. 2010 May 5;299(1):R314–R324. doi: 10.1152/ajpregu.00183.2010

Table 4.

Response to final minute of constant-workload exercise for COPD and Healthy Control groups

	COPD
	Ctrl	PAV	He:21% O₂	60% O₂	He:40% O₂	Healthy Ctrl
Absolute power output, W	62 ± 7	62 ± 7	62 ± 7	62 ± 7	62 ± 7	124 ± 6^*
Relative power output, % of peak	52 ± 2	52 ± 2	52 ± 2	52 ± 2	52 ± 2	52 ± 0
Exercise time, min	9.8 ± 1.2	9.8 ± 1.2	9.8 ± 1.2	9.8 ± 1.2	9.8 ± 1.2	14.7 ± 0.0^*
Apparatus resistance, cmH₂O•l⁻¹•s	0.92 ± 0.12	0.37 ± 0.03^*	0.75 ± 0.06	0.99 ± 0.09	0.86 ± 0.09	1.08 ± 0.07
W_r-insp, cmH₂O•s•min⁻¹	302 ± 37	127 ± 20^*^†	248 ± 37^*	254 ± 36^*	224 ± 31^*	208 ± 18^*
W_r-exp, cmH₂O•s•min⁻¹	635 ± 58	413 ± 25^*^†	454 ± 51^*^†	489 ± 45^*^†	399 ± 51^*^†	172 ± 15^*
SpO₂, %	86.4 ± 2.8	91.0 ± 1.7^*^†	89.7 ± 2.4^*^†	99.8 ± 0.4^*^†	99.1 ± 0.4^*^†	96.4 ± 0.5^*
Heart rate, beats/min	125 ± 7	126 ± 4	121 ± 6	109 ± 7^*^†	113 ± 5^*	126 ± 8
RPE (dyspnea)	8.6 ± 0.5	4.9 ± 0.7^*	5.9 ± 0.7^*	4.9 ± 0.5^*	5.3 ± 0.6^*	4.1 ± 0.6^*
RPE (limb)	8.8 ± 0.5	5.4 ± 0.6^*	6.1 ± 0.8^*	5.4 ± 0.6^*	5.8 ± 0.6^*	4.4 ± 0.5^*
Ti, s	0.63 ± 0.06	0.65 ± 0.05	0.68 ± 0.05	0.77 ± 0.06^*	0.73 ± 0.06	1.05 ± 0.07^*
Te, s	0.98 ± 0.12	1.20 ± 0.13^*	1.19 ± 0.09^*	1.27 ± 0.08^*	1.24 ± 0.07^*	1.28 ± 0.08^*
Ti/T_tot	0.40 ± 0.03	0.36 ± 0.03^†	0.37 ± 0.02^†	0.38 ± 0.02^†	0.40 ± 0.03	0.45 ± 0.01
Vt, l	1.70 ± 0.19	2.31 ± 0.25^*	1.81 ± 0.17^*^†	1.61 ± 0.18^†	1.64 ± 0.17^†	2.41 ± 0.08^*
f_R, breaths/min	35.1 ± 3.0	33.7 ± 3.7^†	32.9 ± 2.7^†	30.1 ± 2.4^*	31.6 ± 2.6^*	26.5 ± 1.3^*
V̇e, l/min	58.9 ± 4.9	77.8 ± 9.9^*^†	60.2 ± 6.5	48.5 ± 4.2^*^†	52.4 ± 4.8^*^†	64.8 ± 3.1^*
V̇o₂, l/min	1.35 ± 0.18	1.36 ± 0.16^†	1.38 ± 0.20^†		1.68 ± 0.12^*^†	2.14 ± 0.06^*
V̇co2, l/min	1.37 ± 0.16	1.33 ± 0.14^†	1.31 ± 0.19^†	1.31 ± 0.14^†	1.37 ± 0.16^†	1.97 ± 0.05
V̇e/V̇o₂	44.2 ± 4.4	57.2 ± 5.6^*^†	43.6 ± 2.1^†		31.0 ± 1.5^*	30.2 ± 0.8^*
V̇e/V̇co₂	42.6 ± 2.9	58.5 ± 3.6^*^†	45.7 ± 3.9^*^†	37.1 ± 1.5	38.1 ± 1.4	32.9 ± 1.3^*
IC_dyn, liters^a	2.29 ± 0.14	^b	2.65 ± 0.13^*^†	2.60 ± 0.19^*^†	2.64 ± 0.10^*^†	3.72 ± 0.25^*
IRV, liters^a	0.63 ± 0.10	^b	0.90 ± 0.11^*^†	1.00 ± 0.14^*^†	1.05 ± 0.18^*^†	1.39 ± 0.14^*
ERV, liters^a	2.31 ± 0.31	^b	1.86 ± 0.31^*^†	1.98 ± 0.20^†	1.92 ± 0.31^*^†	0.92 ± 0.36^*
EILV, %TLC^a	90.0 ± 1.5	^b	86.3 ± 1.8^*^†	85.6 ± 2.0^*	83.5 ± 2.9^*	81.2 ± 1.8^*
EELV, %TLC^a	68.8 ± 2.1	^b	62.3 ± 2.3^*^†	64.4 ± 2.6^†	63.2 ± 2.0^*^†	49.5 ± 1.8^*

Values represent means ± SE. PAV, proportional assist ventilation; W_r-insp and W_r-exp inspiratory and expiratory muscle work, respectively; RPE, rating of perceived exertion; Ti, inspiratory time; Te, expiratory time; T_tot, total time; Vt, tidal volume; f_R, respiratory frequency; V̇co₂, CO₂ production; IC_dyn, dynamic inspiratory capacity; IRV, inspiratory reserve volume; ERV, expiratory reserve volume; EILV, end-inspiratory lung volume; EELV, end-expiratory lung volume.

P < 0.05 vs. COPD-Ctrl;

^†

P < 0.05 vs. Healthy.

n = 6;

IC maneuvers are not feasible during exercise with PAV. See text for description of COPD interventional trials.