneapolis, MN], one HeartMate 3 LVAD [Abbott Laboratories, Abbott Park, IL]) during the study period, a total of 67 encounters of IV anticoagulation infusions (29 UFH and 38 bivalirudin) were retrospectively reviewed. In comparison with use of UFH, bivalirudin was associated with lesser odds of major bleeding complications (odds ratio [OR], 0.29; 95% CI, 0.09-0.97; p = 0.038). We failed to identify any difference in odds of major thrombotic complications (OR, 2.53; 95% CI, 0.47-13.59; p = 0.450). Eight of the patients (28%) on UFH were switched to bivalirudin due to hemorrhagic or thrombotic complications or inability to achieve therapeutic anticoagulation, while two of the patients (5%) on bivalirudin were switched to UFH due to hemorrhagic complications. Bivalirudin was used for a "washout" in eight cases with concern for pump thrombosis-six had resolution of the pump thrombosis, while two needed pump exchange. CONCLUSIONS: Use of bivalirudin for anticoagulation in patients on CF-VAD support was associated with lesser odds of hemorrhagic complications compared with use of UFH. Bivalirudin "washout" was successful in medical management of six of eight cases of possible pump thrombosis.

How to best monitor bivalirudin anticoagulant effect for ECMO and VAD-Comparison of four assay methods.

INTRODUCTION: Unfractionated heparin is widely used as an anticoagulant for extracorporeal life support (ECLS) and usually monitored with activated partial thromboplastin time (aPTT). Due to its limitations in pediatric populations and interferences with monitoring, bivalirudin is being utilized more frequently in these settings. For bivalirudin, other tests have emerged such as dilute thrombin time (dTT) and ecarin chromogenic assay (ECA); however, their utilities in pediatrics are unexplored. Development of suitable, accurate testing for bivalirudin monitoring is paramount to prevent complications. We sought to compare aPTT, aPTT with heparinase (HPTT), dTT1:4, modified dTT1:10, and ECA for monitoring of pediatric ECLS patients anticoagulated with bivalirudin. METHODS: aPTT, HPTT, dTT1:4, dTT1:10, and ECA were measured in 51 specimens from 17 children on bivalirudin-anticoagulated ECLS. Normal pooled plasma was spiked with various bivalirudin concentrations, and aPTT, dTT1:4, dTT1:10, and ECA were measured. In addition, dTT assays were performed using plasma from normal donors spiked with bivalirudin, heparin, and cryoprecipitate. RESULTS: dTT1:4 showed excellent correlation with ECA, while dTT1:4 correlated moderately with aPTT or HPTT. Fifty to 75% of specimens showed discordant results between dTT1:4 and HPTT. We found that dTT1:4 and ECA prolongations are associated with bivalirudin infusion rate; however, there are age-based differences that should be accounted for. The performance of dTT1:10 was similar to dTT1:4, though it was less sensitive to interfering factors (heparin or hyperfibrinogenemia). CONCLUSION: dTT1:10 appears to be more suitable for routine practice due to fewer variations and lower cost for monitoring bivalirudin in pediatric ECLS.

Evaluation and Management of Coagulopathies and Thrombophilias in Pediatric Patients.

The diagnosis of coagulopathy or thrombophilia in pediatric patients can be challenging. Congenital coagulopathies often present in the pediatric period and require appropriate work-up for diagnosis and ongoing management. Acquired coagulopathies of childhood are frequently encountered in hospitalized children and warrant appropriate coagulation testing for goal-directed therapy. The incidence of thrombosis is increasing in pediatric patients. After identifying the presence of thrombus, acute management includes initiating therapeutic anticoagulation. Choice of anticoagulant depends on patient's clinical status, along with availability of the anticoagulant. Thrombophilia evaluation is performed when children present with spontaneous thrombosis. Thrombophilia tests are inaccurate during acute illness.

Trimester-specific thromboelastic values and coagulation activation markers in pregnancy compared across trimesters and compared to the nonpregnant state.

