Purpose of the study: Besides enabling a precise calculation of the needs for blood (in ml) for each type of orthopaedic surgery, an adequate estimation of average total blood loss (TBL) as a function of total blood volume (TBV) enables initiation of blood sparing techniques. Thus, when the balance is negative, erythropoietin could be advisable. The purpose of this work was to analyse the impact of prescribing erythropoietin as a function of the expected blood balance on the rate of homologous blood transfusions. We also wanted to determine the financial impact of this prescription strategy.

Material and methods: This prospective study included 229 patients (153 THA and 76 TKA) who underwent surgery from January 2005 to December 2008 with a standard anaesthesia, analgesia and surgical protocol. TBL was considered to be 10% of TBV for THA and TKA. Mean gain in serum haemoglobin (Hb) per injection of erythropoietin (1 ampoule Eprex) was 0.8 g/dl. Using the patient’s Hb level at the preop exam (Hbpreop), the anaesthetist determined the volume available (VA) for each patient and for each type of operation. When VA was negative, the Hb needed to reach the desired level (HbA) so that VA=0 (zero risk of transfusion) was calculated. The number of Eprex ampoules prescribed (amp) was determined from the formula: (HbA-Hbpreop)/0.8. Hb levels on day 0, day 1, day 3(discharge) and day 28 were noted, as were the number of homologous transfusions and the total number of ampoules of Eprex delivered.

Results: Sixty-six patient received one amp (33.2%), 96 had two amp (42%), 40 three amp (17.5%) and 17 four amp (7.4%). For 220 patients (92%), Eprex delivered was within the approved dose (92%). The mean Hb levels were: Hbpreop=12.4, HbA=13.5, Hbd0=13.9, Hbdischarge=11.2, and Hbd28=11.9. Total consumption was 456 amp instead of 916 (229x4), i.e. a savings of 460 amp corresponding to 173 880 euros (460 x 378 euros). There were six homologous transfusions (2.6%).

Discussion: In orthopaedic surgery, adapted prescription of erythropoietin as a function of the TBL enabled, in this series, a simplification of the prescription procedure and avoided the risks related to high Hb levels > 15g with a financial savings of 760 euros per operation (173880 euros for 229 patients) without increasing the rate of homologous transfusion. This strategy is currently being evaluated for prosthesis revision surgery.