Grant: Project Grant

Cardiac arrest, an entity where the heart stops beating, results in a brain insult called hypoxic ischemic brain injury (HIBI). HIBI occurs from a lack of blood and oxygen supply to the brain when the heart has stopped. beating. HIBI is the main determinant of clinical outcome in patients who have been resuscitated from cardiac arrest. After returning function of the heart, HIBI can continue to occur from insufficient supply of oxygen to the brain, namely from post-resuscitation low blood pressure and low blood oxygen levels. Conventionally, management guidelines have recommended increasing post-resuscitation blood pressure and blood oxygen levels; however, the clinical neurological outcomes in HIBI survivors remain poor. This discrepancy suggests there are gaps in our understanding of this complex disease. Recently, our research group has demonstrated that there appear to be distinct patterns of HIBI patients with respect to how well their brains utilize oxygen. For example, half of HIBI patients are dependent upon increasing blood pressure to achieve improved brain oxygenation and function. The other half of HIBI patients do not appear to be able utilize oxygen normally no matter how much clinicians increase blood pressure or blood oxygen levels. Differentiating between these types of HIBI patients in real time is imperative to identify patients who may especially benefit from interventions aimed at increasing blood pressure and blood oxygen levels. As such, we are proposing a prospective study of HIBI patients using brain monitoring techniques to differentiate these phenotypes in real time. We are attempting to link non-invasive methods of assessing the brain to predict these two patient groups. These non-invasive methods include MRIs of the brain, blood tests that reflect dysfunction in the brain and ultrasound techniques aimed at measuring the brain's blood flow.