Imagine you are recovering from an operation and are fitted with wireless body sensors that allow you to move in the hospital bed or around the room in comfort. Once past the critical recovery stage, you are given the option to leave early if you take the sensors with you. Relaxing at home, your healthcare providers monitor your vital statistics transmitted via a wireless hub connected to your home network.

Fig. 1 – As medical devices integrate more RF and connectivity features, new test and compliance strategies are required. (Credit all images: Averna)

Due to advancements in connectivity, such a scenario is likely to become the norm for post-operative care. But how do we get there? And how do medical device companies ensure we get there safely and securely?

First, let’s first explain what we mean by “connectivity,” because it can have multiple meanings in our industry, including:

  • Connections between devices and smart sensors, and
  • Electronic health record exchanges.

This article will explore these types of connectivity with a focus on how current and near-term changes will likely impact product designs, compliance approaches, and device testing.

Wireless Connectivity and New Regulatory Burdens

One of the biggest connectivity leaps underway in the industry is wireless communication. More and more products are being designed with radio-frequency (RF) chips and capabilities that will allow them to communicate with other devices and networks. Once RF is added to a medical device, however, the regulatory burden often doubles.

For example, medical devices used in the US are regulated by the FDA, which requires extensive quality and safety processes for both product design and manufacture. When RF technology is designed into the medical device, a whole new regulatory agency, the FCC, has its own sets of requirements for product testing, documentation, and compliance. For products used outside the US, there are similar foreign agency regulations, such as ETSI, EMA, and CE marking. (See Figure 1)

Background: The Rise of RF in Medical Devices

One early RF application came about as a way to communicate with an implanted device. In 1999, the FCC allocated spectrum for Medical Implant Communication Service (MICS) and then later expanded it for Medical Device Radiocommunications Service (MedRadio) in 2009.

This spectrum (401 to 457 MHz) is allocated for the use of diagnostic and therapeutic purposes in implanted devices (such as pacemakers and defibrillators) as well as devices that may be worn on the body. These frequencies were chosen to minimize the damage to tissue that radio frequencies might have caused when passing through the body.

Because of the need for rigorous RF testing required for such MICS- and MedRadio-enabled devices, many medtech companies partnered with RF test experts to create and implement the appropriate test and compliance strategies at both the R&D and manufacturing stages.

Consumer RF Test Expertise Making Inroads

When RF tests and measurements are needed for a medical device, many best practices can be leveraged from outside experience, such as the testing done in the cellphone and cable modem industries. Advanced test systems for such “RF rich” consumer electronics need to test multiple RF protocols, including WiFi (IEEE 802.11), Bluetooth, ZigBee, NFC, 2G, 3G, 4G, GPS, DOCSIS, etc. The same principles and best practices can be ported to the medical device space, as a subset of testing under the broad guidelines of the FDA’s 21 CFR Part 820 (practices for quality and safety). (See Figure 2)

Today, the medical device industry integrates many of these consumer RF standards with medical standards like Wireless Medical Telemetry Service (WMTS), MedRadio, and Medical Body Area Network (MBAN). This multitude of standards implies that many new medical devices will have several RF antennas and will need to be tested for multiple RF protocols and frequency bands.

While the complexity of RF connectivity can be daunting, the good news is that most of the protocols are mature and, therefore, the necessary test strategies and equipment are already in place at companies that test consumer devices, meaning they can be integrated and adapted for the specific purposes of medical devices and hospital environments.

Doing No Harm, Despite Increased Use of Wireless

Fig. 2 – Advanced RF testing is quite mature in industries like consumer electronics and can be leveraged and adapted for evolving medical devices.
Maintaining a persistent connection is a common risk element when combining medical devices with wireless technology. While the IEEE 802.11 WiFi protocols are quite mature and cost effective in many scenarios, they were not designed for life-or-death situations where a disruption in connectivity could cause severe harm. The WiFi protocols use unregulated frequency bands (2.4 GHz and 5 GHz), such that other devices could interfere with them. For this reason, medical device designers have to use these protocols carefully and, typically, will only use them for non-real-time or non-urgent communication.

