Intelligent Data Management for Wireless Medical Devices

The adoption of wireless technology is increasing pricing and network service pressures in healthcare.

Organizations in a variety of industries are adopting mobile wireless technologies at an explosive rate. This rapid deployment is dramatically increasing the demand on mobile networks. Wireless carriers claim that supporting the explosion in data services is affecting profitability. The likely outcome will be new data plans to better monetize data services, which could include charging by capacity, speed, time of day, or content type. This change creates uncertainty and potentially high costs in the business models for wireless data applications.

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In the healthcare sector, the adoption of wireless technology and the corresponding strain on mobile networks is likely to generate a premium charge to provide the high quality of service needed to deliver essential data. A wireless medical device delivered at the right purchase price and service cost will require appropriate design effort in terms of connection control and cost-effective use of the wireless network for data delivery, both real-time and nonurgent. But the simultaneous management of all of these design parameters is an added burden to a medical ecosystem that is already heavily loaded with concerns about delivering high–quality medical care and meeting growing regulatory requirements.
A potential solution to the problem lies in medical device design and intelligent data management that offer the ability to deliver services reliably while at the same time managing the cost, battery life, and user experience related to wireless medical devices and the transfer of critical information.

The Move to Mobile

A growing number of consumers worldwide are accessing online services and applications through a variety of mobile devices. In recent years people have become far more comfortable with using devices for online connectivity on a daily basis, from both home and work environments that typically support high-quality, fast broadband connectivity. Many people have become highly dependent on mobile devices in the workplace and at home, and they are accustomed to enjoying a certain level of convenience and reliability with the services that support these devices. Consumers and business professionals alike have come to expect their mobile devices to be always-on with instant connectivity.
However, the fact remains that public-access connectivity today is actually a “best-effort” service. The underlying technologies that support mobility often come under strain in a mobile environment, which affects how well services are delivered to end-users and the experiences they have with their mobile technology.
 
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Organizations such as FDA have recognized the problem with the delivery of mobile medical services. In a draft guidance document entitled “Radio-Frequency Wireless Technology in Medical Devices,” FDA advises device designers to be aware of the situation.
 
“While the quality of service of cellular networks may be acceptable for voice communication, it may not be sufficient for medical functions,” the FDA report states.1 “Connections lost without warning, failure to establish connections, or even slight degradation of service can have serious consequences, especially for wireless transmission of critical medical device alarms, continuous physiological waveform data, real-time control of therapeutic medical devices (such as wireless footswitches), time-critical medical telemetry (such as for real-time patient waveforms and alarms), and wireless control of therapeutic devices.”
 
Many radio frequency (RF) wireless devices use the industrial, scientific, and medical frequency bands such as 2.4GHz, FDA notes, and these can incorporate technology to minimize interference and data errors or corruption. But wireless coexistence and data latency continue to be concerns because the data transfer rate can slow slightly or even dramatically with a rise in the number of similar transmitters in a given location.
 
One well-known example of how the mobile network environment can be strained was when the Apple iPhone was launched. Some wireless networks were driven to the breaking point by the unexpected rate of user adoption combined with an explosion of new applications for the device. The dramatic and sudden increase in iPhone apps generated unexpected demand for data and signaling bandwidth.
 
As any user of mobile devices can attest, this type of oversubscription and the service degradation that results leads to dissatisfaction with the service. People don’t want to experience delays in the delivery of information to their devices when they expect it to be delivered instantaneously.
 
Adding to the aggravation for device users is the excessive consumption of battery power and service costs that do not reflect well on the perception that they are getting a high quality of service or the value they expect from the mobile technology.
 
Meanwhile, based on industry reports, the strain on service providers’ networks is continuing and will not likely end anytime soon. According to the Cisco Visual Networking Index (VNI), an ongoing initiative to track and forecast the impact of visual networking applications, global Internet protocol (IP) traffic has increased eightfold during the past five years and will increase fourfold during the next five years.2
 
Overall, IP traffic will grow at a compound annual growth rate (CAGR) of 32% from 2010 to 2015, Cisco says. The number of devices connected to IP networks will be twice as high as the global population in 2015. A growing amount of Internet traffic is originating with non-PC devices. In 2010, only 3% of consumer Internet traffic originated with non-PC devices, but by 2015 the non-PC share of consumer Internet traffic will grow to 13%. PC-originated traffic will grow at a CAGR of 33% while tablets will grow by 216% and smartphones by 144%.
 
