Brief Apnea and Hypoventilation Reduces Seizure Duration and Shifts Seizure Location for Several Hours in a Model of Severe Traumatic Brain Injury.

Abstract

ObjectiveSeizures are difficult to control in infants and toddlers. Seizures with periods of apnea and hypoventilation are common following severe traumatic brain injury (TBI). In our multifactorial, severe TBI model (cortical impact, mass effect, subdural hematoma, subarachnoid hemorrhage, seizures induced with kainic acid, and brief apnea and hypoventilation), we observed that brief apnea with hypoventilation (A&H) after induced seizure acutely interrupted seizures, leading us to hypothesize that brief A&H might reduce seizure duration beyond the brief hypoxia and hypercapnia for several hours thereafter. The effects of the timing of A&H on seizure duration and location might inform the pathophysiology of this hypoxic-ischemic injury as well as potential treatments. MethodsPiglets (1 week or 1 month old) received multi-factorial injuries. Apnea and hypoventilation (1 min apnea, 10 min hypoventilation; A&H) was induced either before or after seizure induction, or as a control piglets received subdural/subarachnoid hematoma and seizure without A&H. In an intensive care unit, piglets were sedated, intubated, mechanically ventilated, and epidural EEG was recorded for an average of 18 hours after seizure induction. ResultsIn our severe TBI model, A&H after seizure reduced ipsilateral seizure burden by 80% compared to the same injuries without A&H. In the A&H before seizure induction group, more piglets had exclusively contralateral seizures though most piglets in all groups had seizures that shifted location throughout the several hours of seizure. After 8-10 hours, seizures transitioned to interictal epileptiform discharges regardless of timing of A&H. SignificanceEven brief A&H may alter traumatic seizures We will address the possibility of induced spreading depolarization prior to preclinical investigations of hypercapnia with normoxia, with controlled intracranial pressure, as a therapeutic option for children with status epilepticus after hemorrhagic TBI.