The observation period after clinical brain death diagnosis according to ancillary tests: differences between supratentorial and infratentorial brain injury.

OBJECTIVE: To determine the optimal observation period (OBP) in adults with a clinical diagnosis of brain death (BD) using electroencephalography (EEG) or computerized tomography angiography (CTA). METHODS: We conducted a retrospective observational analysis of adult patients with a diagnosis of BD from January 2000 to February 2017. The optimal OBP was defined as the minimum time interval from the first complete clinical neurological examination (CNE) that ensures that neither a second CNE nor any ancillary test (AT) performed after this period would fail to confirm BD. RESULTS: The study sample included 447 patients. In the supratentorial group, the first AT confirmed BD in 389 cases (98%), but in 8 (2%) cases the complementary test was incongruent. In this group, 8 of 245 patients in whom the first AT was carried out within the first 2 h after a complete CNE had a non-confirmatory test of BD versus none of 152 in whom the first AT was delayed more than 2 h (3.0% vs 0.0%; p = 0.026). In the infratentorial group, we found a higher probability of obtaining a first non-confirmatory AT of BD (34% vs 2%; p = 0.0001) and an OBP greater than 32.5 h was necessary to confirm a BD diagnosis. CONCLUSIONS: We found important differences in the confirmation of BD diagnosis between primary supratentorial and infratentorial lesion, and identified an optimal OBP of 2 h in patients with supratentorial lesions. By contrast, in primary posterior fossa/infratentorial lesions, the determination of an optimal OPB remains less accurate and hence more challenging.

Non confirmatory electroencephalography in patients meeting clinical criteria for brain death: scenario and impact on organ donation.

OBJECTIVE: To describe the causes and outcome of adult patients with preserved electroencephalographic activity despite clinical findings suggesting brain death (BD), and its impact on organ donation. METHODS: Retrospective study of the clinical and electroencephalography (EEG) data of all adult patients admitted to our hospital between January 2001 and December 2011 in whom a comprehensive clinical diagnosis of BD was reached following absence of brainstem reflexes and confirmatory apnea tests, were obtained. All patients with clinical findings suggesting BD and an EEG showing brain activity were selected for the analysis. We calculated the brain death interval (BDI) as the time between the first complete clinical examination and confirmatory ancillary test, or the time between the first and second complete clinical examination for BD, in order to analyze the impact on family consent for organ donation. RESULTS: A complete clinical examination and EEG were diagnostic in 289 patients. In 279 (96.5%), the first EEG showed electrocerebral inactivity corroborating the clinical findings of BD. The mean BDI in this group was 4.2 ± 5.8h (median; 1.8[1.0-3.5]). This value was significantly lower than in the group in which only two full clinical evaluations were performed (p<0.0001). In 10 out 289 (3.5%), the first EEG showed at least some brain activity. The mean BDI in this group was 27.2 ± 13.8h (median; 22.9 [19.1-31.2]). In two cases, a third EEG was necessary before obtaining electrocerebral inactivity. A BDI>6h, was positively associated with a family refusal for organ donation (p=0.02). CONCLUSIONS: The rate of EEGs with electrocerebral activity despite clinical findings suggesting BD was only 3.5%. It occurred most frequently with severe brainstem damage. Although in this small percentage of patients, BD diagnosis was notably delayed, in the great majority of cases the use of EEG shortened the BDI. In our series, a BD diagnosis delay >6h negatively affected consent for organ donation. SIGNIFICANCE: The use of EEG can decrease the time interval for brain death diagnosis.