Table 2. Clinical variables of patients with acute exacerbation of COPD based on PA/A ratio.
| Variables | PA/A ratio ≥1 (n=111) | PA/A ratio <1 (n=324) | P value |
|---|---|---|---|
| Arterial blood gas analysis | |||
| pH | 7.36 (0.01) | 7.39 (0.09) | 0.006 |
| PaCO2 (mmHg) | 54.0 (1.9) | 46.0 (1.0) | <0.001 |
| P/F ratio | 259.2 (11.7) | 284.2 (7.3) | 0.07 |
| V/Q mismatch + hypoventilation | 20 (18.0) | 31 (9.6) | 0.02 |
| ARF type | 0.001 | ||
| No ARF | 32 (28.8) | 138 (42.6) | |
| Type 1 ARF | 40 (36.0) | 125 (38.6) | |
| Type 2 ARF | 39 (35.1) | 61 (18.8) | |
| Laboratory findings | |||
| White blood cells (×103/μL) | 10,274 (423) | 11,251 (301) | 0.08 |
| Neutrophil (%) | 77.0 (1.1) | 75.6 (0.7) | 0.29 |
| Eosinophil (%) | 1.2 (0.2) | 2.1 (0.2) | 0.01 |
| Hemoglobin (g/dL) | 12.7 (0.1) | 13.1 (0.1) | 0.08 |
| Platelet count (×103/μL) | 229.6 (0.9) | 231.9 (4.6) | 0.81 |
| Blood urea nitrogen (mg/dL) | 19.8 (1.1) | 19.2 (0.5) | 0.59 |
| Creatinine (mg/dL) | 0.94 (0.05) | 0.92 (0.02) | 0.65 |
| C-reactive protein (mg/dL) | 7.87 (0.76) | 7.33 (0.46) | 0.55 |
| Treatment | |||
| Conventional oxygen therapy | 102 (91.9) | 292 (90.1) | 0.70 |
| High-flow nasal cannula | 12 (10.8) | 15 (4.6) | 0.03 |
| Non-invasive ventilation | 24 (21.6) | 25 (7.7) | <0.001 |
| ICU admission | 13 (11.7) | 28 (8.6) | 0.34 |
| Intubation | 15 (13.5) | 25 (7.7) | 0.08 |
| Antibiotics | 109 (98.2) | 314 (96.9) | 0.73 |
| Steroids | 74 (66.7) | 218 (67.3) | 0.90 |
| Hospital stay (days) | 10.9 (0.6) | 9.5 (0.3) | 0.050 |
| In-hospital mortality | 1 (0.9) | 9 (2.8) | 0.46 |
| Readmission within 12 months | 31 | 88 | 0.39 |
| Death within 12 months | 5 | 24 | 0.42 |
Data are presented as mean (standard deviation), number (%), or number. COPD, chronic obstructive pulmonary disease; PA/A ratio, pulmonary artery-to-aorta ratio; PaCO2, arterial carbon dioxide partial pressure; P/F ratio, arterial oxygen partial pressure to fractional inspired oxygen; V/Q, ventilation-perfusion; ARF, acute respiratory failure; ICU, intensive care unit.