Intranasal Dexmedetomidine for Sedation During Magnetoencephalography

Magnetoencephalography (MEG) is a noninvasive tool used clinically for presurgical evaluation of patients with medically intractable epilepsy. These recordings require patients to lie still for prolonged periods of time in a magnetically shielded room. Children or uncooperative adults with epilepsy may require sedation to reduce movement artefact and obtain high-quality recordings. Potential challenges related to the use of total intravenous anesthesia in the MEG environment include limited access to the patient's airway, remote location, suppression of cortical activity, and increased patient care expenses. We report our experience with intranasal dexmedetomidine as sedation for intractable epilepsy patients undergoing MEG.

Sleep deprivation occurred the night before MEG testing. Intranasal dexmedetomidine (2 μg/kg) was administered and oxygen saturation, blood pressure, and pulse rate were recorded continuously on a monitor outside the magnetically shielded room. A recording of spontaneous neuromagnetic activity was immediately followed by median nerve electrical stimulation.

Twenty-six patients (mean age 12.2 ± 4.2 years) with medically intractable epilepsy were recorded using this protocol. There were no failures of sedation, and although patients experienced transient bradycardia, none required intervention and the recording did not need to be stopped. In all cases, artefact-free MEG recordings were obtained with sufficient interictal discharges available for source analysis.

Our experience suggests that intranasal dexmedetomidine is an advantageous sedation option for children and adults with intractable epilepsy who are undergoing MEG. Further research is needed to determine the best ways to apply these methods to younger children and those with developmental disabilities.