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|Newsletters: Needleless Devices and Bloodstream Infections|
Needleless Devices and Bloodstream Infections
The use of needleless devices for infusing homeTPN and other therapies has grown rapidly since their introduction several years ago. The purpose of these devices is to reduce the risk of needlesticks, and thus the spread of bloodborne pathogens from patients to health care workers and caregivers. This advantage has been proven in many studies, however, there is now concern whether there are hidden risks for the users of needleless devices. It is suspected that the use of needleless devices may put patients at greater risk for a bloodstream infection (BSI).
Most needleless devices have built-in valves which can potentially prevent a complete flushing of the device and therefore enhance the potential for bacterial contamination. Greater bacterial contamination has been proven through in vitro (non-patient) studies by Dr. Dennis Maki, one of the foremost researchers on catheters and BSI in the United States, suggesting a greater risk of BSI in patients using needleless devices is likely.
This patient concern was validated by a retrospective study published by Danzig, L. et. al. from Rhode Island Home Therapeutics and the Center for Disease Control (CDC) in the Journal of the American Medical Association (JAMA) in June 1995. The study showed a significant increase in BSIs for patients infusing TPN and intralipid (IL) at home with a needleless versus a “protected needle” device (the “Interlink” versus the “Clicklock”). This increased association was not seen with other home infusion therapies, such as antibiotics or cancer therapy. The exact reason why TPN/IL and the needleless device resulted in an increased risk of bloodstream infection is not known, but it may reflect the fact that unlike some other infusion therapies, TPN/IL is a good growth stimulus for bacteria which can contaminate the line.
Two other retrospective studies have also shown an increase in BSIs in patients using needleless devices. The patients studied were not necessarily infusing TPN. The first study, by Do, A. et. al. (available in abstract form only), involved four centers, the CDC, Coram Healthcare, Texas Department of Health and Houston City Department of Health. Here researchers investigated the cause of an increasing number of BSIs in home health care patients where three different needleless device systems had been introduced and used successively (the “Safesite,” “Clave” and “Interlink”). The frequency of BSIs was highest when the Safesite needleless device was used (1.2 BSI/1,000 CVC days), less when the Clave was used (0.8 BSI/1,000 CVC days) and still less when the Interlink was used (0.5 BSI/1,000 CVC days). The study also showed a higher BSI rate when the end cap for the needleless device was changed once every seven days compared with once every two days. Finally, the study reported the risk of BSI was higher in patients with a central line who routinely showered.
The second study, by Kellerman, S. et. al. from the CDC, Children’s Hospital of Oakland and the State of California Department of Health Services, was published in the November 1996 issue of The Journal of Pediatrics. This study investigated the cause of increased central catheter-associated BSI rates in pediatric hematology/oncology patients receiving home health care. The study found a significant increase in BSIs in participants using needleless devices, particularly in the African-American, Asian-American and Hispanic participants where they suspect cultural and language barriers may have prevented adequate patient education.
The largest study on needleless devices and BSI (available in abstract form only) was recently completed by Tokars, J. et. al. from the CDC. The study involved more than 800 infusion patients from home care providers in Cleveland, OH, and Toronto, Canada. Seventy-five percent of the patients studied were using needleless devices, and roughly ten percent of the patients were on TPN. (The study did not report what percentage of the TPN patient subgroup were using needleless devices.) Some of the factors associated with increased BSIs were: using the catheter for infusing TPN, having experienced a prior BSI with the same catheter, and using a multilumen catheter. The study showed no significant adverse affect of using a needleless device. However, the relative risk of using the needleless device was not analyzed separately for TPN patients, who compared with other infusion patients showed significant risk in the Danzig paper. In addition, Tokars’ study also showed a trend toward more BSIs with longer end cap use. In discussion with the author, he described the relative risk of BSI as 1.0 for end caps used less than seven days and 1.9 for end caps used more than seven days.
In conclusion, the safety of using needleless devices in home infusion patients continues to be controversial. Factors which seem to put needleless device users at greater risk of BSI include, infusing TPN, changing the end cap of the needleless device less frequently, routine showering with a CVC and lack of proper training in line management.
[Please note that there are several different brands of needleless devices used in the various studies and that the needleless devices available to homeTPN consumers today may have been introduced or modified since these studies took place.]
Copyright © 1995 The Oley Foundation