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Respiratory changes with seizures in localization‐related epilepsy: Analysis of periictal hypercapnia and airflow patterns
Author(s) -
Seyal Masud,
Bateman Lisa M.,
Albertson Timothy E.,
Lin TzuChun,
Li ChinShang
Publication year - 2010
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1167.2009.02518.x
Subject(s) - ictal , anesthesia , apnea , epilepsy , medicine , electroencephalography , hypoxemia , respiratory arrest , respiratory system , respiratory rate , heart rate , blood pressure , psychiatry
Summary Purpose: The rate of sudden unexpected death in epilepsy (SUDEP) approaches 9 per 1,000 patient‐years in patients with refractory epilepsy. Respiratory causes are implicated in SUDEP. We reported that ictal hypoxemia occurs in one‐third of seizures in localization‐related epilepsy. We now report on respiratory changes in the ictal/postictal period including changes in end‐tidal CO 2 (ETCO 2 ) that correlate directly with alveolar CO 2 , allowing a precise evaluation of seizure‐related respiratory disturbances. Methods: One hundred eighty‐seven seizures were recorded in 33 patients with localization‐related epilepsy, with or without secondarily generalized convulsions, undergoing video‐electroencephalography (EEG) telemetry with recording of respiratory data. Results: The ictal/postictal ETCO 2 increase from baseline was 14 ± 11 mm Hg (11, −1 to 50) [mean ± standard deviation (SD) (median, range)]. ETCO 2 peak was at or above 50 mm Hg with 35 of 94 seizures, 60 mm Hg with 15, and 70 mm Hg with five seizures. Eleven of the 33 patients had seizures with ETCO 2 elevation above 50 mm Hg. The duration of ictal/postictal ETCO 2 increase above baseline was 424 ± 807 s (154, 4 to 6225). The duration of ictal apnea was 49 ± 46 s (31, 6–222); most ictal apneic events were central. Oxygen desaturation to 60% or less occurred with 10 seizures, including five that did not progress to generalized convulsions. Respiratory rate and amplitude increased postictally. The peak ictal ETCO 2 change and duration of change were not associated with apnea duration or seizure duration. Peak ETCO 2 change was significantly associated with contralateral seizure spread. Conclusions: Severe and prolonged increases in ETCO 2 occur with seizures. Postictally, respiratory effort is not impaired. Ictally triggered ventilation–perfusion inequality from pulmonary shunting or transient neurogenic pulmonary edema may account for these findings.