CGM and diving

[rddvet]

I use a Libre 2 for fitness. I only dive dry, but have brought my cgm down to about 200ft with no issue from pressure

 

[Duke Dive Medicine]

I use a Libre 2 for fitness. I only dive dry, but have brought my cgm down to about 200ft with no issue from pressure

May I ask how you determined that the pressure didn't cause issues with your device?

Best regards,
DDM

 

[rddvet]

May I ask how you determined that the pressure didn't cause issues with your device?

Best regards,
DDM

It continued to work after the dive another 10 days(when it was supposed to be removed) and my readings were as steady as they were from the cgm before and after it. I track it in a second party app

 

[Duke Dive Medicine]

It continued to work after the dive another 10 days(when it was supposed to be removed) and my readings were as steady as they were from the cgm before and after it. I track it in a second party app

Did you double-check it against a traditional glucometer?

Best regards,
DDM

 

[defibpads]

Came across this gem, although not extensive enough, very interesting conclusion. I am a g7 user and so far haven't had any issues but I keep my dives pretty shallow.

Continuous Glucose Monitoring and Recreational Scuba Diving in Type 1 Diabetes: Head-to-Head Comparison Between Free Style Libre 3 and Dexcom G7 Performance - PubMed

<span><b><i>Background:</i></b> Scuba diving was previously excluded because of hypoglycemic risks for patients with type 1 diabetes mellitus(T1DM). Specific eligibility criteria and a safety protocol have been defined, whereas continuous glucose monitoring (CGM) systems have enhanced diabetes...

pubmed.ncbi.nlm.nih.gov

 

[bvanant]

Did you double-check it against a traditional glucometer?

Best regards,
DDM

We make CGM systems (I was Chief Scientist when MiniMed got the first CGM approved by FDA). We routinely test them to the equivalent of 100 ft salt water to make sure there were no issues. The only issue might be if you were diving dry and you used nitrox to fill your suit. You might see a very small increase in glucose compared to 21% O2 since the enzyme everyone uses has oxygen as a reactant. But the effect will be pretty small maybe a 2% increase in estimated glucose.
Bill

 

[Duke Dive Medicine]

We make CGM systems (I was Chief Scientist when MiniMed got the first CGM approved by FDA). We routinely test them to the equivalent of 100 ft salt water to make sure there were no issues. The only issue might be if you were diving dry and you used nitrox to fill your suit. You might see a very small increase in glucose compared to 21% O2 since the enzyme everyone uses has oxygen as a reactant. But the effect will be pretty small maybe a 2% increase in estimated glucose.
Bill

Thanks for the firsthand perspective! What are your thoughts on using the device you worked with deeper than 100 fsw? When you test the devices, is it in a wet or dry environment? If wet, how do you determine that the tape/seal remains intact?

Best regards,
DDM

 

[rddvet]

Did you double-check it against a traditional glucometer?

Best regards,
DDM

Not after diving, no. But I have randomly spot checked blood vs the cgm many times and they’ve been very similar. My blood glucose is pretty steady other than when I have cheat meals. The cgms that have been dove all fall within the same glucose range as ones that haven’t been dove. And I know my average cgm glucose is very similar to my spot checks.

 

[Duke Dive Medicine]

Not after diving, no. But I have randomly spot checked blood vs the cgm many times and they’ve been very similar. My blood glucose is pretty steady other than when I have cheat meals. The cgms that have been dove all fall within the same glucose range as ones that haven’t been dove. And I know my average cgm glucose is very similar to my spot checks.

You might consider double-checking your CGM readings after diving, especially if diving beyond your device's tested limits.

Best regards,
DDM

 

[bvanant]

Thanks for the firsthand perspective! What are your thoughts on using the device you worked with deeper than 100 fsw? When you test the devices, is it in a wet or dry environment? If wet, how do you determine that the tape/seal remains intact?

Best regards,
DDM

I am pretty sure that deeper will not be an issue but will check next week. The transmitter case is sealed and we test both wet and dry although FDA will not allow us to talk about anything other than 8 feet for 24 hours or equivalent. If the seal breaks you will know pretty soon that water got in, all kinds of alarms will be evident. To test seals we put the device in a classic water pressure rig. We haven't broken any at 100 feet but I will see how high my lab guys will let me run it next week.

Bill