Figure 1: Daily mean blood oxygen saturation levels before and after each HBOT in five COVID-19 patients. Note: Data are expressed as mean ± SD. *P < 0.05, vs. pre-first HBOT; #P < 0.05, vs. post-first HBOT; †P < 0.05, vs. pre-HBOT for that day. HBOT: Hyperbaric oxygen treatments; SO2: oxygen saturation. Reprinted with permission from Harch.