Volume 11 Supplement 3

Fourth International Symposium on Intensive Care and Emergency Medicine for Latin America

Open Access

Dynamic evaluation of central venous pressure for fluid responsiveness assessment in spontaneous breathing dogs

  • E Silva1,
  • P Rehder1 and
  • GA Westphal1
Critical Care200711(Suppl 3):P11

https://doi.org/10.1186/cc5798

Published: 19 June 2007

Background

Variations in intrathoracic pressure interfere with venous return and cardiac output (CO). Inspiratory fall in central venous pressure (CVP) traces (ifCVP) during spontaneous breathing have been recommended for cardiovascular fluid responsiveness (CFR) evaluation. We recently described the usefulness of CVP wave amplitude variation (pressoric vena cava collapsibility index, Cvci) during mechanical ventilation for CFR estimation in critically ill patients. There are no data about the Cvci evaluation during spontaneous breathing.

Objective

To test the hypothesis that Cvci can be used for CFR evaluation during spontaneous ventilation.

Methods

In six male, anesthetized, intubated and spontaneous breathing dogs, CO measurements and CVP waves were registered through a Swan–Ganz catheter while the mean arterial pressure (MAP) was measured through an intraarterial catheter.

After baseline measurements a graded hemorrhage was performed in 10% quota until 50% of the estimated volemia. The total shed blood volume was then re-infused in the same quota. Measurements of the heart rate (HR), CO, MAP, CVP, ifCVP, and Cvci are performed in every bleeding and re-infusion step. The Cvci was calculated with the following formula: Cvci(%) = [(CVPPexp - CVPPins)/CVPPexp] × 100, using the inspiratory (CVPPins) and expiratory central venous pulse pressure (CVPPexp). ifCVP = CVP measured in the 'a' wave base at expiration minus CVP measured in the 'a' wave base at inspiration. Correlations among the CO and other variables were performed using the Spearman coefficient test.

Results

See Table 1. The correlations encountered were: CO and SvO2 (r = 0.94, P < 0.001); CO and Cvci (r = 0.61, P < 0.04); and CO and ifCVP (r = -0.02, P < 0.9).

Table 1

Step

0

-10%

-20%

-30%

-40%

-50%

-40%

-20%

0

CO

2.8 ± 0.5

2.4 ± 0.4

2.2 ± 0.4

1.8 ± 0.5

1.6 ± 0.5

1.4 ± 0.5

1.8 ± 0.4

3.0 ± 0.7

3.5 ± 0.8

ifCVP

2.8 ± 0.4

3.1 ± 0.5

3.8 ± 0.7

3.3 ± 0.5

2.1 ± 0.2

2.7 ± 0.5

4.1 ± 1

3.0 ± 0.5

2.3 ± 0.2

Cvci

-8 ± 6

-11 ± 13

-19 ± 8

-18 ± 15

-27 ± 10

-17 ± 7

-12 ± 20

-11 ± 7

-8 ± 4

Conclusion

We conclude that a pressoric vena cava collapsibility index may be used to detect cardiovascular fluid responsiveness during spontaneous ventilation.

Authors’ Affiliations

(1)
Division of Applied Physiology, Heart Institute, InCor, University of São Paulo Medical School

Copyright

© BioMed Central Ltd 2007

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