The time of computed tomography angiography strongly determines the sensitivity of this imaging technique in the assessment of cerebral circulatory arrest during death by neurological criteria diagnosis procedure
Romuald Bohatyrewicz1, Lidia Wiska2, Łukasz Zwarzany3, Katarzyna Chamier-Ciemińska3, Ewa Trejnowska4, Joanna Sołek-Pastuszka 1, Klaudyna Kojder1, Filip Szeremeta5, Wojciech Walas6, Wojciech Poncyljusz 3, Marcin Sawicki3.
1Department of Anaesthesiology and Intensive Care, Pomeranian Medical University in Szczecin, Szczecin, Poland; 2Tytus Chalubinski Hospital, Ostrów Wielkopolski, Poland; 3Department of Diagnostic Imaging and Interventional Radiology, Pomeranian Medical University in Szczecin, Szczecin, Poland; 4Clinical Department of Cardiac Anesthesia and Intensive Therapy, Silesian Centre for Heart Diseases , Medical University of Silesia, Katowice, Poland; 5Department of Anaesthesiology and Intensive Therapy, Silesian Hospital in Cieszyn, Cieszyn, Poland; 6Department of Anaesthesiology and Intensive Care, Institute of Medical Science, University of Opole, Opole, Poland
Introduction: Computed tomography angiography (CTA) is progressively implemented into national guidelines for the determination of death by neurological criteria (DNC). Unfortunately, this method is not accepted worldwide due to the reports of its various and sometimes low sensitivity.
Our clinical observations suggest that the time interval between the appearance of basic brainstem areflexia (BBA) and carrying out of CTA might be the major factor affecting the sensitivity of this imaging technique. The aim of the study was to verify the impact of the time interval between BBA and CTA on the sensitivity of this imaging technique applied for the confirmation of Cerebral Circulatory Arrest (CCA) during DNC determination procedures.
Methods: According to the Polish guidelines standard CTA with 4-point scale evaluation is used for CCA diagnosis. Appearance of first DNC symptoms is defined as BBA which includes pupils dilation, absence of reaction to light, as well as absence of cough and vomiting reflexes. Apnea test is not performed at this stage of the diagnostic procedure.
A group of 118 patients was selected out of 135 patients undergoing DNC determination including CTA. Seventeen patients were excluded due to incomplete data, especially because of difficulties in the precise identification of the time of BBA appearance. Time intervals between the appearance of BBA and “first attempt” CTA were divided as follows: 0-6 hours, >6-12 h, >12-18 h, >18-24 h and >24 h. In 15 patients with persisted cerebral blood flow in the “first attempt” CTA, the imaging was repeated (“second attempt” CTA), usually the next day.
Results: The results are summarized in the table. During the “first attempt” CTA sensitivity was 87.3% and later, after delayed repetition in primarily negative cases it reached 88.7%. The highest sensitivity of the “first attempt” CTA was observed after twelve hours delay after the appearance of BBA.
Conclusion: Results of our study indicate clear points of diagnostic procedure required for DNC determination. Delay of at least twelve hours after the appearance of BBA seems to be the optimal time for CTA test during DNC diagnosis procedure. In clinical practice very similar time is necessary to conduct all other diagnostic procedures, as the appearance of BBA is usually followed by a few hours observation needed for the sedatives to be eliminated, and thereafter two series of clinical tests have to be carried out. Total time for these diagnostic procedures is rarely below 12 hours.
