por Lynn Shapiro
, Writer | September 23, 2009
Though rare, IV contrast media can sometimes result in patient injury while it is being injected during a CT scan. To alleviate this problem, a team of physicians and engineers at Duke University, lead by radiologist Rendon C. Nelson, M.D., have developed a modified catheter with side holes and slits.
Dr. Nelson tested the catheter using computer modeling and an imaging system to compare the fluid flow from his side-hole catheter with the flow from a standard end-hole device. His study is published in the October issue of the American Journal of Roentgenology. (AJR).
"The strong jet-like velocity of an end-hole catheter can cause contrast media to be injected outside the channel of the vein into the surrounding soft tissue, and injure patients," Dr. Nelson tells DOTmed News.
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"This phenomenon is pretty rare but in our practice at Duke we do 40,000 contrast injections per year and we have 150 to 200 patients where a significant amount of the contrast material is injected into soft tissue rather than into the vein. At times, the soft tissue injury is severe enough to require skin grafts," Dr. Nelson says.
He adds that numeric calculations show that the addition of side holes or slits results in a nine to 30 percent reduction in the velocity of contrast material exiting the end hole of the catheter. "We saw more of a cloud-like dispersal of contrast media [rather] than a jet," he says.
Testing for Thrombosis
Dr. Nelson's team is currently designing subclinical trials for the modified catheter. He hopes the device will be tested on patients later next year.
Although he says his catheter has many advantages, there is some worry that side holes might be thrombogenic, if the heparin [given with the catheter to deter blood clots from forming] leaks out.
"We're testing for heparin leakage, because we think there might be a need for this catheter outside of radiology, [such as] for patients who have been admitted to the hospital, where the catheter is left in a patient for several days," he says. It may also be useful for giving blood products so that a large bore catheter wouldn't be needed."
In radiology units, catheters are only left in place for an hour or two, so whether heparin leaks out or not is a less important issue, Dr. Nelson notes.
Licensing to a Big Company
He tells DOTmed that Duke is considering licensing its catheter to one company, which has a major presence in radiology and is seeking a presence in the catheter arena. He declined to name the company, since they haven't signed on with Duke, as yet.
Source: Duke University Medical Center