Relationships Between Resting Energy Expenditure and Transcranial Doppler Measurements in Patients With and Without Brain Death

Abstract

IntroductionBrain metabolism deteriorates during brain death, suggesting that cerebral metabolic measurements could serve as a prognostic factor. The application of transcranial Doppler can be useful in evaluating patients evolving to brain death. Resting energy expenditure is lower than expected in patients with brain death, and this is caused by the decrease in cerebral blood flow and consequently lower oxygen supply. The primary aim of this retrospective study is to investigate the early metabolic changes in patients with clinical criteria of brain death and examine if these changes are related to a gradual decrease in blood flow velocities in the middle cerebral artery. MethodsAll consecutive patients from 1st June 2018 to 30th April 2022, admitted to the ICU with brain injury and a GCS ≤ 8, were included retrospectively in the study. Patients were allocated into two groups: Group A, patients without clinical signs of brain death (n = 32), and Group B, patients with brain death (n = 34). In each group, three sets of metabolic measurements were performed concomitantly with cerebral blood flow velocities using transcranial Doppler (a) upon admission to the ICU, (b) once hemodynamic stabilization was obtained, and (c) 48 hours after their hemodynamic stabilization or when brain death was confirmed by clinical criteria. Resting energy expenditure (REE) measurements were performed using a metabolic computer. Cerebral blood flow velocities were measured after a period of 30 min using a 2-MHZ 2D ultrasound probe. ResultsBrain-dead patients had a significant decrease in their metabolic parameters as the cerebral blood flow velocities recorded with the transcranial Doppler deteriorated, (

An Update on Brain Death/Death by Neurologic Criteria since the World Brain Death Project

“…131 There have also been new publications evaluating the feasibility and validity of other brain blood flow studies as ancillary tests (e.g., extracranial duplex sonography), the role of optic nerve sheath diameter and resting energy expenditure measurement in BD/DNC determination and the findings on radionuclide studies after TCD ultrasonography did not show complete loss of brain blood flow. [132][133][134][135][136] New Publications Related to Electroencephalography Perhaps related to the fact that the WBDP suggests against use of electroencephalography as an ancillary test, it was rarely addressed in subsequent publications. 1,23 However, in 2022, the Clinical Neurophysiology Society of the Communities of Valencia and Murcia issued the first Spanish guidance on the minimum standards for performing electroencephalography for BD/DNC determination.…”