by Michael Kanis, National Sales Engineering Manager, Proven Process Medical Devices
Machine-to-machine communication (M2M) refers to the sharing of information between two devices. It is a key component in the rapidly growing “Internet of Things” (IoT), the increasing connectivity of devices in the home, workspaces, industry, and beyond. M2M communication can be as simple as the unidirectional transfer of data or as complex as multiplexed signals that allow devices to share a decision-making process. Within medical device manufacturing, M2M communication is one of the fastest growing sectors. According to projections by Global Info Research, the market for connected medical devices will expand from $939 million in 2018 to $2.7 billion by 2023, with the largest growth projected for the United States.
Connected Medical Devices
A number of medical devices benefit from M2M connectivity. Within hospitals, connected monitoring devices provide constant feedback to a central station and can alert staff to emergency conditions such as heart attack, seizure, or low blood oxygen. Medical devices can respond to such emergencies and provide medical assistance before the staff arrives by being triggered at the nurses’ station or increasingly through autonomous decision making by integrated artificial intelligence (AI). In surgery, M2M communication between medical devices can provide visual assistance to doctors during internal procedures or feedback on the progress of the surgery from embedded sensors on surgical instruments.
Beyond the hospital, medical devices are able to monitor health information and provide data to both patient and care provider. Perhaps the best known of such devices are the smart watches that record physical activity, heart rate, and other data. These wearable devices usually connect to the Internet via the user’s phone or a Wi-Fi service. Many are intended to give feedback only to the wearer, who can track trends over time via a connected app. Others can be set up to provide information to medical professionals as well.
In addition to these relatively simple devices, more complex in-home medical devices can benefit from M2M connectivity. Some are stand-alone devices, such as blood sugar level measurement sensors that send daily reports to the care provider or CPAP machines that make it possible for specialists to monitor patient use of the device and the number of instances of apnea that occur during the night. Other medical devices can record critical physical data after surgery, reducing the number of post-operative visits to the doctor’s office. Doctors can follow patient progress in healing and medication adherence, requiring physical visits only when personal medical intervention becomes necessary. These smart devices can also send alerts to medical personnel during an emergency, even when the patient is unable to contact the doctor themselves, allowing emergency medical responders to reach the patient more quickly. GPS-enabled devices can monitor the location of the patient, which can be important in cases of dementia. The monitor can alert family members or medical personnel when an Alzheimer’s patient has wandered out of a predefined geographic area.
M2M communication has also opened the field to new forms of active implantable medical devices. In addition to providing monitoring, implantable devices can also supply intervention when required. Pacemakers have long been able to correct irregular heartbeat. Now they can also monitor the heart’s performance over time and alert the physician as needed. Wireless technology allows devices to receive M2M communications as well, giving doctors the ability to adjust the performance of implants based on biometric feedback. Modifications that previously required the care provider to access the medical device directly can now be made without the need of surgery or even a visit to the medical facility.
Medical Device Design Considerations
When designing new medical devices with M2M communication capabilities, the operational needs of the device or instrument will affect the choice of connective technology. How critical is the function of the device? Is it a free-standing device or implantable? Will it need a physical connection or is wireless technology an option? How much power will the communication module have available? What is the projected operational lifespan of the instrument? Over what distances will the device need to communicate? Is continuous connectivity with other devices required or will occasional contact suffice? How much data loss is tolerable?
One decision that will need to be made surrounds the communications module. The standard with the longest range is the Long-Term Evolution for Machines (LTE-M). LTE-M is a broadband application that uses the same cellular network as 4G phones. Due to their use of embedded SIM cards, LTE-M devices have the most robust security of any of the wireless protocols. The range, global access, and security come with disadvantages, however. These devices require greater power and incur the ongoing cost of subscription to a network provider. Fortunately, most medical devices using M2M communications do not require a global reach or high data rates.
A technology that has been used by hospitals for decades is the IEEE 802.11af standard, which is generally known as White-Fi or Super Wi-Fi. This wireless communications standard originally transmitted on licensed bands—”white spaces”—that were not in active use by local TV broadcast stations. When U.S. broadcasters switched to digital in 2009, many frequencies in the VHF and UHF ranges became clear and available for use. White-Fi communication allows the creation of a local-area network (LAN) that has a range of 100m. An FCC database allocates bands on an ad hoc basis to prevent interference between medical devices in the same geography. This specification has a low data rate and low power consumption. A newer specification IEEE 802.11ah—called HaLow—is similar but makes use of unlicensed frequencies. Its network range is 15–20km. WPA security is used in both standards.
