Extracorporeal Membrane Oxygenation in the Adult

Extracorporal Membrane Oxygenation in Massive Pulmonary Embolism

BACKGROUND

Massive pulmonary embolism (MPE) carries significant 30-day mortality risk, and a change in societal guidelines has promoted the increasing use of extracorporeal membrane oxygenation (ECMO) in the immediate management of MPE-associated cardiovascular shock. This narrative review examines the current status of ECMO in MPE.

METHODS

A literature review was performed from 1982 to 2022 searching for the terms "Pulmonary embolism" and "ECMO," and the search was refined by examining those publications that covered MPE.

RESULTS

In the patient with MPE, veno-arterial ECMO is now recommended as a bridge to interventional therapy. It can reliably decrease right ventricular overload, improve RV function, and allow hemodynamic stability and restoration of tissue oxygenation. The use of ECMO in MPE has been associated with lower mortality in registry reviews, but there has been no significant difference in outcomes between patients treated with and without ECMO in meta-analyses. Applying ECMO is also associated with substantial multisystem morbidity due to systemic inflammatory response, bleeding with coagulopathy, hemorrhagic stroke, renal dysfunction, and acute limb ischemia, which must be factored into the outcomes.

CONCLUSIONS

The application of ECMO in MPE should be combined with an aggressive interventional pulmonary interventional program and should strictly adhere to the current selection criteria.

Mucosal bleeding while on venovenous extracorporeal membrane oxygenation in the setting of vitamin C deficiency

A major complication with extracorporeal membrane oxygenation (ECMO) is bleeding which can occur in up to 40% of cases and can be life-threatening. Minor bleeding may be overlooked and under-reported. While some of the underlying mechanisms such as platelet injury and anticoagulation therapy have been identified, several other factors are still under-researched. Here, we describe a unique case of a subtle mucosal membrane bleeding that is found to be associated with vitamin C deficiency while on treatment with ECMO. Investigating vitamin C levels may be useful in understanding causes of bleeding in some patients on ECMO therapy, particularly if there are risk factors for malnutrition.

Antithrombin during veno-venous extracorporeal membrane oxygenation with heparin anticoagulation: A single-center cohort study

INTRODUCTION

Antithrombin (AT) is a natural anticoagulant essential to enhancing the unfractionated heparin (UFH) anticoagulant effect. Its supplementation in the management of UFH-based anticoagulation during veno-venous extracorporeal membrane oxygenation (VV ECMO) has a strong pathophysiological rationale.

METHODS

This is a single-center, retrospective cohort study of adult VV ECMO patients with anticoagulation maintained by UFH targeting an activated partial thromboplastin time (aPTT) of 40-50 s and AT activity >80%. We compare anticoagulation management and survival outcomes between AT subpopulations, defined by a threshold AT activity ≥80%. Linear and logistic regression analyses were used to evaluate the variation in AT activity and its association with ICU survival.

RESULTS

In 244 patients enrolled from 2009 to 2022, anticoagulation was maintained by a median heparin dose of 11.4 IU/kg/h [IQR: 8.2-14.7] with a mean aPTT of 46.1 s (±7.3) and AT activity of 88.9% (±17.0). A lower mean aPTT, higher dose of UFH and shorter fraction of time without UFH were associated with higher AT activity (p < .01). Higher AT activity showed a consistent association with ICU survival (for 10% increase of AT, odds ratio for ICU mortality: 0.95; 95% CI 0.93-0.97; p value <.01).

CONCLUSIONS

There is a positive association between AT activity and UFH requirements but no significant difference in the rate of bleeding events. A higher mean AT during VV ECMO was associated with ICU survival. Future studies are needed to differentiate between exogenously supplemented versus endogenous AT effect.

Point of care guided coagulation management in adult patients on ECMO: A systematic review and meta-analysis

BACKGROUND

Despite the advancements in extracorporeal membrane oxygenation (ECMO) technology, balancing the prevention of thrombosis and the risk of bleeding in patients on ECMO is still a significant challenge for physicians. This systematic review and meta-analysis aimed to assess the efficacy and safety of viscoelastic point-of-care (POC)-guided coagulation management in adult patients on ECMO.

METHODS

PubMed Medline, Embase, Scopus, Web of Science, and Cochrane Library databases were searched. After quality assessment, meta-analysis was carried out using random effects model, heterogeneity using I2 and publication bias using Doi and Funnel plots.

RESULTS

A total of 1718 records were retrieved from the searches. Fifteen studies that enrolled a total of 583 participants met the inclusion criteria. Of those, 3 studies enrolling 181 subjects were eligible for meta-analysis. In patients managed with POC-guided algorithms, the odds were coherently lower for bleeding (OR 0.71, 95%CI 0.36-1.42), thrombosis (OR 0.91, 95%CI 0.32-2.60), and in-hospital mortality (OR 0.54, 95%CI 0.29-1.03), but not for circuit change or failure (OR 1.50, 95%CI 0.59-3.83). However, the differences were not statistically significant due to wide 95%CIs.

CONCLUSION

Viscoelastic POC monitoring demonstrates potential benefits for coagulation management in ECMO patients. Future research should focus on standardizing evidence to improve clinical decision-making.

REGISTRATION

The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) with registration ID CRD42023486294.

Impact of C-reactive Protein on Anticoagulation Monitoring in Extracorporeal Membrane Oxygenation

OBJECTIVE

To evaluate the impact of inflammation on anticoagulation monitoring for patients supported with extracorporeal membrane oxygenation (ECMO).

DESIGN

Prospective single-center cohort study.

SETTING

University-affiliated tertiary care academic medical center.

PARTICIPANTS

Adult venovenous and venoarterial ECMO patients anticoagulated with heparin/ MEASUREMENTS AND MAIN RESULTS: C-Reactive protein (CRP) was used as a surrogate for overall inflammation. The relationship between CRP and the partial thromboplastin time (PTT, seconds) was evaluated using a CRP-insensitive PTT assay (PTT-CRP) in addition to measurement using a routine PTT assay. Data from 30 patients anticoagulated with heparin over 371 ECMO days was included. CRP levels (mg/dL) were significantly elevated (median, 17.2; interquartile range [IQR], 9.2-26.1) and 93% of patients had a CRP of ≥5. The median PTT (median 58.9; IQR, 46.9-73.3) was prolonged by 11.3 seconds compared with simultaneously measured PTT-CRP (median, 47.6; IQR, 40.1-55.5; p < 0.001). The difference between PTT and PTT-CRP generally increased with CRP elevation from 2.7 for a CRP of <5.0 to 13.0 for a CRP between 5 and 10, 17.7 for a CRP between 10 and 15, and 15.1 for a CRP of >15 (p < 0.001). In a subgroup of patients, heparin was transitioned to argatroban, and a similar effect was observed (median PTT, 62.1 seconds [IQR, 53.0-78.5 seconds] vs median PTT-CRP, 47.6 seconds [IQR, 41.3-57.7 seconds]; p < 0.001).

CONCLUSIONS

Elevations in CRP are common during ECMO and can falsely prolong PTT measured by commonly used assays. The discrepancy due to CRP-interference is important clinically given narrow PTT targets and may contribute to hematological complications.

