Carbon dioxide, oxygen, and serum biomarkers after out-of-hospital cardiac arrest

Sammanfattning: Cardiac arrest is the aprupt loss of cardiac function and circulation, follwed by the loss of consciousness and breathing. Most patients succumb before admission to hospital and survivors frequently suffer from anoxic-ischemic brain injury. The number of patients who survive with good neurological outcome, is low. In this thesis, we investigated the association of abnormal arterial partial pressures of carbon dioxide and oxygen in the phase following the return of spontaneous circulation (ROSC) with neurological outcome at hospital discharge or at follow-up 6 months after out-of hospital cardiac arrest (OHCA). We also investigated the association of abnormal arterial partial pressures of carbon dioxide and oxygen in the phase following ROSC with a brain specific serum biomarker of neurological injury, as a sensitive surrogate marker for anoxic-ischemic brain injury. In a final analysis, we investigated the biomarkers of neurological injury, i.e., glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1) measured at 24, 48 and 72 hours after out-of-hospital cardiac arrest and their predictive accuracy for neurological outcome at 6-month follow-up. Exposure to abnormal arterial partial pressures of carbon dioxide and oxygen was common in resuscitated patients after OHCA, but we did not find an independent association with poor neurological outcome. Abnormal arterial partial pressures of carbon dioxide and oxygen were also not associated with peak levels of the serum biomarker tau at 48 and 72 hours, after OHCA.Serum GFAP, UCH-L1 and their combination (GFAP+UCH-L1) predicted neurological outcome after OHCA with high accuracy over all measuring points. Overall predictive accuracy of GFAP+UCH-L1 was superior compared to neuron specific enolase (NSE), the serum biomarker presently used in clinical practice