Table 2 Perioperative characteristics

Type of surgery

0.31

 Upper Gastrointestinal

45 (6.4%)

33 (5.7%)

12 (9.8%)

 Small intestine with resection

162 (23.0%)

129 (22.2%)

33 (27.0%)

 Colon with resection

109 (15.5%)

90 (15.5%)

19 (15.6%)

 Laparotomy

318 (45.2%)

268 (46.1%)

50 (41.0%)

 Combined small intestine and colon

50 (7.1%)

44 (7.6%)

6 (4.9%)

 Other

19 (2.7%)

17 (2.9%)

2 (1.6%)

Peritoneal contamination

 < 0.0001

 None

440 (62.7%)

377 (65.0%)

63 (51.6%)

 Minimal

107 (15.2%)

91 (15.7%)

16 (13.1%)

 Local pus/abscess

60 (8.5%)

52 (9.0%)

8 (6.6%)

 Diffuse pus or faeces

95 (13.5%)

60 (10.3%)

35 (28.7%)

Peroperative blood loss

0.84

  < 100 ml

558 (88.7%)

454 (88.5%)

104 (89.7%)

 100-500 ml

49 (7.8%)

40 (7.8%)

9 (7.8%)

  > 500 ml

22 (3.5%)

19 (3.7%)

3 (2.6%)

 Missing

74 (10.5%)

68 (11.7%)

6 (4.9%)

Peroperative blood transfusion

31 (4.4%)

23 (4.0%)

8 (6.6%)

0.19

Transferred directly to the ICU postoperatively (on POD 0)

53 (7.5%)

31 (5.3%)

22 (18.0%)

 < 0.001

s-Creatinine (µmol l ⁻¹ ), Median (IQR)

79 (40)

77 (34)

93 (50)

 < 0.0001

eGFR [ml (min 1.73 m ² ) ⁻¹ ], Median (IQR)^e

65 (32)

68 (29.5)

58 (29.5)

 < 0.0001

 Missing

219 (31.2%)

Blood Urea (mmol l ⁻¹ ), Median (IQR)

6.9 (5.1)

6.7 (4.8)

8.8 (6.1)

 < 0.0001

 Missing

61 (8.7%)

p-sodium (mmol l ⁻¹ ), Median (IQR)

137 (5.0)

137 (5.0)

136 (6.0)

0.18

 Missing

25 (3.6%)

p-potassium (mmol l ⁻¹ ), Median (IQR)

3.7 (0.6)

3.7 (0.6)

3.6 (0.8)

0.26

 Missing

28 (4.0%)

p-haemoglobin (mmol l ⁻¹ ), Median (IQR)

8.5 (1.9)

8.5 (1.8)

8.4 (1.8)

0.16

 Missing

35 (5.0%)