Extracorporeal membrane oxygenation in adult patients with sepsis and septic shock: Why, how, when, and for whom

Sepsis and septic shock remain the leading causes of death in intensive care units. Some patients with sepsis fail to respond to routine treatment and rapidly progress to refractory respiratory and circulatory failure, necessitating extracorporeal membrane oxygenation (ECMO). However, the role of ECMO in adult patients with sepsis has not been fully established. According to existing studies, ECMO may be a viable salvage therapy in carefully selected adult patients with sepsis. The choice of venovenous, venoarterial, or hybrid ECMO modes is primarily determined by the patient's oxygenation and hemodynamics (distributive shock with preserved cardiac output, septic cardiomyopathy (left, right, or biventricular heart failure), or right ventricular failure caused by acute respiratory distress syndrome). Veno-venous ECMO can be used in patients with sepsis and severe acute respiratory distress syndrome when conventional mechanical ventilation fails, and early application of veno-arterial ECMO in patients with sepsis-induced refractory cardiogenic shock may be critical in improving their chances of survival. When ECMO is indicated, the choice of an appropriate mode and determination of the optimal timing of initiation and weaning are critical, particularly in an experienced ECMO center. Furthermore, some special issues, such as ECMO flow, anticoagulation, and antibiotic therapy, should be noted during the management of ECMO support.

A Modified 4Ts Score for Heparin-Induced Thrombocytopenia in the Mechanical Circulatory Support Population

OBJECTIVE

To identify risk factors and develop a pretest scoring system to differentiate patients with heparin-induced thrombocytopenia (HIT) in the mechanical circulatory support (MCS) population. The authors present a modified "4TMCS" scoring system, which considers the "type of mechanical circulatory support" that may help identify patients at risk for developing postoperative HIT.

DESIGN

A retrospective cohort study. Patients who underwent cardiac surgery were categorized into 3 groups: (1) normal platelet count, (2) thrombocytopenia with a negative HIT test, and (3) thrombocytopenia with a positive HIT test. A comparison of diagnostic accuracy between the 4Ts and 4TMCS probability scores was performed.

SETTING

At a single adult tertiary-care center.

PARTICIPANTS

A total of 5,314 patients who underwent cardiac surgery between May 1, 2008 and December 31, 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In total, 125 out of 5,314 patients (2.4%) were diagnosed with HIT, of whom 75 out of 5,314 (1.4%) had clinical evidence of thrombosis. Overall, in-hospital mortality was 25.6%, 11.7%, and 1.5% in the HIT(+), HIT(-), and control groups, respectively (p < 0.001). Mechanical circulatory support was associated with a significantly increased risk for HIT, with an incidence of 5.9% in patients receiving MCS versus 1.9% in those without (p < 0.001). Area under the receiver operator curve (AUC) analysis demonstrated improved diagnostic accuracy of the 4TMCS score compared with the 4Ts (AUC = 0.83 v 0.77, p < 0.044). The 4TMCS score had higher sensitivity than the 4Ts, using the guideline-recommended score cutoff of ≥4 (95.2% v 85.7%).

CONCLUSION

Heparin-induced thrombocytopenia is associated with worse outcomes and increased morbidity and mortality in the MCS population. Awareness of patient risk factors and the application of a modified 4TMCS probability score may allow for more accurate screening and treatment of HIT in the MCS population.

Treatment of malignant airway stenosis with extracorporeal membrane oxygenation under low-dose anticoagulation: A case report

The occurrence of airway obstruction due to severe stenosis from lung cancer poses a significant risk of asphyxia. Although the placement of a metallic stent may relieve the obstruction, the procedure is associated with a high risk of asphyxia. To mitigate this risk, extracorporeal membrane pulmonary oxygenation (ECMO) has been proposed to temporarily substitute for cardiopulmonary function during the procedure. However, the use of systemic anticoagulation with heparin during ECMO may increase the likelihood of bleeding during surgery. This case report describes a successful treatment of a patient with malignant central airway obstruction through low-dose heparin veno-venous ECMO. This approach resulted in reduced intraoperative bleeding and invasive operation time, allowing for prompt postoperative withdrawal and recovery.

Acute coronary syndrome associated cardiogenic shock in the catheterization laboratory: peripheral veno-arterial extracorporeal membrane oxygenator management and recommendations

Cardiogenic shock (CS) in acute coronary syndrome (ACS) is a critical disease with high mortality rates requiring complex treatment to maximize patient survival chances. Emergent coronary revascularization along with circulatory support are keys to saving lives. Mechanical circulatory support may be instigated in severe, yet still reversible instances. Of these, the peripheral veno-arterial extracorporeal membrane oxygenator (pVA-ECMO) is the most widely used system for both circulatory and respiratory support. The aim of our work is to provide a review of our current understanding of the pVA-ECMO when used in the catheterization laboratory in a CS ACS setting. We detail the workings of a Shock Team: pVA-ECMO specifics, circumstances, and timing of implantations and discuss possible complications. We place emphasis on how to select the appropriate patients for potential pVA-ECMO support and what characteristics and parameters need to be assessed. A detailed, stepwise implantation algorithm indicating crucial steps is also featured for practitioners in the catheter laboratory. To provide an overall aspect of pVA-ECMO use in CS ACS we further gave pointers including relevant human resource, infrastructure, and consumables management to build an effective Shock Team to treat CS ACS via the pVA-ECMO method.

A Rare Case of Diffuse Alveolar Hemorrhage Caused by Fentanyl Inhalation

Diffuse alveolar hemorrhage (DAH) is a rare but life-threatening pulmonary disorder characterized by blood accumulation in alveolar spaces, often associated with autoimmune diseases and infections. Drug-induced causes of DAH, including inhalation of substances like fentanyl, are emerging concerns. A 40-year-old male with bipolar disorder and polysubstance abuse presented with altered mental status and hemoptysis after inhaling an unknown substance. Physical examination revealed respiratory distress, pinpoint pupils, and severe hypoxemia. Naloxone administration improved his condition. The workup showed negative infection markers, positive fentanyl-specific urine test, and diffuse bilateral opacities on imaging. Bronchoalveolar lavage confirmed DAH with >20% hemosiderin-laden macrophages. Steroid treatment resulted in marked improvement. Drug-induced DAH, such as fentanyl inhalation, should be considered in patients with altered mental status and pulmonary symptoms following substance use. Comprehensive evaluation and targeted treatment are crucial for optimal outcomes.

Comparison of clinical outcomes with cangrelor plus aspirin versus oral dual antiplatelet therapy in patients supported with venoarterial extracorporeal membrane oxygenation

BACKGROUND

Patients with refractory cardiogenic shock from an acute myocardial infarction may receive percutaneous coronary intervention (PCI) and require the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO). The purpose of this study was to compare bleeding and thrombotic events in patients treated with cangrelor plus aspirin versus oral dual antiplatelet therapy (DAPT) while supported with VA-ECMO.

METHODS

We conducted a retrospective review of patients who received PCI, were supported with VA-ECMO, and were treated with either cangrelor plus aspirin or oral DAPT from February 2016 through May 2021 at Allegheny General Hospital. The primary objective was the incidence of major bleeding, defined as Bleeding Academic Research Consortium (BARC) type 3 or greater. The incidence of thrombotic events was a secondary objective.

RESULTS

Thirty-seven patients were included, 19 in the cangrelor plus aspirin group, and 18 in the oral DAPT group. All the patients in the cangrelor group received a dose of 0.75 mcg/kg/min. Major bleeding occurred in 7 patients (36.8%) in the cangrelor group compared to 7 patients (38.9%) in the oral DAPT group (p = 0.90). No patient developed stent thrombosis. Two patients (10.5%) in the cangrelor group had a thrombotic event versus 3 patients (16.7%) in the oral DAPT group (p = 0.66).

CONCLUSIONS

Bleeding and thrombotic events were comparable between patients receiving cangrelor plus aspirin versus oral DAPT while on VA-ECMO.

