The absorption of oxygen from hyperbaric water

Abstract

We tested the hypothesis that skin and muscle absorb O2 from hyperbaric water by soaking the feet of 10 subjects in tap water (CON; 1.8±0.3 mg·L−1 O2, PO2≈50mmHg, 31.5±0.4C°) or hyperbaric water (HYP; 49.6±1.8 mg·L−1 O2, PO2≈960mmHg 31.8±0.4C°) for 5 minutes. In order to show that oxygen was absorbed from the water, blood flow to the foot was arrested for 12 minutes prior to treatment. The occlusion was maintained during treatment and for 5 minutes following treatment. The rate of muscle O2 consumption (VO2mus) was significantly higher in HYP than in CON (0.009 ±0.001vs. 0.003±0.001ml·100g−1·min−1) at the end of treatment. Also, the concentration of oxidized cytochrome oxidase aa3 increased in HYP by 1.5±0.5μM and decreased 0.3±0.3μM in CON during treatment. Skin PO2 measured over plantar muscles in the arch of the foot after treatment was not different between CON and HYP. The PO2 declined from 162±2 to 53±7 in CON and from 158±9 to 57±9 mmHg in HYP over 5 minutes post-treatment. The skin PO2 in the big toe of HYP treated feet declined from 177±9 to 129±5 mmHg post-treatment. Taken together, these data show that a significant amount of oxygen can be absorbed from hyperbaric water by skin. In areas of the foot that lack metabolically active tissues (big toe) excess oxygen accumulates in the skin. In areas that have muscle, oxygen diffuses through the dermal thickness where it is used by the underlying metabolically active muscle..