Table 1 Perioperative factors of patients with or without postoperative pneumonia by univariate analysis (n = 727)
| Variable | Entire cohort (n = 727) | Univariate analysis | ||
|---|---|---|---|---|
| Postoperative pneumonia (n = 143) | No postoperative pneumonia (n = 584) | P-value | ||
| Age (year) | 62.9 ± 11.0 | 63.9 ± 11.8 | 62.6 ± 10.7 | 0.211 |
| Gender (female/male) | 391/336 | 81/62 | 310/274 | 0.444 |
| Weight (kg) | 61.6 ± 9.9 | 63.0 ± 10.3 | 61.2 ± 9.8 | 0.057 |
| Body mass index (kg/m2) | 23.2 ± 2.9 | 23.9 ± 2.9 | 23.0 ± 2.8 | 0.001 |
| Body mass index grading | < 0.001 | |||
| < 24.0 kg/m2 | 465 (64.0%) | 71 (49.7%) | 394 (67.5%) | |
| ≥ 24.0 kg/m2 | 262 (36.0%) | 72 (50.3%) | 190 (32.5%) | |
| Smoking, pack-years | 10.9 ± 23.7 | 8.3 ± 16.5 | 11.6 ± 25.1 | 0.477 |
| Diabetes mellitus | 64 (8.8%) | 10 (7.0%) | 54 (9.2%) | 0.394 |
| Hypertension | 206 (28.3%) | 43 (30.1%) | 163 (27.9%) | 0.608 |
| Coronary heart disease | 9 (1.2%) | 0 (0.0%) | 9 (1.5%) | 0.218 |
| History of lung surgery or chest trauma | 16 (2.2%) | 2 (1.4%) | 14 (2.4%) | 0.750 |
| Preoperative renal insufficiency | 4 (0.6%) | 1 (0.7%) | 3 (0.5%) | 0.584 |
| Forced expiratory volume in 1 s (percentage of predicted value) | 91.1 ± 17.5% | 89.9 ± 17.1% | 91.4 ± 17.6% | 0.364 |
| Forced vital capacity (percentage of predicted value) | 91.7 ± 15.9% | 89.0 ± 14.8% | 92.4 ± 16.1% | 0.023 |
| Peak expiratory flow (percentage of predicted value) | 67.1 ± 23.7% | 67.3 ± 27.1% | 67.0 ± 22.8% | 0.555 |
| Surgical lobe | 0.004 | |||
| Left lung lobe | 279 (38.4%) | 40 (28.0%) | 239 (40.9%) | |
| Right lung lobe | 448 (61.6%) | 103 (72.0%) | 345 (59.1%) | |
| Amount of intraoperative fluids, mL | ||||
| Total | 1529.2 ± 412.1 | 1473.4 ± 396.4 | 1542.8 ± 415.0 | 0.071 |
| Crystalloid | 1235.5 ± 385.0 | 1179.7 ± 354.0 | 1249.1 ± 391.3 | 0.053 |
| Colloid | 293.7 ± 255.9 | 293.7 ± 247.0 | 293.7 ± 258.3 | 0.999 |
| Blood | 0 | 0 | 0 | – |
| Intraoperative bleeding, mL | 48.3 ± 34.0 | 54.2 ± 43.3 | 46.8 ± 31.1 | 0.020 |
| Intraoperative urine output, mL | 406.7 ± 326.7 | 376.9 ± 315.0 | 414.0 ± 329.3 | 0.224 |
| Length of operation, min | 131.7 ± 35.6 | 128.2 ± 35.0 | 132.5 ± 35.7 | 0.191 |
| Length of anaesthesia, min | 159.1 ± 37.5 | 158.8 ± 37.6 | 159.2 ± 37.5 | 0.908 |
| Total intravenous crystalloid infusion in the postoperative 24 h, mL | 1273.5 ± 277.5 | 1321.2 ± 287.6 | 1261.8 ± 274.0 | 0.022 |
| Total intravenous crystalloid infusion grading in the postoperative 24 h | 0.006 | |||
| < 1000 mL | 128 (17.6%) | 26 (18.2%) | 102 (17.5%) | |
| 1000 to < 1500 mL | 461 (63.4%) | 77 (53.8%) | 384 (65.8%) | |
| ≥ 1500 mL | 138 (19.0%) | 40 (28.0%) | 98 (16.8%) | |
| Total intravenous colloid infusion in the postoperative 24 h, mL | 0 | 0 | 0 | – |
| Postoperative pathology | 0.097 | |||
| Malignant tumour n | 634 (87.2%) | 123 (86.0%) | 511 (87.5%) | |
| Benign tumour, n | 10 (1.4%) | 0 (0.0%) | 10 (1.7%) | |
| Benign non-inflammatory disease, n | 7 (1.0%) | 0 (0.0%) | 7 (1.2%) | |
| Inflammatory disease, n | 76 (10.5%) | 20 (14.0%) | 56 (9.6%) | |
| Second operation within 30 days after surgery | 1 (0.1%) | 0 (0.0%) | 1 (0.2%) | 1.000 |
| Postoperative prolonged air leak, n | 17 (2.3%) | 6 (4.2%) | 11 (1.9%) | 0.120 |
