Coated catheters are one potential solution, but good hygiene and proper placement will still produce the best results by Alison McCook
Published in the February 2004 issue of Today's Hospitalist
The 59-year-old man had been in the ICU for four weeks. He had multiple illnesses and was on a respirator, but the central venous catheter in his neck turned out to be his biggest problem.
When his body temperature shot up, doctors found Candida in his blood. He quickly went into an acute septic state and within 24 hours, he was dead, a result of the deadly infection that had hitched a ride on his catheter.
While it’s an extreme example of the harm that catheter-related infections can cause, the story is a sobering
One study found that when less experienced staff changed catheter dressings, the infection rate jumped from 3 percent to 29 percent.
reminder that central lines are an all-too-common cause of serious problems.
In U.S. hospitals, for example, 90 percent of all catheter-related infections occur in patients with central lines. Although the data on attributable mortality from central line infections give an unclear picture, some research has estimated the death rate may be as high as 25 percent. One thing is certain: Central venous catheters cause approximately 250,000 cases of bloodstream infections each year, at a total cost of potentially billions of dollars.
You know the risks that accompany central lines: By puncturing the body’s natural barrier against bacteria and yeast, you’re giving bugs a golden opportunity to creep inside your patients. The problem is that even when you take all the recommended steps to insert and maintain a central venous catheter cleanly, any slip along the way increases the risk an infection will occur.
That’s why preventing these infections is one of the most pressing issues facing hospitals today.
The Joint Commission on Accreditation of Healthcare Organizations has made fighting infections one of its seven patient safety goals for 2004 and is calling on accredited organizations to comply with the CDC’s hand-hygiene guidelines. It is also calling on organizations to manage as sentinel events all identified cases in which patients die or suffer “major permanent loss of function” associated with a health care-acquired infection.
The good news is that hospitalists have access to a new breed of catheters impregnated with antibiotics and antiseptics to kill bacteria and fungi before they reach the blood. The problem is that there are still questions about the efficacy of these new devices and whether they will they help spread antibiotic-resistant bugs. There are also concerns about their cost.
Consequently, experts say that the tried-and-true methods of prevention—good handwashing and sterile barriers—may still be the best place to start when trying to prevent infections at your facility. (See “To prevent catheter-related infections, try getting back to basics” below.) Here are some strategies to avoid bloodstream infections, and a look at the latest techniques to help keep your patients safe.
Site choice and staffing
Infections are more likely to occur when you place a catheter in sites prone to pathogens like a femoral vein or the groin. Inexperience, however, may lead to a less-than-ideal choice of sites. Michael Edmond, MD, hospital epidemiologist for the Virginia Commonwealth University Medical Center in Richmond, explains that staff who don’t have a lot of experience inserting central lines often opt for the ease of the femoral vein.
Perhaps it should come as no surprise, then, that studies have suggested that when inexperienced staff insert and maintain catheters, the risk of infection increases. Creating a dedicated team to handle catheter care can reduce that risk.
While putting together this type of team may increase your hospital’s costs, research shows that the added burden may be more than offset by the savings associated with a lower rate of infections.
For example, in a noteworthy study published in the March/April 1986 Journal of Parenteral and Enteral Nutrition, researchers examined pediatric patients who received central venous catheters for parenteral nutrition. The infection rate was almost 29 percent when residents changed the catheter dressings, compared to 3 percent when a nurse trained in maintaining central lines took on the job.
Other staffing practices can also affect the rate of catheter-related infections. In the March 1996 issue of Infection Control and Hospital Epidemiology, researchers found evidence that significant reductions in the nurse-to-patient ratio may have played a role in a previous outbreak of bloodstream infections from central venous catheters.
To help staff choose a less accessible—and less pathogen-ridden—site, Dr. Edmond suggests using ultrasound to guide the catheter into place. At his hospital, for instance, staff are currently learning to use a handheld ultrasound probe to visualize the vein in which they are placing the catheter.
