Determination of optimal implantation site in central venous system for wireless hemodynamic monitoring

Figures

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  Fig. 1. Image of a patient affected of an abdominal aortic aneurysm. The red arrows highlight the presence of the aneurysm, whereas the blue arrows point at the location of the IVC. The latter is compressed by the bulge of the aneurysm.

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  Fig. 2. Inferior Vena Cava Tributaries: (A) Geeky Medics; Representation of the IVC with the most relevant features studied and their diameters in mm [15]. (B). D1, portion of the IVC immediately superior to the iliac bifurcation. D2, a midway location in the IVC between the lower renal vein and the iliac bifurcation D3, the site of the IVC immediately inferior to the right renal vein. D4 (right) and D5 (left) external iliac veins.

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  Fig. 3. CT scan showing how measurements of diameter and link distances were taken. Link distance was measured both to the front and the back of the patient, as wireless collection of data can be done from either side of the patient.

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  Fig. 4. CT Scans of a patient with peripheral vascular disease. This image represents snapshots of all diameter locations considered: Fig. 4 (A) illustrates D1 location (diameter immediately superior to iliac bifurcation). It can be visualized in parallel to the aorta in contrast. The pelvis in contrast (indicated in blue arrows) is the landmark for D1 location. B illustrates D2 location (midway between the lower renal vein and iliac bifurcation). Further inside the axial view, the kidneys can be visualized. D2 area is surrounded by one-two pairs of lumbar veins. These veins cannot be visualized in the CT scans. Hence, the D2 location is found further inside D1 before the kidneys come into picture. C represents D3 location (diameter immediately inferior to the right renal vein). The red arrow indicates IVC just before it joins the right renal vein to the kidney. The blue arrows point to the location of kidneys. D shows left and right femoral veins indicated in red arrows. Above these arrows, the two bright spots show the aorta in contrast. These two femoral veins (indicated by red arrows) and bright spots further join inside to become IVC and aorta respectively.

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  Fig. 5. Maximum Mean Diameter of IVC (n = 16).

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  Fig. 6. Normal Distribution plotted for diameters D1, D2 and D3.

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  Fig. 7. Vessel occlusion found for locations D1 to D5. Measured area of IVC at the sites, and calculation of occlusion produced by a sensor that is 8 mm2. A threshold of 7% marks the maximum level of occlusion allowed.