COVID-19 outcomes of venovenous extracorporeal membrane oxygenation for acute respiratory failure vs historical cohort of non-COVID-19 viral infections

INTRODUCTION

Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become a support modality for patients with acute respiratory failure refractory to standard therapies. VV ECMO has been increasingly used during the current COVID-19 pandemic for patients with refractory respiratory failure. The object of this study was to evaluate the outcomes of VV ECMO in patients with COVID-19 compared to patients with non-COVID-19 viral infections.

METHODS

We retrospectively reviewed all patients supported with VV ECMO between 8/2014 and 8/2020 whose etiology of illness was a viral pulmonary infection. The primary outcome of this study was to evaluate in-hospital mortality. The secondary outcomes included length of ECMO course, ventilator duration, hospital length of stay, incidence of adverse events through ECMO course.

RESULTS

Eighty-nine patients were included (35 COVID-19 vs 54 non-COVID-19). Forty (74%) of the non-COVID-19 patients had influenza virus. Prior to cannulation, COVID-19 patients had longer ventilator duration (3 vs 1 day, p = .003), higher PaCO2 (64 vs 53 mmHg, p = .012), and white blood cell count (14 vs 9 ×103/μL, p = .004). Overall in-hospital mortality was 33.7% (n = 30). COVID-19 patients had a higher mortality (49% vs. 24%, p = .017) when compared to non-COVID-19 patients. COVID-19 survivors had longer median time on ECMO than non-COVID-19 survivors (24.4 vs 16.5 days p = .03) but had a similar hospital length of stay (HLOS) (41 vs 48 Extracorporeal Membrane Oxygenationdays p = .33).

CONCLUSION

COVID-19 patients supported with VV ECMO have a higher mortality than non-COVID-19 patients. While COVID-19 survivors had significantly longer VV ECMO runs than non-COVID-19 survivors, HLOS was similar. This data add to a growing body of literature supporting the use of ECMO for potentially reversible causes of respiratory failure.

Pediatric surgical interventions on ECMO

Extra Corporeal Membrane Oxygenation (ECMO) has historically been reserved for refractory pulmonary and cardiac support in children and adult. Operative intervention on ECMO was traditionally contraindicated due to hemorrhagic complications exacerbated by critical illness and anticoagulation needs. With advancements in ECMO circuitry and anticoagulation strategies operative procedures during ECMO have become feasible with minimal hemorrhagic risks. Here we review anticoagulation and operative intervention considerations in the pediatric population during ECMO cannulation. Pediatric surgical interventions currently described in the literature while on ECMO support include thoracotomy/thoracoscopy, tracheostomy, laparotomy, and injury related procedures i.e. wound debridement. A patient should not be precluded from a surgical intervention while on ECMO, if the surgery is indicated.

Venoarterial Extracorporeal Membrane Oxygenation After Autologous Stem Cell Transplantation With Pancytopenia: JACC Patient Care Pathways

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides temporary mechanical circulatory support and simultaneous extracorporeal gas exchange for acute cardiorespiratory failure. By providing circulatory support, VA-ECMO gives treatments time to reach optimal efficacy or may be used as a bridge to a more durable mechanical solution for patients with acute cardiopulmonary failure. It is commonly used when a readily reversible etiology of decompensation is identified with very strict inclusion criteria for extracorporeal cardiopulmonary resuscitation use. We present a unique case in which VA-ECMO/extracorporeal cardiopulmonary resuscitation was used after cardiac arrest with pulseless electrical activity in a patient with recurrent lymphoma of the left thigh with recent autologous stem cell transplant.

Venoarterial Extracorporeal Membrane Oxygenation After Autologous Stem Cell Transplantation With Pancytopenia: JACC Patient Care Pathways

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides temporary mechanical circulatory support and simultaneous extracorporeal gas exchange for acute cardiorespiratory failure. By providing circulatory support, VA-ECMO gives treatments time to reach optimal efficacy or may be used as a bridge to a more durable mechanical solution for patients with acute cardiopulmonary failure. It is commonly used when a readily reversible etiology of decompensation is identified with very strict inclusion criteria for extracorporeal cardiopulmonary resuscitation use. We present a unique case in which VA-ECMO/extracorporeal cardiopulmonary resuscitation was used after cardiac arrest with pulseless electrical activity in a patient with recurrent lymphoma of the left thigh with recent autologous stem cell transplant.

Venovenous extracorporeal membrane oxygenation experience in a community level I trauma center

BACKGROUND

There is limited literature of venovenous extracorporeal membrane oxygenation use in a community, non-university, setting in the trauma population.

METHODS

We reviewed our cases over 2 years from March 2018 to March 2020. This study was conducted in a community hospital with a General Surgery residency with no direct affiliation to a medical school. Primary outcome reviewed was survival to discharge. Secondary outcomes included duration of extracorporeal membranous oxygenation (ECMO) support, blood transfusion requirement, complications, and disposition.

RESULTS

Five patients were cannulated during this time period. All patients survived to discharge. Mean time on ECMO was 153.4 h or 6.4 days (range 60-216 h). All patients required a transfusion while cannulated, with a mean of 10 units PRBC transfused (range 3-24). One patient required CPR, one required cessation of heparin drip for bleeding, and one had clinical signs of a stroke. Three patients were discharged to long-term acute care facilities and the other two to acute rehab.

CONCLUSIONS

Community level I trauma centers are capable of handling trauma patients requiring ECMO. It does require a multi-disciplinary team of surgical intensivists and cardiothoracic surgeons along with the support of nursing, respiratory therapists, and perfusionists. The outcomes in this limited series show that ECMO can be a tool utilized in the community setting.

Perioperative Circulatory Support and Management for Lung Transplantation: A Case-Based Review

Lung transplantation (LTx) historically was performed with cardiopulmonary bypass (CPB) or Off-pump. Recent data suggest an increased interest in extracorporeal membrane oxygenation (ECMO) as perioperative circulatory support by many lung transplantation centers worldwide. However, there are no established guidelines for anesthetic management for LTx. We present a patient with a history of systemic sclerosis and interstitial lung disease complicated by acute onset of systemic pulmonary hypertension and right heart failure undergoing LTx. We aim to discuss perioperative circulatory support, including ECMO bridge to LTx, and how best to consider the varied intraoperative strategies of CPB vs ECMO vs off-pump during LTx, intraoperative maintenance, and coagulation management.

Hemostatic alterations during extracorporeal membrane oxygenation in ovine veno-venous and veno-arterial models

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has salvaged many people's life during global pandemics. However, ECMO is associated with a high incidence of hemostatic complications. This study aims to explore the effects of the ECMO system on the coagulation system in the healthy ovine ECMO model.

METHODS

Ten healthy male sheep were included. Five received the veno-arterial ECMO and five received the veno-venous ECMO. Heparin was infused for systemic anticoagulation and was adjusted according to the activated clotting time. Blood routine tests, coagulation factors, anticoagulation proteins, and fibrinolysis markers were tested at the baseline and every 24 h. After weaning, the pump heads were dissected to explore thrombosis.

RESULTS

Platelets decreased in the first 72 h and returned to the baseline at the 120th hour. The neutrophils increased in the first 24 h and returned to the baseline at the 48th hour. Factors II, VII, and X decreased in the first 24 h and gradually increased, while factors VIII, IX, XI, and XII decreased in the first 24 h and remained at a low level. The baseline antithrombin was 73.2 ± 14.4% and reduced to 42.6 ± 9.9% at the 168th hour. Pathology showed seven sheep developed thrombus, but no clinically relevant bleeding or thrombosis events occurred.

CONCLUSIONS

The study explored hemostatic alterations during ECMO in healthy animal models, which eliminated the confounding under critically ill conditions. The study may provide insights into ECMO hemostatic disorders and aid the design of optimal therapeutic strategies.

