New Communication Model for Medical Devices, Continued

I came across an IEEE journal article published in 2008 by two Welch Allyn research engineers.  The article has enough relevance to the topical area of my blog that I plan to devote at least one article to discuss it's contents.  The article addresses wireless communications and specifically, medical-grade wireless networks and issues surrounding their deployment.

I mention the IEEE article because having a reliable connection is a major concern to anyone who would implement a medical application that uses remote programming. Remote programming would involve downloading new instructions, new software or software patches to a device.  That download must be performed safely, securely and without error.  Furthermore, entire connection system would have to be extremely tolerant of errors and connection breaks.  In that vein, I discuss the Rosetta-Wireless connection model in more detail with special emphasis on how the model provides a reliable, logically stable and secure connection with significant throughput.  This is a continuation of the article titled "New Communications Model for Medical Devices" that I published 11 October 2009.  It is also a continuation of the article that I published on 14 October 2009," Medtronic Patent Application: Communication system for medical devices ."

I provide a slightly revised drawing of the connection model below.  (You should see a larger drawing in another window/tab if you click on the drawing). 

 

The area of interest of this discussion is defined by the curly-brace on the right. It is the communications path between the mobile server and the central server. As I had mentioned in my previous post the Central and Mobile Servers are logically identical; i.e., whatever data is on the Central Server will migrate to the Mobile Server and vice versa. So, if a file appears on the CS, it will be mirrored to the PS automatically. Furthermore, since the two servers are logical twins, they continue to maintain a logical connection with each other even when disconnected.

From a security standpoint, all transmissions are encrypted, all data on the mobile server is encrypted and the two system authenticate each other using a shared secret. The data on a Mobile Server is managed by a secure, centralized authority, thus if the Mobile Server is ever stolen, once that stolen Mobile Server contacts a Central Server, the Central Server will send a signal to erase it's data and terminate its operation. This is important because should anyone consider such a model as this for the transfer of medical data, the data and any device that manages that data in the field will have to be secured.

Wireless networks are inherently unreliable, they rely on radio technology with all it's physical instabilities to provide a connection.  Anything moving adds instability by continually moving in and out of coverage. The TCP/IP protocol was not designed to handle communications where there are frequent breaks and re-connections.  The protocol was designed for an “always connected” state.  Furthermore, the endpoints of the communications link – the service provider (server) or the user's equipment (client) – have been designed to “expect” an “always connected state as well.  Neither the network, appliances, user devices or users are designed to handle frequent communication breaks.

The crux of this model and the point of this article is to describe a means for transforming an intermittent and unreliable wireless connection environment into a reliable one. It does this in two ways.

First, the Mobile Server has the capability of utilizing more than one connection simultaneously (opportunistic routing).  If two or three connections are available, data can be send over all the connections simultaneously.  Should a connection suddenly drop, the system reconfigures itself and starts moving data over the remaining channels.  For example, the Mobile Server could have connections both with WiFi and 3G.  The WiFi connection could suddenly drop, but the data would be routed over the 3G connection, seamlessly and without interruption.  Thus the system is able to use connection redundancy in an effective manner and without the need to suddenly switch to an available  wireless connection once that wireless connection drops.  Since it can connect to an infinite number of wireless connections (the software is capable of doing this.  There are no limits on the number of simultaneous connections.), all the software does is move the traffic to the active connection(s). 

Second, the two servers, Mobile and Central, continually maintain a stable connection between each other.  Should their be a connection break, each server preserves the state of the data transfer (in the case of a file - a data or software file - with a known end point) or the state of the session should the transfer be a streaming connection (such as video or voice).  Should all connections drop, when the Mobile and Central Server reconnect, they authenticate each other and restart the transfer of data. 

(One aspect of the system related to its reliability is the capability of the Mobile Server to connect to a variety of Central Servers thus increasing system reliability by providing multiple connection paths to the System Service Provider Servers.)

Finally, it's time to describe the value of the model I've described to the endpoints.  The System Service Provider Servers (or Enterprise Server) is provided a stable, hardwired connection.  The applications running on the System Service Provider Servers are not required to handle any connection problems.  Adding the code to handle intermittent connections just adds to their complexity.  The engineers developing services, particularly those based on remote programming, can be assured that the transfer of data between the System Service Provider Servers and the Mobile Server is reliable and assured.

