About this trial
The purpose of this research study is to better understand what causes Sudden Unexpected Death in Epilepsy (SUDEP). This study will enroll subjects from the University of Iowa Hospitals and Clinics (UIHC) Epilepsy Monitoring Unit (EMU) and Epilepsy Clinics. The investigators will analyze the effects of seizures on breathing, on the cardiovascular system, and on arousal. The investigators are studying these effects because some cases of SUDEP might be due, in part, to an inability to wake up or sense elevated carbon dioxide (CO2) levels when breathing is impaired. Subjects will be followed for ten years after enrollment to monitor their health.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
The subject is between 18 and 99 years of age.
Confirmed or suspected epilepsy.
Admission to the EMU for spell characterization (EMU group) or undergoing care in the University of Iowa Health Care Epilepsy Clinic.
Disqualifiers
History of uncontrolled cardiac, pulmonary, or hepatic disease.
Progressive or uncontrolled neurologic disease unrelated to epilepsy.
Current opioid use.
Women of child-bearing potential who are pregnant or capable of becoming pregnant (e.g. sexual activity within the past 21 days without a highly effective form of birth control or positive urine pregnancy test).
Trial design
Single group
Treatments tested in this trial
6% Carbon dioxide/50% oxygen/balance nitrogen mixture
Other interventionIn the hypercapnic ventilatory response (HCVR) test, the subject will rebreathe a gas mixture that has 6% carbon dioxide and 50% oxygen. This test has been performed for decades for research and clinical purposes. The effects of carbon dioxide inhalation are short lived and do not cause long term consequences. the hypercapnic ventilatory response (HCVR), we will have you
Treatment groups
Trial outcomes
Primary outcomes
Determine the correlation between baseline central CO2 chemosensitivity and the increase in transcutaneous CO2 levels after a seizure.
The change in HCVR slope (change in minute ventilation \[liters/min\] vs change in end tidal CO2 \[mm Hg\]) will be correlated with the increase in transcutaneous CO2 level (mm Hg) provoked by a seizure.
Determine the correlation between baseline central CO2 chemosensitivity and the duration of transcutaneous CO2 elevation above baseline after a seizure.
The change in HCVR slope (change in minute ventilation \[liters/min\] vs change in end tidal CO2 \[mm Hg\]) will be correlated with the duration (minutes) of end tidal CO2 elevation above pre-seizure baseline
Effect of seizures on HCVR slope (liters/min/mm Hg)
The percent change in HCVR slope (liters/min/mm Hg) from baseline that is induced by a seizure will be measured. The HCVR will be administered at 30 minutes, 2 hours, and 18 hours after nonconvulsive seizures. The HCVR will be administered at 2 hours and 18 hours after convulsive seizures.
Determine the stability of the HCVR slope over time in patients with epilepsy. of the HCVR over time in patients with epilepsy
The stability of the HCVR slope (liters/min/mm Hg) measured 8 months for 2 years will be assessed using a generalized linear mixed model.
Secondary outcomes
Change in respiratory rate provoked by seizures
Frequency of breaths (breaths/minute) will be measured using respiratory effort belts around the chest and abdomen
Sponsors and contacts
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University of Iowa
Lead sponsor
National Institute of Neurological Disorders and Stroke (NINDS)
Collaborator