Ranking the effectiveness of autologous blood conservation measures through validated modeling of independent clinical data.

BACKGROUND: Future supply with allogeneic blood transfusions faces several crucial challenges that warrant thorough (re-)evaluation of existing alternatives. Meta-analyses have indicated a significant potential for autologous blood conservation (ABC) measures to reduce the need for allogeneic blood transfusions. The quality of currently available studies, however, prohibits definite conclusions. Under these circumstances, mathematical modeling offers unique opportunities to compare various ABC measures and to test the impact of different variables on efficacy and effectiveness. STUDY DESIGN AND METHODS: We performed an extensive search for clinical ABC studies, focusing on acute normovolemic hemodilution (ANH), intraoperative blood salvage (IBS), or preoperative autologous deposit (PAD). Only ABC studies providing a minimum set of clinical variables were included. Using a clinically validated mathematical model, we then calculated maximal allowable blood loss (efficacy) and increase in red blood cell (RBC) mass (effectiveness) to rank the three techniques. RESULTS: We identified 21 clinical ABC studies, including 3926 patients, as suitable for our model. Our model shows that IBS with high recovery rates is the most efficacious and effective ABC measure. PAD will reveal nearly similar efficacy and effectiveness, only if sufficient time for RBC regeneration has passed and if 4 PAD units or more are available. Our model further demonstrates that ANH as well as IBS with low recovery rates are the least efficacious and effective alternatives. CONCLUSIONS: IBS appears to be the most efficacious and effective ABC measure. PAD can only reduce the need for allogeneic blood transfusions under certain circumstances. ANH does not appear to play an important role in ABC.

[Autologous transfusion--from enthusiasm to reason: clinical practice based on scientific knowledge]. / Autologe Transfusion--Von der Euphorie zur Ratio: Praktisches Handeln aus wissenschaftlicher Erkenntnis.

This symposium (Nottwil/Lucerne, Switzerland, January 20./21. 2006,) gives you the latest review / clinical results / experimental data on autologous transfusion: Routine leucodepletion of preoperative autologous deposit, immunological perspectives, special processing of bacterially contaminated autologous blood, pro and con concerning autologous blood supply as a reasonable alternative, autologous platelet gel, the Austrian benchmark study on RBC-transfusion. The report on this symposium is published in 'AINS' (Thieme); papers will be published in detail in English in "Transfusion Medicine and Hemotherapy" (Karger Inc.) and in German in "Anästhesiologie und Intensivmedizin" (DIOmed Inc.).