Distensibility Index of Inferior Vena Cava
Purpose
The Distensibility Index of Inferior Vena Cava (dIVC) it’s the amount of increase of vena cava diameter after inspiration on a mechanical ventilated patient. This increase will rise when preload is reduced and so can be used to know when a patient its volume responsive[1]. It doesn’t give CVP or the preload of the right heart, but only if it is responsive to more volume.
Measurement
- On a subcostal window, measure the maximum IVC diameter on inspiration (dI) and the minimum IVC diameter on expiration (dE).
- Calculate the dIVC using the following formula:
Conditions and caveats
- The patient must be on volume control ventilation, with tidal volume of about 8,5ml/Kg, breathing rate of 15 and PEEP of 4 mmHg[1].
- There shouldn’t be abdominal hypertension[1], cardiac arrhythmias or cardiopulmonary disease[2], pending more studies
- It must be possible to do a echocardiogram by subcostal approach, so it can’t be used on the very obese or after an laparotomy
- The first study[1] was done on a reduced number of patient. The followup studies were only done on patients with subarachnoid hemorrhage[3] and on renal replacement therapy[4]
Reference Values
dIVC[1] | |
---|---|
Fluid responsive | >18% |
Bibliography
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Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients; Barbier C, Loubières Y, Schmit C, et al; Intensive Care Med; 2004;30(9):1740–6 ↩
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Evaluation of fluid responsiveness in ventilated septic patients: back to venous return;Vignon P.;Intensive Care Med 2004;30(9):1699–701 ↩
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Inferior Vena Cava Distensibility as a Predictor of Fluid Responsiveness in Patients with Subarachnoid Hemorrhage; Moretti R, Pizzi B; Neurocritical Care; 13(1):3–9 ↩
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Inferior vena cava collapsibility to guide fluid removal in slow continuous ultrafiltration: a pilot study; Guiotto G, Masarone M, Paladino F, et al.; Intensive Care Med;2010;36(4):692–6 ↩