Brain death and transcranial Doppler: Experience in 130 cases of brain dead patients
Introduction
In most countries and states the clinical diagnosis of brain death, which is often important for possible organ donation, must be confirmed by appropriate tests, such as EEG, cerebral angiography or radionuclide imaging 1, 2, 3, 4. These confirmatory tests may be the source of major logistical problems, as they are time consuming and require the transportation of critically ill patients. Hence, there is a need to develop other methods. The results obtained during the past few years with transcranial Doppler (TCD) led us to evaluate this non-invasive ultrasonic method, comparing it to standard techniques 5, 6, 7, 8, 9. TCD, demonstrates the arrest of the cerebral circulation with typical intracranial Doppler waveforms. It may thus support the diagnosis of brain death and become a useful alternative to accepted confirmation tests. We have therefore studied, prospectively, patients diagnosed as brain dead by clinical data and accepted confirmation tests, to determine the clinical value of TCD.
Section snippets
Materials and methods
A total of 130 patients hospitalized in the intensive neurosurgical and medical care units, between July 1987 and June 1993 with an established diagnosis of brain death, were evaluated with TCD. They ranged in age from 2 to 88 years (mean: 34). This series includes 13 children below 15 years: aged 2 (n=3), 5 (n=1), 7 (n=2), 8 (n=2), 9 (n=1), 12 (n=1), 15 (n=3). The cause of brain death was known in all the cases. The main cause was head trauma (76 cases, 58.5%) or subarachnoid haemorrhage (27
Results
Two TCD waveform patterns were recorded (Table 1). One was an oscillating, `to and fro', signal (Fig. 1) with a mono or biphasic reverse diastolic signal (190 ICA, 73%) and the second a systolic spike (62 ICA, 24%). The systolic spike was narrow and there was no detectable diastolic flow (Fig. 2). No detectable signal was found on one side in five patients, while the signal was easily identified on the opposite side. In three cases, the systolic component of the Doppler signal was larger,
Discussion
TCD examination of the 130 brain dead patients showed a typical pattern of CCA, confirming on a large prospective series previous findings 5, 6, 7, 8, 13. TCD has been used for 6 years in neurology and neurosurgery intensive care departments in our hospital, and, during that time, no patient displaying a permanent TCD pattern of global circulatory arrest subsequently recovered. Furthermore, in other clinical situations, we never found typical TCD patterns of CCA. The absolute specificity of the
Conclusion
Our experience with TCD in severe comatose and brain dead patients confirms that TCD is a reliable alternative confirmatory test for the diagnosis of brain death. That the examiner should be experienced in ultrasonic methods is an evidence, as should be any person authorized to establish a clinical diagnosis of brain death. As TCD is a non-invasive, bedside, rapid and repeatable method, it should be particularly suitable for diagnosing, especially when EEG is not relevant, as in patients
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