Evaluation of drainable volume measurements and their usage for predicting optimal cardiac support in patients supported by veno-arterial extracorporeal life support.

Veno-arterial extracorporeal life support (VA-ELS) is used to support patients
with acute cardiac failure. In that context, sufficient drainable venous volume
is crucial for reliable and adequate support. To date, no reliable measurement
method exists to monitor drainable volume adequately. Furthermore, it is still
unresolved how to diagnose adequate cardiac recovery.
Previous (pre)clinical studies showed that the calculation of the dynamic
filling index may provide a valuable parameter to monitor the drainable volume
in patients supported by VA-ELS. In addition, a case report showed that
measurement of the dynamic filling index could successfully be used to estimate
cardiac recovery in a single patient supported by VA-ELS in the ICU.

To assess drainable volume and cardiac recovery using standard recorded
perfusion data in patients supported by VA-ELS.

A prospective interventional study.

Small variations in the pump speed of the VA-ELS pump.

The dynamic filling index (DFI) is calculated from standard recorded perfusion
data during small variations (<5%) of the pump speed. The pump speed variations
needed for the estimation of the DFI are relatively small compared to pump
speed variations regularly used by perfusionists to respond to changes in the
patients circulatory status, to obtain adequate venous drainage, and to train
the heart during weaning. Moreover, the variations in pump speed needed to
determine the DFI take less than 3 minutes, and are induced by a perfusionist
who remains present at all times during the measurements. Should any unforeseen
negative reaction occur, the measurement can be stopped immediately without
further consequences. Thus, to the current knowledge the DFI measurements do
not add to the risks already present during VA-ELS.