Evaluation of a Multimodal Heparin Laboratory Monitoring Protocol in Adult Extracorporeal Membrane Oxygenation Patients

BACKGROUND

Anticoagulation monitoring practices vary during extracorporeal membrane oxygenation (ECMO). The Extracorporeal Life Support Organization describes that a multimodal approach is needed to overcome assay limitations and minimize complications.

OBJECTIVE

Compare activated clotting time (ACT) versus multimodal approach (activated partial thromboplastin time (aPTT)/anti-factor Xa) for unfractionated heparin (UFH) monitoring in adult ECMO patients.

METHODS

We conducted a single-center retrospective pre- (ACT) versus post-implementation (multimodal approach) study. The incidence of major bleeding and thrombosis, blood product and antithrombin III (ATIII) administration, and UFH infusion rates were compared.

RESULTS

Incidence of major bleeding (69.2% versus 62.2%, p = 0.345) and thrombosis (23% versus 14.9%, p = 0.369) was similar between groups. Median number of ATIII doses was reduced in the multimodal group (1.0 [IQR 0.0-2.0] versus 0.0 [0.0 -1.0], p = 0.007). The median UFH infusion rate was higher in the ACT group, but not significant (16.9 [IQR 9.6-22.4] versus 13 [IQR 9.6-15.4] units/kg/hr, p = 0.063). Fewer UFH infusion rate changes occurred prior to steady state in the multimodal group (0.9 [IQR 0.3 -1.7] versus 0.1 [IQR 0.0-0.2], p < 0.001).

CONCLUSION

The incidence of major bleeding and thrombosis was similar between groups. Our multimodal monitoring protocol standardized UFH infusion administration and reduced ATIII administration.

Bleeding Hazard of Percutaneous Tracheostomy in COVID-19 Patients Supported With Venovenous Extracorporeal Membrane Oxygenation: A Case Series

OBJECTIVES

Tracheostomy usually is performed to aid weaning from mechanical ventilation and facilitate rehabilitation and secretion clearance. Little is known about the safety of percutaneous tracheostomy in patients with severe COVID-19 supported on venovenous extracorporeal membrane oxygenation (VV-ECMO). This study aimed to investigate the bleeding risk of bedside percutaneous tracheostomy in patients with COVID-19 infection supported with VV-ECMO.

DESIGN

A Retrospective review of electronic data for routine care of patients on ECMO.

SETTING

Tertiary, university-affiliated national ECMO center.

PARTICIPANTS

Patients with COVID-19 who underwent percutaneous tracheostomy while on VV-ECMO support.

INTERVENTIONS

No intervention was conducted during this study.

MEASUREMENTS AND MAIN RESULTS

Electronic medical records of 16 confirmed patients with COVID-19 who underwent percutaneous tracheostomy while on VV-ECMO support, including patient demographics, severity of illness, clinical variables, procedural complications, and outcomes, were compared with 16 non-COVID-19 patients. The SPSS statistical software was used for statistical analysis. The demographic data were compared using the chi-square test, and normality assumption was tested using the Shapiro-Wilk test. The indications for tracheostomy in all the patients were prolonged mechanical ventilation and sedation management. None of the patients suffered a life-threatening procedural complication within 48 hours. Moderate-to-severe bleeding was similar in both groups. There was no difference in 30- and 90-days mortality between both groups. As per routine screening results, none of the staff involved contracted COVID-19 infection.

CONCLUSIONS

In this case series, percutaneous tracheostomy during VV-ECMO in patients with COVID-19 appeared to be safe and did not pose additional risks to patients or healthcare workers.

Bivalirudin Versus Unfractionated Heparin in Patients With Cardiogenic Shock Requiring Venoarterial Extracorporeal Membrane Oxygenation

This study evaluated differences in efficacy and safety outcomes with bivalirudin compared with unfractionated heparin (UFH) in patients with cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation (VA ECMO). We performed a retrospective study at an academic medical center that included patients greater than 18 years of age supported with VA ECMO due to cardiogenic shock from January 2009 to February 2021. The primary endpoint was ECMO-associated thrombotic events normalized to duration of ECMO support. Secondary safety endpoints included major bleeding (per ELSO criteria) and blood product administration. Overall, 143 patients were included in our analysis with 54 having received bivalirudin and 89 having received UFH. Median duration of ECMO support was 92 (interquartile range, 56-172) hours. ECMO-associated thrombotic events per ECMO day were significantly less among those that received bivalirudin ( P < 0.001). In adjusted regression, bivalirudin was independently associated with an increased time to thrombosis when compared with UFH (Exp[B] -3.8; 95% confidence interval, 1.7-8.8; P = 0.002). Patients receiving bivalirudin experienced less major bleeding events ( P = 0.02) with less total red blood cell and fresh frozen plasma administration ( P = 0.04 and P = 0.03, respectively). Bivalirudin is a safe and efficacious alternative to UFH in patients requiring VA ECMO for cardiogenic shock.

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.

Viscoelastic Testing in the Management of Adult Patients on Mechanical Circulatory Support Devices with Focus on Extracorporeal Membrane Oxygenation

Thromboembolic and hemorrhagic complications continue to remain frequent complications that significantly impact the morbidity and mortality of patients implanted with mechanical circulatory support devices (MCSDs). The severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) has resulted in a number of COVID-19 patients being supported by MCSDs, specifically extracorporeal membrane oxygenation (ECMO), which in turn has created a crucial need for rapid assessment of hemostatic status in these patients to avoid bleeding and thrombotic complications. Currently, conventional plasma-based coagulation assays such as prothrombin time and activated partial thromboplastin time (aPTT) are used to assess hemostasis, and the activated clotting time (ACT) and aPTT are the most common tests used to monitor heparin anticoagulation in patients on ECMO. Unfractionated heparin remains the mainstay anticoagulation therapy for patients on ECMO. Extracorporeal Life Support Organization (ELSO) offers little guidance on the subject but does state that each institution should create its internal anticoagulation protocols. Viscoelastic assays (VEAs) are increasingly recognized by ELSO and ECMO community for their potential to assess hemostatic derangements in patients implanted with MCSDs as well as guidance for appropriate hemostatic therapy. This review focuses on the evidence for the use of viscoelastic assays to assess overall hemostasis and to guide the treatment of adult patients connected to an ECMO circuit. Limitations of the use of conventional assays, ACT, and VEA are also discussed.

Effect of Initial Anticoagulation Targets on Bleeding and Thrombotic Complications for Patients With Acute Respiratory Distress Syndrome Receiving Extracorporeal Membrane Oxygenation

OBJECTIVE

To evaluate the effect of anticoagulation targets and intensity on bleeding events, thrombotic events, and transfusion requirements in patients with acute respiratory distress syndrome (ARDS) receiving venovenous extracorporeal membrane oxygenation (ECMO) and continuous-infusion heparin.

DESIGN

A retrospective cohort study.

SETTING

At a single-center, large academic medical center.

PARTICIPANTS

One hundred thirty-six critically ill patients.

INTERVENTIONS

The following three therapeutic targets were implemented over time and evaluated: (1) no protocol (September 2013-August 2016): no standardized anticoagulation protocol or transfusion thresholds; (2) <50 seconds (September 2016-January 2018): standardized activated partial thromboplastin time (aPTT) goal of <50 seconds, maximum heparin infusion rate of 1,200 units/h, transfusion threshold of hemoglobin (Hgb) <8 g/dL; and (3) 40-to-50 seconds (February 2018-December 2019): aPTT goal of 40-to-50 sec, no maximum heparin infusion rate, transfusion threshold of Hgb <7 g/dL.

