Fig. 2.

Above 90% of the patients have a P_aCO₂ below 40 Torr (5.33 kPa). The average P_aCO₂ at 3,510 m is 29.4 Torr. This implies that although the average P_aO₂ can be lower at high altitude during disease, the average P_aCO₂ remains within the normal limits. It also shows that the highest values reached are around 57 and in some extreme but very isolated and serious cases up to 73 Torr (9.73 kPa). At high altitude it is not possible to tolerate a high P_aCO₂