Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Sep 24;6(1):36.
doi: 10.1186/s40635-018-0199-9.

Validation of new marker of fluid responsiveness based on Doppler assessment of blood flow velocity in superior vena cava in mechanically ventilated pigs

Tomas Kovarnik  1   2 , Miroslav Navratil  3 , Jan Belohlavek  3 , Mikulas Mlcek  4 , Martin Chval  5 , Zhi Chen  6 , Stepan Jerabek  3 , Otomar Kittnar  4 , Ales Linhart  3
Affiliations

Validation of new marker of fluid responsiveness based on Doppler assessment of blood flow velocity in superior vena cava in mechanically ventilated pigs

Tomas Kovarnik et al. Intensive Care Med Exp. .

Abstract

Background: We studied a novel approach for the evaluation and management of volemia: minimally invasive monitoring of respiratory blood flow variations in the superior vena cava (SVC). We performed an experiment with 10 crossbred (Landrace × large white) female pigs (Sus scrofa domestica).

Methods: Hypovolemia was induced by bleeding from a femoral artery, in six stages. This was followed by blood return and then an infusion of 1000 ml saline, resulting in hypervolemia. Flow in the SVC was measured by Flowire (Volcano corp., USA), located in a distal channel of a triple-lumen central venous catheter. The key parameters measured were venous return variation index (VRV)-a new index for fluid responsiveness, calculated from the maximal and minimal velocity time intervals during controlled ventilation-and systolic peak velocity (defined as peak velocity of a systolic wave using the final end-expiratory beat). A Swan-Ganz catheter (Edwards Lifesciences, USA) was introduced into the pulmonary artery to measure pulmonary arterial pressure, pulmonary capillary wedge pressure, and continuous cardiac output measurements, using the Vigilance monitor (Edwards Lifesciences, USA).

Results: We analyzed 44 VRV index measurements during defined hemodynamic status events. The curves of VRV indexes for volume responders and volume non-responders intersected at a VRV value of 27, with 10% false negativity and 2% false positivity. We compared the accuracy of VRV and pulse pressure variations (PPV) for separation of fluid responders and fluid non-responders using receiver operating characteristic (ROC) curves. VRV was better (AUCROC 0.96) than PPV (AUCROC 0.85) for identification of fluid responders. The VRV index exhibited the highest relative change during both hypovolemia and hypervolemia, compared to standard hemodynamic measurement.

Conclusions: The VRV index provides a real-time method for continuous assessment of fluid responsiveness. It combines the advantages of echocardiography-based methods with a direct and continuous assessment of right ventricular filling during mechanical ventilation.

Keywords: Animal experiment; Flow measurement; Fluid responsiveness; Hemodynamics; Hypovolemia; Superior vena cava.

PubMed Disclaimer

Conflict of interest statement

Ethics approval and consent to participate

This study was approved by the First Faculty of Medicine Institutional Animal Care and Use Committee and performed at the Animal Laboratory, Department of Physiology, First Faculty of Medicine, Charles University in Prague, in accordance with Act No 246/1992 Coll., on the protection of animals against cruelty.

Consent for publication

All authors of this manuscript have read, and agreed to, its content, and are accountable for all aspects of the accuracy and integrity of the manuscript. The submitted article is original and has not previously been published in another journal, nor is it currently under consideration by another journal.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Screenshot from Doppler analyzer with ECG, airway pressures, flow in SVC, and blood pressure tracings. Shown are, from upper side to lower side, ECG, airway pressure, Doppler flow signal from the SVC, and arterial blood pressure. S systolic forward flow, D diastolic forward flow, VR systolic reversal flow, AR atrial reversal flow, VTI velocity time integral
Fig. 2
Fig. 2
Changes in VRV index during the study. The “X” axis represents changes in volume status (bleeding in percent of estimated blood volume, two times reinfusion with 500 ml of blood, 1000 ml of saline infusion). The “Y” axis represents cardiac output in liters per minute measured by CCO (SwanGanz catheter). Numbers in circles are VRV indexes. This figure was done using data from five animals. VRV venous return variation index, CO cardiac output
Fig. 3
Fig. 3
VRV index in all hemodynamic situations. VRV venous return variation index
Fig. 4
Fig. 4
The curves of VRV indexes for volume responders and volume non-responders. VRV venous return variation index
Fig. 5
Fig. 5
AUC curves for VRV (0.96) and PPV (0.85) for prediction of fluid responsiveness. AUC area under curve, VRV venous return variation index, PPV pulse pressure variations
Fig. 6
Fig. 6
Bland–Altman plots on agreement measures between VRV and PPV. It shows the biggest difference between VRV and PPV around the VRV cutoff point for fluid responsiveness. VRV venous return variation index, PPV pulse pressure variations
Fig. 7
Fig. 7
Shows changes in the VRV index, VTImin in SVC, and static markers for hypovolemia. Values are normalized to 100 points at the baseline. This means that all variables started at 100%, and the graphs show their changes during the different stages of the experiment. VRV venous return variation index, PPV pulse pressure variations, CO cardiac output, EDP end-diastolic pressure, CVP central venous pressure, S peak systolic peak velocity, SV stroke volume, PCW pulmonary capillary wedge pressure, VTI velocity time integral, MAP mean arterial pressure
See this image and copyright information in PMC

References

    1. Holte K, Sharrock NE, Kehlet H. Pathophysiology and clinical implications of perioperative fluid excess. Br J Anesth. 2002;89:622–632. doi: 10.1093/bja/aef220. - DOI - PubMed
    1. Feihl F, Broccard A. Interactions between respiration and systemic hemodynamics. Part I: basic concepts. Intensive Care Med. 2009;35:45–54. doi: 10.1007/s00134-008-1297-z. - DOI - PubMed
    1. Michard F, Teboul JL. Predicting fluid responsiveness in ICU patients: a critical analysis of the evidence. Chest. 2002;121:2000–2008. doi: 10.1378/chest.121.6.2000. - DOI - PubMed
    1. Magder S. Clinical usefulness of respiratory variations in arterial pressure. Am J Respir Crit Care Med. 2004;169:151–155. doi: 10.1164/rccm.200211-1360CC. - DOI - PubMed
    1. Reuter DA, Felbinger TW, Schmidt C, Kilger E, Goedje O, Lamm P, Goetz AE. Stroke volume variations for assessment of cardiac responsiveness to volume loading in mechanically ventilated patients after cardiac surgery. Intensive Care Med. 2002;28:392–398. doi: 10.1007/s00134-002-1211-z. - DOI - PubMed

LinkOut - more resources