MEASUREMENTS AND MAIN RESULTS

Continuous variables were compared using the Kruskal-Wallis test, and categorical variables were compared using Fisher exact tests. The primary endpoint, an incidence of at least 1 bleeding event, was highest in the no-protocol group though not statistically different among groups (39.3% v 26.7% v 34%, p = 0.5). Thrombotic complications were similar. The median units of packed red blood cells transfused were highest in the no-protocol group (3 v 2 v 0.5, p < 0.001).

CONCLUSION

Anticoagulation protocols standardizing aPTT goals to <50 or 40-to-50 seconds may be a reasonable strategy for patients receiving venovenous ECMO for ARDS. More restrictive hemoglobin transfusion thresholds, in combination with lower aPTT targets, may be associated with a reduction in transfusion requirements.

A Comparison of Activated Partial Thromboplastin Time and Activated Coagulation Time for Anticoagulation Monitoring during Extracorporeal Membrane Oxygenation Therapy

BACKGROUND

 Unfractionated heparin is used to prevent coagulation activation in patients undergoing extracorporeal membrane oxygenation (ECMO) support. We designed this study to determine the preferable indicator for anticoagulation monitoring.

METHODS

 We conducted a retrospective study and divided the patients into an activated coagulation time (ACT)-target group and an activated partial thromboplastin time (aPTT)-target group. The correlations between ACT, aPTT, and the heparin dose were explored.

RESULTS

 Thirty-six patients were included (19 aPTT-target and 17 ACT-target patients); a total of 555 matched pairs of ACT/aPTT results were obtained. The correlation between the ACT and aPTT measurements was Spearman's Rank Correlation Coefficient (rs) = 0.518 in all 555 pairs. The Bland-Altman plot showed data points outside the displayed range (51.2-127.7), suggesting that the agreement between ACT and aPTT was poor. The aPTT group had fewer heparin dose changes (2.12 ± 0.68 vs. 2.57 ± 0.64, p = 0.05) and a lower cumulative heparin dose (317.6 ± 108.5 vs. 396.3 ± 144.3, p = 0.00) per day than the ACT group. There was no difference in serious bleeding (9 vs. 5; p = 0.171) or embolism events (3 vs. 3; p = 1.0) or in the red blood cell and fresh frozen plasma transfusion volumes between the ACT- and aPTT-target groups. Similarly, there was no significant difference in the ECMO duration (9 [4-15] days vs. 4 [3-14] days; p = 0.124) or length of ICU hospitalization (17 [5-32] days vs. 13 [4-21] days; p = 0.451) between the groups.

CONCLUSION

 The correlation between ACT and aPTT and the heparin dose was poor. The aPTT group had fewer daily heparin dose changes and a lower cumulative heparin dose per day than the ACT group, with no more bleeding and thrombotic events. Therefore, we recommend aPTT rather than ACT to adjust heparin dose in the absence of better monitoring indicators.

Suppression of Fibrinolysis and Hypercoagulability, Severity of Hypoxemia, and Mortality in COVID-19 Patients: A Retrospective Cohort Study

BACKGROUND

COVID-19 causes hypercoagulability, but the association between coagulopathy and hypoxemia in critically ill patients has not been thoroughly explored. This study hypothesized that severity of coagulopathy would be associated with acute respiratory distress syndrome severity, major thrombotic events, and mortality in patients requiring intensive care unit-level care.

METHODS

Viscoelastic testing by rotational thromboelastometry and coagulation factor biomarker analyses were performed in this prospective observational cohort study of critically ill COVID-19 patients from April 2020 to October 2020. Statistical analyses were performed to identify significant coagulopathic biomarkers such as fibrinolysis-inhibiting plasminogen activator inhibitor 1 and their associations with clinical outcomes such as mortality, extracorporeal membrane oxygenation requirement, occurrence of major thrombotic events, and severity of hypoxemia (arterial partial pressure of oxygen/fraction of inspired oxygen categorized into mild, moderate, and severe per the Berlin criteria).

RESULTS

In total, 53 of 55 (96%) of the cohort required mechanical ventilation and 9 of 55 (16%) required extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation-naïve patients demonstrated lysis indices at 30 min indicative of fibrinolytic suppression on rotational thromboelastometry. Survivors demonstrated fewer procoagulate acute phase reactants, such as microparticle-bound tissue factor levels (odds ratio, 0.14 [0.02, 0.99]; P = 0.049). Those who did not experience significant bleeding events had smaller changes in ADAMTS13 levels compared to those who did (odds ratio, 0.05 [0, 0.7]; P = 0.026). Elevations in plasminogen activator inhibitor 1 (odds ratio, 1.95 [1.21, 3.14]; P = 0.006), d-dimer (odds ratio, 3.52 [0.99, 12.48]; P = 0.05), and factor VIII (no clot, 1.15 ± 0.28 vs. clot, 1.42 ± 0.31; P = 0.003) were also demonstrated in extracorporeal membrane oxygenation-naïve patients who experienced major thrombotic events. Plasminogen activator inhibitor 1 levels were significantly elevated during periods of severe compared to mild and moderate acute respiratory distress syndrome (severe, 44.2 ± 14.9 ng/ml vs. mild, 31.8 ± 14.7 ng/ml and moderate, 33.1 ± 15.9 ng/ml; P = 0.029 and 0.039, respectively).

CONCLUSIONS

Increased inflammatory and procoagulant markers such as plasminogen activator inhibitor 1, microparticle-bound tissue factor, and von Willebrand factor levels are associated with severe hypoxemia and major thrombotic events, implicating fibrinolytic suppression in the microcirculatory system and subsequent micro- and macrovascular thrombosis in severe COVID-19.

EDITOR’S PERSPECTIVE

Inhibitory role of recombinant neorudin on canine coronary artery thrombosis

The anticoagulant application is an effective treatment modality for cardiovascular diseases such as coronary heart disease, unstable angina pectoris, and myocardial infarction. In this study, the antithrombotic effect of recombinant neorudin (EPR‐hirudin, EH) was evaluated using a canine model of coronary artery thrombosis. A canine model with platelet thrombosis in the left circumferent branch of the coronary artery was designed using Folt's method, and the anti‐thrombus activity of EH was investigated. Femoral administration of EH intravenously had a significant dose‐dependent inhibitory effect on canine coronary artery thrombosis and the effective rates were 66.7% (p < .05), 83.3% (p < .05), and 100% (p < .01) after injection of 0.3, 1.0, and 3.0 mg/kg EH, respectively. Furthermore, EH demonstrated lower bleeding, with shorter bleeding time and less bleeding loss than low molecular weight heparin (LMWH). Under the similar effect intensity of EH and LMWH (85 IU/kg), the bleeding time of the EH group at 30 min was shorter, and the blood loss at 30–120 min was less than that of LMWH (p < .05 and p < .05–.001, respectively). EH had a significant dose‐dependent inhibitory effect in the dose range of 0.3–3.0 mg/kg on the coronary artery thrombosis and lower bleeding side effects than LMWH with a similar antithrombosis effect.

Bleeding During Veno-Venous ECMO: Prevention and Treatment

Veno-venous extracorporeal membrane oxygenation (vvECMO) has become a routine treatment for severe lung failure in specialized centers. Spontaneous bleeding complications, however, are observed in 30–60% of patients during vvECMO treatment. Bleeding increases mortality by factors 2–3. Anticoagulation in combination with several acquired bleeding disorders caused by the mechanical pump and the foreign layer of the extracorporeal system contribute to the risk of bleeding. In this review, the mechanisms of the underlying pathologies and the route from diagnosis to treatment are described.

