Anesth Analg 2000;90:142
© 2000 International Anesthesia Research Society
REGIONAL ANESTHESIA AND PAIN MANAGEMENT
The Anticonvulsant Effects of Volatile Anesthetics on Penicillin-Induced Status Epilepticus in Cats
Kohei Murao, MD,
Koh Shingu, MD,
Koichi Tsushima, MD,
Kazuyo Takahira, MD,
Sakahiro Ikeda, MD,
Hideo Matsumoto, MD,
Shin-ichi Nakao, MD, and
Takashi Asai, MD, PhD
Department of Anesthesiology, Kansai Medical University Hospital, Moriguchi, Osaka, Japan
Address correspondence and reprint requests to Koh Shingu, MD, Department of Anesthesiology, Kansai Medical University Hospital, Fumizono-cho 1015, Moriguchi, Osaka 570-8507, Japan. Address e-mail to shingu{at}takii.kmu.ac.jp
Volatile anesthetics may be used to treat status epilepticus when conventional drugs are ineffective. We studied 30 cats to compare the inhibitory effects of sevoflurane, isoflurane, and halothane on penicillin-induced status epilepticus. Anesthesia was induced and maintained with one of the three volatile anesthetics in oxygen. Penicillin G was injected into the cisterna magna, and the volatile anesthetic discontinued. Once status epilepticus was induced (convulsive period), the animal was reanesthetized with 0.6 minimum alveolar anesthetic concentration (MAC) of the volatile anesthetic for 30 min, then with 1.5 MAC for the next 30 min. Electroencephalogram and multiunit activity in the midbrain reticular formation were recorded. At 0.6 MAC, all anesthetics showed anticonvulsant effects. Isoflurane and halothane each abolished the repetitive spike phase in one cat; isoflurane reduced the occupancy of the repetitive spike phase (to 27% ± 22% of the convulsive period (mean ± SD) significantly more than sevoflurane (60% ± 29%; P < 0.05) and halothane (61% ± 24%; P < 0.05), and the increase of midbrain reticular formation with repetitive spikes was reduced by all volatile anesthetics. The repetitive spikes were abolished by 1.5 MAC of the anesthetics: in 9 of 10 cats by sevoflurane, in 9 of 9 cats by isoflurane, and in 9 of 11 cats by halothane. In conclusion, isoflurane, sevoflurane, and halothane inhibited penicillin-induced status epilepticus, but isoflurane was the most potent.
Implications: Convulsive status epilepticus is an emergency state and requires immediate suppression of clinical and electrical seizures, but conventional drugs may be ineffective. In such cases, general anesthesia may be effective. In the present study, we suggest that isoflurane is preferable to halothane and sevoflurane to suppress sustained seizure.
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S. K. Jaaskelainen, K. Kaisti, L. Suni, S. Hinkka, and H. Scheinin
Sevoflurane is epileptogenic in healthy subjects at surgical levels of anesthesia
Neurology,
October 28, 2003;
61(8):
1073 - 1078.
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