Dosemeci Levent, Dora Babur, Yilmaz Murat, Cengiz MelIke, Balkan Sevin, Ramazanoglu Atilla
Department of Anaesthesiology and ICU, Akdeniz University, Antalya, Turkey.
Transplantation. 2004 Jan 15;77(1):71-5. doi: 10.1097/01.TP.0000092305.00155.72.
Although the clinical examination and documentation of the clinical signs of brain death are very uniform, there are significant differences in the guidelines for using technical confirmatory tests to corroborate the clinical signs. The current study examined the utility of transcranial Doppler ultrasonography (TCD) for confirmation of brain death.
After 19 patients were excluded from the study because of lack of bone window or because an apnea test could not be performed because of desaturation, 100 patients (61 patients with clinical brain death, and 39 control patients with Glasgow Coma Score<5) were included in the study. The following TCD findings were accepted as confirmatory of brain death when they were found bilaterally or in at least three different arteries for at least 3 minutes within the same examination: (1) brief systolic forward flow or systolic spikes and diastolic reverse flow, (2) brief systolic forward flow or systolic spikes and no diastolic flow, or (3) no demonstrable flow in a patient in whom flow had been clearly documented in a previous TCD examination.
The sensitivity and specificity of the first TCD examination for confirmation of brain death were 70.5% and 97.4%, respectively. Eighteen patients with clinical brain death required repeat TCD examinations because of detection of forward systolo-diastolic flow or a diastolic to-and-fro flow pattern, which were not confirmatory for the diagnosis of brain death. Brain death was confirmed ultrasonographically in 12 of 18 patients in a second examination after 12.6 +/- 8.3 hours of clinical brain death, in 2 patients in a third TCD examination, and in 1 patient in a fourth examination. Three clinically brain-dead patients had died before the diagnosis was confirmed by repeat TCD examinations. The sensitivity of TCD reached 100% in our study population after the fourth examination.
The sensitivity of TCD is increased with repeat examinations and should be repeated in cases in which systolo-diastolic forward flow is demonstrated after the first TCD. TCD may prolong or shorten the time to declaration of brain death. The necessity of demonstrating cerebral circulatory arrest in patients with clinical brain death is debatable.
尽管脑死亡临床体征的检查及记录十分统一，但在使用技术确证性检查来证实临床体征的指南方面仍存在显著差异。本研究探讨经颅多普勒超声检查（TCD）用于确证脑死亡的效用。
由于缺乏骨窗或因饱和度下降无法进行呼吸暂停试验，19例患者被排除在研究之外，100例患者（61例临床脑死亡患者和39例格拉斯哥昏迷评分<5的对照患者）纳入研究。当在同一次检查中双侧或至少三条不同动脉中发现以下TCD表现至少持续3分钟时，可确证脑死亡：（1）短暂的收缩期正向血流或收缩期尖峰及舒张期反向血流；（2）短暂的收缩期正向血流或收缩期尖峰且无舒张期血流；或（3）在之前TCD检查中血流清晰记录的患者中未检测到血流。
首次TCD检查确证脑死亡的敏感性和特异性分别为70.5%和9... 4%。18例临床脑死亡患者因检测到收缩期-舒张期正向血流或舒张期往返血流模式而需要重复TCD检查，这些表现不能确证脑死亡诊断。18例患者中有12例在临床脑死亡12.6±8.3小时后的第二次检查中经超声确证脑死亡，2例在第三次TCD检查中确证，1例在第四次检查中确证。3例临床脑死亡患者在重复TCD检查确诊前已死亡。在我们的研究人群中，第四次检查后TCD的敏感性达到100%。
TCD的敏感性随重复检查而提高，对于首次TCD检查后出现收缩期-舒张期正向血流的病例应重复检查。TCD可能延长或缩短脑死亡宣告时间。在临床脑死亡患者中确证脑循环停止的必要性存在争议。
