FACTORS AFFECTING DEGREE OF SEDATION AFTER INTRACAROTID AMYTAL INJECTION

The intraarterial amytal procedure (IAP) is used to assess hemispheric support for language and memory. The test requires producing hemianes thesia without rendering the patient unconscious. We retrospectively s tudied factors that relate to undersedation and oversedation in the LA P in 52 patients. Initial amytal dose was 125 mg. To reduce angiograph ic risk, injections were performed only ipsilateral to the side of pla nned surgery unless injection results were unclear. Overall, 31% of pa tients were judged to be ''undersedated'' due to excessively brief dur ation of amytal response; 15% were ''oversedated'' to the point of ina ttentiveness or unconsciousness during the test. Patients with mesial temporal sclerosis (MTS) manifest on magnetic resonance imaging (MRI) were more than twice as likely to have excessive sedation as compared with patients with normal MRI results or with lesions. All patients wi th mixed dominance were oversedated (100%), and patients with nondomin ant injection were less Likely to be oversedated (4%) than patients wi th dominant injections (14%). Patients with Full-Scale IQ (FSIQ) <80 w ere more likely to be oversedated. Presence of angiographic cross-fill ing did not relate to degree of sedation. Sedation level did not predi ct surgical outcome. Knowledge of these factors may enable planning to help avoid ineffective injections and increase patient safety. (C) 19 97 by Elsevier Science Inc.