Once the necessary data or software reaches the Mobile Server, the Mobile Server connects in the usual manner to manage uploads, downloads and messages with a patient's device or devices.  (A discussion for a later article.)

Biotronik (http://www.biotronik.com/portal/home) has just introduced a new Home Monitoring system.  Their Home Monitoring system uses a wearable device monitor/wireless communications device similar to the Mobile Server I have described.  Their Home Monitoring Device appears to be tasked only for remote monitoring, not remote programming.  Biotronik bears watching.

Future-Market Analysis: Global Patient Monitoring

http://www.reuters.com/article/pressRelease/idUS78250+14-Oct-2009+BW20091014

Although I do not endorse any products or companies in this blog, I did come across the notice from Reuters about a market research study regarding the market for global patient monitoring.  I thought that some of my readers might have an interest in the findings from study such as this, so I'm providing the link to the Reuter's press release.  I believe that obtaining the results of this study will require a substantial payment, although I suspect that some of the data will become freely available when journalists review and discuss it. Anyway, I'm posting this for anyone who might be interested.  I ask that if anyone obtains a copy of this study, please leave a comment regarding it on this blog.  Thank you.

2 Million Dollars Stimulus Grant To Fund Research On Wireless Patient Monitoring

http://www.medicalnewstoday.com/articles/167340.php

Wireless researchers and physicians from Rice University and The Methodist Hospital Research Institute won a $2 million Federal grant with the mandate to design and test next-generation wireless platforms and remote patient monitoring devices in Houston.  This program should be worth watching.

Medtronic Patent Application: Communication system for medical devices

On May 31, 2007, the US Patent Office published the Medtronic patent application, Communication system for medical devices, Application number: 20070123955. I came across this patent application today (10/14/2009).  Here's the abstract to the patent application:

A communications device facilitates communication between a medical device and a wireless communications network and comprises a telemetry circuit configured to wirelessly communicate with one or more medical devices, and a computer network communication interface configured to wirelessly communicate directly with a wireless computer network. 


I invite my readers to go to the USPTO website, look-up the patent application, and refer to Figure 3.  You will notice that this looks remarkably like the figure that I published in this blog on 10/11/2009.  There are a few differences, first, the Medtronic communications model is less robust than the one I showed.  Second, the Medtronic model does not show a multi-channel wireless communication or opportunistic routing capability.  Third, the Medtronic model does not include a Central Server and is missing the means to manage the unreliable network-side wireless connection. The differences I discussed are disclosed in a patent application filed in June 2004.  All indications are that a patent will be issued.



The Medtronic patent application bears a remarkable resemblance to US Patent 7,149,511, Wireless Intelligent Personal Server.  The major difference is that the Medtronic patent application is directed towards a medical application whereas Patent #7,149,511 is directed towards general use.  

The communication model defined by Patent #7,149,511 was extended and turned into the model that I showed after extensive analysis and systems modeling.  The communications model shared by both Patent #7,149,511 and the Medtronic patent application showed a lack of robustness.  While the model that I drew has shown itself to be extremely robust, secure and scalable.  The software that Rosetta-Wireless developed used the communications model that I drew. 



I mention this because I was part of a research and development program geared fundamentally towards the development of a secure, sophisticated and robust communications system with capabilities to support the transport of medical communications.  I mentioned in an earlier article in this blog that the NIH was interested in our communications model and it's ability to transport data for medical applications.


I say all this because I believe I understand the purpose of this Medtronic system as proposed in the patent application.  The Medtronic patent application discloses a means for transporting data and programs bidirectionally.  Thus, it is an enabling technology for supporting remote programming.  And if you read the Medtronic application, you will note that it does in fact mention remote programming.  


I believe this application is a marker that defines the level of interest that Medtronic has in remote programming.  And that level of interest appears significant.  They have a series of patents including a significant and broad patent that clearly marks-out the intellectual boundaries of remote programming.  Now, I have come across what can only be defined as an "enabling" technology patent application that defines how data and programming could be transported over wireless.