Reduced anticoagulation targets in extracorporeal life support (RATE): study protocol for a randomized controlled trial

BACKGROUND

Although life-saving in selected patients, ECMO treatment still has high mortality which for a large part is due to treatment-related complications. A feared complication is ischemic stroke for which heparin is routinely administered for which the dosage is usually guided by activated partial thromboplastin time (aPTT). However, there is no relation between aPTT and the rare occurrence of ischemic stroke (1.2%), but there is a relation with the much more frequent occurrence of bleeding complications (55%) and blood transfusion. Both are strongly related to outcome.

METHODS

We will conduct a three-arm non-inferiority randomized controlled trial, in adult patients treated with ECMO. Participants will be randomized between heparin administration with a target of 2-2.5 times baseline aPTT, 1.5-2 times baseline aPTT, or low molecular weight heparin guided by weight and renal function. Apart from anticoagulation targets, treatment will be according to standard care. The primary outcome parameter is a combined endpoint consisting of major bleeding including hemorrhagic stroke, severe thromboembolic complications including ischemic stroke, and mortality at 6 months.

DISCUSSION

We hypothesize that with lower anticoagulation targets or anticoagulation with LMWH during ECMO therapy, patients will have fewer hemorrhagic complications without an increase in thromboembolic complication or a negative effect on their outcome. If our hypothesis is confirmed, this study could lead to a change in anticoagulation protocols and a better outcome for patients treated with ECMO.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04536272 . Registered on 2 September 2020. Netherlands Trial Register NL7969.

A Comparison of Anticoagulation Strategies in Veno-venous Extracorporeal Membrane Oxygenation

Bleeding remains a major source of morbidity associated with veno-venous extracorporeal membrane oxygenation (VV-ECMO). Moreover, there remains significant controversy, and a paucity of data regarding the ideal anticoagulation strategy for VV-ECMO patients. All patients undergoing isolated, peripheral VV-ECMO between January 2009 and December 2014 at our institution were retrospectively reviewed. Patients (n = 123) were stratified into one of three sequential eras of anticoagulation strategies: activated clotting time (ACT: 160-180 seconds, n = 53), high-partial thromboplastin time (H-PTT: 60-80 seconds, n = 25), and low-PTT (L-PTT: 45-55 seconds, n = 25) with high-flow (>4 L/min). Pre-ECMO APACHE II scores, SOFA scores, and Murray scores were not significantly different between the groups. Patients in the L-PTT group required less red blood cell units on ECMO than the ACT or H-PTT group (2.1 vs. 1.3 vs. 0.9; p < 0.001) and patients in the H-PTT and L-PTT group required less fresh frozen plasma than the ACT group (0.33 vs. 0 vs. 0; p = 0.006). Overall, major bleeding events were significantly lower in the L-PTT group than in the ACT and H-PTT groups. There was no difference in thrombotic events. In this single-institution experience, a L-PTT, high-flow strategy on VV-ECMO was associated with fewer bleeding and no difference in thrombotic events than an ACT or H-PTT strategy.

Outcomes of Extubated COVID and Non-COVID Patients Receiving Awake Venovenous Extracorporeal Membrane Oxygenation

Cessation of continuous analgesia and sedation in patients with acute respiratory distress syndrome (ARDS) receiving venovenous (VV) extracorporeal membrane oxygenation (ECMO) facilitates early extubation, family, patient and provider engagement, and mobility. Outcomes associated with an awake ECMO strategy have not been well described in the literature. The purpose of this study was to evaluate outcomes in patients receiving this strategy. This was a retrospective review of ARDS patients receiving awake VV ECMO. The primary outcome was survival to hospital discharge. Secondary outcomes included days requiring ECMO, time from cannulation to extubation, complications, patients requiring tracheostomy, hospital and intensive care unit (ICU) length of stay (LOS), and discharge disposition. In a subgroup analysis, outcomes were compared between non-COVID and COVID ECMO patients. Sixty-two patients were included with a survival to hospital discharge of 85.5%. Days requiring ECMO was 33.0 (0.0-75.0) and cannulation to extubation was 6.0 (4.0-11.0). Three patients received a tracheostomy (4.8%). Bleeding and infection were reported in 80.6% and 82.3% of patients, respectively. Intensive care unit length of stay was 46.0 days (29.0-90.0) and hospital LOS was 51.0 days (32.0-91.0). Over half of the patients (51.6%) were discharged to an acute rehabilitation facility and 27.4% were discharged home. There was similar survival to hospital discharge between the COVID and non-COVID awake ECMO patients (85% in both groups, p = 1.000). This study highlights the impact of an awake ECMO approach on survival to hospital discharge. Future studies are needed to evaluate this approach as compared to current practice to determine if this should become the standard.

How we manage blood product support and coagulation in the adult patient requiring extracorporeal membrane oxygenation

Use of extracorporeal membrane oxygenation (ECMO) is increasing among critically ill adults with cardiac and/or respiratory failure. Use of ECMO is associated with hemostatic alterations requiring use of anticoagulation and blood product support. There are limited guidelines to direct transfusion management in the adult patient supported with ECMO. The objective of this article is to describe (1) the role of the transfusion service in providing transfusion support and current understanding of transfusion thresholds, (2) the complexities of monitoring anticoagulation, and (3) the consideration regarding additional factor concentrates and antifibrinolytics within the context of ECMO support. The information provided should assist ECMO care teams in informing transfusion and anticoagulation practice while highlighting key areas for future research and collaboration.

Extracorporeal Membrane Oxygenation for Pregnant and Postpartum Patients

Extracorporeal membrane oxygenation (ECMO) has seen increasing use for critically ill pregnant and postpartum patients over the past decade. Growing experience continues to demonstrate the feasibility of ECMO in obstetric patients and attest to its favorable outcomes. However, the interaction of pregnancy physiology with ECMO life support requires careful planning and adaptation for success. Additionally, the maintenance of fetal oxygenation and perfusion is essential for safely continuing pregnancy during ECMO support. This review summarizes the considerations for use of ECMO in obstetric patients and how to address these concerns.

Hemorrhagic Resuscitation Guided by Viscoelastography in Far-Forward Combat and Austere Civilian Environments: Goal-Directed Whole-Blood and Blood-Component Therapy Far from the Trauma Center

Modern approaches to resuscitation seek to bring patient interventions as close as possible to the initial trauma. In recent decades, fresh or cold-stored whole blood has gained widespread support in multiple settings as the best first agent in resuscitation after massive blood loss. However, whole blood is not a panacea, and while current guidelines promote continued resuscitation with fixed ratios of blood products, the debate about the optimal resuscitation strategy-especially in austere or challenging environments-is by no means settled. In this narrative review, we give a brief history of military resuscitation and how whole blood became the mainstay of initial resuscitation. We then outline the principles of viscoelastic hemostatic assays as well as their adoption for providing goal-directed blood-component therapy in trauma centers. After summarizing the nascent research on the strengths and limitations of viscoelastic platforms in challenging environmental conditions, we conclude with our vision of how these platforms can be deployed in far-forward combat and austere civilian environments to maximize survival.

HEROES V-V-HEmorRhagic cOmplications in Veno-Venous Extracorporeal life Support-Development and internal validation of multivariable prediction model in adult patients

BACKGROUND

During extracorporeal life support (ECLS), bleeding is one of the most frequent complications, associated with high morbidity and increased mortality, despite continuous improvements in devices and patient care. Risk factors for bleeding complications in veno-venous (V-V) ECLS applied for respiratory support have been poorly investigated. We aim to develop and internally validate a prediction model to calculate the risk for bleeding complications in adult patients receiving V-V ECLS support.

