Effect of Hematocrit and Erythrocyte Density on Intraoperative Blood Loss in Hemophilia A Patients During Total Knee Arthroplasty.

Intraoperative blood loss during total knee arthroplasty in patients with hemophilia varies over a wide range (from 300 to 3000 ml). The reasons have not been clarified yet. We studied the dependence of intraoperative blood loss during total knee arthroplasty in patients with hemophilia A on hematocrit and mean erythrocyte density. Intraoperational blood loss ≥1000 ml was observed in patients with hematocrit <38.5%. In patients with hematocrit >38.5% this parameter depended on the mean erythrocyte density: in patients with increased erythrocyte density, the risk of intraoperational blood loss ≥1000 ml was higher. The increase in erythrocyte density can serve as an indicator of pathological processes, including the processes modulating hemostasis. It can also be assumed that erythrocytes with higher density change blood flow, which affects platelet adhesion to the damaged endothelium. Hematocrit below the threshold level and mean density of erythrocytes above the normal level can be regarded as risk factor for increased intraoperational blood loss.