The Bluetooth and Zigbee standards have an even shorter range. These modules are used to create personal-area networks (PANs) with a range of 10–100m depending on the class of the medical device. Both utilize a low data rate and, therefore, have very low energy requirements. Both have lower levels of security than other standards, with Zigbee providing only basic encryption. Unlike the other standards, Bluetooth and Zigbee require line-of-sight for modules to communicate.
Another design consideration involves the network topology. Different network structures facilitate different types of M2M communication. The simplest is a point-to-point network. This involves the connection of one machine directly to another. An example of this sort of network of medical devices would be the connection of a wearable heart monitor to a user’s phone or a hand-held programmer used to send instructions to an implanted device.
A Star Network involves multiple devices connected to a single central hub. Communication between any two devices must travel through the hub. The hub itself can either be a simple router or a complex control point that sends instructions to the individual nodes. This topology can be expanded into a tree network by connecting several hubs. Such networks are frequently used in homes and businesses, where multiple computers, laptops, printers, and phones are connected to a Wi-Fi router. The router itself is connected to the Internet. Any device on the network wishing to access the Internet must go through the router. This topology allows for greater network coverage. Two devices can communicate with each other even if they are out of range as long as both are connected to networked routers. As a device moves from one location to another, it can switch to the nearest router to maintain communication.
A third topology—one that is particularly suited to low-power medical devices—is known as a mesh topology, a decentralized network where each device is connected to other devices within range. Those medical devices are, in turn, connected to devices within their range, which allows a large number of short-range devices to create a network covering an area greater than any single device could reach. Because connectivity can change as devices move, multiple information packets are sent via various routes on the assumption that at least one packet will reach the correct destination. The network can connect to larger networks—such as the Internet—as long as at least one device is in range of a router. Although this type of network has higher packet loss than other topologies, it is suitable for devices that do not need to be constantly transmitting or receiving data. Because it connects machines located in close proximity, it is an ideal choice for low-power devices.
Additional Benefits of M2M Communication in Medical Devices
Beyond the benefits to patients and medical personnel, M2M communication-enabled medical devices can also help lower the costs associated with medical devices. Alongside the patient data that is transmitted, the device is also able to send information about itself. This can include usage statistics and the results of self-diagnostic processes. This allows device failure to be reported in real time, reducing the response time of medical personnel.
Connected devices can also reduce costs through a relatively new process known as predictive maintenance. Predictive maintenance relies on self-diagnostic data from the medical device. Analysis of these data makes it possible for medical device manufacturers to predict when a device will fail, allowing them to take action before it does. Devices can be serviced just before they require it. In addition to reducing medical device downtime, predictive maintenance can cut costs by eliminating unnecessary maintenance on devices that do not require it. Instead of servicing devices on a regular schedule, engineers can focus their efforts where they provide the greatest benefits.
M2M communication opens an opportunity for market expansion and increased aftermarket service by medical device manufacturers. With connected devices, it is possible to shift responsibility for maintenance from the device owner to the device manufacturer. Medical devices can report their status directly to the manufacturer, eliminating the need for medical providers to monitor the devices and request servicing from the manufacturer. Predictive maintenance can make the service simultaneously more robust and more cost-effective. Analysts expect the predictive maintenance market to grow from $1.4 million in 2016 to $4.9 million by 2021. The shifting of maintenance responsibilities from the medical provider to the medical device manufacturer allows both entities to concentrate on what they do best.
Challenges of M2M Communication
Connected medical devices also present a number of challenges, both to manufacturers and medical providers. Beyond the creation of the medical devices themselves, manufacturers will need to be aware of the infrastructure necessary to use such devices. To connect with nodes beyond their local area, devices will need to have access to larger networks and such networks are usually provided by third parties. Medical device manufacturers, such as Proven Process Medical Devices, will need to assess the availability and cost of such negotiated access when bringing a medical device to market. The personal medical data being transmitted will need to be kept secure, as this information falls under the regulations of the Health Insurance Portability and Accountability Act (HIPPA). Healthcare companies should also examine the scalability of their current network to determine whether it will be able to accommodate the exponential increase in the number of devices that will be connected to their networks. Many hospitals already have tens of thousands of devices in their system, and network demand is only going to increase as new connected medical devices are put in place.
At Proven Process, our engineering team is experienced at designing M2M capable medical devices. If we can answer any questions about M2M communication or your next medical device project, please reach out to our National Sales Engineering Manager, Mike Kanis at 844.817.1145 or write Mike at firstname.lastname@example.org.
About the Author...
Michael Kanis is the National Sales Engineering Manager for Proven Process Medical Devices. He holds a B.S. in Marketing and Entrepreneurial Studies from Babson College. Mike is responsible for all marketing and sales for the firm.