Cisco reports that traffic from wireless devices will exceed traffic from wired devices by 2015. In addition, wired devices will account for 46% of IP traffic by 2015, while Wi-Fi-enabled mobile devices will account for 54% of traffic. Globally, mobile data traffic will increase 26 times between 2010 and 2015. Mobile data traffic will grow at a CAGR of 92% between 2010 and 2015, reaching 6.3 exabytes per month by 2015 (see Figure 1).
 
Figure 1. Wireless internet traffic trends. Source: Cisco and Logic PD.
 

Carriers Take Steps

As mobile medical devices are deployed over the next few years, “always-on” connectivity will likely become a must-have for users. Making sure that a patient’s wireless medical device will work anywhere with a high level of service quality will be a challenge. But if wireless medical devices can’t meet user and caregiver expectations for quality, safety, reliability, and efficacy, there will be an adverse affect on the long-term adoption of wireless medical technology.
To address the quality of experience issues, wireless carriers are requesting that application developers take greater care in designing applications. They are also deploying traffic-shaping measures to provide differentiated service options, each at a price point that reflects the quality of service.
 
Wireless carriers are now certain that they have a need for advanced billing plans to cover their expanding infrastructure costs. Their motives stem from the declining value per megabyte on their data services. Rather than charge per megabyte as a commodity service, they are striving to create a billing model that values their service for the value of the content carried. For example, standard definition video delivery may be bundled into a data plan, but to send or receive high definition video would incur additional costs to the user.
 
Setting the expectation of data transfer only when needed will allow for a more reliable service perception and will target the data content to an appropriately priced service. In doing this, ease-of-use for both patients and care providers will need to be considered and matched to the expectation of today’s smartphone devices.
 
At the business level, these demands will translate into a need to negotiate service deals that best represent the value of the data. Furthermore, to achieve the mix of quality and cost of service, not all data within an application should be treated equal.
 
For the wireless health industry, this issue will add even more uncertainty to business models. But at the same time it also opens up the possibility of negotiating data plans that match the value of the services provided. The healthcare industry needs a way to intelligently manage data so that they can receive a continuous and sustainable level of service at an optimal service price point.

Intelligent Data Management

If a mobile device can somehow separate data into real-time and nonurgent classifications, the device can be configured to use the wireless service at a time when the data cost is lower. If these rules were implemented on the device as a remote managed policy, then they could be changed after deployment and the cost of service adapted to the changing need for patient data availability and location.
 
By segregating data into real-time and nonurgent categories, much of the data can be offloaded to a low-cost service with lower quality of service guarantees, lower-cost routes (such as WiFi) or at an off-peak time, and can happen in an intelligent way. The result is a defined limit to the cost of service, and because WiFi is only turned on when needed and data is aggregated to reduce network signaling and hence the mobile radio on-time, users can see improved battery life. Carriers will also enjoy the reduced signaling on their networks so it is anticipated that they will encourage this type of application.
 
Intelligent data management offers potential benefits to the wireless healthcare industry. Yet, practical exploration of the concept and trials of intelligent data management must occur to generate real-world metrics to support the idea. The process cannot require additional setup by users, additional user maintenance or knowledge, or additional cost to the user. It must allow a device manufacturer or wireless carrier to push a policy to the device that instructs it on how to shape data traffic (for example, which data should be routed over cellular versus WiFi.)
 
In addition, intelligent data management allows healthcare professionals to push setup instructions over cellular devices to the device for connecting to a home WiFi network. This setup is especially important for devices with little or no user interface as well as for elderly or nontechnical users who are not accustomed to connecting to or setting up WiFi networks.
 
Due to the realities of wireless coverage, medical devices will benefit from more than one connectivity choice, such as cellular and WiFi. Connectivity intelligence beyond the existing connection managers will be needed to control which service to use and when, as users will want to avoid complex interactions with connectivity parameters.
Medical service providers will want assurance that high-quality service can be delivered within a certain cost parameter and that the device battery will last for a given period of time. Fortunately, today’s products and approaches can help developers and operators solve these problems.

Medical Applications

Intelligent data management offers potential benefits to key stakeholders, including mobile device users, wireless carriers, device manufacturers, and healthcare providers. For users, the technology will provide a high quality of service and thus a high level of care for patients. It’s also transparent to the user, with no effect on functionality of the device, overall service, or device cost. In general, users will see an improved mobile experience with reduced congestion problems.
 
