Pre-oxygenation and Measures of Gas Exchanges During Seizures in the Epilepsy Monitoring Unit

The primary goal of the study is to assess the effect of pre-oxygenation on oxygen and carbon dioxide levels during seizures in patients admitted at the Epilepsy Monitoring Unit (EMU). The investigators hypothesize that providing oxygen prior to seizures will help eliminate the drops in changes seen during seizures, such as the drop in oxygen saturation and increase in carbon dioxide levels. Research will be done on patients that are admitted to the EMU specifically to have seizures occur and to be recorded on video electroencephalography (vEEG), and the only research intervention will be the use of oxygen prior to some of the seizures. The importance of this research relates to the phenomenon of sudden unexplained death in epilepsy patients (SUDEP). SUDEP cases are typically patients with epilepsy who are found dead by their families in the morning, without a clear cause for death. The risk of SUDEP is as high as 9.3 per 1000 person-years (Shorvon and Tomson 2011). There may be multiple mechanisms for SUDEP to occur, however a leading hypothesis is a decrease in ventilation during the seizure leading to hypoxia. Blood oxygen saturation levels have been found to decrease significantly in 25-50% of patients during or shortly after a seizure while being monitored in hospitals. In rare situations, a significantly lowered oxygen level may trigger a cascade of events from which the body may not be able to recover, leading to SUDEP. In animal models, providing oxygen prior to seizures occurring has been shown to eliminate oxygen desaturation, but more importantly eliminate mortality in animals prone to death due to seizures. Pre-oxygenation is a standard procedure during rapid-sequence induction anesthesia as it reduces the risk of oxygen desaturation during the apneic period of the procedure. On room air, the estimated duration of safe apnea is 1 minute, but this can increase to 8 minutes following pre-treatment with high FiO2 (Weingart and Levitan 2012). This is prim