Emily, Good morning and thank you for your question: Can the Dexcom® G6 CGM be used safely in a hyperbaric chamber? Bliss et al. studied this exact question. Their findings (included below) were published in the Undersea and Hyperbaric Medicine Journal. [1] The findings identified no significant safety concerns with subjecting Dexcom G6 CGM transmitters to hyperbaric environments below an Fi02 of 23.5%. Regarding the Sensor - The sensor was assessed by walking through the manufacturing process and was determined to have no electrical components or enclosed air spaces that could be affected by the hyperbaric environment. [1]
The study compared the CGM against section 14.2.9.3.17.5 of the 2018 National Fire Protection Association 99 (NFPA 99) Health Care Facilities Code requirements. Section 14.2.9.3.17.5 states the following:
14.2.9.3.17.5 Battery-Operated Devices. Battery-operated devices shall meet the following
requirements:
(1) Batteries shall be fully enclosed and secured within the equipment enclosure.
(2) Batteries shall not be damaged by the maximum chamber pressure to which they are exposed.
(3) Batteries shall be of a sealed type that does not off-gas during normal use.
(4) Batteries or battery-operated equipment shall not undergo charging while located in the chamber.
(5) Batteries shall not be changed on in-chamber equipment while the chamber is in use.
(6) The equipment electrical rating shall not exceed 12 V and 48 W.

Safety of a continuous glucose monitoring device during hyperbaric exposure: Bliss, C et al

Methods: Six CGM transmitters attached to estimated glucose value generators (EGVGs) underwent 11 pressurization cycles to 45 feet of seawater (fsw). All transmitters were returned to the manufacturer to assess post-exposure structural integrity. G6 sensors, which contain no electrical components or compressible air spaces, do not pose a risk in the hyperbaric environment.

Results: There was no observed change in preset EGVG readings during hyperbaric exposures. Post-exposure testing revealed no structural compromise after repeated hyperbaric exposures.

Conclusions: The CGM transmitter meets section 14.2.9.3.17.5 of the 2018 NFPA 99 requirements for battery-operated devices allowed for use in a hyperbaric environment. This analysis revealed no significant safety concerns with subjecting Dexcom G6 CGM transmitters to hyperbaric environments.[1]

Discussion: It is important to note that the study was performed in a chamber pressurized with air (Fi02 21%). At the time of the writing of this article, there has not been a published study regarding the safety of a CGM in a 100% oxygen hyperbaric environment.

I am including a link to the Dexcom 6 product safety information for your review. https://www.dexcom.com/en-BH/safety-information

I hope this helps. Please do not hesitate to reach out to me if you have any additional thoughts or questions.
Have a great day, Jeff

References:
1. Bliss C, Huang E, Savaser D: Undersea Hyperb Med. First-Quarter 2020;47(1):13-19. doi: 10.22462/01.03.2020.2.
2. Technical Committee on Hyperbaric and Hypobaric Facilities (HEA-HYP) 2018. 14. Hyperbaric Facilities. In: (NFPA) National Fire Protection Association ed. Nfpa 99: Health Care Facilities Code Handbook. Pp 602-603.

Agree with Jeff. I would approve the Dexcom unit for use in monoplace or multiplace units. Your medical director and safety officer should perform a risk assessment for your units. Record it in your exceptions log. Use this as a quality improvement project for your next UHMS accreditation survey.

HOWEVER, the Freestyle Libre is a NO GO in either chamber. The company is not forthcoming about construction and there appears significant risk in my estimation.