INTRODUCTION: Rotational thromboelastometry (ROTEM) rapidly identifies deficits underlying coagulopathy during massive hemorrhage. Prompt coagulopathy correction is balanced with the risk of blood product overutilization, making the ability to quickly target therapy highly desirable. However, data about ROTEM reference ranges in pregnancy are limited. We hypothesized that ROTEM parameters change across trimesters of pregnancy and differ from the nonpregnant state. Also, we sought to identify which hemostatic test best predicts coagulation activation during pregnancy. METHODS: A prospective cohort study in healthy pregnant patients in the first (n = 34), second (n = 34), and third trimesters (n = 41) against healthy, nonpregnant controls (n = 33) was performed. Citrated blood was collected, and ROTEM, complete blood count, and plasma-based assays of coagulation were performed. Mean ± SD or median [IQR] were compared across trimesters and between each trimester against the nonpregnant state. ROTEM parameters vs. plasma-based assays were also compared. RESULTS: Maximum clot firmness and A10 in FIBTEM correlated strongly with fibrinogen level. INTEM and EXTEM values demonstrated only weak to modest correlation with corresponding tests using plasma assays. Thrombin antithrombin complex (TAT) increased from the first trimester onward, whereas other coagulation activation markers did not show difference compared with control group. CONCLUSION: Rotational thromboelastometry parameters differ variably across trimesters of pregnancy and compared with the nonpregnant state. The development and use of pregnancy-specific values are critical to the proper clinical interpretation of ROTEM in women with serious hemorrhage during different stages in pregnancy. TAT was the earliest laboratory marker for coagulation activation among others.

C-reactive protein-induced activated partial thromboplastin time prolongation in heparinized samples is attenuated by elevated factor VIII.

INTRODUCTION: Activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) activity are used to monitor unfractionated heparin therapy in children on extracorporeal membrane oxygenation (ECMO). Elevated C-reactive protein (CRP) can prolong aPTT and cause discrepancy between these two assays. We aimed to evaluate CRP effect on aPTT and anti-Xa assays in the presence of heparin and to determine whether elevated CRP affects laboratory monitoring in pediatric ECMO patients. MATERIALS AND METHODS: Citrated normal specimens were spiked with CRP, heparin, and recombinant factor VIII (FVIII) and followed by measurement of aPTT and anti-Xa activity. Additionally, aPTT, anti-Xa activity, FVIII, fibrinogen, and CRP were measured in 18 ECMO specimens. RESULTS: Elevated CRP prolonged aPTT in normal specimens with or without heparin, but did not affect anti-Xa assay. In contrast, ECMO specimens showed similar aPTT and anti-Xa values regardless of CRP level. Elevated CRP in specimens was accompanied by increased fibrinogen and FVIII activity. Additional in vitro experiments confirmed that FVIII spiked simultaneously with CRP attenuated CRP-induced aPTT prolongation in heparinized specimens. CONCLUSION: In vitro CRP-induced aPTT prolongation is not observed in pediatric ECMO samples due to concomitant FVIII increase. Discordant changes of CRP and FVIII in plasma could contribute to aPTT/anti-Xa discrepancies observed during heparin therapy in the pediatric population. The anti-Xa assay is preferable for heparin monitoring in pediatric ECMO settings.

Low antithrombin levels in neonates and infants undergoing congenital heart surgery result in more red blood cell and plasma transfusion on cardiopulmonary bypass.

BACKGROUND: Neonates have lower levels of antithrombin (AT) due to immature liver synthetic function. AT deficiency may lead to inadequate anticoagulation with heparin during cardiac surgery resulting in consumption of coagulation factors and increased blood transfusion. The goal of this study is to examine the effect of AT level on the transfusion requirements of neonates and infants undergoing open heart surgery. STUDY DESIGN AND METHODS: This is a prospective, observational study at a tertiary pediatric referral center. Neonates and infants up to 6 months of age undergoing congenital heart surgery with cardiopulmonary bypass (CPB) were enrolled. Demographic, intraoperative, transfusion, and complications data were collected. Preoperative AT level was measured after induction of anesthesia. Prior to separation from CPB, a second blood sample was drawn and AT, thrombin antithrombin complex (TAT), D-dimer, and anti-Xa levels were measured. Linear and logistic regression were performed for data analysis. RESULTS: Preoperative low AT level was significantly associated with increased transfusion of red blood cells (RBCs) and fresh frozen plasma (FFP) during CPB, but not after separation from CPB. The incidence of thrombosis and re-operation were not associated with preoperative AT levels. There was no association between TAT, D-dimer, and anti-Xa levels at the end of CPB and preoperative AT levels. CONCLUSION: Low preoperative AT level is associated with increased transfusion of RBC and FFP on CPB in neonates and infants undergoing congenital heart surgery. Low preoperative AT level did not result in coagulation activation after CPB and after surgery.

Erratum: Deficiency of complement factor H-related proteins and autoantibody-positive hemolytic uremic syndrome in an infant with combined partial deficiencies and autoantibodies to complement factor H and ADAMTS13.

[This corrects the article DOI: 10.1093/ckj/sfy010.].

