title: Blood clot resolution in human cerebrospinal fluid: evidence of first-order kinetics.
abstract: OBJECTIVE
  To determine the kinetics of blood clot resolution in human cerebrospinal fluid.
  
  
  METHODS
  Computed tomographic scans of 17 adult patients with intraventricular hemorrhages were analyzed. Intraventricular clot volume was determined and analyzed over time to determine both a standardized percentage rate and an absolute rate of clot resolution. Results were analyzed by use of regression for cross sectional time-series data. To determine the kinetics of intraventricular clot resolution, the effect of the clot volume on the percentage rate of clot resolution, clot half-life, and absolute rate of clot resolution was analyzed. The potential effect of age, sex, type of hemorrhage, and treatment with external ventricular drainage on the percentage rate of clot resolution was assessed.
  
  
  RESULTS
  The percentage rate of clot resolution was 10.8% per day (95% confidence interval, 9.05-12.61 %), and it was independent of initial clot volume, age, sex, type of underlying hemorrhage, and use of external ventricular drainage. The absolute rate of clot resolution varied directly with the maximal clot volume (R2 = 0.88; P < 0.001). The percentage clot resolution data are consistent with events during the first 24 to 48 hours that antagonize clot resolution.
  
  
  CONCLUSIONS
  These findings demonstrate that intraventricular blood clot resolution in patients with intraventricular hemorrhage follows first-order kinetics. The thrombolytic enzyme system responsible for intraventricular clot resolution seems to be saturated at 24 to 48 hours after the initial hemorrhage.
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA. nnaff@hotmail.com
authors.forename: N J
authors.initials: NJ
authors.lastname: Naff
authors.forename: M A
authors.initials: MA
authors.lastname: Williams
authors.forename: D
authors.initials: D
authors.lastname: Rigamonti
authors.forename: P M
authors.initials: PM
authors.lastname: Keyl
authors.forename: D F
authors.initials: DF
authors.lastname: Hanley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002543:Cerebral Hemorrhage / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000601:surgery; D002552:Cerebral Ventricles; D004322:Drainage / Q000379:methods; D005260:Female; D006801:Humans; D020767:Intracranial Thrombosis / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000601:surgery; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed