Could D-dimer monitoring for ECMO coagulation management be a critical piece of the puzzle? The ability to keep a circuit from clotting off while at the same time not allowing the patient to bleed to death has been a battle in the extracorporeal world for many years. In an I listed my top 5 lab tests to assist with anticoagulation for ECMO patients. D-dimer was not one of them. But should it be?
This may encourage me to add it to the list as a critical piece of the puzzle.
Dornia, C., Philipp, A., Bauer, S., Stroszczynski, C., Schreyer, A. G., Müller, T., Koehl, G. E. and Lehle, K. (2015), D-dimers Are a Predictor of Clot Volume Inside Membrane Oxygenators During Extracorporeal Membrane Oxygenation. Artificial Organs. doi: 10.1111/aor.12460
The case for D-dimer monitoring is a tricky one. This article mentions that increasing D-dimer in the face of unexplained causes could very well be due to clotting in the oxygenator. It is important to rule out other causes. D-dimer may significantly increase due to clots in the cannula, in a CRRT filter or CRRT device added into the ECMO circuit, pulmonary embolus, deep vein thrombosis, or other areas of bleeding that has formed a clot and begun to break down. D-dimer is actually an indicator of clot degradation. It’s a measure of the product that is produced when a clot breaks down. D-dimer test is commonly used when pulmonary embolism or deep vein thrombosis is suspect.
In a recent ECMO case, a sharp rise in D-dimer essay was reported shortly after adding a CRRT system to the ECMO circuit. It was noted that the CRRT lines were attached to the ECMO circuit using clave stop-cocks. The clave stop-cocks were replaced with a high flow adaptor and the D-dimer essays decreased markedly. This highlights the need to rule out other explainable causes of increasing D-dimer before jumping to changing out the oxygenator. But it also strengthens the case for monitoring D-dimer essays to shed light on problems in the ECMO circuit that may be fixed before creating complete “circuit DIC” type complications. It can also highlight undiagnosed bleeding problems within the patient.
Will D-dimer monitoring “fix” all our ECMO anticoagulation issues? No. But could it be an important part of the puzzle to help us see the whole picture as we care for our very complex ECMO patients? It’s worth considering.