Table 3.
Parameters including pulmonary function, arterial blood gas, and sleep study of all participants.
| Variable | IPAH with desaturation (n = 17) | IPAH without desaturation (n = 33) | P value |
|---|---|---|---|
| Pulmonary function (% pred) | |||
| FEV1 | 78.46 ± 11.09 | 77.12 ± 15.21 | 0.751 |
| FVC | 82.19 ± 11.56 | 83.69 ± 13.38 | 0.678 |
| FEV1/FVC | 91.67 ± 9.15 | 95.20 ± 9.31 | 0.451 |
| TLC | 81.67 ± 7.78 | 79.38 ± 13.05 | 0.618 |
| DLCO | 67.85 ± 15.66 | 69.76 ± 11.63 | 0.879 |
| Arterial blood gas | |||
| PaO2 (mmHg) | 61.95 ± 10.51 | 77.92 ± 12.10 | 0.005 |
| PaCO2 (mmHg) | 33.55 ± 3.55 | 35.84 ± 3.32 | 0.133 |
| SPO2 (%) | 91.48 ± 3.55 | 94.75 ± 4.83 | 0.126 |
| Sleep study | |||
| Sleep time (min) | 408.37 ± 11.77 | 388.41 ± 82.74 | 0.532 |
| AHI (events/h) | 1.66 ± 0.87 | 1.64 ± 1.30 | 0.973 |
| ODI | 15.14 ± 6.28 | 13.76 ± 14.58 | 0.808 |
| SPO2 mean (%) | 89.23 ± 1.76 | 94.25 ± 1.90 | <0.001 |
| Minimum SPO2 (%) | 81.43 ± 1.81 | 85.82 ± 6.43 | 0.084 |
| TIB with SPO2 <90% | 199.77 ± 132.42 | 5.34 ± 10.84 | <0.001 |
| CPET parameters | |||
| PeakVO2 (mL/min) | 694.00 ± 271.51 | 844.42 ± 268.58 | 0.19 |
| PeakVO2/kg | 11.57 ± 5.13 | 14.41 ± 4.02 | 0.117 |
| VE/VCO2 (mL/min/kg) | 49.74 ± 14.31 | 40.68 ± 7.73 | 0.023 |
| VE/VCO2 slope | 59.15 ± 29.30 | 41.08 ± 10.99 | 0.014 |
Note: Data are presented as mean ± SD or median (interquartile range).
PAH: idiopathic pulmonary arterial hypertension; FEV1: forced expiratory volume at first second; FVC: forced vital capacity; TLC: total lung capacity; DLCO: diffusion capacity for carbon monoxide of the lung; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; SPO2: oxygen saturation; ODI: oxygen desaturation index; SPO2 mean: mean oxygen saturation; SPO2 lowest: minimum oxygen saturation; TIB with SPO2 <90%: time spent lower than 90% of oxygen saturation; CPET: cardiopulmonary exercise testing; PeakVO2: peak oxygen uptake; PeakVO2/kg: peak kilogram oxygen uptake; VE/VCO2: carbon dioxide ventilation equivalent; VE/VCO2 slope: the slope of carbon dioxide ventilation equivalent.