Figures
- Fig. 1—
A chronic obstructive pulmonary disease patient during a 6-min walking test while on a) supplemental oxygen and b) noninvasive positive-pressure ventilation in addition to supplemental oxygen.
- Fig. 2—
Changes in arterial oxygen tension (Pa,O2) before and after 6-min walking test while on a) supplemental oxygen and b) noninvasive positive-pressure ventilation in addition to supplemental oxygen. The whiskers represent sd. ***: p<0.001
- Fig. 3—
Borg dyspnoea scale following 6-min walking test while on supplemental oxygen and noninvasive positive-pressure ventilation (NPPV) in addition to supplemental oxygen. The whiskers represent the 25th–75th percentile values. ***: p<0.001.
- Fig. 4—
Walking distance after 6-min walking test while on supplemental oxygen and noninvasive positive-pressure ventilation (NPPV) in addition to supplemental oxygen. •: outliers. #: p = 0.027.
Tables
- Table 1—
Demographic data, lung function parameters and mouth occlusion pressures
Subjects n 20 Sex female n 8 Age yrs 65.1±8.7 BMI kg·m−2 28.2±8.6 FVC % pred 50.2±11.1 FEV1 % pred 27.0±7.5 FEV1/FVC % 48.2±12.3 TLC % pred 115.6±27.3 RV % pred 244.0±66.4 PI,maxpeak % pred 51.7±28.3 PI,max1.0 % pred 46.2±22.9 P0.1 kPa 0.40±0.20 P0.1×tI/VT kPa·s×L−1 0.76±0.29 Data are presented as mean±sd, unless otherwise stated. BMI: body mass index; FVC: forced vital capacity; % pred: % predicted; FEV1: forced expiratory volume in one second; TLC: total lung capacity; RV: residual volume; PI,maxpeak: peak maximal inspiratory mouth pressure; PI,max1.0: plateau maximal inspiratory mouth pressure sustained for 1 s; P0.1: mouth occlusion pressure 0.1 s after onset of inspiration during normal breathing; tI: inspiratory time, VT: tidal volume.
- Table 2—
Blood gases, cardiac frequency(fC), blood pressure, dyspnoea and walking distance before and after the 6-min walking test (6MWT).
Supplemental oxygen NPPV and supplemental oxygen Difference after 6MWT 95% CI p-value Before 6MWT Pa,O2 mmHg 72.4±5.6 70.7±8.1 0.16 Pa,CO2 mmHg 50.4±5.7 50.1±7.4 0.64 Sa,O2 % 95.1±1.6 94.7±2.1 0.524 pH 7.40±0.02 7.40±0.03 0.33 fC 89.5±12.2 87.6±15.7 0.67 SBP mmHg 119.5±20.3 122.6±17.2 0.49 DBP mmHg 69.8±14.4 70.4±12.6 0.85 BDS 0 (0/0) 0 (0/0) 0.63 After 6MWT Pa,O2 mmHg 61.6±7.9 81.2±12.4 13.3–26.0 <0.001 Pa,CO2 mmHg 53.3±6.5 51.5±6.4 -3.5– -0.1 0.038 Sa,O2 % 88.8±4.0 94.6±3.4 3.7–7.9 <0.001 pH 7.37±0.03 7.38±0.03 NF 0.21 fC 102.7±14.8 101.5±13.3 -10.0–7.7 0.79 SBP mmHg 133.7±24.2 137.5±19.0 -6.3–13.9 0.44 DBP mmHg 75.3±15.1 80.6±12.1 NF 0.034 BDS 6 (4.5–10) 4 (1.5–4.5) <0.001 6MWD m 222.0±84.8 260.7±64.9 NF 0.027 Data are presented as mean±sd or median (interquartile range), unless otherwise stated. NPPV: noninvasive positive-pressure ventilation; CI: confidence interval; Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension; Sa,O2: oxygen saturation; SBP: systolic blood pressure; DBP: diastolic blood presure; BDS: Borg dyspnoea scale; 6MWD: 6-min walking distance; NF: normality test failed. 1 mmHg = 0.133 kPa.
