Abstract
Aim
The aim of this study was to determine the effects of using the Bellovac autologous blood salvage system on blood transfusion requirements, adverse event rate, post-operative length of stay (POLOS) and mobilisation in patients who have undergone a total knee replacement.
Methods
This is a retrospective cohort study of 471 patients who underwent a total knee replacement (TKR) at our institution between January 2008 and August 2009. All patients received an autologous blood salvage drain in theatre. Their medical records were reviewed and a database created to assess the efficacy of the blood salvage system.
Results
Overall 70% of the patients were re-transfused (77% of males, 65% of females). In the remainder there was too little blood in the drain by the time the re-transfusion window had ended. Re-transfused patients were comparable to those not re-transfused in terms of age, BMI, comorbidity, pre-op mobility, anaesthetic type and pre-operative haemoglobin concentration. Re-transfused patients had lower allogeneic transfusion requirements (6.5 vs 12.9%, p=0.022). This was not a result of the gender discrepancy. Number needed to treat with a re-infusion drain was 8.9 (95%CI 5.8–19.3) to prevent one unit of allogeneic blood being transfused. Re-transfused patients also had a lower post-operative adverse event rate (18 vs 24% p=0.18) but this was not statistically significant. POLOS and post-operative mobilisation were not affected, even after the elimination of patients with adverse events. Cost analysis showed that autologous re-infusion drains (£50 each) were not cost-effective in preventing allogeneic blood transfusion (vein-to-vein cost £135). One adverse event attributable to the re-infusion system occurred: a drain tip had to be removed operatively after becoming bent.
Conclusion
Autologous re-infusion systems are effective but not cost-effective in reducing blood transfusion requirement after TKR. Autologous re-infusion may be associated with a reduced adverse event rate post-operatively.
