title: Ultrasound does not detect early blood loss in healthy volunteers donating blood.
abstract: BACKGROUND
  Ultrasound has been suggested as a useful non-invasive tool for the detection of early blood loss. Two possible sonographic markers for hypovolemia are the diameter of the inferior vena cava (IVC) and the thickness of the left ventricle (LV).
  
  
  OBJECTIVE
  The goal of the study was to evaluate the utility of ultrasound to detect signs of early hemorrhagic shock in healthy volunteers, compared with changes in vital signs.
  
  
  METHODS
  In the current study, healthy volunteers from blood donation drives were used as models for early hemorrhage. Changes in vital signs, IVC diameter, and LV wall thickness were recorded after approximately 500 cc of blood loss.
  
  
  RESULTS
  Thirty-eight subjects were enrolled and completed the study. After blood donation, there was a 7-mm Hg (8%) decrease in mean arterial pressure without a significant change in heart rate. There was a decrease in maximum IVC diameter (IVCmax) (12% decrease [95% confidence interval (CI) -6 to -19] in short axis and 20% decrease [95% CI -12 to -27] in long axis), but no change was seen in the respiratory caval index ((IVCmax - IVCmin)/IVCmax) × 100). There was no change in LV wall thickness.
  
  
  CONCLUSIONS
  In this study, serial changes in vital signs, IVC diameter, and LV wall thickness were clinically insignificant after approximately 500 cc of blood loss in healthy volunteers.
authors.affiliation: Department of Emergency Medicine, MetroHealth Medical Center, Cleveland, Ohio and Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Resnick
authors.forename: Rita
authors.initials: R
authors.lastname: Cydulka
authors.forename: Elke
authors.initials: E
authors.lastname: Platz
authors.forename: Robert
authors.initials: R
authors.lastname: Jones
mesh_terms: D000328:Adult; D001782:Blood Donors; D001794:Blood Pressure / Q000502:physiology; D042241:Early Diagnosis; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008954:Models, Biological; D012771:Shock, Hemorrhagic / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging*; D055815:Young Adult