title: On the value of routine prothrombin time screening in elective neurosurgical procedures.
abstract: OBJECTIVE
  The authors performed a study to evaluate whether preoperative assessment of prothrombin time (PT) is mandatory in patients undergoing routinely planned neurosurgical procedures.
  
  
  METHODS
  The charts of all patients admitted to general wards of the authors' department for routinely planned surgery (excluding trauma and ICU patients) between 2006 and 2010 were retrospectively reviewed. The authors assessed preoperative PT and the clinical courses of all patients, with special consideration for patients receiving coagulation factor substitution. All cases involving hemorrhagic complications were analyzed in detail with regard to pre- and postoperative PT abnormalities. Prothrombin time was expressed as the international normalized ratio, and values greater than 1.28 were regarded as elevated.
  
  
  RESULTS
  Clinical courses and PT values of 4310 patients were reviewed. Of these, 33 patients (0.7%) suffered hemorrhagic complications requiring repeat surgery. Thirty-one patients (94%) had a normal PT before the initial operation, while 2 patients had slightly elevated PT values of 1.33 and 1.65, which were anticipated based on the patient's history. In the latter 2 cases, surgery was performed without prior correction of PT. Preoperatively, PT was elevated in 78 patients (1.8%). In 73 (93.6%) of the 78 patients, the PT elevation was expected and explained by each patient's medical history. In only 5 (0.1%) of 4310 patients did we find an unexpected PT elevation (mean 1.53, range 1.37-1.74). All 5 patients underwent surgery without complications, while 2 had received coagulation factor substitution preoperatively, as requested by the surgeon, because of an estimated risk of bleeding complications. None of the 5 patients received coagulation factor substitution postoperatively, and later detailed laboratory studies ruled out single coagulation factor deficiencies. There was no statistically significant association between preoperatively elevated PT levels and the occurrence of hemorrhagic complications (p = 0.12). Before the second procedure but not before the initial operation, 4 (12%) of the 33 patients had elevated PT.
  
  
  CONCLUSIONS
  The findings suggest that the value of preoperative PT testing is limited in patients in whom a normal history can be ascertained. Close postoperative PT control is necessary in every neurosurgical patient, and better tests need to be developed to identify patients who are prone to hemorrhagic complications.
authors.affiliation: Department of Neurosurgery, Johann Wolfgang Goethe University, Frankfurt/Main, Germany. Stephan.duetzmann@kgu.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Dützmann
authors.forename: Florian
authors.initials: F
authors.lastname: Gessler
authors.forename: Gerhard
authors.initials: G
authors.lastname: Marquardt
authors.forename: Volker
authors.initials: V
authors.lastname: Seifert
authors.forename: Christian
authors.initials: C
authors.lastname: Senft
mesh_terms: D000368:Aged; D001779:Blood Coagulation Factors / Q000627:therapeutic use; D001780:Blood Coagulation Tests; D003955:Diagnostic Tests, Routine; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D020300:Intracranial Hemorrhages / Q000517:prevention & control; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011182:Postoperative Care; D011183:Postoperative Complications / Q000517:prevention & control; D019106:Postoperative Hemorrhage / Q000517:prevention & control / Q000628:therapy; D011300:Preoperative Care; D011517:Prothrombin Time / Q000379:methods* / Q000592:standards; D012189:Retrospective Studies
chemical_list: D001779:Blood Coagulation Factors