Patient blood management in elective total hip- and knee-replacement surgery (part 2): a randomized controlled trial on blood salvage as transfusion alternative using a restrictive transfusion policy in patients with a preoperative Hb above 13 g/dl

The authors conducted a large randomised study to evaluate allogeneic blood transfusion (ABT) in elective adult total hip (n = 1037) or knee (n = 622) replacement surgery patients with a preoperative haemoglobin (Hb) level greater than 13 g/dL, who were managed with cell saver and/or postoperative drain reinfusion devices (AUTO) or a low-vacuum drain (control). The transfusion rate was 7.7% in the AUTO group compared with 8.3% in the CONTROL group (P = 0.19), but costs were increased by €298 per patient (95% CI, 76 to 520) in the AUTO group. The authors conclude that for this patient population autologous intra- and postoperative blood salvage did not reduce ABT use and increased costs, but importantly there were no differences in the rates of reported serious adverse events.

Although the authors recognise the strengths and limitations of the study, some additional comments can be made. Firstly, there were significant between-group differences regarding baseline characteristics. Among patients in the AUTO group, there were more hip surgeries (but the authors did not analyse knee and hip surgeries separately) and females (at higher risk for transfusion, as observed in the first and second Austrian benchmark studies and in the OSTHEO study) [1-3].

Secondly, as shown by the OSTHEO study, the risk for ABT decreased by almost 10% (women) or 8% (men) for each g/dL of preoperative Hb above 13 g/dL. Thus, it plausible that a benefit of AUTO could have been seen for patients with preoperative Hb between 13 and 14 g/dL, as it has been observed in a series of knee replacement patients (n=394) [4]. This benefit of AUTO was also observed for patients with preoperative Hb between 12 and 13 g/dL (n=294) [4], and may be important for patients who do not reach an Hb of 13 g/dL, despite being treated with recombinant erythropoietin, with or without iron [5,6]. Unfortunately, the authors did not analysed data by Hb strata.

Thirdly, as there were no differences in hospital length of stay (7.8 vs. 7.4 days; P = NS) or ICU use (16/1061 vs. 5/698; P = NS) and the authors have not shown any relationship between these parameters and the use of AUTO, this should not been included in the cost model. Conversely, as all patients in the CONTROL group received a low vacuum drain (at an estimated cost €25 of for Bellovac) [4], this should have been included in the cost model. In addition, the cost of OrthoPAT disposable (€160) is considerably higher than that of a reinfusion drain (€61). Therefore, different cost models should have been constructed according to type of surgery, Hb strata and blood salvage device [4].

Patient blood management was introduced as a new concept that involves the combined use of transfusion alternatives in a patient-centred way in order to limit or avoid ABT and improve patients’ outcome. Valuable data from large and well-conducted studies like this are supposed to help in choosing the combination of strategies that better fulfill this goal in selected patient populations, but unfortunately data seem to have been analysed following the principle of “one size fit all”.

– Manuel Muñoz

References

1. Gombotz H et al. Transfusion 2007;47:1468-80.
2. Gombotz H et al. Transfusion 2014; May 8 [Epub ahead of print] doi: 10.1111/trf.12687.
3. Rosencher N et al. Transfusion 2003;43:459-69.
4. Muñoz M et al. Blood Transfus 2013;11:260-71.
5. So-Osman C et al. Anesthesiology 2014;120:839-51.
6. Basora M et al. Br J Anesth 2013;110:488-90.

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