New needleless valves leading to spike in BSIs
Solving one problem and creating another
Health care epidemiologists are reporting an increase in bloodstream infections (BSIs) due to the use of needleless mechanical valve devices that connect to central venous catheters.
Originally intended to prevent needlesticks and protect health care workers from bloodborne infections, the devices now appear to be increasing the risk of BSIs in patients.
Trend uncovered at SHEA
Several studies documenting the trend were described recently in Los Angeles at the annual meeting of the Society for Healthcare Epidemiology of America (SHEA).
"We are now aware of over 20 institutions that have recognized this problem," said William Jarvis, MD, a former investigator at the Centers for Disease Control and Prevention (CDC) and now a private infection control consultant in Hilton Head, SC.
Jarvis provided a sweeping overview of the emerging problem, noting that it first came to light at the 2004 SHEA meeting in Philadelphia.
"The first report of this was actually at the SHEA meeting last year, and I don’t know that it got a great deal of attention by those of us attending the meeting," he said.
In that study, investigators at the University of Virginia (uva) in Charlottesville saw an increase in BSIs associated with the introduction of mechanical valves.1
"The mechanical valves were introduced in May 2002, and by June, they had seen literally a 61% increase in BSIs," Jarvis pointed out.
"Between January-May 2002 vs. May-December 2002, their BSI rate went from 2.2 to 3.5 per 1,000 patient days, which was statistically significant," he explained.
Looking at the types of pathogens associated with the mechanical valve device, the UVA investigators found a 3.7-fold increase in contamination of blood cultures in general; a 2.5-fold increase in catheter-related BSIs with common skin organisms; and a 1.8-fold increase in non-skin organisms, Jarvis told SHEA attendees.
"[They] felt this increase was really related to the introduction of mechanical valves," he said.
"The decision at the hospital to change to mechanical valves was not made by infection control — was not even known by infection control. It was made by occupational health for reduction of needlestick injuries, even though after the introduction of the needless device, there were no data that showed that needlestick injuries were changed at all," Jarvis noted.
Those findings were reinforced by two similar papers presented at the 2005 SHEA meeting, including one describing a similar problem at Johns Hopkins University Hospital in Baltimore.2
"[They] noticed from Quarter 1 to Quarter 4 of 2004, the BSI rate went up from 4.1 to 17.3 BSIs per thousand CVC days," Jarvis said.
"Interestingly, 40% of the BSIs were caused by candida species, [and] 20% of them were polymicrobial — both relatively unusual events," he added.
The surge in infections was linked to the introduction of a new positive-placement mechanical valve.
"Nurses reported leaking and cracking when they were using these mechanical valves, and they returned to the previous mechanical valve," he said. "Their BSI rate went up after [originally] changing the mechanical valves then decreased very rapidly after they moved back to the previous mechanical valve."
Disinfection problems cited
The third report was presented by epidemiologists at Wake Forest University School of Medicine in Winston-Salem, NC.3
"It gives us some insight into what might be the problem here," Jarvis explained at SHEA.
Quantitative blood cultures of blood from intensive care unit (ICU) patients were drawn through the needleless mechanical valve port. Blood was obtained from the initial syringe pullback, which is normally discarded.
"[That] first blood drawback is normally discarded and then you obtain the blood for blood culture," Jarvis said.
"But they took that initial blood and cultured it to see what was the rate of contamination in these mechanical valves. They had 226 discards from 83 patients and found that 39 of 226 or 17% of them were culture-positive," he noted.
Colony-forming units were very low in some cases, but some pathogens were present in sufficient numbers to pose potential problems. A nursing practice survey revealed that 31% of the nurses did not disinfect the needleless valve port before accessing the system.
"Those of us who are clinicians don’t really understand these products very well," Jarvis said.
"We don’t understand how they work. We don’t understand the internal mechanisms, and we don’t understand how we need to disinfect them," he explained.
"Oftentimes, the same can be said of the sales staff who are selling you these devices. They don’t understand how you are using them or misusing them and can’t really educate you very well," Jarvis continued.
If the mechanical valves are not disinfected properly, then bacteria can set up within the nooks and crannies of the device. "[That] can lead to contamination of the fluid path," Jarvis said.
"You can have gaps around the plunger that harbor bacteria. And the gaps may not be accessible for disinfection. That again can lead to fluid contamination. That can especially occur if you are having multiple breaks in the system, uses of syringes, and repeated flushing," he continued.
Look alike, sound alike
The products look alike and often sound alike, but may have different procedures for use and disinfection, Jarvis added.
"I can tell you that many of the hospital epidemiologists and infection control professionals who I have talked to that are at hospitals and are noticing an increase in BSIs — when I ask them which valve they use, they often cannot tell me," he said.
"It may be familiar to the people in purchasing, or it may be to the people in the ICU, but oftentimes infection control is completely unaware of it," Jarvis added.
The mechanical valve devices have been introduced in recent years to replace the original split-septum needleless ports introduced in the 1990s. The idea apparently was to maintain the needlestick prevention aspect while reducing occlusion or clotting.
"Split septum were initially introduced to reduce health care worker needlestick injuries," Jarvis said.
"We accomplished that with the split septum. Initially, the split septums were associated with BSI outbreaks, but it wasn’t just a device problem — but rather the device plus the infection control practices. As the infection control practices improved, the BSI rates with these devices went down," he noted.
The unanswered question is whether the new generation of mechanical devices causes more problems then they actually solve.
"We now have the mechanical valves introduced to not only reduce needlestick injuries but also to presumably reduce catheter occlusion," Jarvis explained. "The data are out as to whether that is really the case or not. We need to understand whether changing from one to another really has any effect on needlestick injuries and occlusion," he stressed.
"If it doesn’t, then you may use different criteria for selecting which kind of device you are going to use. The increased BSI [rates] associated with mechanical valves may be caused by inadequate infection control practices, they may be caused by the device, or they may be caused by both," Jarvis added.
- Hall KK, Geffers C, Giannetta E, et al. Outbreak of bloodstream infections temporally associated with a new needleless IV infusion system. Abstract 285. Presented at the Society for Healthcare Epidemiology of America annual conference. Philadelphia; April 2004.
- Cosgrove SE, Bradley K, Mckee C, et al. Increase in catheter related bloodstream infections (CR-BSI) in pediatric intensive care units temporally associated with a change in the needleless intravenous port. Abstract 26. Presented at the Society for Healthcare Epidemiology of America annual conference. Los Angeles; April 2005.
- Karchmer TB, Cook EM, Palavencino E, et al. Needleless valve ports may be associated with a high rate of catheter-related bloodstream infection. Abstract 307. Presented at the Society for Healthcare Epidemiology of America annual conference. Los Angeles; April 2005.