Abstracts

Rationale: Hypoxemia with partial seizures has been reported in small series of patients. Methods: We systematically studied 30 consecutive patients with localization-related epilepsy admitted for inpatient video-EEG telemetry. Respiratory parameters, including pulse oximetry data, were recorded synchronized with EEG, video and the electrocardiogram. Anticonvulsant medications were reduced during the hospitalization.Results: Twenty-one of 30 patients had oxygen desaturations below 90% during one or more seizures. Oxygen desaturations with partial seizures alone or with partial seizures before onset of secondary generalization were studied. 134 seizures were recorded, 39 of which had associated oxygen desaturations. The mean desaturation nadir was 79.4% (range <50% to 89%). The mean lag from seizure onset to desaturation below 90% was 70.1 seconds. The mean duration of desaturation was 85.6 seconds. There was no statistical difference in the duration of seizures with desaturations (mean 98 seconds) compared with seizures with no desaturation (mean 93 seconds). Temporal lobe localization was most common (left 9 seizures; right 17 seizures). Nine patients had no desaturations with any of 52 seizures. The mean duration of seizures was 66 seconds (range 13-366 seconds). Temporal lobe localization was most common (left 7 seizures; right 21 seizures). There was no significant difference in mean age, 35.6 years (16-62 years) compared with 41.2 years (18-62), or body mass index, 24.6 (SD 5.4) compared with 22.3 (SD 2.9), between the two groups. Conclusions: Hypoxemia commonly occurs in association with partial seizures and may be pronounced. Seizure-related hypoxemia may be a factor in sudden unexplained death in epilepsy.