Similar to advances in pain management, the perioperative blood loss management has improved dramatically over the past decade.   
Tranexamic Acid (TXA) is credited for a large part in decreasing postoperative transfusions after TJA.
The coagulation cascade is dynamic balance of continuous formation and degradation of clots, whereby signals from our body tips the scale in favor of one or the other (this is a gross simplification of the process). The medication is administered just prior to incision and often again during surgery and it minimizes bleeding by preventing degradation of fibrin clots. Importantly this medication is not associated with increased risk for thrombotic events such as strokes, MI, PE, or DVT. The medication is shown to decrease transfusions after THA and for TKA  .
Hemodilution. Another popular technique to minimize blood loss. By giving a lot of IV fluids during surgery, the hemoglobin becomes diluted within the blood, and therefore less is lost per volume of blood loss.
Transfusion thresholds. The dependence on hemoglobin values is decreasing with the greater recognition that everyone is different and that vital signs in conjunction with hemoglobin trends are likely the best guide to transfusion. Transufing people if hemoglobin is above 9 g/dL has no effect on risk for complications even if people have a history of cardiac disease, and below 8, patients with cardiac disease or other medical conditions may benefit from transfusion, while younger, healthier patients may do well even if their hemoglobin drops below 7 g/dl. Generally, all people should be transfused if hemoglobin dips below 6. Why should we care about transfusions anyway? There are risks such as allergic reaction, low but real risk of viral disease transmission. One study examined infection rates in patients that received transfusion, and after adjusting for associated risk factors, there did not appear to be an independent risk for infection .
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