Commentary: Arterial blood gases in SCUBA divers at depth

In a recent interesting study (Paganini et al., 2024), arterial PO2 was measured 18 while diving to 15 and 42 meters of freshwater (mfw). It was explored whether 19 calculation of arterial PO2 at depth could use the arterial/alveolar (partial pressures of 20 oxygen ratio (a:A ratio) at 1 ATA, as suggested by Moon et al., (1987). The a:A ratio 21 calculated from the baseline arterial blood gases obtained at rest, out of the water, 22 adequately predicted the PaO2 at depth. However, at the greater depth of 22 mfw the 23 calculation proved to be inaccurate. Also, Weaver and Howe (1992), presented higher 24 PaO2 than predicted by the a:A ratio. 35 can be related to a better timing between perfusion and elevated PAO2. Modeling this 36 assumption in a single compartment lung, Arieli and Farhi (1985) presented that at