J Korean Epilepsy Soc.  2006 Jun;10(1):41-45.

Relationship between End-Tidal CO2 and Frequency of Interictal Spikes during Hyperventilation in Temporal Lobe Epilepsy

• Kim S
• Kwon OY
• Kang H
• Park KJ
• Choi NC
• Lim BH

Abstract

PURPOSE: To determine whether the change of end-tidal pCO2 (ETCO2) level by hyperventilation evokes seizures or epileptiform discharges in temporal lobe epilepsy.
METHODS
Twenty-four temporal lobe epilepsy patients were enrolled in this study. Hyperventilation was done for 5 min during EEG recording. We gathered data on ETCO2 levels during hyperventilation. The data included baseline ETCO2 (B-ETCO2), ETCO2 after 5 min of hyperventilation (5 min-ETCO2), the mean value of the ETCO2 (M-ETCO2), and the change in ETCO2 between baseline and the level after 5 min of hyperventilation (delta ETCO2). We counted the numbers of interictal spikes and considered the cases with more than 120% increments of the number during hyperventilation as the cases with the increased number of spikes. We compared the four variables between two groups, divided according to the increment to hyperventilation.
RESULTS
Seizures were not induced by hyperventilation in all the cases. Thirteen of 24 patients were in the increment group. The M-ETCO2 was 33.0+3.3 mmHg (mean+SD) in the increment group and 29.4+5.3 in the no-increment group (p=0.064). The delta ETCO2 was 13.0+5.3 and 14.0+5.3, respectively (p=0.622). The 5 min-ETCO2 was 28.2+4.8 and 24.8+5.9, respectively (p=0.077).
CONCLUSION
In this study, the frequency of interictal spikes was increased well by hyperventilation. The spike increments were not associated with the ETCO2 level or the change of that, but maybe with the individual susceptibility.

Keyword

Hyperventilation; Temporal lobe epilepsy; Carbon dioxide

MeSH Terms

Carbon Dioxide
Electroencephalography
Epilepsy, Temporal Lobe*
Humans
Hyperventilation*
Seizures
Temporal Lobe*
Carbon Dioxide