Table 3– Oxygen pulse measured at metabolic isotimes at baseline and 6 months

		LVRS O₂ pulse	p-value	Non-LVRS O₂pulse	p-value
50%V′_CO₂
Baseline		5.7 (4.9–6.8)	0.006	4.1 (3.7–5.7)	0.84
6 months		6.3 (5.5–8.0)	0.006	4.3 (4.0–4.8)	0.84
75%V′_CO₂
Baseline		6.6 (5.2–8.0)	0.01	4.7 (4.0–6.0)	0.84
6 months		7.0 (6.3–8.9)	0.01	4.9 (3.9–5.6)	0.84
100%V′_CO₂
Baseline		7.2 (5.7–9.2)	0.02	5.5 (4.3–6.8)	0.81
6 months		8.3 (6.6–10.2)	0.02	5.5 (4.4–7.1)	0.81

Data are presented as median (interquartile range), unless otherwise stated. Comparisons are made within-group (e.g. O₂ pulse at 50% maximal carbon dioxide production (V′_CO₂,max) for lung volume reduction surgery (LVRS) at baseline versus 6 months).