More to come ...

Washington Post: David Steinhaus: Telemedicine Is Here

Recent article in the Washington Post (9/23/2009) discussing the value of telemedicine.   David Steinhaus is an employee of Medtronic.  Here's the link:

http://www.washingtonpost.com/wp-dyn/content/article/2009/09/23/AR2009092303525.html 

Harvest Bioelectricity to Power Implants?

Do you remember the movie The Matrix? There's an important scene where Morpheus tells Neo that the people connected to the matrix are nothing more than batteries to power the machines. The matrix exists to harvest biologically generated power.

I cannot state that everything in the movie's script was accurate.  However, I can state with confidence that biological organisms generate electrical power.  The question is whether that electrical power can be harvested?  The matrix could do it, but anything can happen in the movies.  

I recently came across a new start-up company that has licensed technology from the University of Colorado that will allow implanted devices to harvest electrical power from their environment, the human body.  The company is called Biotricity Medical Inc. (www.biotricitymedical.com) and they're headquartered in Hopkinton, Massachusetts.  Here's the announcement as printed in The Tech Transfer Blog:

The University of Colorado at Boulder (CU-Boulder) has executed an option agreement with Biotricity Medical Inc. to develop technology for implantable biogenerators, which would provide a potentially inexhaustible power supply to implanted medical devices such as pacemakers and insulin pumps. The underlying technology was developed in the lab of Simon Rock Levinson, professor of physiology and biophysics at the University of Colorado School of Medicine. The company’s first planned product, EpiVolt, is a tiny, implantable biogenerator that will provide power indefinitely to devices such as pacemakers, insulin pumps, cochlear implants, artificial retinas, and vagal nerve stimulators. The device is composed of living electricity-generating cells that use the body’s natural chemicals and processes to create electric power. “It’s an inexhaustible source of power that will be much smaller than the batteries it will replace,” Levinson says. “This will allow the EpiVolt to be permanently implanted in very small spaces along with the device that it powers, without the need for long connecting wires running through the body to a remote battery power source."

The question is whether or not this will work.  This technology does seem to be worth watching.

As I had mentioned in an earlier article, limited power was the intractable problem that we faced when I worked for Rosetta-Wireless.  We had overcome of variety of significant problems and built a software system with a "bullet-proof" communications system and a variety of other capabilities.  The remaining problem was powering the mobile server.  

The fundamental problems that we faced several years ago have largely been solved by developments in battery and processor technology over the past few years.  That experience taught me a great deal about coming up with different methods for powering a mobile system. We attempted to devise methods that would enable us to harvest power from the environment to supplement the battery.  Biotricity's method for harvesting power won't have solved the power problems for Rosetta-Wireless, but it could provide the additional power demands required by sophisticated, wireless medical implants. 
 
The next post will discuss the specifics for creating a secure and robust connection over wireless.  

Savings from Telehealth

http://www.cataractoutsourcing.com/healthcare-it/telehealth-save-billions/

Supporting data to indicate that telehealth has both medical and financial benefits. Remote monitoring and programming are some of the technologies that support telehealth systems.

New Communications Model for Medical Devices

I was the Chief Technologist for Rosetta-Wireless, a high-technology start-up company that won a $2 million Advanced Technology grant from the National Institute of Standards and Technology (NIST).  I was the primary author of the technology grant proposal, the systems architect and the principal investigator on the project.  With the intelligence, talents and hard-work of a highly talented group of telecommunications and computer software engineers, we created a software system that with minor modifications could support the system pictured below.  In this post, I describe the fundamental capabilities of this system depicted.  (I have no concerns about describing this system, it's patent protected.)  In later posts, I'll go into greater detail how this system could be the best means to support bi-directional communications with implanted medical devices.

Let's begin at the top of the drawing.  The top portion of the diagram shows a basic configuration that allows device clinics to access patient data from a repository (Remote Programming & Data Monitoring Servers) managed by the device manufacturer.  The device clinics access the repository over a web connection.  From their browser they can manage the patient data collected on the device company's computerized repository.  Currently, device clinics can only monitor patients.  Remote programming would allow patients' devices to be managed through this same user interface. 

