Artificial Pancreas: What is it and What Does it Do for Diabetes?
As part of my attempt at Clif Notes for busy parents, here’s a brief explanation of the three components of an articificial pancreas. This is summarized from the current issue of Countdown to a Cure, the JDRF magazine:
An artificial pancreas must have three key parts:
1. A sensor that continuously monitors blood glucose levels. The FDA recently approved a continuous sensor called the Guardian RT, which uses a subcutaneous catheter (like a pump does) and must be changed every three or four days. The sensor wirelessly transmits readings to a monitor every five minutes. The FDA has also given “pre-market approval” to the FreeStyle Navigator, which consists of a sensor inserted under the skin, a transmitter that snaps on to the sensor, and a receiver the size of a pager; readings would take place every minute. Another company is also working on a long-term sensor that would surgically implanted (under local anesthetic) and would last a year. There are other minimally-invasive sensors in the pipeline, but with no mention of FDA approval: a watch that applies weak electrical currents to the skin; a patch that utilizes laser technology and a wireless meter; and a number of technologies that use infra-red light and fluorescence to measure glucose levels.
2. An insulin delivery system. The insulin pump is the furthest along of the three key parts, and has revolutionized how people with type 1 receive their insulin. The FDA has already approved an integrated blood glucose meter and insulin pump from Medtronic and Becton, Dickinson. The latest development is a wireless pump called the Omnipod, which has a small insulin-containing “pod” that sticks to the skin, and a wireless unit that is both a glucose meter and a wireless controller for the pump. However, both of these require finger pricks, and both are considered an “open loop” system because they send glucose readings to the pump and calculate a recommended dose that the wearer must approve before hitting “deliver.”
3. A computer brain that calculates the correct dose of insulin based on blood glucose. This is what makes it a “closed loop” system. The problem with continuous readings is this: if parents like us tend to overthink the four-to-six readings a day we have now, (Why is she low? Did I get the carb count wrong? Or was it gym class?) imagine how it will be with 864 readings in a weekend, which is what they’re promising. “One of the advantages of closing the loop is that it ‘steps over’ the need to understand how best to use the information,” one scientist said. There was a long complicated discussion in this article about computer algorithms and how to program such a device to keep people within their target range, but it sounds to me like the scientists know exactly how to do that. They seem more concerned with making sure that the sensors are good enough for the computer to rely on the readings as accurate before calculating the dose.
The most interesting quote in the article was this one: “There are two schools of thought,” Darrell M. Wilson MD, chief of pediatric endocrinology at Stanford, says. “One is that it has to be perfect, and produce results that reflect non-diabetic physiology almost exactly. The other is that we need a technology that is better than what we have now, that it doesn’t have to be perfect. I’m in the latter camp. If we can show a significant improvement in control, we would go a long way down the road to helping people with diabetes. Waiting for perfection ignores the difficulties that all our patients and families have with the current technology.”
I agree. It’s like that old saying, The perfect is the enemy of the good.
Next blog: how an artificial pancreas relates to finding a cure.
Published On: February 22, 2006