But the clever part of LifeTouch is not so much what it measures as what it does with the collected raw data.
Isansys needed the monitor (or patch) to be unobtrusive and inexpensive yet able to connect to the hospital's Intranet. Wireless technology looks after the connectivity, eliminating inconvenient cables (which can generate unwanted artifacts in the ECG signal).
To keep it unobtrusive, the device is compact and light. And because the patch needs to be cheap, it uses proven, readily available electronics.
Typical ECG waveform (normal sinus rhythm) showing standard features, including those measured by the LifeTouch HRV011.
Isansys chose Nordic Semiconductor's nRF24AP2 single-chip connectivity, 2.4GHz, ultra-low-power transceiver running ANT's RF protocol software (with Isansys's own application layer) for the wireless functionality. Processing power is provided by Energy Micro's Gecko microcontroller. A CR2032 3V coin cell powers the electronics.
LifeTouch samples at 1,000Hz with 12-bit resolution, generating 12 kilobits of data per second. But instead of continuously transmitting across the wireless link, which would place a heavy toll on the battery, the device uses an intelligent data reduction algorithm whereby the key clinical parameters are extracted from the relatively large volume of raw data. The algorithm is extremely efficient and can reduce the 12kbps down to just a few hundred bits per second of essential data.
"We didn't need a radio with large bandwidth, but we did need one that was ultra-efficient and consequently yielded long battery life," says Errey. "That's one of the reasons why we chose Nordic's ANT chip."
According to Errey, Bluetooth wireless technology was not a good choice, because of power consumption and the fact that if the signal were lost, it would take a long time to reestablish the link. A ZigBee wireless connection was not suitable, because it's primarily designed for control applications, rather than healthcare. And low-power WiFi was far too demanding on the battery.
"The battery life using ANT technology is terrific," Errey says. "We've been able to transmit useful ECG data continuously for 150 hours from a single CR2032 coin cell battery. In a normal operational mode" -- transmitting four times a second with the microcontroller continually analyzing data -- "the battery life is specified for 100 hours of continuous operation."
The ECG patch transmits to a gateway device that acts as a hub -- which will eventually take the data from all of the patient wireless monitoring devices and perform more processing on the information before sending it via TCP/IP to the hospital Intranet.
Isansys' LifeTouch utilizes ANT's proven software protocol, as used in millions of wireless applications across the world. According to Errey, the ANT ecosystem increased the company's confidence in the technology.
On top of the base ANT protocol, Isansys has developed its own customized application layer that meets the stringent requirements demanded in medical implementations.
"It's important that we can maintain the required regulatory status of the protocol for the lifetime of the product," says Errey. "That includes not making clinical decisions on the rare occasions that data isn't successfully transmitted across the wireless link. The software tells us when that happens."
Such technology "will be mandated for every hospital patient in a few years' time, because it serves as a quantitative measure of healthcare delivery," he says. "The ability to provide this measure will become universal on the clinical care side, because, among other things, it will ensure that the hospital can prove to interested parties that it has met its duty-of-care obligations."
According to Errey, this issue will become even more important in 2012 as many major medical insurers in the United States threaten to classify intensive care readmissions as a failure by the hospital and refuse to pay for care. "I think that makes LifeTouch very timely. And it means wireless health monitoring is going to be vast. I really think this is the next big thing."
Jay Tyzzer is a senior application engineer with Nordic Semiconductor.
Between this post and the post last week on a device used to monitor vitals more for wellness purposes, we're getting a great picture of how smaller electronics, wireless technologies, and novel packaging are coalescing to deliver a new generation of wireless devices that can really raise the bar on patient care.
The software angle here is particularly interesting. Am I understanding correctly that the algorithms parse through the continuous data streams to highlight just essential data? Seems like it's akin to what's being called "big data" analytics" in the business world to uncover patterns and intelligence in everything from social media streams to data pouring off of wireless sensors. Pretty cool stuff.
I'm glad to know that WiFi is not the wireless network used here, since it's so eminently hackable.
That said, I'm not familiar with the ANT wireless transmission standard used within the hospital before the data goes to TCP/IP. How hackable is it? How secure is it?
This technology has high potential to save lives, but in reading the article, I did not see any mention of encryption for the wireless signal. I would think that confidentiality of patient records would be at the forefront of the technology.
What possible commercial or criminal interest could there be in hacking this data? If the patient has already been through intensive care, his/her insurance credentials are shot, so the insurance companies don't stand to gain from intercepting data. Data security is therefore a non-issue - simple packet ID would be enough.
I wish no one had to worry about hackers in any application, but we do. Unfortunately, data security is never a non-issue, and wireless networks are eminently hackable. At least in the US, confidentiality of patient records is a legal issue. So I'm still curious about the ANT standard and encryption.
Full disclosure: I work in Nordic Semiconductor's marketing department. First, it's important to note that Lifetouch monitors are not currently being offered for commercial or clinical use in the U.S. The Isansys HRV011 is currently undergoing medical trials in a clinical environment in Europe. As in the U.S., patient confidentiality is a big deal there and transmitted data is fully encrypted. Isansys uses the ANT base protocol (see www.thisisant.com) but adds its own proprietary application layer for added security. As "Noswad" comments the only thing that's attached to the patient is the 'patch' shown in the picture at the head of the article.
InterestedInRF, thanks for the clarification about where the device is sold, and especially thanks for the info about data security and the ANT protocol.
WiFi, when properly secured (e.g. with WPA2) is quite secure The reason it's inappropriate here has to do with power requirement for WiFi.