The important part of this diagram is the communications model between the patient's device and the company's server system.  Beyond the company's firewall is a system called the "Central Server."  It has a reliable, high speed connection from itself to the company's server system.  The Central Server has a logical "twin," the "Mobile Monitoring Server."  It is a logical twin in the sense that when ever something is sent to one server, that server mirrors whatever it is to the other server.


The Mobile Monitoring Server is a mobile computer system similar to an iPhone.  It is intended to be with the patient at all times.  It communicates with a Central Server (and can communicate only with a Central Server thus providing exceptional security and reliability) over any available wireless connection.  It uses a system that we call "Opportunistic Routing to communicate over a diversity of wireless channels.  It can communicate with the Central Server over one or more channels simultaneously.  The Mobile Monitoring Server is also responsible for managing the wireless connection.  The system is designed to seamlessly communicate data bi-directionally over an unreliable data communications network without losing a single bit of information and it has the ability to send large amounts of data over wireless connections reliably, and without error.  And it works.  


Furthermore, the Central Server provides a stable connection to the company's server system.  This would be crucial to remote programming to insure that once a set of instructions or new software is sent, destined for the patient's implanted device, that it get's there, guaranteed.  And even if there's a break in the wireless connection, it will still get to it's destination.


The Mobile Monitoring Server connects to the implanted device (I show a St. Jude Pacemaker model that currently uses this wireless communications channel) using an FCC designated channel calls MICS. (I'll leave it to you to research.)  MICS operates in the low 400 Mhz range and has substantial limits on the level of power that can be used for transmission.  Both the frequency and the power levels insures that the implanted device cannot communicate directly with either WiFi or 3G.  Furthermore, medical devices can use only limited power for communications.  Their batteries are small and the battery life is calculated in years. 


Many of my next posts will cover specific scenarios related to remote programming and how they would communicate over this communications model.  I'll probably do some gloating and describe why this is a superior model to all others.  


However, even with relatively low power consumption, remote programming faces a problem, one that might be it's Achilles heel.  That's the problem of power and having enough of it.  When I was with Rosetta-Wireless, power was the major problem that we had to face.  There have been significant improvements in battery technology and the development of low power processors, etc.  But, as far as I can tell, the problem for remote programming does not lie with the Mobile Device, it lies with the implanted device.  The amounts and frequency of data communication required for a full-fledged remote programming system to be effective is extremely large.  Many megabytes, possibly gigabytes of data and software would be transferred to the implanted device.  This will require significant amounts of power.  However, I have come across a new company that I think may provide a significant breakthrough with the ability to harvest electrical power from the person with the implanted device.  Stay tuned.

Medtronic International Patent Application: Remote Programming of Implantable Medical Devices

Medtronic has an international patent application that extends Remote Programming, particularly, the capability to maintain security and safety of patients.  Before I dive into the details, the authors of this patent application make some very interesting points regarding the value of remote programming.  I'd like to quote a few items from that application.  It provides a clear argument regarding the value of remote programming.

... if the medical conditions of a patient with an implantable device warrant continuous monitoring or adjustment of the device [e. g. a pacemaker], the patient would have to stay in the hospital indefinitely. 

From personal and discussions with others, people want to live at home, not in a hospital or a nursing home.  Remote programming can be one tool that makes this possible even for people with severe, irreversible heart failure.  

Yet another condition ... requires that a patient visit a clinical center for occasional retrieval of data from the implanted device ... .  Depending on the frequency of data collection, this procedure may pose a serious difficulty and inconvenience for patients who live in rural areas or have limited mobility.  ... in the event a need arises to upgrade the software of an implantable medical device, the patient will be required to come to the clinic or hospital to have the upgrade installed.

Consider a patient who lives in the middle of the Navajo Reservation.  The Navajo Reservation (that surrounds the Hopi Reservation) lies in the northeast corner of Arizona and takes in parts of Utah and New Mexico.  To say the least, it is huge, rural and a very long way from any major metropolitan area.  It would be a significant burden for someone living in the middle of the Navajo Reservation to travel to any of the likely places where a device physician would be located.  Remote programming would be a significant help to these patients.

The essence of the patent application

The following quote summarizes the purpose of the patent application.