Structural characterization of a clinically described heparin-like substance in plasma causing bleeding.

Heparin-like substances (HLS) have been described in various clinical situations, including in settings of liver disease associated with infection, transplant, and metastasis. HLS are generally attributed to circulating glycosaminoglycans. Initial results for this patient showed coagulopathy due to liver disease without HLS. Two weeks after liver transplantation, a 10 year-old female with liver failure patient began to bleed from catheter insertion sites, mouth, and nares and HLS was suspected. The patient subsequently died and these clinical samples resulted in the isolation of a single heparan sulfate (HS) present at high concentrations in the plasma. Analysis of this HS showed it had an intermediate between heparin and HS with low antithrombin-mediated anticoagulant activity. We speculate that this 10-year old patient might have a platelet function defect influenced by this unusual HS. Endothelial defects not measurable by our methods might have also contributed to the observed bleeding complications.

Tortuosity-powered microfluidic device for assessment of thrombosis and antithrombotic therapy in whole blood.

Accurate assessment of blood thrombosis and antithrombotic therapy is essential for the management of patients in a variety of clinical conditions, including surgery and on extracorporeal life support. However, current monitoring devices do not measure the effects of hemodynamic forces that contribute significantly to coagulation, platelet function and fibrin formation. This limits the extent to which current assays can predict clotting status in patients. Here, we demonstrate that a biomimetic microfluidic device consisting stenosed and tortuous arteriolar vessels would analyze blood clotting under flow, while requiring a small blood volume. When the device is connected to an inline pressure sensor a clotting time analysis is applied, allowing for the accurate measurement of coagulation, platelets and fibrin content. Furthermore, this device detects a prolonged clotting time in clinical blood samples drawn from pediatric patients on extracorporeal membrane oxygenation receiving anticoagulant therapy. Thus, this tortuosity activated microfluidic device could lead to a more quantitative and rapid assessment of clotting disorders and their treatment.

Utilization and outcomes of massive transfusion protocols in women with and without invasive placentation.

Objective: Our objective was to compare women with and without invasive placentation for whom the massive transfusion protocol (MTP) was activated. In addition, we evaluated the differences in clinical management and blood product utilization between the two groups and described the activation of MTP over time.Study design: This is a retrospective cohort study of women for whom the MTP was activated from January 2012 through July 2016. Two groups were compared, those with invasive placentation (accreta, increta, percreta) and those without.Results: We identified 87 women for whom the MTP was activated, the majority (62.1%) did not have invasive placentation. Women with invasive placentation were more likely to have had a prior cesarean delivery and placenta previa (both p < .001). Women with invasive placentation were more likely to undergo hysterectomy, experience more blood loss, and receive cell salvage (all p ≤ .04). Blood product utilization was similar between the two groups, with the exception of cell-salvage, which was more commonly used for women with invasive placentation. The proportion of deliveries necessitating MTP activation ranged from 1.4 to 2.6 per 1000 deliveries.Conclusion: Invasive placentation accounts for less than half of the cases complicated by activation of an MTP. Cases with invasive placentation were more likely to result in a vertical uterine and skin incision or a hysterectomy. With the exception of cell-salvage, blood product utilization was similar.

Hemostatic Management of Extracorporeal Circuits Including Cardiopulmonary Bypass and Extracorporeal Membrane Oxygenation.

Cardiopulmonary bypass and extracorporeal membrane oxygenation (ECMO) cause hemostatic derangements that can predispose patients to both bleeding and thrombotic complications. Often, patients present for urgent surgery while taking medications including antiplatelet agents, vitamin K antagonists, and direct oral anticoagulants, which must be recognized, monitored, and managed. During extracorporeal circulation, appropriate anticoagulation, most commonly with heparin, is required to maintain blood flow and avoid thrombotic complications. However, anticoagulation and other effects of extracorporeal circuits can also have an undesired consequence of bleeding. Extracorporeal circulation leads to coagulopathy that may require therapy with blood products such as platelets, cryoprecipitate, and plasma in case a patient bleeds. Platelet dysfunction related to exposure to a foreign circuit is a primary concern, as is the development of acquired von Willebrand syndrome, which frequently remains undetected on routine testing. Hemorrhagic complications in ECMO, such as intracranial hemorrhage, pulmonary hemorrhage, and hemithorax, can occur. Hemostatic agents including antifibrinolytics, desmopressin, fibrinogen concentrates, and other factor concentrates may be needed to achieve hemostasis in these often-challenging patients. Managing bleeding on extracorporeal support requires careful monitoring and a thoughtful approach.