Table 1 Patients’ demographic information

Number of patients

53

53

Gender (Male/Female)

23/30

30/23

0.174

Age (year)

54.79 ± 8.54

54.92 ± 12.03

0.948

Weight (kg)

64.87 ± 11.52

65.24 ± 17.21

0.897

Height (m)

1.63 ± 0.073

1.65 ± 0.096

0.249

BMI (kg/m2)

24.19 ± 3.30

23.74 ± 4.92

0.578

Preoperative diagnosis

 Lumbar spinal stenosis

47

51

0.141

 Spondylolisthesis

6

2

Level of fusion

 L2-L3

1

0

0.795

 L3-L4

3

3

 L4-L5

29

29

 L5-S1

20

21

ASA classification

 I

35

29

0.233

 II

18

24

Fibrinogen level

2.86 ± 0.58

2.83 ± 0.59

0.813

Patient’s blood volume (ml)

4008.11 ± 626.59

4092.18 ± 833.09

0.558

Preoperative haematocrit (%)

39.49 ± 4.44

40.85 ± 4.26

0.110

Preoperative hemoglobin (g/L)

133.02 ± 18.14

138.04 ± 15.56

0.129

Preoperative red blood cells (10^12/L)

4.48 ± 0.45

4.49 ± 0.48

0.913

Incidence of pre-operative anemia

24.53%

20.75%

0.643