title: Sensitivity of transcranial Doppler for confirming brain death: a prospective study of 270 cases.
abstract: OBJECTIVE
  The reported sensitivity of transcranial Doppler ultrasonography (TCD) for confirming brain death (BD) ranges from 91% to 100%. We assessed the frequency and causes of false-negative results in TCD examination in a series of patients with BD and in the literature.
  
  
  METHODS
  We carried out a prospective TCD examination of consecutive patients with the clinical diagnosis of BD.
  
  
  RESULTS
  In 204 (75.5%) of 270 patients, TCD showed a pattern compatible with BD. The causes of the false-negative results were persistent flow in the intracranial arteries in 47 (17.4%) patients and a lack of signal in 19 (7%). Absence of sympathomimetic drug use [odds ratio (OR) 5.4, 95% confidence interval (CI) 1.8-16.0, P = 0.003) and female gender (OR 3.7, 95% CI 1.1-12.5, P = 0.03) were associated with false-negative results. A review of 16 studies showed a sensitivity of 88% and a specificity of 98% of TCD for confirming BD.
  
  
  CONCLUSIONS
  The sensitivity of TCD for confirming BD may be lower than previously reported, but is probably similar to that of other non-invasive methods. The specificity of TCD is close to 100%. Uniform criteria are needed for the routine use of TCD as a confirmatory test for BD.
authors: Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. gfreitas@ufrj.br
authors: G R
authors: GR
authors: de Freitas
authors: C
authors: C
authors: André