医療機器に危険な無線ICタグ /RFID

 医療用のサプライ品に使用されている無線追跡タグRFIDが、ペースメーカーを含めた医療機器に潜在的に危険な干渉を起こす可能性があるとの報告がされた。
 アムステルダムのVrije大学の研究者はペースメーカー、通風機、輸液ポンプ、および麻酔機器を含む41個の集中治療医療機器をテストした。123のテストで34例が干渉が見られた。34のうち22が危険な干渉と判定された。
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Wireless Chips: a Threat to Hospital Patients?
Certain Tags on Medical Supplies May Interfere With Pacemakers, Other Medical Devices
By AUDREY GRAYSON June 24, 2008
http://abcnews.go.com/Health/HeartDiseaseNews/story?id=5237036&page=1

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.

画像wi-fi
New research suggests certain microchips used for tracking of medical supplies could interfere with hospital and medical equipment.
(ABC News Photo Illustration)

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.

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Page last updated at 23:47 GMT, Tuesday, 24 June 2008 00:47 UK
'Hospital risk' from radio tags

画像Ventilator
Ventilators could potentially be affected

Lifesaving equipment in hospitals may be switched off by radio-frequency devices used to track people and machines, Dutch scientists claim.

Radio frequency identification devices (RFIDs) are on the rise in healthcare, helping identify patients, and reveal the location of equipment.

The Journal of the American Medical Association study found they could interfere with machines.

But NHS computer specialists said RFIDs could eventually make patients safer.


Even the most seductive technology will interact in the tightly-coupled healthcare world in ways physicians and other members of the healthcare team had better understand, or they and their patients may pay a dear price
Dr Donald Berwick
Institute for Healthcare Improvement

There are two types of RFID, one which transmits information, and another, "passive", device which can be "read" by a powered machine when it is held nearby.

They are small and cheap enough to be in everyday use in society, in everything from security and travel cards - such as London Transport's Oystercard, to anti-theft devices on goods in shops, and hospitals are starting to become aware of their potential.

At Heartlands Hospital in Birmingham, patients heading for the operating theatre wear an RFID wristband, so that even when anaesthetised, their full identity, including a picture, can be downloaded into a PDA held nearby.

Turned off

The latest research, conducted at Vrije University in Amsterdam, tested the effect of holding both "passive" and powered RFIDs close to 41 medical devices, including ventilators, syringe pumps, dialysis machines and pacemakers.

A total of 123 tests, three on each machine, were carried out, and 34 produced an "incident" in which the RFID appeared to have an effect - 24 of which were deemed either "significant" or "hazardous".

In some tests, RFIDs either switched off or changed the settings on mechanical ventilators, completely stopped the working of syringe pumps, caused external pacemakers to malfunction, and halted dialysis machines.

The device did not have to be held right up to the machine to make this happen - some "hazardous" incidents happened when the RFID was more than 10 inches away.

Patient safety

Dr Donald Berwick, from the Institute of Healthcare Improvement in Cambridge, Massachusetts, said: "Design in isolation is risky - even the most seductive technology will interact in the tightly-coupled healthcare world in ways physicians and other members of the healthcare team had better understand, or they and their patients may pay a dear price."

A spokesman for NHS Connecting for Health, which manages various IT projects across the health service, said that RFIDs had the potential to deliver big improvements in patient safety, reducing mistakes caused by the wrong identification of patients.

She said: "Any product such as this which is for use in a healthcare setting has to meet a standard which means it is very unlikely to interfere with medical equipment.

"This risk is more likely to come from RFID tags from other sources - such as a travel card, a tag on clothing, or on another retail item."

A spokesman for the Medicines and Healthcare Products Regulatory Agency said that, as for mobile phone use, individual Trusts needed to make risk assessments about the use of RFIDs.

He said: "Despite much debate in the literature on the subject of electromagnetic interference (EMI) of medical devices by mobile telephones and other sources of radiofrequency transmission, the MHRA has received very few reports of adverse events caused by this problem over the last seven years or so.

"Of those incidents reported, only a very small number have been proven to be as a direct result of EMI."

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Electromagnetic Interference From Radio Frequency Identification Inducing Potentially Hazardous Incidents in Critical Care Medical Equipment

Remko van der Togt, MSc; Erik Jan van Lieshout, MD; Reinout Hensbroek, MSc; E. Beinat, PhD; J. M. Binnekade, PhD; P. J. M. Bakker, MD, PhD

JAMA. 2008;299(24):2884-2890.

Context Health care applications of autoidentification technologies, such as radio frequency identification (RFID), have been proposed to improve patient safety and also the tracking and tracing of medical equipment. However, electromagnetic interference (EMI) by RFID on medical devices has never been reported.

Objective To assess and classify incidents of EMI by RFID on critical care equipment.

Design and Setting Without a patient being connected, EMI by 2 RFID systems (active 125 kHz and passive 868 MHz) was assessed under controlled conditions during May 2006, in the proximity of 41 medical devices (in 17 categories, 22 different manufacturers) at the Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands. Assessment took place according to an international test protocol. Incidents of EMI were classified according to a critical care adverse events scale as hazardous, significant, or light.

Results In 123 EMI tests (3 per medical device), RFID induced 34 EMI incidents: 22 were classified as hazardous, 2 as significant, and 10 as light. The passive 868-MHz RFID signal induced a higher number of incidents (26 incidents in 41 EMI tests; 63%) compared with the active 125-kHz RFID signal (8 incidents in 41 EMI tests; 20%); difference 44% (95% confidence interval, 27%-53%; P < .001). The passive 868-MHz RFID signal induced EMI in 26 medical devices, including 8 that were also affected by the active 125-kHz RFID signal (26 in 41 devices; 63%). The median distance between the RFID reader and the medical device in all EMI incidents was 30 cm (range, 0.1-600 cm).

Conclusions In a controlled nonclinical setting, RFID induced potentially hazardous incidents in medical devices. Implementation of RFID in the critical care environment should require on-site EMI tests and updates of international standards.


Author Affiliations: Spatial Information Laboratory, Institute of Environmental Studies, VU University, Amsterdam, the Netherlands (Mr van der Togt and Dr Beinat); Department of Intensive Care and Mobile Intensive Care Unit (Drs van Lieshout and Binnekade), Department of Clinical Epidemiology, Biostatistics and Bioinformatics (Dr Binnekade), and Department of Quality Assurance and Innovation (Dr Bakker), Academic Medical Centre, University of Amsterdam, Amsterdam; TNO Netherlands Organization for Applied Scientific Research, Leiden, the Netherlands (Mr Hensbroek); and Faculty of Sciences, University of Salzburg, Salzburg, Austria (Dr Beinat).


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