METHODS

Data from adult patients reported to the extracorporeal life support organization (ELSO) registry between the years 2010 and 2020 were analyzed. The primary outcome was bleeding complications recorded during V-V ECLS. Multivariable logistic regression with backward stepwise elimination was used to develop the predictive model. The performance of the model was tested by discriminative ability and calibration with receiver operating characteristic curves and visual inspection of the calibration plot.

RESULTS

In total, 18 658 adult patients were included, of which 3 933 (21.1%) developed bleeding complications. The prediction model showed a prediction of bleeding complications with an AUC of 0.63. Pre-ECLS arrest, surgical cannulation, lactate, pO₂ , HCO₃ , ventilation rate, mean airway pressure, pre-ECLS cardiopulmonary bypass or renal replacement therapy, pre-ECLS surgical interventions, and different types of diagnosis were included in the prediction model.

CONCLUSIONS

The model is based on the largest cohort of V-V ECLS patients and reveals the most favorable predictive value addressing bleeding events given the predictors that are feasible and when compared to the current literature. This model will help identify patients at risk of bleeding complications, and decision making in terms of anticoagulation and hemostatic management.

Heparin Monitoring with an Anti-Xa Protocol Compared to Activated Clotting Time in Patients on Temporary Mechanical Circulatory Support

BACKGROUND

Temporary mechanical circulatory support (tMCS) devices are used for patients with severe cardiac or respiratory failure; however, these patients are at high risk for clotting and bleeding. The best method to monitor heparin in these patients has not been established.

OBJECTIVE

To determine the risks for bleeding and clotting while monitoring heparin with either anti-Xa or activated clotting time (ACT) in tMCS patients.

METHODS

A retrospective cohort study was conducted on tMCS patients who received heparin adjusted according to an anti-Xa or ACT protocol. The primary outcome was incidence of major bleeding. Pertinent secondary outcomes were individual components of the primary outcome, clotting events, and time to therapeutic range.

RESULTS

There were 103 patients included in the study: 53 in the ACT group and 50 in the anti-Xa group. Overall, there were 30 (56.6%) patients with major bleeding in the ACT group, compared with 16 (32%) patients in the anti-Xa group (P = 0.017). An anti-Xa-based protocol was associated with a decreased hazard of major bleeding (hazard ratio = 0.388 [0.215-0.701]; P = 0.002) in the univariate analysis. In the multivariable analysis, an anti-Xa protocol remained associated with a significantly lower hazard of bleeding. Findings were similar when broken down into more discrete subgroups of the entire cohort, extracorporeal membrane oxygenation life support (ECMO), and non-ECMO groups.

CONCLUSION AND RELEVANCE

Anti-Xa monitoring was associated with a lower hazard of bleeding during tMCS compared to an ACT-based protocol. Further studies should evaluate if anti-Xa monitoring should be preferentially used in tMCS.

Conversion From Activated Clotting Time to Anti-Xa Heparin Activity Assay for Heparin Monitoring During Extracorporeal Membrane Oxygenation

OBJECTIVES

Anticoagulation with unfractionated heparin remains the most common therapy used to prevent circuit thrombosis during extracorporeal membrane oxygenation, but no consensus exists on the optimal method or targets for heparin monitoring. From 2015 to 2018, we switched from monitoring heparin during extracorporeal membrane oxygenation using activated clotting times to anti-Xa heparin activity assays. This study describes the transition from activated clotting time to anti-Xa heparin activity assay monitoring and the associated clinical changes.

DESIGN

Retrospective analysis at single institution.

SETTING

Referral Children's Hospital.

PATIENTS

A total of 145 pediatric patients over 152 extracorporeal membrane oxygenation runs using 206 extracorporeal membrane oxygenation circuits.

INTERVENTIONS

Anticoagulation protocol quality improvement.

MEASUREMENTS AND MAIN RESULTS

From 2015 to 2018, heparin monitoring during extracorporeal membrane oxygenation changed from hourly activated clotting time to anti-Xa heparin activity assay every 6 hours with an associated 75% reduction in the circuit changes per extracorporeal membrane oxygenation day. Over the 4 years, patients with an average anti-Xa heparin activity assay of at least 0.25 U/mL showed a 59% reduction in circuit changes per extracorporeal membrane oxygenation day compared with less than 0.15 U/mL. In addition to its association with reduced circuit changes, anti-Xa heparin activity assay monitoring was also associated with reduced heparin dose changes per day from 11 ± 4 to 2 ± 1 (p < 0.001), smaller heparin dose changes (less variation in dose), and reduced diagnostic phlebotomy volumes from 41 ± 6 to 25 ± 11 mL/day (p < 0.001). The number of patients with reported bleeding decreased from 69% using activated clotting time to 51% (p = 0.03). Transfusion rates did not change.

CONCLUSIONS

Over 4 years, we replaced the activated clotting time assay with the anti-Xa heparin activity assay for heparin monitoring during extracorporeal membrane oxygenation. Minimum anti-Xa heparin activity assay levels of 0.25 U/mL were associated with reduced circuit changes. Further studies are needed to determine the optimum anti-Xa heparin activity assay therapeutic range during extracorporeal membrane oxygenation.

Low vs standardized dose anticoagulation regimens for extracorporeal membrane oxygenation: A meta-analysis

Background

To compare the safety and efficacy of low-dose anticoagulation (LA) with that of standardized dose anticoagulation (SA) for patients supported with extracorporeal membrane oxygenation (ECMO).

Methods

PubMed, MEDLINE, the Cochrane Library, and Web of Science were screened for original articles. Screening was performed using predefined search terms to identify cohort studies reporting the comparison of LA with SA in patients supported with ECMO from Nov 1990 to Jun 2020. The effect size was determined by the odds ratio (OR) with the 95% confidence interval (CI).

Results

An analysis of 7 studies including a total of 553 patients was performed. LA (Low-heparin group) was administered to 255 patients, whereas the other 298 patients received SA (Full-heparin group). The incidence of gastrointestinal tract hemorrhage (OR 0.36, 95% CI 0.20–0.64) and surgical site hemorrhage (OR 0.43, 95% CI 0.20–0.94) were significantly lower in patients who underwent LA compared with that in those who underwent SA. The rates of hospital mortality (OR 0.81, 95% CI 0.42–1.56), successfully weaning off of ECMO (OR 0.80, 95% CI 0.30–2.14), pulmonary embolism (OR 0.79, 95% CI 0.24–2.65), intracardiac thrombus (OR 0.34, 95% CI 0.09–1.30), intracranial hemorrhage (OR 0.62, 95% CI 0.22–1.74), and pulmonary hemorrhage (OR 0.77, 95% CI 0.30–1.93) were similar between the two groups.

Conclusions

This meta-analysis confirms that LA is a feasible and safe anticoagulation strategy in patients supported by ECMO. Future studies should focus on the long-term benefits of LA compared with SA.

Hypercoagulopathy, acquired coagulation disorders and anticoagulation before, during and after extracorporeal membrane oxygenation in COVID-19: a case series

BACKGROUND

Thromboembolism and bleeding contribute to Coronavirus disease 2019 (COVID-19)'s morbidity and mortality and are also frequent complications of venovenous extracorporeal membrane oxygenation (vvECMO). As the interaction of the underlying pathologies caused by vvECMO in COVID-19 is barely understood, we designed this study to better differentiate coagulation disorders in COVID-19 patients before, during and after vvECMO-support.

METHODS

Observational case series, six consecutive patients with Coronavirus acute respiratory distress syndrome supported with vvECMO treated in the anaesthesiologic ICU in a third level University ECMO-centre. We measured routine coagulation parameters and assessed coagulation factors. We also conducted advanced von Willebrand factor (VWF) multimer analysis, platelet aggregometry and immunological screening.

