Enduring Disturbances in Regional Cerebral Blood Flow and Brain Oxygenation at 24 Hours after Asphyxial Cardiac Arrest in Developing Rats

BACKGROUND: Disturbances in cerebral blood flow (CBF) and brain oxygenation (PbO(2)) are present early after pediatric cardiac arrest (CA). CBF-targeted therapies improved neurological outcome in our CA model. To assess the therapeutic window for CBF- and PbO(2)-targeted therapies, we propose to determine if CBF and PbO(2) disturbances persist at 24 h after experimental pediatric CA. METHODS: Regional CBF and PbO(2) were measured at 24 h after asphyxial CA in immature rats (n=26, 6–8/group) using arterial spin label MRI and tissue electrodes, respectively. Results. In all regions but the thalamus CBF recovered to sham values by 24 h; thalamic CBF was >32% higher after CA vs. sham. PbO(2) values at 24 h after CA in cortex and thalamus were similar to shams in rats who received supplemental oxygen, however, on room air, cortical PbO(2) was lower after CA vs. shams. CONCLUSION: CBF remains increased in the thalamus at 24 h after CA and PbO(2) is decreased to hypoxic levels in cortex at 24 h after CA in rats who do not receive supplemental oxygen. Given the enduring disturbances in this model and the lack of routine CBF or PbO(2) monitoring in patients, our data suggest then need for clinical correlation.