The Food and Drug Administration is reminding providers to take precautions when conducting MRI studies of patients with implantable infusion pumps because of the potential for magnetic interference with the devices.
The FDA has received reports of serious adverse events, including patient injury and death, because patients with implantable infusion pumps haven't been properly prepped before undergoing MRI studies. Interaction between the magnets in an MRI scanner and ferrous materials within a medical device can cause medical devices to malfunction, interfere with imaging or even to be pulled towards the MRI magnets from within the patient's body, damaging tissue.
In the case of some infusion pumps, magnetic interference can force the valves of a medicine reservoir open and potentially cause a drug overdose in the patient. Implantable infusion pumps are most often used to deliver long-term treatments, such as anti-spasticity medication to cerebral palsy patients, long-term infusion of painkillers or targeted infusion of chemotherapy. They're refilled on a regular basis.
In November, Mount Olive, N.J.-based Flowonix told the U.K. Medicines and Healthcare products Regulatory Agency—the British equivalent of the FDA—that it had received reports that patients implanted with its pumps were undergoing MRI procedures in which clinicians neglected to remove medication from the pump, as recommended in the devices' instructions. The British agency's alert didn't acknowledge any specific events that may have occurred.
Facilities need to make sure that they have protocols in place that ensure the proper screening of patients to find out if they have any implants or other devices that could cause magnetic risk, said Erin Sparnon, engineering manager in the health devices group at the ECRI Institute. ECRI is a not-for-profit organization that researches medical devices and also offers accident investigation services for medical devices.
Device labels will offer three different categories for MRI safety: MR safe, MR unsafe or MR conditional, the latter meaning that the provider must take certain steps to ensure that the device can be used safely where imaging is taking place. Instructions vary across different device models and manufacturers, so it's important that technicians look into the specific steps they must take with any given device, Sparnon said.
Technicians should ask patients about pacemakers, joints, nerve stimulators, stents and many other products, Sparnon said. Even magnetic ink in some tattoos can cause an issue. Metal detectors are standard in many facilities as a final safety check before a patient enters the imaging suite.
“Hospitals need to be very careful about understanding the MR safety of each device, and nondevices too,” Sparnon said. “Simple things like chairs—everything that enters that environment.”
