Table 1 Central hemodynamics and arterial pressure variations at the four volemic levels

No resistor

   Cardiac output (l/min)

3.2 ± 0.7

7.5 ± 1.6*

7.9 ± 2.0

7.7 ± 2.2

   Stroke volume (ml)

24 ± 5

65 ± 11*

63 ± 10

62 ± 10

   Central venous pressure (mmHg)

0 ± 2

6 ± 2*

7 ± 2*

8 ± 2*

   Intrathoracic blood volume (ml)

485 ± 88

814 ± 177*

849 ± 156

924 ± 213

   Central venous oxygen saturation

0.89 ± 0.05

0.99 ± 0.04*

1 ± 0.02

0.98 ± 0.04

   Lactate (mmol/l)

1.2 ± 1.3

2.4 ± 1.8

1.9 ± 1.2

1.2 ± 0.8

   Base excess (mmol/l)

4.1 ± 1.5

2.2 ± 1.7

2.2 ± 1.6

3.0 ± 1.9

Systolic pressure variation

   No resistor (%)

5 ± 2

3 ± 2

2 ± 1

2 ± 1

   Inspiratory resistor (%)

10 ± 5^†

4 ± 2*

5 ± 2

4 ± 2

   Expiratory resistor (%)

11 ± 2^†

4 ± 2*

4 ± 1

3 ± 2

   Inspiratory/expiratory resistor (%)

13 ± 5^†

5 ± 3*

5 ± 2

4 ± 2

Pulse pressure variation

   No resistor (%)

17 ± 5

12 ± 2*

12 ± 4

12 ± 1

   Inspiratory resistor (%)

25 ± 6^†

16 ± 4* ^†

16 ± 6 ^†

15 ± 5^†

   Expiratory resistor (%)

25 ± 6

13 ± 6*

12 ± 3

11 ± 3

   Inspiratory/expiratory resistor (%)

26 ± 7^†

14 ± 6* ^†

14 ± 5^†

13 ± 6^†