The Association Between Intraoperative Cell Salvage and Red Blood Cell Transfusion in Cardiac Surgery – An Observational Study in A Patient Blood Management Centre
Cardiac surgery is commonly associated with high blood loss and the need for allogeneic red blood cell (RBC) transfusion. In addition, 20–30% of cardiac surgical patients suffer from anaemia [1]. Brouwers et al. [2] analysed > 11,000 cardiac surgical patients and revealed a transfusion rate of > 50%. Karkouti et al. [3] analysed > 9000 patients undergoing cardiac surgery and revealed that severe intraoperative blood loss is associated with an 8.1-fold higher mortality rate. Studies indicate that allogeneic RBC transfusions lead to an increased number of adverse outcome events like postoperative low output failure [4].
In order to minimise the risks associated with peri- operative RBC transfusion, patient blood management (PBM) has evolved. PBM is an approach to reduce anaemia (pillar 1), minimise iatrogenic blood loss (pillar 2), and optimise patient-specific tolerance of anaemia (pillar 3), in order to maintain the patient’s own blood volume. In particular, the second pillar comprises blood conservation strategies to manage perioperative bleeding including the use of cell salvage (CS) [5]. CS collects blood by aspiration from the operative field to produce autologous RBC for re-transfusion [6]. A meta-analysis based on 47 trials, involving 21 cardiac surgical trials, demonstrated that CS is efficacious in reducing the overall need for allogeneic RBC transfusion in cardiac surgical patients by 29% [7].
These studies, however, have several limitations. Sample sizes of trials were low. Study populations included in the in meta-analysis ranged between 24 and 541, with a majority (19 out of 21 studies [90.5%]) of studies analysing patient populations with less than 100 patients [7]. Trials with low numbers of patients are important to understand the impact of the intervention; however, they might often be underpowered to detect clinical differences of the intervention. Furthermore, the majority of the studies did not include patients undergoing aortic surgery, focusing instead on coronary artery bypass grafting (CABG) and cardiac valve surgery only. Aortic procedures are also known to account for high intraoperative blood loss, with a transfusion rate of up to 88% [2].
The implementation of PBM measures, including CS, is an integral part at the University Hospital Frankfurt [8–10]. Here, we evaluate the benefit of CS in a large number of patients undergoing elective cardiac surgery at a designated PBM centre. We hypothesised that the use of CS is associated with a decreased proportion of patients exposed to RBC transfusion as an individual measure in a comprehensive PBM program.
