What would you like to know about his current anticonvulsant regimen? Is it important to know levels? Why? Would you insist on this information prior to anesthetizing him? Why or why not? If he is poorly controlled on this multimodal regimen, would you cancel the case in favor of adding another medication to hopefully improve his seizure control? What if he is not likely to improve and will require the diagnostic procedure anyway?

Is he at any increased risk for perioperative morbidity from seizures? Why?

Would you insist on an IV prior to induction or is it okay for him to undergo a mask induction with a volatile agent? Is a parent-present induction all right, or is this “too high a risk?”

What are the relevant equipment issues related to the MRI environment?

The efficacy of his anticonvulsant therapy has to be questioned. This may relate to the frequency and duration of his seizures. Grand mal seizures of the tonic-clonic variety are usually the easiest to control, particularly if they originate in a single seizure focus, but generalized tonic-clonic seizures associated with a progressive metabolic disease or complex partial seizures are more difficult to control. Multimodal therapy is often required in these circumstances. The history is important here; he may be optimally (although poorly) controlled with this regimen and yet require a diagnostic study to determine whether there is a specific focus that needs mapping, particularly if surgical resection is anticipated. Blood levels are important to obtain for a baseline, but often, pediatric patients may be optimally controlled with levels either below or above recommended ranges. In this regard, communication with the neurologist is critical because they can add to the historical perspective of the child’s treatment.

Seizure thresholds may be affected by the administration of or the withdrawal from a general anesthetic, in the first case raising the threshold and in the second case lowering it. Therefore, during emergence, the patient maybe at increased risk for a seizure. All of the general inhalation anesthetics as well as the majority of intravenous hypnotic agents are anticonvulsant. Some inhalation agents produce myoclonus or promote seizure activity in association with hyperventilation (enflurane, sevoflurane) but can also act as anticonvulsants. Methohexital, particularly in association with hyperventilation, can act as a pro-convulsant medication. Propofol is anticonvulsant. Given the multiple attempts at intravenous access, the increased stress of the patient and the likelihood that much air has been swallowed during the attempts, a parent-present inhalation induction may produce a calmer child. In a sitting to partially upright position, with the application of gentle cricoid pressure, a completely asleep child will be a much better candidate for IV placement and the completion of this induction intravenously with the use of a muscle relaxant if placement of an endotracheal tube is considered. Rather than dealing with insistence one way or the other with the parents, it is probably wiser to educate them about the various options. I would be inclined to proceed with a mask induction as outlined above, but if there were other considerations supervening, then another individual could attempt intravenous access and continue with a rapid sequence induction if, for example, active reflux was a consideration.

I would not insist on an IV prior to induction. While there is always some risk to a mask induction in this age group, it usually revolves around fear of separation and fear of the unknown. The separation can be dealt with by a parent-present induction and the fear of the unknown with a preinduction medication strategy of a rectally administered barbiturate such as thiopental (not methohexital because of its seizure-lowering potential). If crying and struggling are minimized, then the patient’s risk of preinduction seizure is lowered because of less stress and the risk of aspiration lowered because of less aerophagia.

Ferrous-containing elements of the anesthetic equipment have to be eliminated for the sake of patient safety as well as the test results. Iron-containing materials become missiles in the MRI scanner, depending on iron content and mass, but magnetic attraction obeys the inverse square law such that the closer it gets to the bore of the magnetic, the greater the attraction becomes and therefore, with greater mass, can easily become a projectile. Oxygen tanks, tables, and anesthesia machines have been “sucked into” the bore of the magnet and attest to the risks of not considering these issues with regard to patient safety. For the provider, anything in pockets that contains iron can become projectile as well, such as a stethoscope, scissors, etc. In addition, personal identification cards such as hospital ID cards and credit cards can have their information rendered useless; beepers and telephones will have their radiofrequency chips scrambled to the point of uselessness.