One wireless technology that is making inroads in hospital environments is the Real-Time Locating System (RTLS). By adding RTLS tags to hospital equipment such as gurneys or medical carts, staff can track and locate key resources and even patients. While this technology can have many applications, it also requires use of wireless networks. RTLS device makers, therefore, need to design and test their products to ensure they do not create any harmful interference that might disrupt other devices operating within a hospital’s increasingly busy wireless frequency band.

Coming Soon: Regulated MBAN Connectivity

To mitigate some RF congestion and interference issues, in 2012 the FCC allocated spectrum (2,360 to 2,400 MHz) for the new MBAN “small-area” protocol. Companies like GE Healthcare and Philips are designing smart sensors and transceiver equipment to utilize MBAN for what is expected to be millions of medical devices in the next five years. These smart sensors would replace typical wired devices—such as those measuring temperature, blood pressure, pulse, and glucose levels—and each sensor would wirelessly transmit to a central hub. The hub might be a tablet-style device, which aggregates data from the sensors and can then transmit the EHR to another network.

The MBAN protocol requires significantly less power than Bluetooth, ZigBee, or WiFi, and would work on a regulated frequency band, such that the sensors would not interfere with other hospital equipment. Using such sensors would give added comfort and mobility to the patient, letting him or her move more easily in the hospital and even take the devices home for remote monitoring by the physician. (See Figure 3)

Design verification and functional test strategies for such devices are similar to those already implemented for numerous mass-market products. These consumer electronics use multiple antennas and protocols, and their compliance and existing interoperability test infrastructure is quite mature. While the MBAN protocol is new, its test strategies will be similar to those done by companies in other industries testing in the 2.4 GHz spectrum.

Improving EHR Connectivity

Fig. 3 – Operating in the 2,360 to 2,400 MHz frequency range, regulated MBAN devices promise increased patient mobility and autonomy.
The increased online availability of, and access to, personal health records is adding impetus to the drive to standardize electronic health records (EHRs), since there is currently no consensus on the definition of an EHR. One emerging standard is ISO/IEEE 11073. Large organizations, such as US federal government departments and private healthcare providers, will likely be at the forefront of defining standard formats and data models for EHRs.

As well, when processing EHRs, care must be taken to comply with recent Health Insurance Portability and Accountability Act (HIPAA) rules to protect consumers as well as security protocols such as FIPS 140-2. Most of the rules boil down to this statement from the 2,400-year-old Hippocratic Oath, “Whatever, in the course of my practice, I may see or hear, whatever I may happen to obtain knowledge of, if it be not proper to repeat it, I will keep sacred and secret within my own breast.”

Even though EHR consensus from every country and/or insurance provider is unlikely in the near term, medical device manufacturers still need to design their products with sufficient flexibility that they will be able to effectively adapt and test once an EHR standard takes hold.

Looking Towards a More Connected Future

In summary, since most of the RF connectivity challenges facing the industry have already been solved in other industries, that expertise can be capitalized on for medical device testing. Additionally, the EHR connectivity challenge is really one of data security and data model standardization. This type of challenge has already been solved by Internet-security companies. Thus data security can be solved using off-the-shelf encryption protocols such as WiFi Protected Access II (WPA2). Data model flexibility can be solved in a way similar to Internet browsers, which flexibly handle the disjointed protocols of HTML, FTP, Java, ASP, etc.

Finally, the biggest challenge for medical device manufacturers will be to incorporate these new technologies, standards, and best practices under the existing umbrella of safety (i.e., the FDA’s 21 CFR Part 820 guidelines), while simultaneously complying with more FCC-type regulations. To support this effort, test and technology expertise from outside the industry will become increasingly important as medical device makers search for, and employ, the most effective test strategies and systems to ensure their products feature seamless connectivity, while continuing to provide the very best in patient care.

This article was written by Patrick Kelly, a Customer Solutions Architect consultant, and Benoit Richard, VP of Innovation, Strategy & Marketing, at Averna. For more information, Click Here .

Medical Design Briefs Magazine

This article first appeared in the April, 2015 issue of Medical Design Briefs Magazine.

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