Application of transcranial Doppler ultrasonography for the diagnosis of brain death
Objective: To determine the clinical validity of transcranial Doppler ultrasonographic (TCD) signs of total cerebral circulatory arrest for confirmation of brain death and to define the test protocol. Design: Study of a diagnostic test. Setting: General and neurosurgery intensive care units. Patients: 137 patients in a coma (Glasgow Coma Score 3–5), caused by various pathological conditions, observed from January 1992 to July 1998. 84 patients met the clinical criteria of brain death; 43 patients out of 137 received sedative drug therapy and 31 of these developed brain death. Results: Total cerebral circulatory arrest was demonstrated by TCD in 81 patients. All of them proved to be brain dead according to subsequent clinical examination In 29 of 31 patients who had received sedative drug therapy TCD examination showed total cerebral circulatory arrest 12–48 h before the formal confirmation of the diagnosis. In 1 out of 84 clinically brain dead patients a false negative result was obtained. In 2 of 84 cases, no clear signals from intracranial vessels were obtainable. Fifty-three patients who did not meet the clinical criteria for brain death showed no TCD signs of total cerebral circulatory arrest. The specificity of the TCD test for confirmation of brain death was 100 % and the sensitivity 96.5 %. Conclusions: In agreement with previously published data, we conclude that TCD ultrasonography is a highly specific and sensitive confirmatory test and should be included as an additional test in the protocol for the assessment of brain death.
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