ANT is a short range protocol that is more suited to low-power app like this.
Medical miniaturization is clearly a new frontier in product design. The components and electronics capabilities are there. So the challenge now largely resides on the packaging and assembly side, including sophisticated, multilayer packages with adhesives etc. Software is also a key component. We've covered this numerous times this year; see for example "Small Device Brings Big Comfort to Post-Surgical Patients.
Medical miniaturization is clearly a new frontier in product design. The components and electronics capabilities are there. So the challenge now largely resides on the packaging and assembly side, including sophisticated, multilayer packages with adhesives etc. Software is also a key component. We've covered this numerous times this year; see for example "Small Device Brings Big Comfort to Post-Surgical Patients.
Don't know if I missed it in the article, but how big is this? Is it just a matter of taping it on the patient and leaving it there? Does it need to be wired to sensors around the body?
There is a link to the manufacturer website. It is a self contained unit that transmit data to a central hub. It appears to be about 4-5" long and 1-2" wide.
This is a very good start with respect to miniaturization... but there are several things readers need to keep in mind... a lot of things actually, for acceptance in the USA in clinical environments as an approved medical device for patient care. There are many short comings with the current device, and the likelihood of acceptance in the USA (both FDA and product market acceptance) would be extremely questionable. However, there would be a good application for this technology in the home monitoring, military and in athletics, where basic EKG data would be nice to have, just not as diagnostic (this already exists for such purposes using ANT+ in common basic physiological monitoring equipment.. watches and HR/breathing), but is very cheap and easy to implement... but WILL NEVER BE USING IN CLINICAL SETTINGS IN THE USA.
First... a little bit about ECGs (EKGs in the US) and sensors. One of the primary disadvantages of only using one electrode to detect the minute electrical signals of the heart is that those signals are highly directional. In fact, there are 12 general directions monitored in what are called 12 Lead EKGs (the gold standard... however, most real-time monitoring is of only one "lead", which is associated with one of the 12 general directions. Unfortunately, using just a single leads is not going to give any "sense of direction" and would be just a simple summary of the electrical activity all the leads. This impedes the ability of the intelligent analysis systems to determine arrhythmia changes (changes to the baseline EKG) beyond those specific to general time-related analysis and the application of chaos theory to detect sudden cardiac death for example, which is well documented in the medical literature. The primary 6 leads, are called limb leads, and are used for basic cardiac monitoring and provide longitudinal electrical "axis" data and better wave form analysis for different "parts" of an EKG. These are the classic 3 or 4 wire "patches" seen on the 4 corners of the chest. 3 wire systems (3 patches) can only record a single limb lead. All 4 patches or limb attachments (back in the old days the "limb" leads were actually your arms and legs) must be present to record all 6 limb leads... which provide about 85% of the diagnostic data needed to do a full cardiac electrical analysis. Note that automatic defibrillators use one limb lead for analysis (across 2 wires). The remaining 6 leads of a 12 lead EKG are called cardiac, or chest leads. They record data from immediately around the heart, to provide a more of a 3D image, as the heart doesn't lie flat in the chest and tends to hang to the left.
Since a single lead requires at least 2 wires to measure a polar electrical signal, this is the minimal requirement for defibrillators, and hence any electronic patient record system associated with defibrillation. For more advanced purposes... anything beyond defibrillation, more than one lead must be immediately accessible for recording purposes. Hence, any ICU/CCU/ER/Ambulance (clinical environment) will always use multiple leads, as that is the standard of care in the USA. So until this system can use multiple wireless sensors to capture multiple leads, and buffer that data for analysis and/or just raw transmission, this approach will not do much good in clinical settings in the USA. Not capturing all the raw data would also have significant issues in clinical settings.
Unfortunately, cardiac monitoring for the purposes of an electronic patient record, in clinical settings the USA, requires the raw EKG data from multiple simultaneous leads... true leads. Analysis of the data is by FDA certified software/hardware, after which data can be stored and accessed by "event or significant change from a baseline", which is also recorded on a regular basis.
The FDA hurdles for this device are significant... it would need to go through at least two rounds of FDA acceptance for two separate functions.... the physical device itself, and the software it uses for both intelligent data analysis and data transmission. These are significant hurdles. Physically, the device would need to tolerate repeated defibrillations, including direct discharge contact, and would need to function with external pacemakers. The 2.4 GHz range is very susceptible to noise, especially high powered WiFi... which begs the question of why use ANT+ in clinical settings, especially when you need a gateway to TCP/IP anyway.
Given what FDA approval would cost (millions), and given that the EKG wires are not really a hassle to clinical providers as long as they are not attached to a physical monitor (read... this means the wires are attached to a wireless hub that is attached to the patient and sends all lead data [not summaries or events] via TCP/IP [with full buffering] over WiFi, with IEEE 802.1 physical security certs and WPA2 Enterprise encryption) you will never see this device in a clinical setting in the USA as it doesn't meet clinical standards.
Thanks for the insight, rgbenoit. I have a question, though: If this is a home monitoring device, as you suggest, would it still have value? Can home users understand an ECG?
By refining topologies and using new fluid technology, Moog's new peak sine drive controller increases available power without increasing controller volume.
Lantronix Inc. has expanded its line of controllers for sensor networks with the release of a rugged controller that improves management of automation systems used in a number of industries, including manufacturing, oil and gas, and chemicals.
Inspired by the hooks a parasitic worm uses to penetrate its host's intestines, the Karp Lab has invented a flexible adhesive patch covered with microneedles that adheres well to wet, soft tissues, but doesn't cause damage when removed.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
7 
