Comparison of different retransfusion strategies in cardiothoracic surgery

Intra- and postoperative bleeding in patients undergoing cardiac surgery is a
major complication which may lead to homologous blood transfusions and
postoperative complications. After cardiopulmonary bypass (CPB), a residual
blood volume remains in the heart-lung machine, which may be retransfused to
the patient in order to normalize blood volume and coagulation. However,
retransfusion of diluted blood is inefficient, since it has low hematocrit and
coagulation properties. Concentration of this residual blood volume may enhance
its hematocrit and coagulation properties such that the need for homologous
blood transfusions in these patients is reduced. The present study therefore
aims to compare three blood concentrating techniques with the standard
retransfusion technique in order to establish an optimal retransfusion strategy
for patients that may reduce the number of homologous blood transfusions.

1. Which of the three retransfusion techniques based on hemoconcentration
(centrifugation, ultra filtration or cell separation) leads to a reduction in
homologous blood transfusions as compared to control (retransfusion of diluted
blood)?
2. Which of the three retransfusion techniques lead to a reduction in
pro-inflammatory markers and an increase in coagulation proteins as compared to
control?

Single-center prospective randomized controlled intervention study

Use of different hemoconcentration retransfusion techniques after
cardiopulmonary bypass.

Residual blood of the heart-lung machine is normally directly retransfused in
CABG patients. A disadvantage of this technique is that the residual blood
volume is highly diluted thereby leading to retransfusion of blood with a low
hematocrit and poor coagulation properties. As a consequence, most patients
receive additional homologous blood transfusions, which may alter the risk for
infections and activation of inflammatory pathways. Patients will be randomized
to four different groups: A) control group (retransfusion of diluted blood), B)
centrifugation group, C) ultra filtration group and D) cell-separation group.

Blood sampling
For this study, a total of 10 ml of blood will be drawn while the patient is
under anesthesia. This will not add up to patient discomfort.

Control patients
Control patients will receive standard clinical care (retransfusion of diluted
blood). Since this treatment modality does not differ from routine clinical
care, it will not add up to patient discomfort and risk. However, it is
expected that this group of patients has a higher need for homologous blood
transfusions as compared to the hemoconcentration groups, thereby increasing
the risk for inflammation and infection.

Hemoconcentration
Hemoconcentration techniques are legally and clinically approved for
concentration of residual blood volumes. The application of hemoconcentration
may reduce the need for homologous blood transfusion, which might be beneficial
for the patient. Since the hemoconcentration techniques are clinically
validated and safe, the use of these devices will not add up to patient
discomfort.