A new method of assessing glucose control has been available for the past few years.
Called Continuous Glucose Monitoring, it has the potential to revolutionize diabetes care.
Since this webpage was originally written several years ago, three companies have developed and are now selling Continuous Glucose Monitoring (CGM) devices in the USA:
- Medtronic MiniMed Guardian® REAL-Time Continuous Glucose Monitoring System (www.minimed.com/products/guardian/) "Leading the way in continuous, 24-hour glucose monitoring, the Guardian REAL-Time System offers new levels of protection, confidence, and freedom."
- DexCom SEVEN PLUS (www.dexcom.com) "The SEVEN® PLUS is on the job 24/SEVEN, continuously measuring your glucose and giving you valuable information — like where you are and where you've been. Plus, it shows you where you're headed and how fast you're going there…"
- Abbott Laboratories FreeStyle Navigator (www.freestylenavigator.com) "The new FreeStyle Navigator® Continuous Glucose Monitoring System, a revolutionary advance in managing diabetes."
Better CGM devices
The original MiniMed device did not display glucose values, but subsequent models from all three companies do display glucose values, as well as trends of whether the values are increasing or decreasing.Integration of CGM into insulin pumps has begun. Medtronic MiniMed has developed the MiniMed Paradigm® REAL-Time Insulin Pump and Continuous Glucose Monitoring System, which they state is "the world's only system to integrate an insulin pump with REAL-Time continuous glucose monitoring." (Other companies are developing similar integrated products. And there are reports of the development of integrated pump/CGM devices that can recognize hypoglycemic glucose values, and instruct the pump to automatically shut off insulin delivery.
The following essay was written in May 2000, and indicates the state-of-the-art at that time:
We have entered a new era in diabetes care! Recently, some endocrinologists have reported the results of data from MiniMed's continuous glucose monitoring system (CGMS). While this device currently does not provide the user with a continuous readout of blood glucose levels, it does the next best thing. When downloaded into your endocrinologist's computer, it provides three days of information useful in identifying problems and adjusting treatment programs. Several studies have shown that this does lead to improvements in overall blood glucose control (lower glycohemoglobin values and fewer hypoglycemic events).
You probably are checking blood sugar levels several times a day. While this information is important in making gross adjustments in your treatment plan, 3 or 4 blood sugars is now shown to be insufficient in fine-tuning. When blood sugar is checked intermittently, what is seen is only a few points in time. And it is impossible to tell from a single number if the level is rising or falling, and therefore there is a fifty-fifty chance that the wrong decision will be made about what to do.
The sensor provides a true picture of glucose control. It averages interstitial fluid (ISF) glucose levels every five minutes. Therefore, when data are printed out, you see a graphic representation of what was going on during the monitored period. This information can be used to identify problems, and fine-tune the insulin, meals, and exercise program. For example, in one study, the fluctuations occurred in greater frequency than expected; the excursions lasted longer than had been thought; and there was unrecognized hypoglycemia and hyperglycemia: most of the unrecognized hypoglycemia occurred during the night, and most of the hyperglycemia occurred three or more hours after meals (especially after a high-fat meal like pizza!).
How does it work?
A small sterile disposable glucose-sensing device called a sensor is inserted into the subcutaneous tissues, using the same procedure as when inserting the needle on the end of the catheter used with insulin pumps. This sensor measures the change in glucose in ISF, and sends the information to a beeper-sized black box (called a monitor) which stores the results for three or four days worth of data. The monitor must be calibrated daily by entering at least three blood glucose readings obtained at different times, using a standard blood glucose meter. You will also be expected to enter insulin doses, exercise, and meal information into both a logbook and the monitor. After three days, the monitor is taken back to your endocrinologist's office, where it is placed in a docking station, which is connected to a standard personal computer. Specialized software then downloads the stored information, so that you and your diabetes team can review the data and decide on a treatment plan aimed at correcting any problems.Later, repeated CGMS testing and followup HgbA1c levels can be done to see whether the changes worked.
The Impact of CGMS
For the first time we can see what happens to glucose levels on a minute-to-minute basis, and evaluate trends, during normal daily activities. We expect that the availability of CGMS dramatic impact on the way diabetes is treated.Contact your diabetes team to inquire about CGMS availability in your area. More information can be found on-line at MiniMed's website.
Also see
(http://www.diabetesnet.com/diabetes_technology/new_monitoring.php) "Work is advancing on easier testing technologies, currently a $3 billion yearly market, as companies try to capture a dominant share of this lucrative monitoring market. To be a player, testing has to be easy, accurate, and forego painful finger-sticks."
Non-Invasive and Minimally-invasive and Continuous Glucose Monitors at the Diabetes Monitor. Continuous Monitoring Technology
