Table 1 Patient characteristics and acid-base parameters

N

64

281

55

Age (years)

65 ± 10

63 ± 13

62 ± 12

Sex male, n (%)

37 (58)

158 (56)

32 (58)

ASA classification, n (%):

ASA 1

2 (3)

6 (2)

0 (0)

ASA 2

17 (27)

102 (36)

21 (38)

ASA 3

40 (63)

151 (54)

26 (47)

ASA 4

5 (8)

22 (8)

8 (15)

Indication for HDU admission, n (%):

Type of surgery

42 (66)

194 (69)

39 (71)

Patient comorbidities

22 (34)

87 (31)

16 (29)

Surgical blood loss (ml)

1141 ± 1350

772 ± 958

694 ± 1023

Infusion fluids^a:

Balanced crystalloid (Sterofundin®, ml/kg)

37 ± 23

33 ± 20

31 ± 18

Unbalanced crystalloid (0,9% NaCl, ml/kg)

12 ± 10

9 ± 7

8 ± 6

Balanced colloid (Volulyte®, ml/kg)

6 ± 8

4 ± 6

4 ± 6

Unbalanced colloid (Voluven®, ml/kg)

2 ± 4

2 ± 4

1 ± 3

Acid-base parameters:

 pH

7.31 ± 0.03

7.40 ± 0.03

7.48 ± 0.02

 pCO₂ (kPa)

6.0 ± 1.0

5.6 ± 0.6

5.1 ± 1.0

 HCO₃⁻ (mmol/L)

22.6 ± 3.6

26 ± 3.0

28.2 ± 5.4

 Sodium (mmol/L)

140 ± 4

139 ± 3

139 ± 5

 Chloride (mmol/L)

110 ± 6

107 ± 4

105 ± 6

 Lactate (mmol/L)

1.8 ± 1.9

1.1 ± 0.7

1.2 ± 0.6

 Albumin (g/L)

28 ± 6

30 ± 6

30 ± 6

 BE (mmol/L)

− 4 ± 3

1 ± 3

4 ± 4

 AG corrected (mmol/L)

14 ± 4

12 ± 2

11 ± 3

 SID apparent (mmol/L)

36 ± 4

38 ± 3

39 ± 7

 SID effective (mmol/L)

33 ± 4

37 ± 4

39 ± 6

 SIG (mmol/L)

3 ± 3

1 ± 2

0 ± 2

Length of stay (days)

15 ± 11

13 ± 10

13 ± 10

AKI, n (%)

10 (16)

12 (4)

0 (0)

Pulmonary embolism, n (%)

3 (5)

5 (2)

2 (4)

Myocardial infarction, n (%)

1 (2)

1 (0)

3 (6)

Unplanned ICU admission, n (%)

14 (22)

25 (9)

5 (9)

Mortality, n (%)

8 (13)

6 (2)

2 (4)