Managing the Precarious Hemostatic Balance during Extracorporeal Life Support: Implications for Coagulation Laboratories

Abstract

For the past four decades, extracorporeal life support (ECLS) has been used to treat critically ill adult and pediatric patients with cardiac and/or respiratory failure unresponsive to medical management, and there are increasing numbers of centers performing ECLS for numerous indications worldwide. Despite the progress with advancing technology, hemorrhagic and thrombotic complications occur frequently and are associated with worse outcomes, but the exact cause is often elusive or multifactorial. As a result of the interaction between blood and a nonendothelialized circuit, there is activation of coagulation, fibrinolysis, as well as an increased inflammatory response; thus, anticoagulation of the patient and circuit is necessary. While unfractionated heparin (UFH) remains the mainstay anticoagulant used during ECLS, there is a paucity of published data to develop a universal anticoagulation guideline and centers are forced to create individualized protocols to guide anticoagulation management, frequently while lacking expertise. From an international survey, centers often use a combination of tests to guide management, which in turn can lead to discordant results and confused management. Studies are urgently needed to investigate optimization of current anticoagulation strategies with UFH, as well as use of alternative anticoagulants and nonthrombogenic biomaterials.

Blutgerinnungsstörungen unter ECMO- und LVAD-Therapie

“…Zusätzlich erfolgt eine dauerhafte systemische Antikoagulation, üblicherweise ebenso mit unfraktioniertem Heparin. Zum Monitoring der Antikoagulation können aktivierte partielle Thromboplastinzeit (aPTT), Anti-Faktor-Xa-Aktivität, ACT oder Thrombelastografie eingesetzt werden [8,10]. In ▶ Tab.…”

“…Vor-und Nachteile der verfügbaren Testverfahren für das Monitoring der Antikoagulation mit unfraktioniertem Heparin während ECMO (übersetzt aus[10]). Rezeptors aus einem niedrigaffinen in einen hochaffinen Bindungszustand für Fibrinogen.…”

Preanalytical Variables in Coagulation Testing: Setting the Stage for Accurate Results

“…Mechanical or support interventions such as extracorporeal membrane oxygenation (also known as extracorporeal life support), hemodialysis, continuous venovenous/arteriovenous hemodialysis, blood oxygenators, or aortic balloon pumps may induce a mild consumptive coagulopathy in adults, which may be more pronounced in neonates and pediatric patients (weight associated). 58,59 These mechanical interventions require anticoagulation which may be partially performed within the circuit, systemic (unfractionated heparin [UFH]), or local to device (citrate within device and calcium gluconate out of the device). Often, in these acute and seriously ill patients, POC methods (e.g., activated clotting time or THEG) are often measurement methods of choice, but laboratory methods may also be used to confirm POC findings.…”

“…Often, in these acute and seriously ill patients, POC methods (e.g., activated clotting time or THEG) are often measurement methods of choice, but laboratory methods may also be used to confirm POC findings. 59 Other mechanical assisting devices, such as left ventricular pumps, create a turbulent flow environment, causing an immediate acquired type 2 VWD from mechanical shearing of the VWF protein. 60 Numerous pharmaceutical interventions that are designed to either alter or replace hemostatic factors in hemostasis may or may not have an impact on coagulation testing.…”

Laboratory Assessment of Hemostatic and Anticoagulant Therapy

“…Extracorporeal life support is a life-saving strategy associated with the frequent occurrence of bleeding and clotting complications, often with ruinous outcomes. 16 The demand for anticoagulation of the extracorporeal circuit and the acquired coagulation changes associated with this circuit are in part the basis for such complications. Dr. Winkler meticulously explains the complex and often multifactorial nature of these complications as well as anticoagulant management and measurement methods in patients on extracorporeal life support.…”