Usefulness of (Tc^99m) HM-PAO scan in supporting clinical brain death in children: Uncoupling flow and function

Objective: To determine the usefulness of (Tc^99m) HM-PAO scan in supporting the clinical diagnosis of brain death. Design: Retrospective review. Setting: Paediatric Intensive Care Unit. Subjects: A total of 39 paediatric patients had HM-PAO scans conducted to confirm the presence of brain death or to assess the degree of brain injury. Interventions: All patients had (Tc^99m) HM-PAO injected before the scan was conducted. Measurements and main results: Fifty-four scans were done in 39 patients. The majority of cerebral injury was as a result of closed head injury or asphyxia/anoxia. There were 20 scans which demonstrated no cerebral blood flow (CBF); however, in 26 situations patients were clinically brain dead. All of the patients who continued to have CBF in the presence of clinical brain death sustained asphyxial/anoxic injuries. Conclusions: The HM-PAO scan is a useful non-invasive portable tool for supporting the diagnosis of brain death when there is absent CBF. However, continued flow may be present in asphyxial/anoxic injuries in the presence of clinical brain death.