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We’ve done many columns on things that can go wrong while patients are in the radiology suite or the MRI suite. The MRI suite, in particular, presents special challenges for those responding to unanticipated events. That is the reason that training and simulation exercises are so important in preparing all staff for such events.
One such event is the airway emergency occurring in a patient in the MRI suite. Patients undergoing MRI often have multiple acute medical conditions plus comorbidities that may place them at risk for events during MRI. Many of the inpatients are receiving opiates or other drugs that may depress respiration. Add to that the fact that many patients are given sedation before undergoing MRI because of claustrophobia and it should be no surprise that airway emergencies happen in the MRI suite.
Anesthesiologists McClung and Subramanyam (McClung 2020) addressed airway emergencies in the MRI suite in a recent issue of the APSF (Anesthesia Patient Safety Foundation) Newsletter. They begin with a discussion about the importance of understanding the MRI environment is divided into four Zones designated I through IV, with Zone IV being the MRI scanner magnet room. They stress that the MRI magnetic field is “invisible, always on, and can affect ferromagnetic equipment of any size in Zone IV, potentially converting it to a projectile that is drawn into the scanner with a strength and speed that can be deadly”. They also note that, in addition to risks to humans, damage to equipment can occur from such events. (You may recall in our January 7, 2010 Patient Safety Tip of the Week “Even More Concerns About MRI Safety” we noted a Swedish study showing that material injuries were more common than actual human injuries in MRI projectile incidents but the potential for serious human harm was very high).
They then discuss equipment issues, noting that very few airway devices have been specifically designed for safe use in MRI. Medical devices and equipment that might be used in the MR environments should be labelled as MR unsafe, MR conditional, or MR safe. Some laryngeal mask airways and endotracheal tubes contain small amounts of ferromagnetic material but may be designated “MR conditional” because, while they might affect image quality, they are not likely to cause patient harm. Those airway devices have been used safely along with plastic oropharyngeal airways and bag mask ventilation units. But they stress that classic metal laryngoscopes are considered unsafe as malfunction with sudden failure to operate can occur in Zone IV and nickel in the laryngoscope battery is ferromagnetic. Instead, single-use or reusable “MRI-conditional” devices should be used. (Some such devices are expensive but cost considerations would pale compared to costs of a malpractice settlement related to using MR-unsafe devices.)
Next, they stress process and procedures, relying heavily on the most recent update of the ASA practice advisory on anesthetic care for magnetic resonance imaging (ASA 2015). That stresses that, during an airway emergency, anesthesia professionals and other health care providers must be prepared to enter Zone IV quickly. The advisory states that “Alternative MRI safe/conditional airway devices should be immediately available in the MRI suite.” Personnel must recheck themselves for presence of ferromagnetic objects and equipment prior to entering the scanner. That is where we think it’s important for the MRI staff to serve as “traffic cops” during that emergency to enforce checking for ferromagnetic objects. The practice advisory states that airway equipment immediately available to the team in Zone III should be MR-conditional for all scanners in the location. “If it is safe, the airway should be supported with bag mask ventilation while the patient is removed from Zone IV to a nearby location in Zone III or Zone II where a full complement of airway and resuscitation equipment can be used and emergency personnel summoned for help.”
We think it is critical that every facility performing MRI imaging conduct drills and simulations so that all staff responding to an event in the MRI suite are aware of the hazards and know how to properly respond in a manner safe to all. That can be especially problematic in academic medical centers where hew housestaff are continually rotating in and out or in small community or rural facilities where locum tenens or temporary staff are being used. In such circumstances, it is crucial that their initial orientation to the facility include education about the hazards of the MRI suite.
This is actually a good topic for a FMEA (failure mode and effects analysis). You need to ask questions about availability of MR-safe equipment in the MRI suite, what training responding staff are likely to have had, how MRI staff are deployed to help those responders avoid safety issues as they arrive, and others.
Some of our prior columns on patient safety issues related to MRI:
McClung H, Subramanyam R. Airway Emergencies and Safety in Magnetic Resonance Imaging (MRI) Suite. APSF Newsletter 2020; 35(1): 10-11 February 2020
ASA (American Society of Anesthesiologists). Practice advisory on anesthetic care for magnetic resonance imaging: an updated report by the American Society of Anesthesiologists task force on anesthetic care for magnetic resonance imaging. Anesthesiology 2015; 122: 495-520