We recently demonstrated that patients with increased blood loss due to intraoperative coagulopathy show a persistent pre-, intra- and postoperative increase in
fibrin monomer concentration. We thus tested the hypothesis that preoperative
fibrin monomer concentrations can be used as a risk
indicator for intraoperative blood loss in a study designed for diagnostic test evaluation in 168 patients admitted to the surgical service of our hospital. Intraoperative blood loss increased with preoperative
fibrin monomer concentration (median blood loss of 50, 100, 200 and 400 ml in preoperative
fibrin monomer quartile groups 1 to 4, p<0.001, ANOVA on ranks; interquartile comparisons p < 0.05 (4/6), Mann Whitney Rank Sum test). In contrast, intraoperative blood loss was unrelated to preoperative values of prothrombin time, activated partial thromboplastin time and platelet count. By multivariate (logistic regression) analysis, only
fibrin monomer remained a significant predictor of intraoperative blood loss > 500 ml when age, gender, BMI,
fibrin monomer and the different types of
surgical procedures (
tumor surgery, vascular surgery,
cholecystectomy, gastric banding, varicous vein surgery and
hernia repair) were included as independent variables. Most importantly, accuracy evaluation showed that preoperative
fibrin monomer concentration < 3 microg/l excluded intraoperative blood loss > 500 ml with 92% sensitivity and 95% negative predictive value. These results support our hypothesis that preoperative
fibrin monomer concentrations are related to intraoperative blood loss in elective surgery.
Fibrin monomer should be further investigated for it's potential to serve as a routine tool for preoperative risk stratification of intraoperative
bleeding.