Wireless Chips: a Threat to Hospital Patients?

Certain Tags on Medical Supplies May Interfere With Pacemakers, Other Medical Devices


June 24, 2008—

A type of device commonly used on tracking tags for medical supplies could cause potentially dangerous interference with critical care medical devices — including pacemakers — new research suggests.

A study published Tuesday in the Journal of the American Medical Association finds that radio frequency identification (RFID) tags, which are often used to track medical supplies and devices, may interfere with the functioning of some medical devices and could potentially cause serious harm to a patient utilizing a critical care device.

This study highlights the dangers that can be associated with otherwise beneficial technological developments, says study author Dr. Donald Berwick, professor in the Department of Health Policy and Management at Harvard University's School of Public Health.

"The study highlights the fact that we really need our healthcare system to understand technologies are always double-edged," Berwick explained. "They can bring benefit but usually also have concurrent hazards, so we need to be sophisticated and wise about these technologies and how we use them."

The RFID tags used to track medical supplies are similar to the security tags attached to clothing in stores, or those used for security access cards. The tags generate signals with radio frequencies to "communicate" with one another.

Researchers at Vrije University in Amsterdam tested 41 critical care medical devices, including pacemakers, ventilators, IV pumps and anesthesia machines, among others. They moved three types of RFID tags from two different manufacturers around each device at different distances to detect the point at which the machine malfunctioned, if at all.

Out of 123 tests, they detected 34 instances in which interference had occurred. After an interference issue was detected, the researchers asked five intensive care doctors to qualify the interferences as minor, moderate, or severely hazardous to a patient who might be using the machine.

Of the 34 interference issues identified, the independent panel of intensive care doctors classified 22 of the interferences as hazardous.

Berwick added that although this research has identified a serious potential hazard with this technology in the healthcare setting, he would not recommend that the use of RFID tags in hospitals be discontinued.

"This was studied in an ICU room with no patients, so I think there should be immediate further study to see if the kind of interference they detected is replicable and if it could it hurt patient outcomes," Berwick said. "I think it would be overreacting to turn off the [RFID tags] or remove them from Intensive Care Units."

A Ubiquitous Threat?

Indeed, the looming question mark left by this research is how damaging the RFID tag's interference with medical devices can be to a patient, and whether patients utilizing these medical devices should be wary of coming too close to the nearly unavoidable RFID tags.

Although the most common use of RFID tags is to improve the tracking of inventory for a business or manufacturer, the tags seem to have crept into almost every imaginable place in our society: from our passports, to our tollbooths, to our library books and our bus passes, the RFID tags surround our day-to-to lives.

But what if a heart patient who has an implanted defibrillator tries on a t-shirt in a clothing store that has an RFID security tag attached to it? Would the radio waves emitting from the tag cause enough interference to make the implanted device would malfunction?

These are questions that most experts say we just don't have the answers to yet.

"It really depends on the power generated by the device causing the interference," said Dr. John Halamka, chief information officer of Harvard Medical School and of Beth Israel Deaconess Medical Center in Boston. "And unfortunately, in some cases with certain devices, we don't really know what kind of interference they could cause to a machine being used by a patient."

However, experts say it is important to distinguish between passive RFID tags and active RFID tags.

Passive tags are more commonly used in hospital settings, and because they have no internal power supply, they are less likely to interfere with many devices. These RFID tags require a "reader" device to detect their radio wave emissions, such as when an RFID wristband on a hospital patient is scanned by a "reader" machine.

Active tags, however, do contain internal power supplies and constantly broadcast their signal to a reader. These types of RFID tags are more likely to emit radio waves that can interfere with medical devices.

Today, RFID tags are used to track medications, medical equipment, and sometimes even patients within a hospital.

For instance, Beth Israel Deaconess Medical Center uses passive RFID tags to track babies in the neonatal intensive care unit by way of RFID wristbands. Each baby's RFID wristband corresponds to an RFID tag on the container his or her mother's milk. This way, the RFID scanner is used to ensure that the infant receives the right milk, and even leaves a traceable audit trail.

But because the use of RFID tags in the hospital setting has gone from "hardly at all" to "couldn't survive without them" in a relatively short period of time, many experts are wondering what concurrent risks might be associated with the widespread use of the technology.

Some Hospitals Taking Steps

In order for the RFID-dependent healthcare system to work, Halamka says the proper precautions must always be taken.

In 2001, the Beth Israel Deaconess Medical Center instituted a policy requiring that all hospital workers are trained on the potential interferences caused by RFID devices. Moreover, they require that all devices generating electromagnetic interference be kept at least three feet away from patients.

Halamka added that certain critical care devices are even shielded so as to avoid any potential interference by a device emitting radio or electromagnetic waves. Moreover, hospital workers in the Clinical Engineering Group at Beth Israel are constantly testing any new device that enters into the hospital to make sure that it doesn't interfere with existing equipment used for patient care.

However, the Beth Israel Deaconess Medical Center seems to be far ahead of the curve when it comes to preemptive precautions against any interference to medical devices caused by RFID tags; very few other medical centers have instituted any policies to protect from interference caused by these tags.

Dr. Richard O'Brien, an emergency physician at Moses Taylor Hospital in Scranton, Penn., and the spokesperson for the American College of Emergency Physicians, believes that the policies at Beth Israel should be the standard for medical centers around the country.

"I believe the message is … that in the critical care environment, we have to have on site testing and follow international standards," O'Brien said.