Is a Second Transcranial Doppler Study Needed to Confirm Neurocirculatory Arrest?

BACKGROUND

In determining brain death, transcranial Doppler (TCD) is one of the recommended ancillary tests when clinical examinations and apnea tests are contraindicated. The American Academy of Neurology 2023 guideline updates and 2020 World Brain Death Project advise conducting two TCDs 30 min apart to diagnose neurocirculatory arrest. Our study aimed to evaluate whether a second TCD is necessary when the first TCD shows neurocirculatory arrest (no flow, oscillating flow, or systolic spikes).

METHODS

We conducted a single-center retrospective analysis of patients admitted to intensive care units from January 1, 2021, to February 1, 2025, at a community-based academic hospital. We included patients whose first study showed neurocirculatory arrest and who subsequently underwent a confirmatory TCD at least 30 min apart. A total of 48 patients were included in our final analysis. We compared the findings of the first TCD study with those of the second study and noted any differences.

RESULTS

In all 48 patients (100%), the second TCD confirmed the findings of the first TCD. Of these 48 patients, 44 patients (91.7%) had the same flow pattern on repeat TCD examination and 4 patients' (8.30%) TCDs showed different flow patterns, although still consistent with neurocirculatory arrest. Of the 44 patients with the same flow patterns found on first and repeat TCD examinations, 18 patients (40.9%) had both TCDs demonstrate brief systolic spikes; three patients (6.80%) had both TCDs demonstrate brief systolic spikes and oscillating flow; eight patients (18.2%) had both TCDs demonstrate no flow; seven patients (15.9%) had both TCDs demonstrate no flow and brief systolic spikes; one patient (2.30%) had both TCDs demonstrate no flow, brief systolic spikes, and oscillating flow; and, lastly, seven patients (15.9%) had both TCDs demonstrate oscillating flow.

CONCLUSIONS

We found that requiring two sequential TCD examinations to confirm neurocirculatory arrest may be unnecessary when the first TCD shows neurocirculatory arrest. Further investigation and studies such as ours in larger populations are warranted.