Predicted O2 @ altitude
for COPD:
PaO2alt=22.8-2.74(X)+0.68(Y)
COPD'er will likely need O2 if PaO2<72,SaO2<94% on RA
for restrictive lung Dz:
PaO2alt=25.0-3.12(X)-0.62(Y)
where X=altitude in thousands ft
Y=PaO2 @ sea level
