title: Diagnostic Accuracy of Transcranial Doppler for Brain Death Confirmation: Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  Transcranial Doppler is a useful ancillary test for brain death confirmation because it is safe, noninvasive, and done at the bedside. Transcranial Doppler confirms brain death by evaluating cerebral circulatory arrest. Case series studies have generally reported good correlations between transcranial Doppler confirmation of cerebral circulatory arrest and clinical confirmation of brain death. The purpose of this study is to evaluate the utility of transcranial Doppler as an ancillary test in brain death confirmation.
  
  
  METHODS
  We conducted a systematic review of the literature and a diagnostic test accuracy meta-analysis to compare the sensitivity and specificity of transcranial Doppler confirmation of cerebral circulatory arrest, by using clinical confirmation of brain death as the criterion standard.
  
  
  RESULTS
  We identified 22 eligible studies (1671 patients total), dating from 1987 to 2014. Pooled sensitivity and specificity estimates from 12 study protocols that reported data for the calculation of both values were 0.90 (95% CI, 0.87-0.92) and 0.98 (95% CI, 0.96-0.99), respectively. Between-study differences in the diagnostic performance of transcranial Doppler were found for both sensitivity (I(2) = 76%; P < .001) and specificity (I(2) = 74.3%; P < .001). The threshold effect was not significant (Spearman r = -0.173; P = .612). The area under the curve with the corresponding standard error (SE) was 0.964 ± 0.018, while index Q test ± SE was estimated at 0.910 ± 0.028.
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that transcranial Doppler is a highly accurate ancillary test for brain death confirmation. However, transcranial Doppler evaluates cerebral circulatory arrest rather than brain stem function, and this limitation needs to be taken into account when interpreting the results of this meta-analysis.
authors.affiliation: From the Department of Neurology (J.J.C., G.T., M.D.M., A.V.A.), University of Tennessee Health Science Center, Memphis, Tennessee jjwchang@hotmail.com.
authors.forename: J J
authors.identifier: http://orcid.org/0000-0002-0825-3008
authors.initials: JJ
authors.lastname: Chang
authors.affiliation: From the Department of Neurology (J.J.C., G.T., M.D.M., A.V.A.), University of Tennessee Health Science Center, Memphis, Tennessee Second Department of Neurology (G.T., A.H.K.), Attikon University Hospital, School of Medicine, University of Athens, Athens, Greece International Clinical Research Center (G.T.), St. Anne's University Hospital in Brno, Czech Republic.
authors.forename: G
authors.identifier: http://orcid.org/0000-0002-0640-3797
authors.initials: G
authors.lastname: Tsivgoulis
authors.affiliation: Second Department of Neurology (G.T., A.H.K.), Attikon University Hospital, School of Medicine, University of Athens, Athens, Greece Department of Neurology (A.H.K.), University of Ioannina, School of Medicine, Ioannina, Epirus, Greece.
authors.forename: A H
authors.identifier: http://orcid.org/0000-0002-6359-0023
authors.initials: AH
authors.lastname: Katsanos
authors.affiliation: From the Department of Neurology (J.J.C., G.T., M.D.M., A.V.A.), University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: M D
authors.identifier: http://orcid.org/0000-0002-6665-3114
authors.initials: MD
authors.lastname: Malkoff
authors.affiliation: From the Department of Neurology (J.J.C., G.T., M.D.M., A.V.A.), University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: A V
authors.identifier: http://orcid.org/0000-0001-8871-1023
authors.initials: AV
authors.lastname: Alexandrov
mesh_terms: D001926:Brain Death / Q000175:diagnosis*; D005260:Female; D006801:Humans; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*