Thank you for your question. Advances in patient monitoring devices give providers and clinicians the ability to remotely track trends in a diabetic patient’s blood glucose level. Specifically, Continuous glucose monitoring (CGM) device. This advancement will undoubtedly help us provide the highest level of care to our patients. Can a CGM be used safely in a hyperbaric chamber? Bliss et al. studied this exact question. The findings identified no significant safety concerns with subjecting CGM transmitters to hyperbaric environments. [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.
The prohibition of lithium and lithium–ion batteries for portable patient care equipment and the language regarding the manufacturer’s approval or third-party testing have been removed. While this revision deletes the prohibition of lithium and lithium–ion batteries, other protections remain in place. This revision will allow a limited quantity of lithium and lithium–ion batteries for essential equipment. Cells phones and personal electronic devices would still be prohibited. Temperature limits only required equipment for chamber operation or patient care, and a preventive maintenance program are all in place for the Class A chamber. At the time of this writing, Chapter 14 requirements for battery-operated devices are more conservative than the FAA regulations for carry-on baggage. The reported incidents that have occurred have been related to battery charging, large volume shipments, loose batteries shorting out, overheating caused by mixed batteries, exposure to high temperature, and so on. To the committee’s knowledge, there have been no documented cases of fires from primary or secondary lithium or lithium–ion batteries that were not being charged, were contained within the device as designed, were part of a required preventive maintenance program, and were not exposed to heat. [2]

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.

Based on the current information the device (monitor) should not enter the monoplace chamber. As it relates to the sensor (patch), I would recommend performing a risk assessment prior to allowing it into the chamber. This will allow for documentation of risks and mitigating measures that should be taken.

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.