A continuous glucose monitor (CGM) is an interstitial monitor that uses a flexible sensor placed under the skin and offers glucose readings every five minutes.
An artificial pancreas is the Holy Grail of diabetes technology. We are not there yet, but new technology is moving us closer by managing insulin more precisely than ever before — and changing the trajectory of patients’ lives in the process.
A continuous glucose monitor (CGM), sometimes called a continuous blood glucose monitor, actually measures glucose in the interstitial fluid using a flexible sensor placed under the skin. The sensor can remain for one week to 10 days and offers glucose readings every five minutes.
While CGMs were wired in the past, they now use wireless transmitters that remain outside the skin and can send readings to a receiver or even a cellphone. The information can be shared among family members for added safety and support of a child’s diabetes care.
This technology continues to evolve, and an implantable device that can remain under the skin for three to six months already has been approved by the U.S. Food and Drug Administration for adults. It is expected to be available to children in the coming years.
During my fellowship training in endocrinology and diabetes, I completed research on insulin-glucose algorithms, which are used to calculate insulin needs based on past, current and predicted glucose levels. Those algorithms now have been fully realized in the form of closed-loop hybrid insulin pump systems using CGMs. This advanced type of insulin pump communicates with the CGM and responds to changes in the glucose level by raising or lowering the amount of insulin being given.
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Improved glucose control and fewer diabetes complications
A closed-loop hybrid insulin pump system does more than improve the quality of patients’ daily lives by making diabetes management easier. It also gives patients the potential for healthier, longer lives by reducing complications such as kidney failure, cardiovascular diseases, peripheral neuropathy and blindness. In the past, we worried that these complications were inevitable. As new insulin formulations and advanced technology have been developed, the future is looking brighter.
This new technology is called a hybrid system because it still requires users to monitor and use the pump to give insulin for food, but the need to give extra insulin for high blood glucose levels is greatly reduced because the pump is able to ramp up insulin as the glucose level rises. As a result, we are seeing an incredible impact on patients’ overall glucose control.
Patients and their families typically think about their diabetes control all the time. It invades every part of their daily lives. With this device, they don’t have to think about it so much. If used appropriately by an engaged user and family who are willing to make sure the pump and CGM are working effectively, it’s truly fantastic.
Accommodating families wary of continuous glucose monitor implantation and cost
There are barriers to adopting this technology, which currently is offered by two companies in the U.S. The insulin pump and CGM are placed using needles that can be painful when inserted under the skin, and the devices must be worn every day. The devices also are expensive and are not covered by some insurance companies.
At the Wendy Novak Diabetes Center, we understand families have different needs, and we work hard to accommodate all of them. For families who don’t have the means or desire to adopt the closed-loop hybrid system, we offer a range of other technologies to help them manage their child’s Type 1 diabetes. One option is to use the CGM with an alternative nonhybrid insulin pump or with insulin injections.
In addition, there are two types of external subcutaneous insulin pumps, a tubed pump and a patch pump. Each type of pump requires a cannula inserted under the skin to allow for insulin dosing. The tubed pump delivers insulin from a controlling device through a small tube connected to an insertion set with the cannula. The patch pump is placed on the skin, and the patient uses a remote device to control insulin delivery. Basal insulin is given by the pump on an hourly basis and is programmed to match individual need. The user also uses the pump to give bolus insulin, which is dosed based on consumed carbohydrates and glucose level.
Cutting-edge technologies integral to modern diabetes care
For those who are unable to afford or prefer not to use an insulin pump, insulin can be given using syringes or insulin pens. Insulin pens allow an individual to use a dial to select the dose, and they are safer and more convenient than syringes. An electronic “smart” insulin pen also is available, which has its own mobile app and allows the user to track how much insulin was given at a particular time. The app can track food and blood glucose with digital reporting features, and it even has a temperature gauge. If the pen becomes too hot or too cold, it alerts the user before the insulin is destroyed.
Dozens of diabetes apps for smartphones offer a full range of options for tracking food and glucose. Some have databases to look up food and see how many grams of protein, fat and carbs they have, and guide the user on dosing properly. Others allow users to upload information from the insulin pump for tracking purposes. Some even employ educational games to help children and adults with their diabetes care.
Technology has been part of diabetes care since the 1940s, but only over the past 20 years have we seen how truly influential it can be in not only helping to improve diabetes control, but also to improve daily life. From advanced glucose meters and smart insulin pens to CGMs and closed-loop hybrid systems, today technology is an integral part of diabetes care. While perhaps we are not far from a true artificial pancreas, until then we will continue to provide our patients and families with the best support, education and cutting-edge technology available.
Kupper A. Wintergerst, M.D., is director, Wendy Novak Diabetes Center; Wendy L. Novak endowed chair of pediatric diabetes care and clinical research; and professor of pediatrics and division chief, Pediatric Endocrinology, University of Louisville School of Medicine.