Table 2 Comparison of characteristics according to occurrence of pneumothorax
| Â | No pneumothorax | Pneumothorax | p-value | Multivariate analysis | |
|---|---|---|---|---|---|
|  | N = 97 (81.5%) | N = 22 (18.5%) | OR (95% CI) | p- value | |
Median age, years | 65.0 (55.0–71.5) | 64.5 (58.0–72.0) | 0.760 | 1.0 (0.958–1.047) | 0.949 |
Sex (male) | 62 (63.9) | 14 (63.6) | 0.980 | 1.3 (0.440–3.895) | 0.628 |
Height, cm | 163.0 (156.0–169.5) | 165.0 (156.8–170.8) | 0.415 |  |  |
BMI, kg/m2 | 22.7 (20.5–25.7) | 20.8 (19.5–23.0) | 0.012 | 1.2 (1.011–1.356) | 0.035 |
Ever smoker | 28 (28.9) | 6 (27.3) | 0.881 | Â | Â |
Charlson Comorbidity Index | 3 (2–4) | 2 (2–3.5) | 0.447 |  |  |
Underlying disease | |||||
 Congestive heart failure | 8 (8.2) | 3 (13.6) | 0.431 |  |  |
 Chronic lung disease—airway | 5 (5.2) | 4 (18.2) | 0.037 | 0.2 (0.050–1.160) | 0.076 |
 Chronic lung disease—ILD | 17 (17.5) | 5 (22.7) | 0.553 |  |  |
 Chronic kidney disease | 27 (27.8) | 4 (18.2) | 0.352 |  |  |
 Chronic liver disease | 8 (8.2) | 1 (4.5) | 1.0 |  |  |
 Solid cancer | 31 (32.0) | 6 (27.3) | 0.801 |  |  |
 Hematologic malignancy | 20 (20.6) | 2 (9.1) | 0.360 |  |  |
History of lung operation | 8 (8.2) | 5 (22.7) | 0.063 | Â | Â |
History of pneumothorax | 0 (0) | 1 (4.5) | 0.185 | Â | Â |
CRRT due to AKI | 38 (39.2) | 3 (13.6) | 0.023 | Â | Â |
Clinical parameters | |||||
 WBC, × 103/μL | 9.9 (5.7–14.8) | 11.5 (6.1–22.4) | 0.162 |  |  |
 Lactate, mmol/L | 2.2 (1.5–5.1) | 1.8 (1.4–2.1) | 0.130 |  |  |
 C-reactive protein, mg/L | 129.2 (69.9–208.2) | 100.5 (10.1–160.2) | 0.108 |  |  |
 Procalcitonin, ng/mL | 1.5 (0.5–5.2) | 0.3 (0.2–0.5) | 0.008 |  |  |
 PaO2/FiO2 ratio at admission day | 83.6 (66.7–111.0) | 79.4 (61.6–101.1) | 0.372 |  |  |
 PaO2/FiO2 ratio at 3-day after admission | 38.2 (31.0–43.5) | 39.2 (31.7–49.3) | 0.446 |  |  |
 PaO2 at admission day | 87.7 (70.1–117.4) | 94.1 (80.7–108.9) | 0.433 |  |  |
 PaO2 at 3-day after admission | 84.6 (71.2–100.5) | 74.4 (63.5–85.5) | 0.063 |  |  |
 A-a gradient at admission day | 263.8 (165.9–458.5) | 338.0 (262.2–427.7) | 0.556 |  |  |
 A-a gradient at 3-day after admission | 197.6 (127.6–318.1) | 267.1 (148.0–350.5) | 0.324 |  |  |
APACHE II score | 27 (21–32) | 21 (18–32) | 0.129 |  |  |
SOFA score | 8.0 (6.0–12.0) | 7.0 (4.5–8.0) | 0.003 |  |  |
SAPSII | 37.0 (30.0–51.0) | 35.0 (24.5–45.0) | 0.134 |  |  |
Bacterial respiratory infection | 12 (12.4) | 3 (13.6) | 1.000 | Â | Â |
Fungal respiratory infection | 7 (7.2) | 0 (0) | 0.346 | Â | Â |
Cytomegalovirus antigenemia | 54 (55.7) | 21 (95.5) |  < 0.001 | 13.9 (1.737–111.072) | 0.013 |
Tracheostomy | 34 (35.1) | 11 (50) | 0.192 | Â | Â |
28-day mortality | 38 (39.2) | 7 (31.8) | 0.521 | Â | Â |
In-hospital mortality | 68 (70.1) | 17 (77.3) | 0.502 | Â | Â |
Mechanical ventilator parameters | |||||
 Respiratory rate, /min | 20.0 (16.0– 24.0) | 20.0 (18.0–26.0) | 0.379 |  |  |
 Tidal volume at admission day, mL/kg | 6.7 (6.1–7.6) | 6.8 (6.2–7.5) | 0.405 |  |  |
 Peak pressure at admission day, cmH2O | 25.0 (22.0–30.0) | 26.0 (22.8–32.3) | 0.420 |  |  |
 Peak pressure at 3-day after admission, cmH2O | 26.0 (20.3–30.0) | 26.0 (21.0–34.5) | 0.357 |  |  |
 Maximal peak pressure, cmH2O | 29.0 (25.0–34.0) | 31.5 (26.0–38.5) | 0.205 |  |  |
 Positive expiratory end pressure, cmH2O | 7.0 (5.0–10.0) | 5.5 (5.0–8.0) | 0.069 |  |  |
 Dynamic driving pressure, cmH2O | 19.0 (15.0–26.8) | 17.0 (14.0–22.0) | 0.166 |  |  |