The change of red blood cell properties and platelet function over time during extracorporeal life support

Rationale: Extracorporeal life support (ECLS) is increasingly used in the
intensive care unit and has resulted in improved survival of patients with
critical respiratory or circulatory failure. However the incidence of
hemorrhage and to a lesser extent thromboembolic events during an ECLS
treatment are significant. Hemolysis as an expression of membrane instability
may be preceded by changes in aggregation and deformability of the red blood
cells. Platelet dysfunction can be caused by hemolysis but also due to changes
in aggregation. Systemic inflammatory response might also play a roll. It is
likely that ECLS affects red blood cell and platelet function after its
initiation, the time course of these changes and their clinical relevance is
yet unclear.

Objective: Primary objective: Red blood cell aggregation and elongation
(deformability) assessed by a laser assisted optical rotational cell analyzer
(LORCA) on days 1-3, and within 24 hours after weaning of ECLS. Secondary
objectives are red blood cell aggregation and elongation (deformability)
assessed by a LORCA on 5, 7, 10, 14, 21 (when appropriate) and platelet
aggregation assessed by the multiple platelet function analyzer (Multiplate)
and Von Willebrand-factor, free hemoglobin, reticulocytes and D-dimers on days
1, 2, 3, 5, 7, 10, 14, 21 (when appropriate) and within 24 hours after weaning
of ECLS.

Observational cohort study

The risk and burden of an extra 5 ml blood on the study days taken from the
arterial line is deemed in proportion to the potential value of the research.
This study will not be beneficial for the subject. The risk of participation is
considered negligible and the burden minimal because the arterial line is in
place as part of standard care. Patients on ECLS are critically ill patients
and therefore in the majority of the cases incapacitated due to critical
illness and/or sedation.