The present invention is directed toward providing a remote programming method for use with implantable medical device systems that helps ensure safe, secure programming of a medical device in a remote location.

The quote isn't particularly well-written, but it does convey what this patent is addressing: it's addressing the security problem.  Briefly, here's the problem, as it stands, anyone in a device clinic or for that matter, a hospital with a computer log-in who has access to a patient's records or has the ability to perform remote programming is provided with the ability to do virtually anything to the patient's device remotely.  This is a not a safe situation for the  patient and it's a potentially massive legal problem for the device managers.

Medtronic has defined a multi-layered or tiered system whereby certain people are provided with a specific level or levels of authorization.  For example, a clerical person may be granted authorization to review patient records and verify that certain scheduled changes and updates to patients' devices have been performed.  On the other hand, device physicians may be granted full authorization to see and do anything and everything. 

The security system that they propose is not unlike other security systems in the field.  Agencies in the Federal Government, National Laboratories, many companies, etc. all have authorization systems similar to the one being proposed.  The difference is that this addresses remote programming of medical devices.  

The patent application is narrow enough so that I suspect that Medtronic will likely receive an International Patent.  That's assuming that there are no patent applications in the same domain that have preceded the Medtronic application.  It does make clear Medtronic's strong interest in this area of technology.  Patient care is the future of the medical device industry and clearly, Medtronic has clearly recognized this.

Next time, I'll dive into remote programming and issues related to data communication.  I'll intersperse these posts to discuss the Achilles Heel of Remote Programming: Electrical Power.  And a way that this problem might be solved.  Say tuned.  These next posts should be interesting and informative.

Medtronic Patent 7,565,197: Migrating Instructions Among Implants (Updated 6 Apr 2015)

An intriguing but not fully explained claim in this patent is claim number 29.  It is a double-dependent claim in that it depends on two previous claims (claims 1 and 25); nevertheless, it describes a means for migrating instructions or data from one implanted device to another.  Here's the claim ...

The method of claim 25 wherein the remote medical device is an implantable medical device and
transmitting the remote programming instructions comprises transmitting the data to a remote external medical device capable of communicating with the implantable medical device and further transmitting the remote programming instructions from the external medical device to the implantable medical device, the remote external medical device receiving the updated state token value whenever the implantable medical device and the external medical device are in communication.

Here's how I read the meaning of this claim.

• There are by implication two external medical devices. One is implanted ... and there could be multiple implanted devices ... and the other is external to the central data system. This could be the patient's bedside wireless communication device, it could be a laptop computer, an iPhone, etc. Conceivably, it could be an Apple Watch. The central data system is in communication with the external device and the external device is in communication with the implanted device. See http://medicalremoteprogramming.blogspot.com/2015/03/internet-of-things-from-connected.html for more details on the means for communications. What is described is a mediated connection with the implanted medical device.
• A patient could have two or more implanted devices both of whom are in communication with a single external device.
• The implanted devices operate more or less independently from each other, however, they could be working as part of a therapeutic system to address a single problem or a particular class of problems, e. g., cardiac or neurological.
• For those not familiar with implanted medical devices, they have both sensing and stimulation capabilities.  The stimulation is most effectively delivered when the conditions are right ... as sensed by the sensors and computed by implant's internal processor.
• If implanted devices are working semi-autonomously, there may be a need for one implanted device to send its data to another device to which it is logically connected.  
• If two or more implanted devices are going to work as a system, they must have the capability to transmit data to each other and/or have the capability to transmit to an external device that will in turn relay the information to the other devices or would act as a central manager, take the data produced by the implanted device, perform it's own calculations and then send instructions to all the implanted devices.
  
• I believe this claim describes fundamentally both methods for managing two or more implanted devices working to deliver systematic and multi-faceted therapy to address a single medical problem.

I am most familiar with cardiac devices and I cannot think of a reason to have more than one device implanted to manage any heart problem.  The heart is nicely contained and localized.  However, the nervous system is well distributed and it would be reasonable to consider having multiple devices collaborating to deliver a particular therapy or set of therapies. 

I certainly can see a cardiac patient requiring an insulin infusion pump. I suspect that there are many people living today who have both implanted devices.