title: Coagulation factor levels in neurosurgical patients with mild prolongation of prothrombin time: effect on plasma transfusion therapy.
abstract: OBJECTIVE
  Neurosurgical patients often have mildly prolonged prothrombin time (PT) or international normalized ratio (INR). In the absence of liver disease this mild prolongation appears to be due to the use of very sensitive PT reagents. Therefore, the authors performed relevant coagulation factor assays to assess coagulopathy in such patients. They also compared plasma transfusion practices in their hospital before and after the study.
  
  
  METHODS
  The authors tested 30 plasma specimens from 25 patients with an INR of 1.3-1.7 for coagulation factors II, VII, and VIII. They also evaluated plasma orders during the 5-month study period and compared them with similar poststudy periods following changes in plasma transfusion guidelines based on the study results.
  
  
  RESULTS
  At the time of plasma orders the median INR was 1.35 (range 1.3-1.7, normal reference range 0.9-1.2) with a corresponding median PT of 13.6 seconds (range 12.8-17.6 seconds). All partial thromboplastin times were normal (median 29.0 seconds, range 19.3-33.7 seconds). The median factor VII level was 57% (range 25%-124%), whereas the hemostatic levels recommended for major surgery are 15%-25%. Factors II and VIII levels were also within the hemostatic range (median 72% and 118%, respectively). Based on these scientific data, plasma transfusion guidelines were modified and resulted in a 75%-85% reduction in plasma orders for mildly prolonged INR over the next 2 years.
  
  
  CONCLUSIONS
  Neurosurgical patients with a mild prolongation of INR (up to 1.7) have hemostatically normal levels of important coagulation factors, and the authors recommend that plasma not be transfused to simply correct this abnormal laboratory value.
authors.affiliation: Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Karén
authors.initials: K
authors.lastname: Matevosyan
authors.forename: Christopher
authors.initials: C
authors.lastname: Madden
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Barnett
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Beshay
authors.forename: Cynthia
authors.initials: C
authors.lastname: Rutherford
authors.forename: Ravindra
authors.initials: R
authors.lastname: Sarode
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000502:physiology; D001779:Blood Coagulation Factors / Q000378:metabolism*; D017707:Erythrocyte Transfusion / Q000706:statistics & numerical data*; D005167:Factor VII / Q000378:metabolism; D005169:Factor VIII / Q000378:metabolism; D005260:Female; D006488:Hemostasis, Surgical; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011516:Prothrombin / Q000378:metabolism; D011517:Prothrombin Time
chemical_list: D001779:Blood Coagulation Factors; D005167:Factor VII; D011516:Prothrombin; D005169:Factor VIII