Cell Salvaging Reduces the Severity of Dilutional Coagulopathy (as Evaluated Through the Consumption of Blood Products) in Liver Transplantation.
Authors: Pereira Marta I , Marques Gilberto P , Bento Carlos 
Published: October 2019

Abstract
Abstract 2290

Background:
Intra-operative autologous red blood cell (RBC) salvaging (SRBC) reduces requirements for allogeneic RBC transfusion during surgery, and should be considered in surgeries with anticipated blood losses over 1 L. However, the auto-transfusion of large volumes of SRBC can lead to dilutional coagulopathy, due to the loss of clotting factors and platelets during cell processing, worsening the outcome of surgery.
Orthotopic liver transplantation (OLT) has historically been associated with major blood loss and massive blood transfusion due to the aggressiveness of surgery, the anhepatic phase and the pre-existing underlying disease. While transfusion requirements have been greatly reduced over the past decade, large volumes correlate with worsened prognosis and can also lead to dilutional coagulopathy.
Most published series on cell salvaging focus on orthopedic, cardiac or oncologic patients, and data on its use in liver transplantation remains insufficient and contradictory, with the suggestion that salvage is associated with a higher degree of dilutional coagulopathy than allogeneic transfusion.

Methods:
We performed a retrospective analysis of a 5-year series of OLT patients undergoing surgery (including for fulminant liver failure) in our Centre, comparing the number of units of Red Cell Concentrate (RCC) transfused during each procedure and the volume of autologous SRBC obtained intra-operatively and reinfused before the conclusion of surgery, with the number of units of fresh frozen plasma (Plasma) and Platelet Concentrate (PC) consumed, as a clinical marker of the depth of coagulopathy, both through univariate and multivariate analysis.

Results:
A total of 218 OLTs were analyzed; an average of 13.6±17.5 units (U) of RCC, 7.4±12.4 U of Plasma and 5.0±7.9 U of PC were used. In one third of patients (30.7%) no allogeneic RCC was transfused, and in a further third (34.4%) less than 5 U were consumed, resulting in a median of 2 U of RCC per patient. A mean of 1003.4±1061.3 mL of SRBC were reinfused in the 70 patients (32.1%) who underwent salvage.
There was no correlation between the number of RCC units and the volume of SRCB infused (−0.04, p=NS), and the mean volume of SRBC was not different between patients who were transfused with RCC (315.3±845.4) and those who were not (337.7±527.0, p=NS); on the other hand, patients who underwent cell salvage used significantly less units of RCC (3.3±6.1) than those who did not (9.4±14.1, p<0.001).
We found a strong correlation between the number of Plasma and PC units administered (0.73, p<0.001), and between the number of RCC and Plasma (0.91, p<0.001) and PC units (0.68, p<0.001) used; patients who were transfused with at least 1 U of RCC consumed significantly more Plasma (18.7±18.7 U) and PC (7.1±8.6 U) than patients who did not receive any allo-RCC (1.9±4.0, p<0.001 and 0.3±1.8, p<0.001, respectively). Likewise, there was a significant correlation between the volume of SRBC and the number of Plasma (0.63, p<0.001) and PC units used (0.31, p=0.009); however, patients who underwent cell salvage used significantly less Plasma (7.4±11.7 U) and PC (2.8±6.1 U) than patients who did not (16.1±19.1, p<0,001 and 6.1±8.4, p=0.002, respectively), and patients who received only autologous SRBC were transfused with significantly less Plasma (2.0±4.4 U) and PC (0.0±0.0 U) than patients who received only allogeneic RCC units (20.6±19.8, p<0.001 and 7.6±8.9, p<0.001, respectively).

Discussion:
The choice to use SRBC was introduced a priori, as reflected in the absence of correlation between the volume of RCC and SRBC used. However, the use of salvaging resulted in a significantly lower need for allogeneic RCC.
The volume of allo or auto-RBC needed during surgery correlated with the severity of coagulopathy, and the number of Plasma and PC units administered to revert it were strongly correlated, as expected. However, the choice to use SRBC was associated with a decrease in the volume of Plasma and PC needed, when compared to surgeries without salvaging. Likewise, the exclusive use of SRBC resulted in a significantly lower use of Plasma and PC during surgery than the exclusive use of allo-RCC.

Conclusion:
In our series, intraoperative salvaging not only reduced the consumption of RCC, but was also associated with a lower severity of surgical coagulopathy, as evaluated clinically through the number of units of Plasma and PC needed to stabilize the patient.

Disclosures:
No relevant conflicts of interest to declare.