M.M. Lozano, S. Givens
Profusa, Inc, California, United States
Keywords: hypoxia; continuous wireless monitoring; oxygen biosensor; trauma; altitude evacuation
In an anesthetized swine model, Lumee (Profusa, Inc) sensors were placed subcutaneously for continuous tissue oxygen measurements 5 days prior to injury that consisted of head fluid percussion followed by 30% hemorrhage. Groups were injured (n=29) and Sham (n=14). After 2h post-injury, anesthesia was switched (n=37) from gaseous to IV before simulated aeromedical evacuation. The aero-simulation occurred in a hypobaric chamber at 8000ft for 4 hours followed by 1 hour stabilization at 300ft. Animals [Hypo (19), Normo (18)], were further divided according to the FiO2 received (21%, 40%, 54%, 100%). Vital signs and Lumee (LOI: Lumee Oxygen Index) data were normalized and analyzed with 2 way-Anova for the 5 hours evacuation duration between groups and treatments. Interestingly, regardless of the groups or treatments, all animals exhibited an approximately 3-fold increase in LOI% during the transition to the hypobaric and this impaired the analysis of LOI% among groups. At simulated landing from 8000ft to 300ft, tissue oxygenation increased noticeably in the hypo groups. Some of the physiologic indices and different parameters underlined some advantages of oxygenation above normal FiO2 but could not support the benefit/harm of supplementation at 100% FiO2 during aeromedical evacuation. These preliminary findings warrant further consideration.