Static versus dynamic filtration principle
Usually (in Germany) an arterial filter with a pore size of 40 µm is being used in every on-pump case to filter particles and bubbles over 40 µm. However the efficacy of statical screenfilters is limited in regard to microair. Particularly when large amounts of bubbles occur, the bigger part can be detected behind the filter medium with a delay. Despite of a mesh size of 40 µm bubbles up to 120 µm occur behind the filter. The more bubbles enter a statical screen filter, the less effective the filter medium becomes. In a case of sucking in air at the venous cannula this can result in extremely high numbers of microairbubbles, over a million airbubbles have been measured in such cases (the average measurement detects 30.000 bubbles).
The efficacy of the DBT is not at all being influenced by the number of microairbubbles due to it’s working principle and construction. The DBT reduces dependent on flow rate, hematocrit, bubble size, and other factors, though it reduces at least 75% of the amount of microairbubbles and therefore significantly better than the arterial filter.
Avoiding and filtering embolism is more effective than treating the consequences. The DBT is the solution for a problem being ignored for a long time due to a lack of remedy.