title: Transcranial Doppler detection of cerebral fat emboli and relation to paradoxical embolism: a pilot study.
abstract: BACKGROUND
  The fat embolism syndrome is clinically characterized by dyspnea, skin petechiae, and neurological dysfunction. It is associated mainly with long bone fracture and bone marrow fat passage to the systemic circulation. An intracardiac right-to-left shunt (RLS) could allow larger fat particles to reach the systemic circulation. Transcranial Doppler can be a useful tool to detect both RLS and the fat particles reaching the brain.
  
  
  RESULTS
  We prospectively studied patients with femur shaft fracture with RLS evaluation, daily transcranial Doppler with embolus detection studies, and neurological examinations to evaluate the relation of RLS and microembolic signals to the development of fat embolism syndrome. Forty-two patients were included; 14 had an RLS detected. Seven patients developed neurological symptoms; all of them had a positive RLS (P=<0.001). The patients with an RLS showed higher counts and higher intensities of microembolic signals (P=<0.05 and P=<0.01, respectively) compared with those who did not have an RLS identified. The presence of high microembolic signal counts and intensities in patients with RLS was strongly predictive of the occurrence of neurological symptoms (odds ratio, 204; 95% confidence interval, 11 to 3724; P<0.001) with a positive predictive value of 86% and negative predictive value of 97%.
  
  
  CONCLUSIONS
  In patients with long bone fractures, the presence of an RLS is associated with larger and more frequent microembolic signals to the brain detected by transcranial Doppler study and can predict the development of neurological symptoms.
authors.affiliation: Cardiac and Stroke Institute, Jackson Memorial Hospital, University of Miami Miller School of Medicine, FL, USA. aforteza@med.miami.edu
authors.forename: Alejandro M
authors.initials: AM
authors.lastname: Forteza
authors.forename: Sebastian
authors.initials: S
authors.lastname: Koch
authors.forename: Iszet
authors.initials: I
authors.lastname: Campo-Bustillo
authors.forename: Jose
authors.initials: J
authors.lastname: Gutierrez
authors.forename: Diogo C
authors.initials: DC
authors.lastname: Haussen
authors.forename: Alejandro A
authors.initials: AA
authors.lastname: Rabinstein
authors.forename: Jose
authors.initials: J
authors.lastname: Romano
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Zych
authors.forename: Robert
authors.initials: R
authors.lastname: Duncan
mesh_terms: D000293:Adolescent; D000328:Adult; D004620:Embolism, Fat / Q000000981:diagnostic imaging* / Q000209:etiology; D019320:Embolism, Paradoxical / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D005264:Femoral Fractures / Q000150:complications / Q000601:surgery; D054092:Foramen Ovale, Patent / Q000150:complications; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D055815:Young Adult