RESULTS

We identified various phases of coagulation disorders: Initially, intensely activated coagulation with highly increased VWF and factor VIII activity in acute COVID-19, then severe acquired von Willebrand syndrome and platelet dysfunction during vvECMO leading to spontaneous bleeding and finally, hypercoagulopathy after vvECMO explantation. Five of six patients developed immunological abnormalities enhancing coagulation.

CONCLUSIONS

Coronavirus-induced coagulopathy and bleeding disorders during vvECMO cannot be discriminated via 'routine' coagulation tests. Precise and specific analyses followed by the appropriate treatment of coagulation disorders may help us develop tailored therapeutic concepts to better manage the phases described above.

Argatroban Anticoagulation for Adult Extracorporeal Membrane Oxygenation: A Systematic Review

BACKGROUND

Heparin is the widely used anti-coagulation strategy for patients on extracorporeal membrane oxygenation (ECMO). Nevertheless, heparin-induced thrombocytopenia (HIT) and acquired anti-thrombin (AT) deficiency preclude the use of heparin requiring utilization of an alternative anticoagulant agent. Direct thrombin inhibitors are being proposed as potential alternatives with argatroban as one of the main agents. We aimed to review the evidence with regard to safety and efficacy of argatroban as a potential definitive alternative to heparin in the adult patient population undergoing ECMO support.

METHODS

A web-based systematic literature search was performed in Medline (PubMed) and Embase from inception until June 18, 2020.

RESULTS

The search identified 13 publications relevant to the target (4 cohort studies and 9 case series). Case reports and case series with less than 3 cases were not included in the qualitative synthesis. The aggregate number of argatroban treated patients on ECMO was n = 307. In the majority of studies argatroban was used as a continuous infusion without loading dose. Starting doses on ECMO varied between 0.05 and 2 μg/kg/min and were titrated to achieve the chosen therapeutic target range. The activated partial thormboplastin time (aPTT) was the anticoagulation parameter used for monitoring purposes in most studies, whereas some utilized the activated clotting time (ACT). Optimal therapeutic targets varied between 43-70 and 60-100 seconds for aPTT and between 150-210 and 180-230 seconds for ACT. Bleeding and thromboembolic complication rates were comparable to patients treated with unfractionated heparin (UFH).

CONCLUSIONS

Argatroban infusion rates and anticoagulation target ranges showed substantial variations. The rational for divergent dosing and monitoring approaches are discussed in this paper. Argatroban appears to be a potential alternative to UFH in patients requiring ECMO. To definitively establish its safety, efficacy and ideal dosing strategy, larger prospective studies on well-defined patient populations are warranted.

Extracorporeal Gas Exchange for Acute Respiratory Distress Syndrome: Open Questions, Controversies and Future Directions

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) in acute respiratory distress syndrome (ARDS) improves gas exchange and allows lung rest, thus minimizing ventilation-induced lung injury. In the last forty years, a major technological and clinical improvement allowed to dramatically improve the outcome of patients treated with V-V ECMO. However, many aspects of the care of patients on V-V ECMO remain debated. In this review, we will focus on main issues and controversies on caring of ARDS patients on V-V ECMO support. Particularly, the indications to V-V ECMO and the feasibility of a less invasive extracorporeal carbon dioxide removal will be discussed. Moreover, the controversies on management of mechanical ventilation, prone position and sedation will be explored. In conclusion, we will discuss evidences on transfusions and management of anticoagulation, also focusing on patients who undergo simultaneous treatment with ECMO and renal replacement therapy. This review aims to discuss all these clinical aspects with an eye on future directions and perspectives.

Subdural extravasation of crystalloids and blood products through a scalp peripheral intravenous catheter into the subdural space of a neonate on veno-arterial extracorporeal membrane oxygenation

We describe a rare and devastating complication of a malpositioned scalp peripheral intravenous catheter (PIV) that resulted in subdural extravasation of infused fluids and midline shift in a critically ill neonate who required extracorporeal membrane oxygenation (ECMO). Recognition of increased intracranial pressure was hindered by the hemodynamic changes of being on ECMO and only identified by routine surveillance ultrasonography. Awareness of this complication may lead providers to seek alternate sites for vascular access in such patients, and encourage closer monitoring for this complication when an alternate site is unavailable.

Disseminated Intravascular Coagulation Score Is Related to Short-term Mortality in Patients Undergoing Venoarterial Extracorporeal Membrane Oxygenation After Cardiac Surgery

Disseminated intravascular coagulation (DIC) score is associated with short-term mortality in various conditions but has not been studied in postcardiotomy cardiogenic shock (PCS) patients supported with venoarterial extracorporeal membrane oxygenation (VA-ECMO). The objective of this study was to evaluate the relationship between DIC score at day 1 from VA-ECMO initiation and short-term mortality. We included all PCS patients supported with VA-ECMO at the Beijing Anzhen Hospital between January 2015 and December 2018. Multivariable logistic regression analysis was performed to assess the relationship between DIC score at day 1 and in-hospital mortality, and adjust for potential confounding variables. Of 222 PCS patients treated with VA-ECMO, 145 (65%) patients were weaned from VA-ECMO, and median (IQR) ECMO support duration was five (3-6) days. In-hospital mortality was 53%. The median (IQR) DIC score at day 1 was five (4-6). Patients with DIC score ≥5 at day 1 (overt DIC) had higher in-hospital mortality as compared with patients with DIC score <5 (64% vs. 22%; P < 0.001). After adjusting for age, sex, ECMO indication, and peak serum lactate, a one-point rise in DIC score [OR, 2.20; 95% confidence intervals (CI), 1.64-2.95] or DIC score ≥5 at day 1 (OR, 4.98; 95% CI, 2.42-10.24) was associated with an increased risk of in-hospital mortality. The area under the receiver operating characteristic curve for DIC score at day 1 was 0.76 (95% CI, 0.69-0.82). Our study suggests that DIC score at day 1 is associated with short-term mortality in patients undergoing VA-ECMO after cardiac surgery, independent of age, sex, disease characteristics, and severity of illness.

Platelet transfusion is associated with 90-day and 1-year mortality for adult patients requiring veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Studies examining one-year mortality respecting component blood transfusion are sparse. We hypothesize that component blood product transfusions are negatively associated with 90-day and 1-year survival for all patients requiring veno-arterial (VA) or veno-venous (VV) ECMO.

STUDY DESIGN AND METHODS

This was an IRB-approved retrospective cohort analysis of 676 consecutive patients requiring ECMO at the University of Pittsburgh between 2005 and 2016. Patients were analysed both as an entire cohort and as two subsets with respect to ECMO modality (VA vs. VV). Additional data collected and analysed included patient characteristics, laboratory values and blood product transfusion.

RESULTS

Multivariable analysis revealed that platelet transfusion was associated with 90-day mortality (OR: 1·05, P = 0·037) and one-year mortality for the entire cohort (OR = 1·05, P = 0·046,). Platelet transfusion volume was also associated with mortality in the VA-ECMO subset of patients at both 90 days (OR = 1·08, P = 0·03) and one year (OR: 1·11, P = 0·014). Age, peak International Normalized Raton ECMO, nadir haemoglobin (on ECMO) and final haemoglobin (after ECMO) were significantly associated with mortality for patients requiring VA-ECMO. For VV-ECMO patients, age, INR and peak creatinine on ECMO were associated with mortality. No individual component blood product was associated with one-year mortality for patients requiring VV-ECMO.

CONCLUSION

Platelet transfusion was associated with increased 90-day and 1-year mortality for patients requiring VA-ECMO.