Table 1.
Baseline characteristics
| Variables | Without POD n = 146 | With POD n = 78 | χ2 /Z/t | P value |
|---|---|---|---|---|
| Demographics | ||||
| Age (years), mean ± SD | 51.20 ± 11.38 | 55.58 ± 11.42 | 2.741 | 0.007a |
| BMI (kg/m2), mean ± SD | 24.05 ± 3.69 | 25.63 ± 4.35 | 2.726 | 0.007a |
| Sex (Female), n (%) | 36 (24.7%) | 20 (25.6%) | 0.026 | 1.000b |
| Comorbidities | ||||
| Hypertension, n (%) | 108 (74.0%) | 56 (71.8%) | 0.123 | 0.726 b |
| Diabetes, n (%) | 16 (11.0%) | 5 (6.4%) | 1.238 | 0.266b |
| Smoking, n (%) | 33 (22.6%) | 25 (32.1%) | 2.365 | 0.124b |
| Drinking history, n (%) | 30 (20.5%) | 27 (34.6%) | 5.303 | 0.021b |
| Laboratory values | ||||
| Preoperative TSH (mIU/L), mean ± SD | 2.20 ± 1.75 | 2.02 ± 1.65 | 0.748 | 0.455a |
| Preoperative FT3 (pmol/L), mean ± SD | 5.08 ± 1.78 | 4.57 ± 1.05 | 2.694 | 0.008 a |
| Preoperative FT4 (pmol/L), mean ± SD | 13.30 ± 4.08 | 11.69 ± 6.40 | 2.291 | 0.023 a |
| Preoperative cortisol (nmol/l), median (Q1, Q3) | 316.64 (281.18,376.56) | 399.31 (334.95,451.85) | 7.005 | < 0.001c |
| Preoperative IL-2 (pg/ml), median (Q1, Q3) | 2.56 (1.94,3.16) | 3.21 (2.72,3.69) | 6.201 | < 0.001c |
| Preoperative PCT (ng/mL), median (Q1, Q3) | 0.03 (0.02,0.05) | 0.05 (0.04,0.06) | 6.306 | < 0.001c |
| White blood cell count (× 109/L), median (Q1, Q3) | 9.0 (7.2, 12.2) | 9.2 (7.8, 13.4) | 1.440 | 0.120 c |
| Red blood cell count (× 1012/L), median (Q1, Q3) | 5.2 (4.0, 5.8) | 5.1 (4.0, 5.5) | 0.336 | 0.870 c |
| Hemoglobin (g/L), median (Q1, Q3) | 120 (112, 140) | 118 (112, 142) | 0.205 | 0.770 c |
| Platelet count (× 109/L), median (Q1, Q3) | 170 (135, 222) | 160 (134, 199) | 1.995 | 0.354 c |
| Serum creatinine (μmol/L), median (Q1, Q3) | 80.7 (75.0, 119.4) | 96.7 (80.0, 120.0) | 1.800 | 0.341 c |
| Serum total bilirubin (umol/L), median (Q1, Q3) | 48.8 (27.5, 74.5) | 76.9 (65.0, 98.8) | 4.780 | 0.002 c |
| Serum albumin (g/L), median (Q1, Q3) | 37.4 (35.5, 42.0) | 38.1 (35.0, 42.2) | 0.259 | 0.805 c |
| Serum globulin (g/L), median (Q1, Q3) | 24.0 (22.2, 28.0) | 24.3 (22.3, 28.5) | 0.411 | 0.693 c |
| D-Dimmer (ug/L), median (Q1, Q3) | 183 (45,355) | 194 (58,349) | 0.570 | 0.580 c |
| Ejection fraction (%), median (Q1, Q3) | 61 (54, 66) | 60 (53, 66) | 0.300 | 0.799 c |
| Intraoperative data | ||||
| Catogeries of surgery, n (%) | 3.064 | 0.559 b | ||
| Isolated AAD surgery | 97 (66.4) | 47 (60.3) | ||
| Combined valve surgery | 30 (20.5) | 15 (19.2) | ||
| Combined coronary artery bypass grafting | 9 (6.2) | 6 (7.7) | ||
| Combined valve and coronary surgery | 8 (5.5) | 7 (9.0) | ||
| Combined other types of cardiac surgery | 2 (1.4) | 3 (3.8) | ||
| Deep hypothermic circulatory arrest time, min, median (Q1; Q3) | 16.5 (13.5, 20.5) | 17.5 (14.5, 22.5) | 1.032 | 0.505 c |
| Cardiopulmonary bypass time, min, median (Q1; Q3) | 145 (100, 186) | 155 (115, 190) | 0.575 | 0.668c |
| Aortic cross clamp time, min, median (Q1; Q3) | 59.4 (48.5, 70.0) | 62.3 (52.8, 72.6) | 1.008 | 0.588c |
| Lowest rectal temperature (°C), mean ± SD | 23.30 ± 2.45 | 23.55 ± 2.60 | 0.712 | 0.477a |
| Transfusion of red blood cells (units), mean ± SD | 4.50 ± 3.50 | 4.85 ± 3.80 | 0.692 | 0.490 a |
| Transfusion of platelet (units), mean ± SD | 8.88 ± 3.50 | 9.40 ± 3.50 | 1.059 | 0.291 a |
The Shapiro–Wilk test was used to assess data distributions. Results are expressed as n (%) or mean ± standard deviation (SD), median (Q1; Q3)
POD postoperative delirium, BMI body mass index, Q1 first quartile, Q3 third quartile, FT3 free triiodothyronine, FT4 free thyroxine, TSH thyroid stimulating hormone, IL-2 interleukin-2, PCT procalcitonin, AAD acute aortic dissection
aStudent’s t test
bchi-squared or Fisher’s exact test. c Wilcoxon rank-sum test
Bold mean statistical significances were determined due to a two-tailed P value < 0.05