Table 2 Hemodynamic and tissue oxygenation parameters before and after 500 mL of volume expansion according to the response of VO₂ in fluid-responder patients

Heart rate (beats/min)

108 ± 34

102 ± 26*

110 ± 27

109 ± 26

Mean arterial pressure (mmHg)

66 ± 16

79 ± 13*

74 ± 13

85 ± 10*

Cardiac index (L/min/m²)

2.59 [1.42–3.03]

3.02 [2.09–3.71]*

3.25 [2.49–3.65]^#

3.81 [3.48–4.23]^#,*

Stroke index (mL/m²)

19.4 [13.1–35.9]

27.0 [22.5–43.8]*

30.8 [21.5–34.1]^#

41.0 [31.6–41.4]*

Minute ventilation (L/min)

10.4 ± 2.0

–

8.5 ± 1.5^#

–

Arterial pH

7.35 [7.32–7.38]

7.36 [7.35–7.37]

7.23 [7.21–7.30]^#

7.22 [7.22–7.31]^#

Base excess (mmol/L)

–7.21 ± 4.74

–7.11 ± 4.21

–8.15 ± 4.20

–8.25 ± 3.89

SaO₂ (%)

99 [90–100]

98 [94–100]

94 [91–96]^#

95 [92–98]^#,*

Hemoglobin (g/dL)

10.1 ± 1.3

9.5 ± 1.1*

10.7 ± 1.0

10.1 ± 0.9^#,*

CaO₂ (mL)

12.8 ± 2.0

12.8 ± 1.7

13.2 ± 1.4

13.2 ± 1.2

PaCO₂

31 ± 5

31 ± 6

43 ± 8^#

42 ± 7^#

CaCO₂ (mL)

37.1 [30.0–49.2]

37.2 [28.8–46.4]*

40.5 [35.6–46.9]

37.2 [34.9–42.8]*

Venous pH

7.31 [7.24–7.34]

7.33 [7.27–7.33]

7.22 [7.18–7.24]^#

7.21 [7.20–7.27]^#,*

ScvO₂ (%)

63 ± 11

63 ± 10

58 ± 14

69 ± 10^#,*

CcvO₂ (mL)

8.4 ± 2.0

8.1 ± 1.6*

8.2 ± 2.2

9.6 ± 1.8^#,*

PcvCO₂ (mmHg)

40 ± 7

38 ± 7*

49 ± 7^#

47 ± 6^#,*

CcvCO₂ (mL)

43.4 [35.1–53.3]

41.4 [31.8–49.6]*

43.6 [40.2–47.3]

39.9 [37.9–43.3]*

DO₂ (mL/min/m²)

297 ± 86

381 ± 84*

409 ± 80^#

529 ± 84^#,*

VO₂ (mL/min/m²)

95 ± 27

134 ± 30*

148 ± 43^#

145 ± 37

OE

0.34 ± 0.11

0.37 ± 0.10*

0.37 ± 0.15

0.28 ± 0.09^#,*

∆PCO₂ (mmHg)

7.0 [6.0–14.0]

6.0 [5.0–12.0]*

4.0 [3.7–9.0]^#

3.0 [3.0–6.0]^#,*

∆ContO₂ (mL)

4.3 ± 1.6

4.7 ± 1.4*

5.0 ± 2.1

3.7 ± 1.1^#,*

∆ContCO₂ (mL)

5.2 [3.9–6.3]

3.0 [2.8–4.2]*

1.8 [0.3–4.7]^#

1.5 [0.5–3.3]^#,*

∆PCO₂/∆ContO₂ (mmHg/mL)

2.20 [1.70–2.33]

1.66 [1.10–1.96]*

1.05 [1.02–1.14]^#

1.13 [0.83–1.35]^#

∆ContCO₂/∆ContO₂

1.22 [1.05–1.26]

0.65 [0.65–0.70]*

0.53 [0.09–0.64]^#

0.46 [0.14–0.70]^#

Lactate (mmol/L)

5.8 [3.2–7.6]

5.0 [2.8–6.9]*

2.9 [2.1–4.9]^#

2.7 [1.4–4.4]^#,*