Intracarotid etomidate is a safe alternative to sodium amobarbital for the Wada test

The Wada procedure (the intracarotid amobarbital procedure) has been used widely to evaluate the hemispheric dominance of language and memory before temporal lobe surgery in patients with medically refractory seizures. Because of repeated shortage of sodium amobarbital, attempts have been made to find a suitable alternative to sodium amobarbital. The aim of our study was to review our experience with the use of etomidate as an alternative to sodium amobarbital for Wada testing in patients with medically refractory seizures.

After the ethics approval, we retrospectively reviewed the charts of 29 consecutive patients who underwent Wada test with etomidate. Data from a total of 50 hemispheric injections were reviewed and analyzed. This included the electroencephalographic and motor effects of etomidate injection and their time course (onset and recovery), Wada test results (language laterality and memory performance), and all adverse events during the procedure.

Intracarotid administration of etomidate produced a predictable electroencephalographic and motor effects in all patients. The desirable effect was seen with a single bolus dose of 2 mg followed by an infusion. Shivering was the most common side effect, seen in all the patients. Successful testing was possible in nearly all patients without any major side effects. The "pass rate" of valid tests was in good accord with our previous experience with the use of sodium amobarbital.

From our experience, etomidate is a safe alternative to sodium amobarbital for the Wada test for determining the hemispheric dominance for speech and in predicting the memory outcome.