Effects of Hyperbaric Oxygen Therapy on Glucose Homeostasis in Patients Living With Diabetes Mellitus
Description:
The purpose of this Research Study is to determine whether the Dexcom G6® continuous glucose
monitoring (CGM) system accurately estimates blood glucose in diabetic patients undergoing
hyperbaric oxygen (HBO2) exposure. The study-specific CGM system is approved by the FDA (U.S.
Food and Drug Administration).
Subjects will have the Dexcom CGM inserted underneath the skin of their abdomen. This is done
in the office. It is secured to the skin by use of an adhesive patch. The sensor measures
glucose levels just underneath the skin. A transmitter is fastened on top of the sensor and
sends this information wirelessly to a receiver or compatible smart device. Study
participants will also have second sensor inserted in the subcutaneous tissue on the back of
the arm as a backup in case of data loss. The subjects will wear the sensors for at least 48
hours and then return to the Hyperbaric Medicine Clinic.
At the Hyperbaric Medicine Clinic, study staff will check the CGM system to make sure it has
been working properly. The first 2-hour session will be a control where participants will sit
quietly (as they would in the hyperbaric chamber) and will not be allowed to consume
carbohydrates unless directed to by the hyperbaric department hypoglycemia protocol. The
following day for the HBO2 session, subjects will be fitted for an oxygen hood and given a
standard HBO2 treatment. Investigators will obtain concurrent transcutaneous oximetry
measurements (TCOM) attached no farther than 3 cm from the commercial CGM on the abdomen to
measure tissue oxygenation in the region of the CGM only during HBO2 exposure.
The hyperbaric oxygen therapy chamber can accommodate 12 patients at a time. Study subjects
could be in the chamber along with regularly scheduled patients. In the chamber the pressure
will increase to approximately 2-1/2 times normal atmospheric pressure (2.4 atmospheres
absolute [ATA]). Once they reach the treatment pressure, subjects will breathe oxygen by
placing the hood over their head and securing it in place. They will breathe oxygen for a
30-minute period, and then take the hood off for 5 minutes for an "air break." They will have
a total of three 30-minute oxygen periods and two 5-minute air breaks. A subject will be in
the hyperbaric chamber for approximately 2 hours.
Blood sampling will be identical for both the control and HBO2 exposure days. Subjects will
have a peripheral intravenous (IV) catheter placed and a total of 12 samples collected to
measure venous blood glucose (12 timepoints), glucagon levels (3 timepoints) and HgA1c, (one
time). A RN or MD will be inside the chamber to monitor the subjects and to obtain the IV
blood samples. Because CGMs have not been established to be reliable under HBO2 conditions in
patients with DM, the protocol will collect Point-of-Care (POC) glucose measurements using
the hospital’s standard glucometer (Nova Biomedical, Waltham, MA) and the AccuChek Inform II
POC glucometer (Roche Diagnostics, Indianapolis, IN) at each testing point. This will be done
using a lancet to pierce the skin of the fingertip to get a drop of blood.
Subjects in both groups will also be required to perform home glucose monitoring (4 times per
day) and record mealtimes and the time of any medications taken throughout the study period.
Subjects will return to the clinic on Day 10. The CGM sensor will be removed and the
transmitter and display device collected by staff. Removed sensors will be returned to the
manufacturer for analysis. That is the end of the subject’s study participation.
Condition:
Diabetes Mellitus, Type 2
Treatment:
Hyperbaric Oxygen
Start Date:
March 2020
Sponsor:
Legacy Health System
For More Information:
https://clinicaltrials.gov/show/NCT04261738