Variable	Normal (N=54)	Low baseline oxygen (N=23)	Abnormal (N=17)	P-value
Oxygen saturation level (%)	96 (95–97)	94 (92–96)	95 (93–96)	< 0.001
Partial pressure of oxygen in arterial blood (%)	72 (65–79)	64 (58–67)	66 (58–73)	0.021
Percent predicted total lung capacity (%)	88 (76–101)	80 (67–96)	80 (66–90)	0.019
Percent predicted FEV1 (%)	68 (55–79)	67 (45–75)	66 (50–86)	0.56
FEV1/FVC	73 (66–77)	74 (67–83)	79 (74–84)	0.030
Percent predicted DLCO (%)	67 (57–81)	55 (45–72)	56 (37–72)	0.045
- P-values result from Kendall’s correlation coefficient tau or a Cochran-Armitage trend test.