Endogenous heparinoids induced massive hemorrhage postoperatively following THA.

A 64-year-old woman presented with right hip pain of 6 years' duration, accompanied by limping of 1 years' duration. Preoperative pelvis radiograph showed narrowing of joint space, osteophyte formation, and cystis degeneration of the femoral head surrounded by bony sclerosis, without obvious collapse of the femoral head; the diagnosis was osteoarthrosis. The patient's blood pressure on admission was 128/76 mm Hg. The patient had no special previous history. Preoperative blood and coagulation tests were normal. Total hip arthroplasty was performed via a posterolateral approach, and intraoperative bleeding was 400 mL. In the first 10 hours postoperatively, the drainage volume decreased slowly, the initial dose of 0.3 mL Fraxiparine was administered, and the blood pressure was 84∼92/45∼56 mm Hg. The drainage volume increased gradually, and 10 hours after administration of Fraxiparine, the drainage volume increased sharply and maintained at a high level. Protamine was applied and the drainage volume decreased sharply, furthermore, a high concentration of endogenous heparinoids were detected in the blood. Although no direct evidence were detected, it was clear that the massive hemorrhage was associated with administration of low-molecular-weight heparin (LMWH). The administration of LMWH combined with continuous low blood pressure caused by surgery and massive bleeding that resulted in low perfusion and inflammation in microcirculation, induced endogenous heparinoid synthesis in endothelial cells, and elevated concentration of endogenous heparinoids in blood led to more severe bleeding. Therefore, caution should be taken with administration of anticoagulant therapy in patients with massive hemorrhage, especially in patients with continuous low blood pressure.