November 25, 2019

A team of researchers at VUMC who are developing a non-invasive way to capture venous waveforms to assess and monitor volume status was awarded a five-year R01 grant. Bret Alvis, MD, the principle investigator, leads a team of physicians from both the Departments of Anesthesiology and Surgery and engineers from the Department of Engineering. “This is the first grant I am the principal investigator on. It’s extremely exciting and a testament to the great team I am lucky enough to be a part of,” he said.


Alvis explained that it wasn’t until recently that technology was good enough to amplify the peripheral signals to non-invasively capture venous waveforms. “We have been trying to make sense of these waveforms in various clinical volumes states,” he said.


The grant will provide funding for them to study and better understand how the venous waveforms change specifically in patients with volume overload. “We are trying to better understand fluid status both in the vasculature and outside of it as well. We hypothesize we can use the amplitudes of these venous waveforms to quantify the volume status in and outside blood vessels,” he said.


He explained that there isn’t currently a great way to monitor how much blood is in the blood stream. “We use a lot of data points like blood pressure, heart rate and central venous pressures to make our best clinical ‘guess.’ But research has shown these are quite poor in detecting someone’s volume status, despite the fact that knowing how much volume a patient requires is very important in a multitude of clinical scenarios. Whether it is determining if a patient is hemorrhaging, requiring volume resuscitation, or is in a volume overloaded state, knowing if they need more or less fluid is extremely important because all of it can affect organ function.”


Alvis said his experience as an anesthesiologist helps him with this research because he interacts with patients with a multitude of disease processes and gets to collaborate with a multitude of people in his clinical work. “It was an easy transition to collaborate in my research work. I have a base line understanding that is helpful in studying venous waveforms. At the heart of all of this, we are trying to better understand volume status, which is the focus of any anesthesiologist or critical care doctor. Every anesthesiologist wants to know a patient’s volume state and we can’t do that very well right now,” he said.

He explained that this is a new, novel concept, developed here at VUMC, that requires a team and the collaborative nature of VUMC. “It is a lot of work and a lot of fun because we get to discover together and teach each other.”