Wireless carriers will benefit from a reduced burden on their networks. They will also be able to have pricing plans that might reduce data bandwidth allowances during high-congestion periods for a reduced fee, similar to the home heat-saver pricing plans that natural gas providers offer. Device manufacturers will be able to manage expenses from the data transfers that will inevitably occur with value-based pricing models enforced by wireless carriers. Care providers such as hospitals, clinics, and doctors will benefit in ways similar to other users. They will experience transparency, better mobile experiences with reduced congestion problems, and high quality of care for patients, and they won’t see an increase in cost.
 
There are several examples of medical devices in use today or being developed for future use that would benefit from intelligent data management. Among these are the continuous blood glucose monitors used by diabetes patients. When the concern level is low for a diabetic patient, the data, although collected frequently, can be delivered one batch at a time when rates are relatively low (e.g., in the early morning). If the patient’s situation suddenly becomes critical (e.g., if there is a reading of serious hypoglycemia that could result in fainting or serious injury), data could be delivered immediately at a higher cost of delivery that is appropriate to the value of care response.
 
Other examples are cellular pacemakers that will be capable of collecting vital readings such as body weight, blood pressure, oxygen saturation, or temperature, and using that data to improve pacing or sending the information wirelessly to a healthcare provider. Another application is a continuous blood pressure monitor that uses piezoelectric elements (displacement of ions from motion against the cuff material), infrared (reflection or absorption of infrared waves by oxygenated hemoglobin), or magnetic fields (measuring how blood flow disturbs magnetic fields) that are also fitted with cellular radios.
 
While the latter two types of devices do not exist today, they are expected to be available within the next few years. Intelligent data management will become very important to the optimal function of these types of devices.
Transparency must be a key characteristic of intelligent data management. Although the design and operation of multiconnected devices will be complex behind the scenes, such devices must be operationally transparent to the patient and caregiver and financially equivalent to consumer mobile technology. These factors will be especially important in geriatric care and for people with physical and cognitive challenges, where the user may not have the expected technical or physical ability to determine which type of connectivity should be used. Intelligent data management is a potential solution to a problem that will become increasingly significant for the healthcare industry as care providers and patients rely more heavily on wireless medical devices.
 
Manufacturers must design devices that address connection control and the delivery of data, both real-time and nonurgent, while delivering wireless products at an appropriate price and service cost. Because the simultaneous management of these design parameters is yet another burden for an already heavily burdened medical system, a new method must be found to help manage the flow of data to and from devices.
 
Intelligent data management provides a method of better managing the costs, battery life, and user experiences with mobile medical devices. As the use of these devices continues to grow and further strains wireless networks, intelligent data management will offer the ability to deliver a service cost effectively and reliably.

Designing for Wireless Coexistence

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Another issue facing the wireless medical device market is wireless coexistence. A growing number of devices—both medical and nonmedical—now include wireless radios, which  creates the potential for interference between the radios and other circuitry when they coexist and operate within the same RF spectrums.
 
If not designed carefully, interference between the device electronics and the radio subsystems will result in reduced radio performance. It also reduces range and battery life, and in many cases, results in failure to pass regulatory certifications.
 
To create and successfully deliver market-leading wireless medical devices, the designer must consider the radio performance during all use cases of the device. It is very easy to overlook the effect of the digital circuitry (such as the screen electronics) and its effect on wireless performance. It is common to see high harmonics of a USB signal or digital-display signal interfere with the wireless radio. It is even more common for such interference to significantly reduce the performance of GPS receivers. For instance, let’s say a patient wearing a blood glucose monitor reaches an alarming condition. The monitor display should signal alarm status by flashing at full brightness. This flashing could create interfering signals that fall in the frequency band of the wireless radio or GPS receiver, preventing it from successfully notifying the patient or the caregiver, or providing the correct location information to healthcare providers.

Conclusion

Accurate and on-time transmission of data is essential for many medical devices. Patient health and safety can depend on the effective use and performance of these devices. Although wireless device manufacturers, wireless service providers, and device users are facing significant challenges due to the rapid adoption of all types of wireless devices, they must effectively overcome these hurdles and maximize the true value of wireless technology.
 
Reference
1. FDA Draft Guidance,“Radio-Frequency Wireless Technology for Medical Devices,” issued January 3, 2007.
 
Mark Benson is director of software strategy at Logic PD (Minneapolis). Ben Toner is business manager, mobile solutions at Roke Manor Research (Hampshire, UK).

 

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