This is an exciting time for diabetes technology!

Each week diabetes news outlets light up with information about technology designed to improve blood sugar control and reduce the burden of managing diabetes. The general goal of diabetes management is to lessen the risks of complications caused by high and low blood sugars.  However, the daily effort required to manage blood sugars can be very burdensome for people who are dependent on insulin therapy.  A person’s insulin needs can vary day-to-day and juggling all of the variables that affect blood sugar can feel like swinging a bat at a curve ball.  Sometimes the insulin delivery matches up to the needs and the blood sugar responds perfectly and other times, the best swing delivers an unpredictable response.

Recently, technology has stepped up to the plate with automated insulin delivery (AID) systems. AID systems involve an insulin pump equipped with an algorithm to deliver insulin based on the sensor glucose data from a continuous glucose monitor (CGM).  The current FDA approved AID system available in the United States is Medtronic’s MiniMed 670G which launched in 2017. Next at bat is the Tandem t:slim X2 pump paired with the Dexcom G5 CGM. FDA approval for this system is expected around summer 2018 time frame.

More players and more advanced algorithms are waiting in the dug out looking to emerge onto the field in the next 1-3 years.

While technology aims to relieve human effort, we often still need to perform maintenance tasks to help technology along.  There are some basic care practices that will remain essential for AID systems to perform well.  If you are a currently using an AID system or considering upgrading in the near future, here are some habits that are worth refining to improve your success with pump therapy, CGM use and AID technology.  Consider these suggestions as a Spring training checklist aimed at developing strong habits for optimum performance.

Ready, Infusion Set, Go!

In pump therapy, insulin infuses through flexible tubing and into a tiny catheter which is inserted in the body.  Catheter reliability is essential for smooth insulin delivery and successful pump therapy.  If the catheter crimps or gets pulled out of the subcutaneous tissue, insulin delivery is compromised and high blood sugars will ensue.  Here are some recommendations for maintaining good catheter function.

  • Choose Wisely – If you experience crimped catheters frequently, take some time to explore other types of sets.  The options typically include straight-in flexible catheter, straight-in steel catheter or angled flexible catheter.  Ask your doctor, nurse or CDE which set might work best for your body type and lifestyle.  Your pump company can supply samples and training on different sets.  Please note that the choices do not apply to users of the Omnipod (a tubeless pod-style insulin pump).
  • Rotate and Change Out – Move the infusion set around within the approved areas and change the infusion set every 2-3 days.  These practices will help limit fatty tissue build-up and ensure optimum insulin absorption.

Count Carbs, Bolus, Eat … Repeat!

With the current Minimed 670G system the user is still responsible for delivering boluses for food and high blood sugar corrections.

  • Bolus accurately – Carbohydrate counting remains a key skill.  Accurate estimates can prevent post-meal blood sugar spikes which can decrease alerts due to high blood sugar.
  • Bolus early – The rapid-acting insulins approved for use in pump therapy take a few minutes to enter the blood stream once delivered.  Delivering a meal bolus 10-15 minutes before eating can help prevent high blood sugars after meals.  This may also alleviate alerts and help the user stay in Auto Mode.  If a user consistently boluses in advance, it is easier to determine if the carb ratio needs to be adjusted.

Regulate and Calibrate

CGM users are instructed to check blood sugar by finger stick and enter the value into the pump to calibrate the system.  Calibrations are still essential for the Medtronic Guardian 3 and Dexcom G5 CGMs.  For CGM accuracy and safety, it is best to understand the manufacturer instructions and to follow a routine for calibrations.  Best practices include the following;

  • Wash hands with soap and water and dry thoroughly prior to finger stick.
  • Use the same meter for all calibrations.
  • Calibrate when blood sugars are not rapidly changing.
  • Contact pump company when sensor errors occur.  The company collects data on sensor issues and can provide valuable support to the user.

Step Back and See the Big Picture

Day-to-day details emerge into patterns when the pump and CGM data is uploaded using the manufacturer’s software.  The user and health care provider can review the patterns together and discover habits or settings that can be adjusted to improve the experience.  I advise patients to take some time to establish their software account and learn how to upload their devices.  The initial effort will pay off as future uploads are simple and the collected data can be very enlightening.

Now, you might be wondering if automated insulin delivery systems actually reduce the burden of care for a person who is insulin-dependent.  This technology is really in its infancy and some of the above recommendations will be obsolete in the future. Faster-acting insulins will allow for less forethought in bolusing.  Advanced algorithms will help prevent post-meal spikes. Pre-calibrated CGMs will be available in AID systems.  For now, it is worth assessing basic skills.  Consider how your catheter, bolus, calibration and uploading habits are affecting your current experience. Decide if any fine-tuning is necessary and then build essential tasks into routine practices.  A little effort spent refining skills and equipment can improve performance of the AID system and ultimately improve blood sugar control and reduce the burden of diabetes management.


Sandi Spicer-Moore, MA, RD, LD, CDE, BC ADM

Certified Diabetes Educator at Cecelia Health