Antimicrobial Catheter

by David Galloway

Photo: Dr. Issam I. Raad

Dr. Issam I. Raad, professor and chair ad interim of the Department of Infectious Diseases, Infection Control, and Employee Health, was recently honored for inventing an antimicrobial catheter that prevents infections, saving 25,000 lives a year. Here, Dr. Raad demonstrates the catheter to a patient before inserting it.

Five million central venous catheters are inserted in patients in the United States every year. Even the most conservative estimates suggest that catheter-related sepsis will develop in at least 200,000 of these patients. Catheters are now the number one cause of bloodstream infections in patients with cancer and other critically ill patients. At least 25,000 patients die each year of catheter-related infection.

“Every two years we lose 50,000 patients, which is almost equivalent to the number of people we lost in Vietnam over a 10-year period,” said Issam I. Raad, M.D., F.A.C.P., professor and chair ad interim of the Department of Infectious Diseases, Infection Control, and Employee Health at The University of Texas M. D. Anderson Cancer Center. “Twenty-five thousand people are dying every year of things that we put into their veins to try to help them.”

The catheters, which allow repeated intravenous administration of medications, blood products, and chemotherapy without separate needle sticks, unfortunately also offer easy access for bacteria and fungi. The catheter connects the skin, which is a contaminated environment, with the bloodstream, which is supposed to be a sterile environment. Therein lies the danger.

“Catheters can get infected in different ways, but mainly, bugs that are on the skin migrate along the external surface, colonize the tip of the catheter, and invade the bloodstream,” Dr. Raad said. “Or there’s another route: From the hands of medical personnel, bugs can go through the hub, through the lumen, and invade the bloodstream.” Either way, the result is often sepsis, which proves fatal in one of four intensive-care unit cases.

The number of patients becoming infected and dying is dropping quickly, though, as physicians around the world have begun using an antimicrobial catheter invented by Dr. Raad and a fellow researcher from Houston, Rabih O. Darouiche, M.D., a professor in the Department of Physical Medicine and Rehabilitation at Baylor College of Medicine. For their life-saving invention, Drs. Raad and Darouiche were honored this summer with the Outstanding Inventor of the Year Award for 2004, presented by the Houston Intellectual Property Law Association. Previously, the only medical doctor to receive the award was Denton A. Cooley, M.D., founder of the Texas Heart Institute, who was honored in 1998 for his inventions related to heart surgery and other types of surgery.

Ten years ago, Drs. Raad and Darouiche decided that catheter-related infection was a problem waiting for a solution. Others had attempted to coat catheters with antibiotics, but their efforts fell short because the antimicrobial activity was too short-lived to help patients whose catheters might stay in place for 30 days or longer.

Rather than just coating the surface, Dr. Raad and his colleagues developed a method that allows antibiotics, specifically minocycline and rifampin, to permeate the plastic of the catheter, providing much more durable protection. “We use various ketones, like butyl acetate or acetone, mix the antibiotics with the acetone, and put the catheter in,” said Dr. Raad. “The catheter swells because of the acetone and takes into its wall these two antibiotics.” Cook Critical Care of Bloomington, Indiana, has licensed the technology and is now manufacturing the catheters.

In a study published in the New England Journal of Medicine in 1999, the investigators found that the rate of catheter-related sepsis dropped to nearly zero in patients with antibiotic-permeated catheters. “This is almost infection proof,” Dr. Raad said.

The U.S. Centers for Disease Control and Prevention issued guidelines in 2002 calling for the use of an antimicrobial central venous catheter in adults whose catheter is expected to remain in place for more than five days.

For more information on this topic or for questions about M. D. Anderson’s treatments, programs, or services, call askMDAnderson at (877) MDA-6789.

Other articles in OncoLog, September 2004 issue:

M. D. Anderson Physician Honored for Inventing an Antimicrobial Catheter That Prevents 25,000 Infection-Related Deaths a Year

by David Galloway