Circulation 107,515 • Volume 27, No. 2 • Fall 2012   Issue PDF

MRI-Compatible Handle and Blades

Edward D. Hon, MD

A Dear Q&A,

Would you consider having an MRI-compatible laryngoscope handle and blades necessary, or merely desirable, for safe administration of LMA anesthesia to children aged 2 to 12 years? Are MRI-compatible handle and blades necessary for administering deep propofol sedation to children aged 2 to 12 with natural airways?

Edward D. Hon, MD
Kamuela, Hawaii

A Dear Dr. Hon,

As is well known, a satisfactory airway may transition to a failed airway for any number of reasons at any time. Every anesthesia professional should have the ability to intubate with a laryngoscope when planning LMA anesthesia. While there may be concern over the expense of purchasing equipment that may be used infrequently, if at all, it is insurance that an unusual event may be handled with a high degree of patient safety.

A complete set of MRI-compatible laryngoscopes in a box including handle, blades, and batteries is available for purchase from several manufactures of laryngoscopes and MRI-compatible accessories. MRI Non-Magnetic Lithium Laryngoscope Batteries are an equally important consideration. Traditional batteries inside the magnetic field may become depleted quickly and can be drawn into the magnet.

Another useful addition to your MRI suite would be a policy for how to handle a failed airway or a cardiac arrest in the MRI suite. The basis for a policy may be constructed considering the following:

The area where the MR scanner is housed is divided into 4 safety zones in accordance with the ACR Guidance for Safe MR Practices: 2007.

  • Zone 1 includes all areas freely accessible to the general public, which may be an anesthesia induction room or simply the corridor outside the MRI Suite. Conventional equipment can be used in Zone 1.
  • Zone 2 indicates the interface between publicly-accessible uncontrolled Zone 1 and the restricted Zones 3 and 4. The MRI screening room where participants are greeted and screened before entering the scanner room is Zone 2.
  • Zone 3 is the region in which free access by unscreened non-MR personnel or ferromagnetic objects or equipment can result in serious injury or death. Zone 3 is highly restricted. The MRI Console Room and MRI Equipment Room are Zones 3a and 3b, respectively.
  • Zone 4 is synonymous with the MR scanner itself, that is, the physical confines of the room within which the MR scanner is located. Zone 4, by definition, will always be located within Zone 3 as it is the MR magnet and its associated magnetic field that generates the existence of Zone 3.

In the event of a respiratory or cardiac arrest, or other emergency within Zone IV for which medical intervention or resuscitation is required, the patient should be emergently removed from Zone IV to a predetermined magnetically safe location. This is in consideration of the chaos that can accompany a rescue effort and could easily lead to someone bringing a metal object into Zone 4 inadvertently. An appropriate patient stretcher can be placed in the MRI scanner room to facilitate rapid transport of the patient to a lower zone for resuscitation if needed.

MRI-compatible laryngoscope handle and blades can be kept in the MRI control room for emergencies where a patient would need to be intubated in the scanner. MRI-compatible laryngoscopes, blades, and batteries can be used in Zone 4. There is real value to having an MRI-compatible laryngoscope available, because it creates a comfort level for the anesthesia providers who feel they have an option for managing an airway in Zone IV if needed. It also creates a comfort level for the MRI techs who are responsible for insuring that safety of the MRI environment. If establishing an airway must be done in either Zone 4 or Zone 3, the compatible laryngoscope provides a greater measure of patient safety and comfort for all involved.

Reference

  1. Kanal E, BarkovichAJ, Bel C, et al. ACR guidance document for safe MR practices: 2007. Am J Roentgenol 2007;188:1447-74.

The APSF Committee on Technology

Numerous questions to the Committee on Technology are individually and quickly answered each quarter by knowledgeable committee members. Many of those responses would be of value to the general readership, but are not suitable for the Dear SIRS column. Therefore, we have created this simple column to address the needs of our readership.

The information provided is for safety-related educational purposes only, and does not constitute medical or legal advice. Individual or group responses are only commentary, provided for purposes of education or discussion, and are neither statements of advice nor the opinions of the APSF. It is not the intention of the APSF to provide specific medical or legal advice or to endorse any specific views or recommendations in response to the inquiries posted. In no event shall the APSF be responsible or liable, directly or indirectly, for any damage or loss caused or alleged to be caused by or in connection with the reliance on any such information.