title: Coagulation tests during cardiopulmonary bypass correlate with blood loss in children undergoing cardiac surgery.
abstract: OBJECTIVE
  To examine whether coagulation tests, sampled before and during cardiopulmonary bypass (CPB), are related to blood loss and blood product transfusion requirements, and to determine what test value(s) provide the best sensitivity and specificity for prediction of excessive hemorrhage.
  
  
  METHODS
  Prospective.
  
  
  METHODS
  University-affiliated, pediatric medical center.
  
  
  METHODS
  Four hundred ninety-four children.
  
  
  METHODS
  Coagulation tests.
  
  
  RESULTS
  Demographic, coagulation test, blood loss, and transfusion data were noted in consecutive children undergoing cardiac surgery. Laboratory tests included hematocrit (Hct), prothrombin time, partial thromboplastin time (PTT), platelet count, fibrinogen concentration, and thromboelastography. Stepwise linear regression analysis indicated that platelet count during CPB was the variable most significantly associated with intraoperative blood loss (in milliliters per kilogram) and 12-hour chest tube output (in milliliters per kilogram). Other independent variables associated with blood loss were thromboelastography maximum amplitude (MA) during CPB, preoperative PTT, preoperative Hct, and preoperative thromboelastography angle and shear modulus values. Thromboelastography MA during CPB was the only variable associated with total products transfused (in milliliters per kilogram). Of all tests studied, platelet count during CPB (< or = 108,000/microL) provided the maximum sensitivity (83%) and specificity (58%) for prediction of excessive blood loss (receiver operating characteristic analysis). Blood loss was inversely related to patient age; neonates received the most donor units (median, 8 units; range, 6 to 10 units).
  
  
  CONCLUSIONS
  During cardiac surgery, coagulation tests (including thromboelastography) drawn pre-CPB and during CPB are useful to identify children at risk for excessive bleeding. Platelet count during CPB was the variable most significantly associated with blood loss.
authors.affiliation: Department of Anesthesiology, University of Washington School of Medicine, Seattle, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Williams
authors.forename: S L
authors.initials: SL
authors.lastname: Bratton
authors.forename: E C
authors.initials: EC
authors.lastname: Riley
authors.forename: C
authors.initials: C
authors.lastname: Ramamoorthy
mesh_terms: D001780:Blood Coagulation Tests; D016063:Blood Loss, Surgical; D001803:Blood Transfusion; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D002675:Child, Preschool; D005260:Female; D006400:Hematocrit; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010976:Platelet Count; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011517:Prothrombin Time; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013916:Thrombelastography