NOTE: If you have any questions for "Ask the Doctor," please send them to the VOICE editorial office. The only questions Dr. Wilson will be able to answer are the ones used in this column.
Wesley W. Wilson, MD has retired as an Internal Medicine practitioner at the Western Montana Clinic in Missoula, Montana. Dr. Wilson was diagnosed with type 1 diabetes in 1956, during his second year of medical school. He remains interested and involved in diabetes education for patients and professionals.
Q: I have heard there is now a continuous blood glucose monitor worn at the belt like an insulin pump. I use an insulin pump. Does this mean there is soon going to be a pump that meters my blood and then sets itself?
A: At the scientific meeting of the American Diabetes Association, held June 2000, in San Antonio, Texas, there was a great deal of excitement about this development, "constant glucose monitoring," and at least one manufacturer had an attractive female wearing a constant glucose meter as a demonstration. One of the insulin pump manufacturers is now selling a highly specialized constant glucose monitoring device, meant to be used only by physicians to determine patient glucose profile. The other two pump manufacturers claim to be working on constant glucose monitoring systems.
Clearly, the intention is to have the ongoing glucose sensor coupled with an insulin pump, so some degree of automated insulin delivery can be provided. It's not here yet, but should arrive in the near future.
Such an automated device would not in fact be an "artificial pancreas," for there is a great deal of difference in insulin action between insulin administered by subcutaneous injection or infusion and insulin normally secreted from the beta cells of the pancreas directly to the portal vein and then transported to the liver. The liver is our main regulator of glucose metabolism, and insulin has a far greater effect on glucose metabolism in the liver than when it circulates in the peripheral arteries and veins. Blood insulin levels are much higher in well-controlled diabetes treated with sub-Q insulin than in non-diabetic individuals, and insulin effect is delayed and blunted when the insulin is given subcutaneously. We will need to know how to adjust our treatment, when we go from today's "tight control" to a regime of constant glucose monitoring and automatic insulin administration. Pump manufacturer Disetronic is working on a method of administering insulin by way of a cannula directly into the abdominal cavity so that the insulin is quickly picked up and taken to the portal vein. This should allow a more "normal" insulin action (more closely resembling that of endogenous insulin), but I'd be cautious, since there would seem to be some increased risk of intra-abdominal infection whenever there is penetration of the abdominal cavity.
This perhaps confusing discussion may help us understand that more knowledge and experience are needed before such an "autopilot" system can be widely used. New developments are occurring very rapidly in the diabetes research field, and it is the responsibility of those of us with diabetes to keep ourselves informed. Publications such as , and the ADA's Diabetes Forecast are reliable sources of up-to-date information. Unfortunately, some of the information available online, on the world wide web, is not accurate. It is important to consult reliable sources, to avoid the "sensational," regardless how it may sound in the TV news releases. The American Diabetes Association sponsors a yearly scientific meeting, an excellent place to hear both what is new and exciting and what didn't pan out.
I remain fascinated with the rapid improvements in diabetes management, and for that reason I plan to continue attending the ADA scientific meeting each year.
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