Table 5 Comparison of patients with reduced and normal exercise capacity
Variables | VO2 peak < 85% (n = 12) | VO2 peak ≥ 85% (n = 48) | p value |
|---|---|---|---|
Patient’s characteristics | |||
Age (years) | 65.4 (59.8–72.3) | 68.1 (58.1–71.8) | 0.96 |
BMI (kg/m2) | 33.4 ± 6.2 | 30.1 ± 4.5 | 0.04 |
Smoker or former smoker | 8 (66.7%) | 26 (54.2%) | 0.52 |
ICU stay (days) | 29.7 ± 13.1 | 19.1 ± 11.3 | 0.006 |
Ischemic heart disease | 1 (8.3%) | 4 (8.3%) | > 0.99 |
COPD | 1 (8.3%) | 4 (8.3%) | > 0.99 |
Asthma | 2 (16.7%) | 4 (8.3%) | 0.59 |
Pulmonary embolism | 3 (25%) | 13 (27.1%) | 0.88 |
Respiratory rehabilitation | 9 (75%) | 30 (62.5%) | 0.41 |
Chest computed tomography scan # | |||
Emphysema | 4 (33.3%) | 7 (14.6%) | 0.69 |
Reticulations | 9 (75%) | 33 (68.7%) | > 0.99 |
Traction bronchiectasis | 8 (66.7%) | 27 (56.2%) | 0.74 |
Honeycombing | 0 (0.0%) | 3 (6.2%) | > 0.99 |
Ground-glass opacities | 4 (33.3%) | 25 (52.1%) | 0.24 |
Pulmonary function tests | |||
FEV1 (% predicted) | 97.4 ± 16.9 | 110.8 ± 19.7 | 0.03 |
FVC (% predicted) | 97.5 ± 17.8 | 110.8 ± 16.9 | 0.01 |
TLC (%predicted) | 87.7 ± 12.6 | 95.9 ± 14.3 | 0.07 |
DLCOcor (%predicted) | 91.3 (65.6–98.1) | 103 (92.3–114.2) | 0.01 |
KCO (%predicted) | 96.1 ± 29.9 | 104.8 ± 15.5 | 0.16 |
CPET at AT | |||
PetCO2 (mmHg) | 39.3 ± 6.9 * | 39.6 ± 5.5 ** | 0.87 |
Anaerobic threshold (%VO2 peak predicted) | 59.1 (49.1–65.2) | 66.1 (58.1–73.2) | 0.01 |
CPET at peak | |||
Performance | |||
Reasons for stopping exercise | |||
Leg discomfort | 8 (66.7%) | 25 (52.1%) | 0.51 |
Dyspnea discomfort | 4 (33.3%) | 18 (37.5%) | > 0.99 |
Both | 0 (0.0%) | 3 (6.2%) | > 0.99 |
Others | 0 (0.0%) | 2 (4.2%) | > 0.99 |
Effort duration (sec) | 547.6 ± 128.9 | 585.7 ± 86.2 | 0.21 |
Workload (% predicted) | 85.7 (80.1–96.9) | 107.2 (98.4–124.5) | < 0.0001 |
V′O2 (L/min) | 1.6 ± 0.5 | 2.0 ± 0.5 | 0.03 |
V′O2 (L/min, % predicted) | 82.1 (73.7–83.7) | 101.9 (94.6–107.7) | < 0.0001 |
V′O2 (ml/min/kg) | 16.9 ± 4.2 | 23.0 ± 4.7 | 0.0001 |
V′O2 (ml/min/kg, % predicted) | 82 (73.9–83.9) | 101.6 (94.8–107.5) | < 0.0001 |
MET | 4.8 ± 1.2 | 6.6 ± 1.3 | 0.0001 |
Ventilation | |||
VE (L/min) | 74.9 ± 21.9 | 83.6 ± 21.9 | 0.22 |
RER | 1.1 ± 0.1 | 1.1 ± 0.1 | 0.14 |
Breathing reserve (%) | 34.4 ± 15.4 | 32.1 ± 13.4 | 0.61 |
PetCO2 (mmHg) | 34.0 ± 5.3 * | 34.3 ± 5.3 ** | 0.86 |
Circulation | |||
HR (beats/min, %predicted) | 94.3 ± 11.9 | 97.2 ± 12.9 | 0.49 |
Heart rate reserve (%) | 4.1 (0–18.6) | 1.6 (0–14.7) | 0.68 |
VO2 pulse (%predicted) | 83.9 ± 11.3 | 108.7 ± 18.6 | < 0.0001 |
ΔHR/ΔV′O2 | 47.5 (36.6–51.2) | 39.9 (32.2–47.5) | 0.08 |
ΔV′O2/ΔWR | 13.9 (12.9–16.1) | 14.3 (13.6–15.3) | 0.54 |
Gas exchange | |||
VE/VO2 ratio | 45.7 ± 7.9 | 42.1 ± 6.1 | 0.08 |
OUES (L/min) | 1.6 (1.5–2.0) | 1.9 (1.7–2.3) | 0.14 |
VE/VCO2 ratio | 39.5 (33.5–47.0) | 37.5 (34–41) | 0.36 |
VE/VCO2 slope | 37.2 ± 7.6* | 37.2 ± 6.6* | 0.99 |
VD/Vt | 0.35 (0.28–0.40)* | 0.29 (0.25–0.34)** | 0.06 |
pH | 7.3 ± 0.04** | 7.3 ± 0.05 | 0.36 |
pCapO2 (mmHg) | 78.2 (54.2–82.1)* | 83.8 (76.8–87.1)** | 0.05 |
pCapCO2 (mmHg) | 35.9 (33.4–39.4)** | 34.7 (30.7–37.3) | 0.14 |
P(A-a) (mmHg) | 43.49 (29.7–60.5)* | 35.2 (31.2–44.8)** | 0.23 |
Metabolic | |||
Lactatemia (mmol/L) | 7.2 ± 2.4* | 7.7 ± 2.2 | 0.54 |