Identification of separation phenomenon during brain death determination of potential organ donor and analysis of relative factors

Guixing Xu, Ping Yu, Ping Xu, Donghua Zheng


Background: With analyzing the incongruent phenomenon of electrical active and cerebral blood flow in brain death determination and screening the related factors, offer correct explanations and countermeasure to ensure the successful implementation of donation after brain death.

Methods: Relevant clinical data of potential brain death organ donors were prospectively collected between June 2018 and May 2019. The related parameters of neurological examination, laboratory examination and neuroimaging examination during the period of brain death determination were dynamically recorded. Separation phenomenon was used as grouping factors to screen the factors related to separation phenomena through univariate and multivariate analysis.

Results: According to the inclusion criteria, 127 patients were included in the study. Among 22 patients (17.3%) with incongruent phenomenon, 17 (77.3%) had electrical silence earlier than cerebral blood flow arrest, and 9 (22.7%) had cerebral blood flow arrest earlier than electrical silence. Univariate and multivariate analysis showed that age <14 years (OR=6.25, 95%CI 1.21-32.22, p=0.028),  SBP≥140 mmHg (OR=7.43, 95%CI 1.62-33.99, p=0.010), primary brainstem injury (OR=15.89, 95%CI 3.04-82.93, p=0.006), spontaneous respiratory arrest time ≤72 hours (OR=11.96, 95%CI 1.59-89.78, p=0.009) and decompression craniotomy(unilateral or bilateral) (OR=16.28, 95%CI 2.25-117.73, p=0.001) were associated with separation phenomenon..

Conclusions: Separation phenomenon is a common during the confirmation test of brain death determination in China, and should be correctly recognized. To adopt corresponding measures according to risk factors is useful for successful implementation of donation after brain death.


Brain death, Cerebral blood flow, Cerebral electrical activity, Confirmatory tests, Organ donation, Separation phenomenon

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Brain Injury Evaluation Quality Control Centre of National Heath. Commission Criteria and practical guidance for determination of brain death in children. Chinese J Pediatr. 2019;57(5):331-5.

Brain Injury Evaluation Quality Control Centre of National Heath, Neurocritical Care Committee of Chinese Society of Neurology, Neurocritical Care Committee of Chinnese neurologist association. China Criteria and practical guidance for determination of brain death in adults (Second Edition) Chinese Medical J. 2019;99(17):1288-92.

Welschehold S, Boor S, Reuland K, Thömke F, Kerz T, Reuland A, et al. Technical aids in the diagnosis of brain death: a comparison of SEP, AEP, EEG, TCD and CT angiography. Dtsch Arztebl Int. 2012;109(39):624-30.

Xu G, Guo Z, Liang W, Xin E, Liu B, Xu Y, et al. Prediction of potential for organ donation after circulatory death in neurocritical patients. J Heart Lung Transplant. 2018;37(3):358-64.

He X, Xu G, Liang W, Liu B, Xu Y, Luan Z, et al. Nomogram for predicting time to death after withdrawal of life-sustaining treatment in patients with devastating neurological injury. Am J Transplantation. 2015;15(8):2136-42.

Lewis A, Adams N, Chopra A, Kirschen MP. Use of Ancillary Tests When Determining Brain Death in Pediatric Patients in the United States. J Child Neurol, 2017;32(12):975-80.

Kramer AH. Ancillary testing in brain death. Semin Neurol. 2015;35(2):125-38.

Xu L, Zhang S, Jiang B. Recent advance in relation between collateral circulation and prognoses of ischemic stroke based on multimodal imaging evaluation. Chin J Neuromed, 2019:18(11):1168-72.

Su Y, Yang Q, Liu G, Zhang Y, Ye H, Gao D, et al. Diagnosis of brain death: confirmatory tests after clinical test. Chin Med J (Engl). 2014;127(7):1272-7.

Saver JL. Time is brain-quantified. Stroke. 2006:37(1):263-6.

Wijdicks EFM. Pitfalls and slip-ups in brain death determination. Neurol Res. 2013;35(2):169-73.

Rech TH, Moraes RB, Crispim D, Czepielewski MA, Leitao CB. Management of the brain-dead organ donor: a systematic review and meta-analysis. J Transplantation. 2013;95(7):966-74.

Frisardi F, Stefanini M, Natoli S, Cama V, Loreni G, Di Giuliano F, et al. Decompressive craniectomy may cause diagnostic challenges to assess brain death by computed tomography angiography. Minerva Anestesiol. 2014;80(1):113-8.

Roth C, Ferbert A. Subarachnoid Hemorrhage and Isolated Brainstem Death. Fortschr Neurol Psychiatr. 2016;84(6):377-84.

Rosenblum WI. Immediate, irreversible, posttraumatic coma: a review indicating that bilateral brainstem injury rather than widespread hemispheric damage is essential for its production. J Neuropathol Exp Neurol. 2015;74(3):198-202.

Dasen G, Yun C, Yue. Shuyuan. Multi-mode neural electrophysiological monitoring in carotid endarterectomy. Chin J Neuromed. 2018;17(10):1037-40.

Guixing XU, Zheng D, Liao Y, Guo Z, Xiaoshun HE. The 3-durgs-effect analysis of vasopressin,thyroxine and corticosteroids in 109 brain death donors[J]. Chin J Organ Transplant. 2018;39(6):364-8.

Kalanuria A, Nyquist PA, Armonda RA, Razumovsky A. Use of Transcranial Doppler (TCD) ultrasound in the Neurocritical Care Unit. Neurosurg Clin N Am. 2013;24(3):441-56.

Chang JJ, Tsivgoulis G, Katsanos AH, Malkoff MD, Alexandrov AV. Diagnostic Accuracy of Transcranial Doppler for Brain Death Confirmation: Systematic Review and Meta-Analysis. AJNR Am J Neuroradiol. 2016;37(3):408-14.