Relative factors for "incongruent phenomenon" of brain electrical activity and cerebral blood flow during brain death determination for potential organ donors

Objective To identify the relative factors for "incongruent phenomenon" of brain electrical activity and cerebral blood flow during brain death determination for potential organ donors, and intensify the understanding and cognition of this phenomenon. Methods The clinical data of 127 potential donors accepted donation after brain death (DBD), admitted to our hospital from June 2018 to May 2019, were collected prospectively. All patients preferred brain electrical activity and cerebral blood flow assessments as the confirmatory tests of brain death determination. For patients with "incongruent phenomenon", further test of median nerve short latency evoked potential or brain electrical activity and cerebral blood flow assessments after waiting for 24 h were performed to confirm brain death determination again. Fifteen parameters, such as gender, age, time of spontaneous respiration arrest, blood pressure, operative types, neurological examination, neuroimaging index, and serum Na+ level, were selected; univariate and multivariate Logistic regression analyses were used to identify these risk factors related to "incongruent phenomenon". Results Among the 127 patients, 22 patients (17.3%) appeared "incongruent phenomenon"; 17 (77.2%) had electrical silence earlier than cerebral blood flow arrest, and 5 (22.7%) had cerebral blood flow arrest earlier than electrical silence. Multivariate Logistic analysis showed that age≤14 years (OR=6.250, 95CI: 1.201-32.220, P=0.028), systolic blood pressure≥140 mmHg(OR=7.430, 95CI: 1.621-33.992, P=0.010), primary brain-stem injury (OR=15.890, 95CI: 3.042-82.930, P=0.006), spontaneous respiratory arrest time≤72 h (OR=11.964, 95CI: 3.045-82.932, P=0.006), and unilateral/bilateral decompressive craniectomy (OR=16.281, 95CI: 1.590-89.785, P=0.001) were independent risk factors for "incongruent phenomenon". Conclusion "Incongruent phenomenon" is common in confirmatory test of brain death determination in China; patients with age≤14 years, systolic blood pressure≥140 mmHg, primary brain-stem injury, spontaneous respiratory arrest time≤72 h, and decompressive craniectomy (unilateral/bilateral) are more likely to have "incongruent phenomenon". Key words: Organ donation; Brain death; Electroencephalogram; Cerebral blood flow; Incongruent phenomenon