There are several anesthetic concerns for magnetic resonance imaging (MRI). Anesthesia providers in general do not like to go anywhere outside of our domain, the operating room (OR), to provide anesthetics. In fact, for years now at our institution, we have called it “going on safari.” However, anesthetic provision in remote locations is becoming more and more common as increasing numbers of therapeutic and diagnostic procedures are performed outside of the OR. Complicated procedures require akinesis, often for long periods, as well as life support and even resuscitation, and the best and safest way to meet those needs is with anesthetic care.
Besides being out of our comfort zone, such remote locations can be difficult places to provide anesthesia, owing to room size, darkness, a lack of knowledge by hospital staff as to our needs, provision of medical gases, suction, and the like. On top of that the environment can be potentially hazardous, owing to different types of radiation, so hazardous that we must sometimes monitor the patient from another area by video monitoring.
In the case of MRI, we must deal with issues of anesthesia equipment concerns. Not all anesthesia equipment is “MRI safe”; that is, equipment made from ferromagnetic material can not only interfere with the quality of the MRI image but also damage the patient, personnel, or equipment if it is in the magnetic field of the MRI, causing the equipment to become a projectile. Incidents during which gas cylinders, for instance, along with other pieces of metallic items that may have made their way into the MRI room itself have commonly been reported as causing patient injury, even death, from the great pull of the MRI magnet. In addition to injury from objects flying into the magnetic field causing injury, burns to the patient can also occur from the use of standard monitoring cables, pads, and probes.
So how can we actually monitor a patient in the MRI suite? Fortunately, there is anesthesia equipment and monitoring that is available that will minimize any chance of patient injury, and also not interfere with the MRI image. The purpose of this chapter is not to discuss techniques of providing anesthesia for MRI, but to show how this specialized equipment is “MRI compatible.”
The simplest way to provide ventilation to a patient undergoing an MRI is with spontaneous ventilation. A bag valve mask (BVM) can be used to provide positive-pressure ventilation by an endotracheal tube or supraglottic device; masking a patient in an MRI would prove difficult because of access problems. Of course, if using a BVM, the operator would need to remain in the MRI room itself along with the patient. Although no adverse health effects from magnetic waves have been discovered, it is perhaps prudent ...