The role of Amicar in decreasing perioperative blood loss in idiopathic scoliosis

Study Design. Four separate studies on the role of Amicar in decreasing perioperative blood loss in idiopathic scoliosis. Objectives. To assess the efficacy and possible mechanisms of action for Amicar. Summary of Background Data. Preliminary prospective, randomized double-blind and analysis of same-day anterior spinal fusion (ASF), fibrinogen, and posterior spinal fusion (PSF) studies have demonstrated Amicar to be effective in idiopathic scoliosis surgery. Increased fibrinogen secretion is a possible explanation. Methods. Amicar is administered at 100 mg/kg over 15 minutes not to exceed 5 g at anesthesia induction. Maintenance is 10 mg/kg per hour until wound closure. Results. Preliminary study: Amicar (N = 28) was effective compared with a control group (N = 31). Perioperative blood loss and transfusion following PSF were 1,604 +/- 517 mL and 1.1 +/- 1.0 U in the Amicar group compared with 2,312 +/- 994 mL and 2.1 +/- 1.1 U in the control group (P < 0.003). Prospective, randomized double-blind study confirmed this efficacy, although primarily in postoperative suction drainage: 1,391 212 mL and 1.1 +/- 1.0 U compared with 1,716 +/- 513 mL and 2.1 +/- 1.3 U (P < 0.002). A fibrinogen study (N = 21) demonstrated steady and excessive increase following PSF: before surgery it was 266 +/- 63 mg/dL and on the fifth postoperative day 699 +/- 94 mg/dL. In same-day anterior and posterior spinal surgery, Amicar was again effective, but primarily in decreasing chest tube drainage and during PSF. Group 1 (N = 15, no Amicar 3,807 105 mL and 3.1 +/- 1.5 U; Group 2 (N = 27, Amicar for PSF only) 2,080 659 mL and 1.9 +/- 0.9 U; and Group 3 (N = 16, both ASF and PSF) 2,183 851 mL and 1.0 +/- 0.8 U. Conclusions. Amicar appears highly effective in decreasing perioperative blood loss. This results in less autologous blood donation, blood transfusion, costs, and complications. Its mechanism of action is uncertain but may be related to increased fibrinogen secretion.