Bacteria was found on 7.8 percent of the catheters removed after three days, the study found, and on 8.6 percent of the catheters removed after seven days, for a difference of 0.8 percent.
They described this as a modest reduction that "appears safe."
However, one expert remained dubious as to the advisability of leaving dressings on for longer than the standard three days.
"What is extremely important here is that, while the infection rate did not increase with these less-frequent dressing changes, this finding applied only to unsoiled dressings," said Dr. Pascal James Imperato, dean of the graduate program in public health at the State University of New York Downstate Medical Center, New York City.
Because leakage and soiling are very common at catheter insertion sites, it wasn't surprising that the study found that the absolute decrease in dressing changes was modest, Imperato said.
"In other words, in most patients, the dressings need to be changed every three days -- if not more often -- because of leakage and soiling," he said. "Thus the findings of this study have limited practical application."
The U.S. Centers for Disease Control and Prevention have more on protecting patients from infection.
SOURCES: Pascal James Imperato, M.D., M.P.H., dean, distinguished service professor, Graduate Program in Public Health, State University of New York Downstate Medical Center, New York City; Marc Siegel, M.D., associate professor of medicine, New York University School of Medicine, New York City; March 25, 2009, Journal of the American Medical Association
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