Table 2 Univariate analysis of clinical covariates with postoperative acute kidney injury (AKI)

Surgical information

 Surgical procedure (n (%))

0.747

  AVR + MVR + TVR (n (%))

0 (0.0)

1 (1.9)

  AVR + MVR + TVP (n (%))

45 (97.8)

49 (92.5)

  AVP + MVP + TVP (n (%))

0 (0.0)

2 (3.8)

  AVR + MVR (n (%))

1(2.2)

1 (1.9)

 Cardiac ablation (n (%))

13 (28.3)

12 (22.6)

0.421

 Length of surgery (min)

241.9 ± 44.9

281.6 ± 74.4

0.002

 Intraoperative inotropic score

5.0 (4.0, 5.0)

5.0 (5.0, 8.0)

0.002

Intraoperative Fluid management

 Crystalloid (ml)

700 (700, 700)

700 (700, 800)

0.009

 Colloid (ml)

0 (0, 0)

0 (0, 0)

0.367

 PRBC (ml)

0 (0, 0)

0 (0, 0)

0.316

 Platelets (ml)

0 (0, 0)

0 (0, 0)

0.352

 FFP (ml)

0 (0, 340)

195 (0, 393)

0.279

 Cryoprecipitate (ml)

0 (0, 0)

0 (0, 0)

0.185

 Homologous RBC (ml)

500 (450, 700)

500 (500, 775)

0.379

 Urine output (ml)

300 (200,550)

375 (200, 500)

0.638

 Blood loss (ml)

400 (300, 450)

400 (300, 500)

0.150

CPB course

 Total CPB time (min)

141 (120, 162)

153 (120, 191)

0.166

 Cross-clamp time (min)

92.5 (74.0, 115.0)

95.0 (71.0, 109.0)

0.891

 Lowest Hb during CPB (g/dL)

7.7 (7.0, 9.1)

8.4 (7.4, 9.1)

0.122

 Lowest MAP during CPB (mmHg)

41.5 (34.0, 46.0)

40.0 (36.0, 46.0)

0.872

 Lowest temperature during CPB (℃)

31.0 ± 0.7

30.9 ± 0.9

0.612

 Dopamine (mg)

0 (0, 0)

0 (0, 0)

0.271

 Nonepinephrine (ug)

0 (0, 20)

0 (0, 25)

0.678

 Epinephrine (ug)

0 (0, 0)

0 (0, 0)

0.807

 Isoproterenol (ug)

0 (0, 0)

0 (0, 0)

0.170

 Isosorbide (mg)

0 (0, 0)

0 (0, 0)

0.522

 Aramine (mg)

0 (0, 2)

0 (0, 2)

0.515

 Torasemide (mg)

10 (0, 10)

10 (10, 10)

0.016

 Hydroprednisolone (mg)

0 (0, 100)

100 (0, 180)

0.210

 PRBC (ml)

0 (0, 260)

0 (0, 240)

0.940

 PRBC Storage duration (d)

11 (9, 11)

12 (9, 15)

0.318

 FFP (ml)

0 (0, 0)

0 (0, 0)

0.418

 Crystalloid (ml)

1000 (1000, 1000)

1000 (1000, 1000)

0.693

 Colloid (ml)

1000 (1000, 1000)

1000 (1000, 1000)

0.423

 Urine output (ml)

800 (350, 1200)

600 (300, 1000)

0.156

CCU

 APACHE II score

18 (18, 18)

18(18 18)

0.837

 Intubation time (h)

22.3 (17.8, 25.0)

26.5 (21.0, 45.1)

0.0006

 Length of CCU stay (hours)

46.1 (43.5, 68.5)

68.0 (62.0, 90.0)

0.006

 Readmitted to CCU (n (%))

0 ( 0.0)

4 (7.6)

0.121

 Furosemide (mg)

20 (0, 40)

20 (20, 40)

0.056

 Hydrprednisone (mg)

0 (0, 0)

0 (0, 0)

0.627

 Inotropic Score

8 (5, 10)

6.5 (3, 8)

0.250

 Crystalloid (ml)

2342.5 (2043.0, 2659.0)

2639.0 (2324.0, 3121.0)

0.021

 Colloid (ml)

0 (0, 0)

0 (0, 0)

0.222

 Albumin (ml)

0 (0, 0)

0 (0, 0)

0.333

 PRBC (ml)

0 (0, 0)

130 (0, 290)

0.002

 PRBC Storage (d)

13 (8, 14)

12 (8, 15)

1.000

 FFP (ml)

400 (352.5, 772.5)

700 (440, 960)

0.058

 Urine output (ml)

3370 (2730, 3880)

3070 (2620, 3950)

0.352

 Chest tube drainage (ml)

445 (325, 600)

350 (225,775)

0.431

Length of hospital stay (d)

11 ± 5

11 ± 4

0.811

Postoperative complications

 Death (n (%))

0 (0.0)

4 (7.5)

0.164

 Reoperation (n (%))

2 (4.4)

2 (3.8)

1.000

 New AF or flutter (n (%))

0 (0.0)

2 (3.8)

0.284

 Stroke (n (%))

0 (0.0)

0 (0.0)

1.000

 Acute hepatic injury (n (%))

3 (6.5)

18 (34.0)

0.001

Pulmonary events (n (%))

 Pulmonary infection (n (%))

19 (41.3)

33 (62.3)

0.037

 Atelectasis (n (%))

6 (13.0)

20 (37.7)

0.005

 Pleural effusion (n (%))

3 (6.5)

10 (18.9)

0.070

 Pneumothorax (n (%))?

1 (2.2)

1 (1.9)

1.000

 Cardiac dysfunction (n (%))

5 (10.9)

8 (15.1)

0.535

 Gastrointestinal bleeding (n (%))

2 (4.3)

3 (5.7)

1.000

 Respiratory failure (n (%))

5 (10.9)

13 (23.5)

0.079

 Thrombosis (n (%))

0 (0.0)

2 (3.8)

0.284

 Wound infection (n (%))

2 (4.4)

3 (5.7)

1.000

 MODS (n (%))

0 (0.0)

5 (9.4)

0.093

 Sepsis (n (%))

0 (0.0)

1 (1.9)

1.000

 Postoperative day 3 delirium

4 (8.7)

3 (5.7)

0.846