Abstract

Aim: Brain death (BD) determination is a standardized process primarily based on clinical evaluation, including the apnea test, with ancillary diagnostic methods used selectively when needed. In real-world practice, discordance between clinical assessment and ancillary imaging may complicate the evaluation process. To describe real-world use of the apnea test and ancillary diagnostic methods, particularly computed tomography angiography (CTA), during the brain death evaluation process in an adult intensive care unit (ICU).
Materials and Methods: This retrospective observational study included adult patients in whom the brain death evaluation process was initiated in a single ICU between January 2022 and September 2025. Clinical records were reviewed for apnea test performance, use of ancillary diagnostic methods, CTA findings, timing of diagnostic steps, and final clinical outcomes. The primary outcome was process-level concordance between apnea test results and CTA findings.
Results: The apnea test was completed in the majority of patients. CTA was used selectively as an ancillary diagnostic method and demonstrated heterogeneous findings. In a small subset of cases, CTA findings were discordant with the clinical evaluation, and definitive brain death was not confirmed in these patients. Early imaging and altered cranial integrity were common features among discordant cases.
Conclusion: In routine ICU practice, the apnea test is feasible in most patients undergoing brain death evaluation. Ancillary diagnostic methods, including CTA, should be interpreted within the broader clinical context, particularly when discordant findings arise. These results highlight the importance of a stepwise, context-sensitive approach to brain death determination.

Key words: Brain death, death by neurologic criteria, apnea test, ancillary diagnostic tests, computed tomography angiography, intensive care unit