title: Shock index in diagnosing early acute hypovolemia.
abstract: OBJECTIVE
  The aim of this study was to determine the hemodynamic response and calculated shock index (SI=heart rate [HR]/systolic blood pressure [SBP]) in early acute blood loss.
  
  
  METHODS
  This was a prospective observational study that enrolled healthy blood donors. Patients were excluded if not eligible for blood donation. Baseline vital signs were obtained, 450 mL of blood was removed over 20 minutes, and vital signs were repeated immediately postdonation while lying and after 1 and 5 minutes of standing. Difference was tested using a paired t test with P<.01 set for significance.
  
  
  RESULTS
  Forty-six patients were enrolled; means for each time interval are shown below with 95% confidence intervals.
  
  
  CONCLUSIONS
  A significant elevation in mean SI was observed in healthy volunteers after standing for 1 and 5 minutes. Although significant changes in HR and SBP were observed, these indices were still within "normal" limits. The SI may be more useful in early hemorrhage than either the HR or SBP alone.
authors.affiliation: Department of Emergency Medicine, New York Methodist Hospital, Brooklyn, NY 11215, USA. rhbirkhahn@pol.net
authors.forename: Robert H
authors.initials: RH
authors.lastname: Birkhahn
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Gaeta
authors.forename: Doug
authors.initials: D
authors.lastname: Terry
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Bove
authors.forename: John
authors.initials: J
authors.lastname: Tloczkowski
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D001782:Blood Donors; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged