Abnormal Ventilatory Response to Carbon Dioxide: a Potential Biomarker for Seizure Induced Respiratory Depression & Modification by SSRI

Sudden unexpected death in epilepsy patients (SUDEP) is devastating outcome for some patients with epilepsy. It ranks second only to stroke among neurological diseases in years of potential life lost. Patho-mechanisms of SUDEP remain not well understood, however peri-ictal respiratory dysfunction likely plays an important role in many cases. Literature supports a critical role for the serotonergic system in central control of ventilation. Serotonin neurons in the raphe nuclei of the brainstem sense rising carbon dioxide and low pH, thereby stimulating breathing and arousal. These responses may serve as mechanisms that protect against asphyxia, particularly during sleep or the post-ictal state. In mouse models of seizure-induced sudden death, pre-treatment with selective serotonin reuptake inhibitor (SSRI) agents prevents death following seizures. Hence, the investigators hypothesize that a subset of drug resistant epilepsy patients who have impaired central chemo-responsiveness have a greater degree of peri-ictal respiratory depression, therefore a higher risk of SUDEP. The investigators further hypothesize that fluoxetine will improve central chemo-responsiveness and therefore will reduce peri-ictal respiratory depression.