Kellie's Top Tips: Continuous Glucose Monitoring Devices
By: Kellie Rodriguez, MSN, CDE, CPT
Director, Education Services
Diabetes Research Institute
University of Miami
We have seen incredible advancements in diabetes management technologies over the past 10 years, providing immense benefit to people with diabetes, including children and families living with type 1 diabetes.
Let’s look at: Continuous Glucose Monitors, known more readily as CGMs.
CGM systems measure glucose levels in the interstitial fluid (fluid between cells), providing the ability to obtain up to 288 glucose values over a 24-hour period. Such technology provides invaluable trending information – virtually a “DVD version” of glucose levels.
In Children with Type 1 Diabetes
A continuous awareness of glucose information can be invaluable for parents during the overnight period, with variable exercise patterns and in understanding a child’s glucose responses to foods eaten.
Children with type 1 diabetes are often very sensitive to insulin and exercise, creating challenges with glucose control that can be made more manageable through CGM.
Traditional glucose monitoring using a finger stick glucose reading provides a photo of the glucose value – a reading at one particular moment in time. We traditionally request that kids with type 1 monitor their glucose levels 4-6 times a day at minimum, but even with this commitment, we could be missing out on important glucose information.
When a person monitors his or her blood glucose level, we need to make assumptions about what is happening to the glucose level at the time and in between one glucose result and the next.
Sensor report: 24-hour glucose information
For instance, if you see a glucose reading of 133mg/dl when you check it, your natural instinct may be to be pleased. At that moment however, you have no real information about the way that glucose level is trending – up, stable or importantly, dropping rapidly.
CGM does not replace finger stick checks. Due to the placement of CGMs into the interstitial fluid, there is an expected ‘lag time’ of potentially 15-20 minutes between finger stick blood glucose readings and the CGM reading, potentially resulting in a significant discrepancy in readings if the glucose is rising or falling quickly. When using a CGM, it is therefore still necessary to use traditional finger sticks to make insulin decisions.
4 CGM systems available on the market in the US:
The Dexcom G4 and Guardian systems are stand alone CGM systems and can therefore be utilized with any insulin regimen – syringe, pen or pump.
|CGM is now increasingly covered through insurance plans – the respective CGM company has staff to assist with insurance inquiries. The Dexcom G4, though not approved for use in children or adolescents, has, as with the Medtronic CGM, been used by children. In CGM systems for patient use (CGM options 1-3 above), they all have certain basic features in common, with the ultimate choice usually based on patient or prescriber preference.
Basic features include:
- System includes a receiver (display), transmitter, and subcutaneous sensor.
- Wireless system – glucose sent via radiofrequency.
- Waterproof sensors/transmitters (not receiver)
- Require periodic calibration with finger stick blood glucose readings
- Multiple on-screen trend graphs.
- Customizable alarms for high/low glucose values.
- Arrows indicate rate & direction of BG change
- Warm-up period at beginning of sensor session.
- Minimal skin irritation, even with prolonged sensor life
- Insurance coverage varies from plan to plan.
The Medtronic sensor has the advantage currently of being able to be connected wirelessly with the mySentry, a glucose monitoring system similar in concept to a remote baby monitoring device.
Placed by a parent’s bedside, the mySentry displays the child's insulin pump and glucose information on a visual color screen throughout the night, while the child is sleeping in a separate room. Individualized alarms and alerts for high or low glucose levels enable notification to parents in the overnight period. Unfortunately insurance coverage has been challenging.
Medtronic My Sentry monitor
It is important that parents be mindful and research what is available, ensuring that all major diabetes management decisions are discussed with their child’s health care team. Certified Diabetes Educators (CDEs) are an excellent resource to assist with navigating the maze of available products and tools.