TABLE 2

Examples of equations for predicting hypoxaemia

PaO2Alt=0.410×PaO2Ground+17.652
PaO2Alt=0.519×PaO2Ground+11.855×(FEV1 L)−1.760
PaO2Alt=0.453×PaO2Ground+0.386×(FEV1 % pred)+2.44
PaO2Alt=22.8−(2.74×altitude in 1000s of feet)+0.68×PaO2Ground

PaO2Alt: predicted arterial oxygen tension at altitude (in millimetres of mercury); PaO2Ground: measured arterial oxygen tension at sea level (in millimetres of mercury); FEV1: forced expiratory volume in 1 s; % pred: % predicted. Information from [10].