Abstract
During the intracarotid amobarbital procedure (IAP) at the University of
Michigan, continuous scalp EEG monitoring guides the timing for
presentation of memory items and post-injection testing. Most of our
patients have undergone bilateral injections. The interval between
injections varied from 22 to 60 minutes depending on the test and recovery
time, as well as the time to catheterize the second side. After noting a
trend toward prolonged electrographic recovery following the second
injection, we tested our clinical impression that recovery of the second
hemisphere may be influenced by 1) the time between injections and 2)
which hemisphere is injected first (epileptogenic or nonepileptogenic).
To study these questions, we analyzed EEG recovery data from 48
consecutive IAPs. Approximately half the patients had the epileptogenic
side injected first. We found that 1) electrographic recovery after the
second injection is prolonged if the interval between bilateral injections
is less than 40 minutes and 2) electrographic recovery is more rapid after
injection of the epileptogenic hemisphere. We now recommend waiting at
least 45 minutes between injections. The pathophysiology of more
prolonged amobarbital effect on the nonepileptogenic hemisphere than on
the epileptogenic hemisphere remains unclear.
Selwa, L.M., Buchtel, H.A. and Henry, T.R. (1997)
Electrocerebral
recovery during the intracarotid amobarbital procedure: Influence
of interval between
injections. Epilepsia. 36:1294-1299
http://www-personal.umich.edu/~gusb/selwa1.html