ECMO Anticoagulation and Hemostasis 5

Question 1

What pattern on ROTEM/TEG is most consistent with acquired hypofibrinogenemia in an ECMO patient?

Accepted Answer

Normal clotting time with significantly reduced maximum clot firmness on FIBTEM

Answer

FIBTEM (which inhibits platelet contribution) showing reduced maximum clot firmness specifically indicates fibrinogen deficiency as the cause of impaired clot strength.

Question 2

A pediatric ECMO patient on heparin develops catheter-site bleeding with an ACT of 190 seconds and platelet count of 110,000/μL. What additional test helps identify platelet dysfunction as a contributor?

Accepted Answer

Platelet function assay (PFA-100) or TEG platelet mapping

Answer

Platelet function assays or TEG platelet mapping can identify acquired platelet dysfunction from ECMO circuit exposure even when platelet count appears adequate.

Question 3

What is the theoretical advantage of using heparin-bonded ECMO circuits regarding anticoagulation management?

Accepted Answer

They reduce circuit thrombogenicity, potentially allowing lower systemic heparin doses

Answer

Heparin-bonded circuits reduce surface thrombogenicity, allowing some programs to use lower systemic heparin doses or, in select stable patients, brief anticoagulation-free periods.

Question 4

In ECMO patients with both active bleeding and circuit clot, which viscoelastic TEG parameter guides the decision to use antifibrinolytic therapy?

Accepted Answer

LY30 (percent lysis at 30 minutes)

Answer

LY30 greater than 3% on TEG indicates significant fibrinolysis, guiding use of antifibrinolytics like tranexamic acid to reduce ongoing clot dissolution and bleeding.

Question 5

Which factor most significantly increases thrombin generation on ECMO beyond the circuit surface itself?

Accepted Answer

Systemic inflammatory response activating the extrinsic coagulation pathway

Answer

ECMO triggers a systemic inflammatory response that activates tissue factor expression on monocytes and endothelium, driving extrinsic pathway thrombin generation beyond circuit contact activation alone.

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO Anticoagulation and Hemostasis 5