title: Use of hematocrit changes as an indicator of blood loss in adult trauma patients who receive intravenous fluids.
abstract: OBJECTIVE
  To validate the use of changes in hematocrit as an indicator of blood loss in adult trauma patients receiving IV fluids and to identify parameters of hematocrit changes that may differentiate between patients with and without hemorrhage.
  
  
  METHODS
  A descriptive, retrospective chart review.
  
  
  METHODS
  A convenience sample of 90 adult trauma patients at an urban level I trauma center emergency department who received IV fluids for whom hematocrit measurements were available.
  
  
  METHODS
  Records were reviewed for patients with documented hematocrit readings before and after receiving 2 L of IV fluid, noting the time between hematocrit measurements. Patients were divided into groups: Group 1 consisted of 74 subjects with no hemorrhaging (< 500 ml blood loss); group 2 consisted of 16 subjects in whom hemorrhage occurred (> 500 ml of blood loss).
  
  
  RESULTS
  In group 1 (nonhemorrhage group), the mean hematocrit change was -5.3%; in group 2 (hemorrhage group) the hematocrit change was -8.3%. The findings showed a statistically significant difference (p < 0.05) between the groups for both the repeat hematocrit scores and the change in hematocrit scores. On the basis of a hematocrit decrease of 5% or less, 97% of the patients would have been correctly assigned to the nonhemorrhage group.
  
  
  CONCLUSIONS
  Hematocrit determinations are a valid indicator of blood loss in trauma patients receiving IV therapy. The use of repeat hematocrit readings for clinicians trying to differentiate those with significant blood loss and the effects of IV fluid administration remains limited.
authors.forename: K S
authors.initials: KS
authors.lastname: Oman
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D005440:Fluid Therapy; D006400:Hematocrit; D006470:Hemorrhage / Q000097:blood* / Q000209:etiology / Q000628:therapy; D006801:Humans; D008297:Male; D009104:Multiple Trauma / Q000150:complications*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity