Table 1 Patient characteristics in quartiles according to oldest red blood cell (RBC) transfusion during the ICU stay

Age, years

66 (58, 76)

66 (57, 75)

65 (54, 74)

66 (55, 75)

0.686

Male gender

82 (57.3%)

102 (65.4%)

114 (63.7%)

113 (64.9%)

Operative admission

80 (55.9%)

85 (54.5%)

92 (51.4%)

74 (42.5%)

0.067

Emergency admission, n/total

105/143 (73.4%)

114/153 (74.5%)

146/174 (83.9%)

149/172 (85.6%)

0.004

Emergency surgery <1 week

38 (26.6%)

42 (26.9%)

58 (32.45)

49 (28.2%)

0.369

Cardiac or vascular surgery

44 (30.8%)

56 (35.9%)

41 (22.9%)

29 (16.7%)

<0.001

Trauma

9 (6.3%)

6 (3.8%)

16 (8.9%)

13 (7.5%)

0.303

Severe sepsis

34 (23.8%)

50 (32.1%)

69 (38.5%)

69 (39.7%)

0.011

DIC

5/140 (3.5%)

12/151 (7.9%)

13/170 (7.6%)

16/168 (9.5%)

0.239

Acute kidney injury

52 (36.4%)

78 (50.0%)

69 (38.5%)

69 (39.7%)

0.029

Renal replacement therapy

8 (5.6%)

28 (17.9%)

34 (19.0%)

26 (14.9%)

0.004

SAPS II score

35 (27, 44)

36 (30, 50)

40 (28, 55)

38 (31, 53)

0.050

Maximum SOFA score

8 (6, 10)

9 (6, 11)

9 (6, 11)

9 (6, 11)^a

0.031

Mechanical ventilaiton

110 (76.9%)

132 (84.6%)

149 (83.2%)

132 (75.9%)

0.112

Vasoactive use

111 (77.6%)

124 (79.5%)

142 (79.3%)

130 (74.7%)^a

0.751

Lactate, mmol/L^b

1.96 (1.20, 3.40)

2.80 (1.50, 3.40)

2.40 (1.44, 4.60)

2.54 (1.50, 4.77)

0.009

Age of all RBCs, days

11 (9, 12)

14 (11, 15)

17 (13, 20)

17 (12, 26)

<0.001

Maximum age of RBCs, days

12 (10, 13)

15 (14, 16)

21 (19, 22)

29 (27, 32)

<0.001

Transfused units, n

2 (2, 4)

3 (2, 5)

3 (2, 6)

4 (2, 8)

0.001

RBC units over 14 days old, n

0

2 (1, 3)

2 (1, 4)

3 (2, 6)

<0.001

Massive transfusion pre-ICU^c

8 (5.6%)

9 (5.8%)

7 (3.9%)

15 (8.6%)

0.312

Admission hemoglobin, g/L ^d

100 (90, 112)

97 (88, 107)

97(88, 110)]

98 (85, 113)

0.544