Electrocerebral Signature of Cardiac Death

Background Electroencephalography (EEG) findings following cardiovascular collapse in death are uncertain. We aimed to characterize EEG changes immediately preceding and following cardiac death. Methods We retrospectively analyzed EEGs of patients who died from cardiac arrest while undergoing standard EEG monitoring in an intensive care unit. Patients with brain death preceding cardiac death were excluded. Three events during fatal cardiovascular failure were investigated: (1) last recorded QRS complex on electrocardiogram (QRS 0 ), (2) cessation of cerebral blood flow (CBF 0 ) estimated as the time that blood pressure and heart rate dropped below set thresholds, and (3) electrocerebral silence on EEG (EEG 0 ). We evaluated EEG spectral power, coherence, and permutation entropy at these time points. Results Among 19 patients who died while undergoing EEG monitoring, seven (37%) had a comfort-measures-only status and 18 (95%) had a do-not-resuscitate status in place at the time of death. EEG 0 occurred at the time of QRS 0 in five patients and after QRS 0 in two patients (cohort median − 2.0, interquartile range − 8.0 to 0.0), whereas EEG 0 was seen at the time of CBF 0 in six patients and following CBF 0 in 11 patients (cohort median 2.0 min, interquartile range − 1.5 to 6.0). After CBF 0 , full-spectrum log power ( p < 0.001) and coherence ( p < 0.001) decreased on EEG, whereas delta ( p = 0.007) and theta ( p < 0.001) permutation entropy increased. Conclusions Rarely may patients have transient electrocerebral activity following the last recorded QRS (less than 5 min) and estimated cessation of cerebral blood flow. These results may have implications for discussions around cardiopulmonary resuscitation and organ donation.