Estimation of Fibrinogen Concentration During Extracorporeal Circulation in Pediatric Cardiac Surgery

Maintenance of adequate fibrinogen levels during cardiopulmonary bypass (CPB) is important in assuring adequate post-CPB hemostasis. Fresh frozen plasma (FFP) is used in the pediatric CPB circuit as a prime constituent as a source of coagulation factors, including fibrinogen; yet the resultant on-CPB fibrinogen concentration is related to multiple factors. Accurate formulas for predicting post-dilutional fibrinogen levels and the minimal FFP volume to prime the extracorporeal circuit (ECC) to maintain post-dilutional fibrinogen levels greater than 100 mg/ dL were developed prospectively from seventy-five infant and pediatric patients. The patients weighed less than twenty-five kilograms and underwent CPB for the correction of various congenital cardiac anomalies. Variables expected to affect fibrinogen level were: height, weight, body surface area, pre-dilutional hematocrit, pre-dilutional fibrinogen concentration, patient circulating blood volume, circuit priming volume, FFP volume added to the prime pre-CPB, pre-CPB blood loss, and volume added by anesthesia pre-CPB. Equations to predict the post-dilutional fibrinogen value and the minimal volume of FFP to add to the ECC prime were formulated using multiple linear regression with the results shown in the tables below. VARIABLE REG COEF STD ERROR 2TAIL SIG Dependent variable: Post-dilutional fibrinogen value PRIME VOL 0.06 0.02 0.001 FFP VOL 0.05 0.02 0.011 INTERCEPT 29.37 17.10 0.090 r = 0.477, p = 0.0001, std error = 24.38 mg/dL Dependent variable: Minimal FFP volume to add to prime WEIGHT -17.19 3.38