Postoperative Blood Salvage after knee arthroplasty: are they still useful? A retrospective cohort study

Background and Goal of Study: Blood salvage (BS) is important to implement the second pillar of Patient Blood Management to avoid anaemia after total knee arthroplasty (TKA). Our primary outcome was to assess BS usefulness to decrease allogenic blood transfusion (ABT) rate in TKA. Materials and Methods: a retrospective, observational cohort study was conducted on consecutive patients scheduled for TKA with BS or not. Demographic, comorbidity, surgical and anesthetic data, laboratory pre and postoperative results, volume of blood drained, and reinfused from BS and the requirement of ABT were recorded. Parametric and non-parametric tests were employed. p< 0.05 was accepted as significant. Results: 260 patients were included (130 per cohort). The amount of postoperative bleeding was 713.1 +445.4 ml. 26.5% received ABT. BS reduced transfusion in 13,1% (p=0,024) with RR 1,65 (CI 1,085-2,52)]. Risk factors for postoperative bleeding were: male gender, atrial fibrillation, preoperative anti-platelet therapy and cementless primary TKA. Risk factors for ABT: ASA > II, preoperative hemoglobin < 13 g/dl, knee revision, anti-platelet therapy, longer surgery time. Patients transfused had lower hemoglobin values (p<0.001), and longer medium LOS (+2.5 days, p=0.026). Conclusion: The use of BS in TKA showed benefits reducing allogenic blood transfusion and length of hospital stay. BS would remain an effective, safe and cheap alternative to tranexamic acid in patients with high risk of thromboembolism events operated of TKA.