Abstract 16444: Real-Time Assessment of Vascular Access Complications
Background: Vascular access (VA) can lead to bleeding complications at the VA site. We tested the hypothesis that impedance changes from electrodes embedded within a standard sheath can predict perivascular bleeding.
Methods: Currently available VA sheaths were modified with 4 pole electrode arrays. These arrays were used to take real-time bioimpedance (BI) measurements in porcine and ovine models under variable physiologic conditions. The dual-lumen design isolated the electronic components in the outer lumen from the inner lumen, allowing completely unimpeded functionality of the sheaths. As saline was injected into the perivascular space at specific times, the BI was automatically calculated in real time. BI measured at the beginning of each perivascular injection was compared to BI measured halfway through the injection. A linear increase was seen, correlating the absolute BI increase to the volume of injectate.
Results: In 5 animals, the average increase in normalized impedance per cc of fluid was 4.8±1.6%. Each time, the device was able to definitively detect the presence of internal bleeding. Ultrasonography confirmed that the changes in BI corresponded to the extravasation of fluid and did so temporally with the injections.
Conclusion: The use of a sheath, virtually identical to those used in clinical practice, and real-time BI calculation enables very early detection of perivascular bleeding. Because of the device's fidelity, it can detect bleeding well before any clinical signs appear; as such, its use may mitigate the extent of clinical complications. The technique is validated in animal models but requires further clinical studies. Figure. Top: Prototype with electrode rings on external surface. Bottom left: Ultrasound image of fluid extravasation. Bottom right: Vertical lines represent injections of saline and increase in impedance at multiple frequencies proportional to fluid volume can be appreciated.
- © 2011 by American Heart Association, Inc.