Blood loss, fluid balance, and blood product conservation in the pediatric patient have all become significant elements of our practice. Of particular interest is WAC’s role in major orthopedic procedures such as spine fusion. Our group currently is in the practice of using antifibrinolytics along with deliberate hypotension in an effort to minimize blood loss. This discussion will focus on the evidence behind antifibrinoloytic therapy.

Esther S. Schouten and colleagues performed a meta-analysis aimed at comparing the effectiveness of three antifibrinolytic drugs, aprotonin, aminocaproic acid, and tranexamic acid (TXA). The drugs were used in the setting of congenital heart disease repair and scoliosis correction. Table 4, page 188 most clearly illustrates the results from scoliosis cases. Aprotonin lowered blood loss by (on average) 385 cc, TXA by 682 cc, and aminocaproic acid by 59 cc. Transfusion data for aprotonin and aminocaproic acid was too heterogenous to effectively report. TXA lowered packed red blood cell transfusion by an average of 349 cc per patient and fresh frozen plasma by 15 cc per patient. Complication rates of the drugs were discussed as well (page 186). Aprotonin was removed from the market during this study due to elevated risk of renal failure, stroke, and generalized mortality. Sixteen of the studies involved in this meta-analysis addressed complications associated with aminocaproic acid and TXA. Thirteen of the sixteen noted no complications. The remaining three described cardiogenic complications found in cardiac surgery studies. No complications were noted with tranexamic acid use in this analysis. Relative cost was mentioned as well (page 189). Aprotonin was listed as costing twenty five times the cost of TXA and eighty times the cost of aminocaproic acid.

Accompanying articles include Jan C. Horrow and colleagues’ paper examining the dose response curve of tranexamic acid and Navil Sethna and colleagues’ paper regarding TXA use in scoliosis repair. Horrow’s data indicates that TXA inhibits blood loss at a dose of 10 mg/kg followed by infusion of 1 mg/kg/hour and that doses above this provide no additional benefit. Anecdotally speaking, there is a great deal of variation regarding this dose. Institutions routinely use anywhere from one to ten times this dose. Sethna’s article is included as much for it’s description of routine management of scoliosis repair at his institution as for it’s data regarding TXA. Note table 2, page730 for average IV fluid administration and the first paragraph of page 728 for routine monitoring and anesthetic standards, including deliberate hypotension, at that hospital.