Variables

Frequency N = 305 (%)

Pre-op Na < 135 N = 94 (%) Mean ± SD

Pre-op Na 135 - 145 N = 211 (%) Mean ± SD

X² t-test

P-value

Gender

Females

119 (39.0)

32 (34.0)

87 (41.2)

2.6

0.02

Males

186 (61.0)

62 (66.0)

124 (58.8)

Age, years

16 - 39

88 (28.9)

8 (8.5)

80 (37.9)

4.4

0.001

40 - 59

126 (41.3)

25 (26.6)

101 (47.9)

≥60

91 (29.8)

61 (64.9)

30 (14.2)

Surgeries

Cardiac

102 (33.5)

51 (54.3)

51 (24.2)

5.6

<0.001

Major Vascular

90 (29.5)

27 (28.7)

63 (29.9)

Intermediate

15 (4.9)

5 (5.3)

10 (4.7)

Minor

98 (32.1)

11 (11.7)

87 (41.2)

BMI, kg/m²

<19.5

71 (23.3)

9 (9.6)

62 (29.4)

2.9

0.002

19.5 - 24.9

88 (28.9)

17 (18.1)

71 (33.6)

25.0 - 29.9

91 (29.8)

46 (48.9)

45 (21.3)

>30.0

55 (18.0)

22 (23.4)

33 (15.7)

Mean SBP, mmHg

305 (100)

152.1 ± 9.2

132.5 ± 4.6

6.3

<0.001

Mean DBP, mmHg

305 (100)

95.4 ± 7.2

83.6 ± 2.3

4.3

<0.001

Mean SPO₂, (%)

305 (100)

95.2 ± 8.8

97.7 ± 9.5

6.4

<0.001

Serum biochemistry

Hematocrit, %

305 (100)

33.6 ± 3.8

38.4 ± 8.1

5.9

<0.001

Albumin, mg/dl

305 (100)

35.1 ± 11.5

33.9 ± 9.8

0.9

0.07

Creatinine, umol/l

305 (100)

103.4 ± 14.2

111.7 ± 5.6

5.1

<0.001

eGFR, ml/min

305 (100)

68.3 ± 5.2

60.8 ± 9.7

6.8

<0.001

Urea mmol/l

305 (100)

46.7 ± 3.8

71.2 ± 7.8

6.2

<0.001

Chloride, mmol/l

305 (100)

100.5 ± 6.9

96.1 ± 4.2

5.4

<0.001

Bicarbonate, mmol/l

305 (100)

23.8 ± 4.6

20.1 ± 7.2

4.9

<0.001

Potassium, mmol/l

305 (100)

4.7 ± 2.2

4.6 ± 3.4

0.7

0.8

Days on admission

<7

143 (46.9)

19 (20.2)

124 (58.8)

6.3

<0.001

7 - 13

22 (7.2)

6 (6.4)

16 (7.6)

14 - 27

106 (37.8)

47 (50.0)

59 (27.9)

>28

34 (1.1)

22 (23.4)

12 (5.7)

Comorbidities