We’ve all heard some version of the moral story about the shepherd boy who raised several false alarms (lies) about a wolf attacking his sheep herd. This story is often used to teach children the importance of truthfulness and credibility.
As people who live with diabetes and related treatment technology like insulin pumps and CGMs, we understand this myth as we extend personal relationship dynamics to technology intimately intertwined with our personal lives.
I’ve lived with CGMs for 17 years now and for the last 10 years I’ve elevated my CGM to the decisive position of automatically delivering insulin in response to glucose levels it “senses.” When It senses glucose close enough to actual glucose levels, everything is peachy.
When the CGM diverges too much from glucose reality, things become difficult. I have, over the last 17 years, learned how to use presoaking tactics and calibration techniques to guide most CGM sensors and the algorithms they talk to along a path that is usually both safe and healthy. And when it goes wrong, it sounds an audible alarm.
This is when things can go awry. I tell my CGM algorithm to sound an alarm at 65 mg/dL. I know people have various views about what works best for them but this is what currently works for me!
My time in range (65-120) is usually north of 85% and often above 90% with lows < 55 at < 1%. My low glucose variability, CV% < 20, means that trending lows are shallow and provide ample time to correct. A GMI of 5.6% and an A1c in the low 5% range all affirm my personal safety. This, of course, all hinges on an accurate and reliable CGM reading.
One CGM malfunction mode absolutely tries my last nerve. Often enough, during a sound sleep my CGM alarms at 65 but a fingerstick reveals 85. I calibrate but the algorithm thinks it knows better than me and ignores my calibration and after one or two post-cal readings in the low 80s, it returns to the low 60s. I fingerstick again and find 85 once more. This drives me nuts!
In the last year or so, I’ve learned that in situations like this, I can turn off my Dexcom and Loop apps and continue sleeping with my pump stored basal rates and other settings leading the way forward. I learned the hard way about the real risk this tactic includes!
Two weeks ago, I experienced a similar scenario but, hampered by lost sleep, I made a poor decision and survived a serious hypo, the worst in years. It occurred during a rare afternoon nap. I had a poor night’s sleep the night before. My glucose level after my morning meal stayed stubbornly high (160-180) and resisted several attempted insulin corrections.
Looking back, my insulin corrections were overly aggressive yet my changing levels of insulin resistance made things tricky. The sleepiness that motivated my decision to nap also impaired my judgement. I turned off the Dexcom app and Loop to avoid what I thought would be false low alarms. I could have foreseen and avoided this risk and I will in the future!
In any setback, direct action that will change the outcome is the best resolution. After 17 years of Dexcom CGM use, I’ve decided to give the Eversense 365 system a try. It’s known to completely eliminate compression lows and to be more accurate in the low range. It also can give an on-body vibration alarm which seems like an effective answer to me.