A Design Concept by Erik C. Kiaer
Diabetes Control unit -
a closed loop system
Current testing - medicating cycle
The entire process is user dependent and required four distinct steps where errors may be introduced.
A chronic disease is a handicap. Increasingly however, it is not the disease in itself that creates the handicap, but the prejudice people have of the disease. People with disabilities can to a large degree lead normal lives with the aid of medication or technology. As science and technology finds new solutions to medical problems, people with disabilities and chronic diseases can be helped to lead normal lives without the stigmas that are connected with bulky technology aids and invasive medication methods.
Some diabetics need to daily monitor blood Sugar levels, and administer insulin according to need. These are often invasive procedures involving syringes and specialized equipment. Today, new Insulin injectors and monitoring devices have reduced the inconvenience of the daily diabetic routine, but with new advances in electronics and medicine, there are new and non-invasive methods for monitoring blood and administering medication. Combined with small, powerful computers, the daily procedures that are necessary for diabetics can be made even less intrusive and cumbersome.
Issues for the design of a diabetes control unit
- remove image of disease as a handicap
- issues of control - who is in command, the patient or the health care professionals?
- new opportunities afforded by new technology and miniaturization
- issues of "invasiveness" in blood testing, monitoring and insulin injection
- need for tight control over blood sugar levels - minimize risks of suffering from long term complications
Who is affected?
Approximately 13 million Americans have diabetes of type I or II. Of these, 3 million require insulin daily. How insulin is administered depends on the individual and the degree of the disease. For all cases, however, it is a matter of knowing one's own body and the dietary restrictions that control the need for insulin in order to live a normal life.
What is the problem?
People with diabetes who require daily injections of insulin need to monitor their blood glucose levels daily in order to best control the disease. The monitoring and injection of insulin are presently two dependent, but separate processes. The most common methods for monitoring and injection require puncturing of the skin. This can cause the patient discomfort and is a reason for the relatively low number of diabetics who actually monitor their blood sugar levels. The current methods for testing blood sugar and for administering insulin are unnecessarily invasive and complicated. Combining the two dependent processes into one, simplified process would greatly reduce the problems associated with diabetes control. In addition, the use of new, non-invasive methods for testing and medicating would help increase the number of patients who regularly test their blood sugar levels, and thereby help reduce the onset of diabetes related complications in the future.
Proposed closed loop system
One closed loop, user-independent process with manual override.
The user for my diabetes control system will be people who need tight control over blood sugar levels. This is potentially all people with diabetes who require insulin daily.
Self-monitoring of blood glucose Self-monitoring of blood glucose (SMBG) is a way to adjust the amount of insulin that is injected by directly measuring the amount of glucose in the blood. The goal of SMBG is to enable more accurate administering of insulin and maintain a normal level of blood sugar to avoid hypo- or hyperglycemia (low or high blood sugar). It has been shown that the patients who do SMBG on a regular basis have fewer diabetes-related complications than patients who do not perform SMBG (see sidebar for specifics about SMBG). Today, the cost, accuracy and the inconvenience and discomfort associated with the test keep many patients from performing SMBG. New methods of monitoring blood glucose are being developed that do not involve taking a blood sample.
Use of insulin
Insulin is usually administered orally or by injection - either at set times of the day with a syringe or an injection pen, or continuously with the aid of an Insulin pump. New methods for insulin delivery are being developed, that use electricity to transport the large insulin molecules across the skin. The method used depends on each individual case. The injection amount depends on the test results and the activity level of the patient. The goal of insulin injections is to maintain normoglycemic blood sugar levels. Experience and knowledge of one's body can to a certain degree allow a patient to maintain normal blood sugar levels, but frequent testing and adjustments to the administered insulin dose will be more accurate and lead to fewer complications in the long run.
Iontophoresis uses a low-voltage electrical field to drive drugs across the skin--from a dispenser as inconspicuous as a wristwatch. The electric current, which is about ten times less shocking than a household light socket, is completely painless.
The method's advantages over transdermal patches, which passively diffuse small-molecule drugs like nicotine and estrogen across the skin, is that is works on larger molecules such as insulin and growth hormone. It could also be used to provide pain-killing relief at the touch of a button, allowing a patient to dose himself as needed.
