Ensuring Safety During Anesthesia for MRI

Some protocols to follow were suggested in the June 2002 Newsletter of the American Society of Anesthesiologists (ASA).

Many children are deeply sedated or anesthetized when having an MRI exam as are some adults. Thus, anesthesiologists are often present for the MRI exam, and they can be important for establishing systems that will minimize MRI problems. The location and method of emergence and recovery depend on the individual patient. Many anesthesiologists use propofol, because both children and adults recover quite quickly. Recovery usually takes place in the secondary anesthesia area outside the magnet room.

Only certain metals—iron, nickel, and cobalt, to name a few—are magnetic. Items made of nonmagnetic aluminum, titanium, copper, silver, and gold are safe where missile dangers are concerned and are among the materials used to make MR-compatible intravenous (IV) poles, fixation devices, and nonmagnetic anesthesia machines. If susceptible metal items such as infusion pumps must be brought into the MRI magnet room, it is safer to position those objects in the magnet room before the patient enters the magnet bore. Everyone in the magnet room, including the patient, should wear ear plugs.

When anesthesia is induced, either a trained nurse or second anesthesiologist should assist until the patient is stable inside the magnet. All physiologic monitoring devices must be MRI-compatible. If the fiberoptic pulse oximeter in the magnet room does not work, it is not possible to use a standard pulse oximeter from the outside station. Anesthesiologists in the magnet room can provide additional safety, especially if positioned near the door, by being ready to stop and check anyone who seems to be entering with metal objects. If a potentially life-threatening problem arises, it must be possible to quickly take the patient out of the magnet to the primary anesthesia station where everything is ready for optimum care.

If there is an accident and some kind of missile flies into the magnet, causing injury while pinning the patient to the inside of the bore, the superconducting magnets can be turned off immediately by the MRI technicians. Meanwhile, the anesthesiologist should be removing the patient out of the magnet. The magnet is on and the magnetic field operative only as long as the superconducting electric current is maintained.




Related Links:
American Society of Anesthesiologists