Electricity can also flush substances such as glucose out of the body.
Stepping up the electric current, scientists at the Massachusetts Institute of Technology aim to deliver extremely rapid jolts of electricity to create temporary pores in the skin, a process they call electroporation. Although the technique is still very much in the research stage, the MIT team hopes to come up with a gadget worthy of Dick Tracy--a watch-size device that would provide a continuous feedback loop in diabetics, painlessly sensing glucose levels and transmitting insulin as needed.
Add it all together and medicine as practiced on the sick bay of the starship Enterprise doesn't seem so far away after all. Beam us up, Scotty, we're coming aboard.
Closed loop system
A closed loop system (CLS) for controlling diabetes would include a monitoring system and an insulin administering system linked to provide continuous control of blood glucose levels. With the possibilities afforded us by the miniaturization of electronics and computing power, long term data collection and analysis can further improve the accuracy of diabetes control. Issues of exercise and diet that directly affect insulin needs can be incorporated into the system.
Technology and medical research
By linking the monitoring function of a closed loop system with a home computer, or a PDA, information on foods and types of exercise can be used to calculate correct insulin doses. Simple and quick downloading of daily schedules, prepared on a home computer or PDA can help the patient plan their daily schedule with regards to exercise, diet and medication. Wireless communicators can provide up to date information on the patient's past history and be a link to a personal health provider, with consulting and emergency functions.
- The Timex Datalink method of downloading data is one way to link the wearable units and a computer in a simple manner without the need for special cables.
- Polar heart rate monitors store an athletes heart rate profiles and allows for downloading to a computer for diary keeping. A wireless RF signal sends the heartbeat signal from the monitor strapped around the chest to a wristwatch.
- The Swatch Pager is a watch that doubles as a cellular pager.
- Nexus Telecommunications systems Ltd. in Tel Aviv has invented a low-cost system for two-way paging. A subscriber creates as many as 300 possible messages in advance and stores them in the paging company's computer, assigning each a number. To respond to a page, the subscriber simply scrolls through a list of printed messages on the pager screen and transmits back the appropriate ntimber--say, 124 for "Blood sugar normal, 12 AM." The paging-company computer translates the number and forwards the message by fax, E-mail, or by phone using a synthesized voice. For emergency situations, or as a daily update, this could be of good use.
- Iontophoresis - use of low-voltage electricity to transport insulin across skin (see sidebar).
- Electroporation - use of electricity to measure blood glucose levels as well as inject insulin (see sidebar).
Final Design The existing methods for diabetes control requires several separate steps; taking a blood sample, testing the blood in a glucometer, preparing an insulin dose and injecting the insulin.
New technology and advances in medical research are making it Possible to give individuals with diabetes more control over their disease, while at the same time reducing the inconvenience Of current methods for blood testing and insulin injection.
New, non-invasive testing methods, combined with innovative ways for delivering insulin without syringes makes it possible to "close" the loop, and deliver insulin automatically according to continuous monitoring of blood glucose.
Iontophoresis is a new way to transport large molecules such as insulin across skin, using low-voltage electricity. Electricity can also be used to flush glucose out of the blood for testing. InsuLink combines these two functions.
On the back of the watch, two electrodes monitor blood glucose levels and delivery insulin, non -invasively.
A rubber flap covers the opening of the insulin storage container, which holds one day's supply of insulin.
There are four main functions of the InsuLink watch:
- glucose monitoring/time keeping;
- review of history, settings and alarms;
- two-way paging and computer link;
- emergency communication mode that sends out an emergency signal and informs people of the user's condition.
The option button scrolls through the options within the different functions. The Adjust and Start/Stop buttons select and activate the different options.
A product simulation gives new users an introduction to the use of the system.
A datalink between the InsuLink watch and a computer allows the user to download schedules or watch calibrations (depending upon type of insulin used) as well as store daily readings on the computer for medical reference.
Large, easily differentiated buttons andan easily readable, high contrast display accommodates the long term complications from which people with diabetes often suffer, such as impaired vision and decreased sensitivity in extremities.
NOTE: This product does not exist. It is a design concept only.
Printed with the permission of Erik C. Kiaer.
Last Updated: Thursday August 29, 2002 20:59:44
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