And to give doctors in training a leg up on preventing catheter-related infections, Virginia Commonwealth requires all doctors who complete the ICU rotation to attend an educational program that reviews the steps physicians can take to reduce infections from central venous catheters. Dr. Edmond says the program primarily emphasizes the importance of sterile techniques and adequate protection when inserting the catheter.
He explains that the program is successful because it works with doctors early in their training. The goal is to keep housestaff from simply imitating doctors who first taught them the technique—and who may not take all the proper precautions.
When an organization does establish a program to review basic preventive techniques, it is critical to make sure that someone is following up with staff to ensure those steps are being taken, says Leonard A. Mermel, DO, medical director of the department of infection control at Rhode Island Hospital.
“Just telling people what to do is the first step. You need continuous monitoring programs in place to make sure they’re actually being done, and hospitalists have the means to do that,” says Dr. Mermel, who is also associate professor of medicine at Brown Medical School and president-elect of the Society for Healthcare Epidemiology of America.
New breed of catheters
One problem with central venous catheters is that they are sometimes left in patients for longer than necessary, increasing the risk of infection. While the obvious solution is to remove central lines as soon as you’re no longer using them, the reality is that some of your patients will need a catheter for a long period of time.
In these instances, some experts suggest considering a tunneled catheter, which is associated with a lower risk of infection. The downside is that inserting this type of catheter requires a minor surgical procedure. For patients who need a catheter for only a short period, the reduced risk of infection may not be worth the added risk associated with surgery, says Debaroti Borschel, MD, a hospitalist at the University of Michigan Hospital in Ann Arbor.
Some hospitals are choosing to use catheters coated with an antibiotic or antiseptic. The goal is to kill bacteria crawling on the inside or outside of the device before they can reach the bloodstream.
Catheters coated with chlorhexidine on the inside and chlorhexidine combined with silver-sulfadiazine on the outside are expensive—about $25 more than noncoated devices—but research indicates that they may more than pay for themselves in certain patients.
A study in the Aug. 11, 1999, Journal of the American Medical Association, for example, suggested hospitals could save between $68 and $391 per catheter by using the devices in patients who have a high risk of infection. (Those individuals include patients who are in the ICU or receiving total parenteral nutrition.)
In another unpublished study, Dr. Borschel and her colleagues found that antiseptic-coated catheters reduced infection risk by almost 40 percent among all patients in the ICU at the University of Michigan Hospital in Ann Arbor.
Another strategy is to replace noncoated catheters with devices that are impregnated with minocyclin/rifampin on external and internal surfaces. While these catheters cost even more than the antiseptic-coated catheters, an article in the Jan. 7, 1999, New England Journal of Medicine showed that they may be even more effective, with a rate of infection that was one-twelfth that seen with the chlorhexidine devices.
Dr. Mermel points out that the NEJM study used a first-generation form of the antiseptic catheter, which was coated only on the outside. Researchers have yet to compare the minocyclin-rifampin catheter to the newer, doubly-coated form of the antiseptic catheter, he says. As a result, he suspects the second-generation antiseptic catheter will prevent infections even more effectively than the earlier device.
Concerns about drug resistance
Not surprisingly, using catheters packed with antibiotics raises serious concerns about drug resistance.
To date, no study has thoroughly demonstrated that antibiotic-coated catheters have any influence on the presence of resistant bugs in the hospital, according to George Abraham, MD, assistant program director of the internal medicine residency program at St. Vincent’s Hospital in Worcester, Mass. He says he believes that because the antibiotic adheres to the material of the catheter, it does not spread into the bloodstream.
Consequently, he says, the bacteria theoretically die the moment they are exposed to the antibiotic on the catheter surface. Dr. Abraham, who is also assistant professor of medicine at the University of Massachusetts Medical School, says that the bacteria may simply not get a chance to linger in the presence of the agent long enough to develop any resistance.
Others wonder whether the new devices are worth both the extra cost and the potential risk of drug resistance, particularly for hospitals that have a low rate of infections.
“If you’ve done all those other steps well, are antibiotic-coated catheters still cost-effective, and do they still reduce the rate of infections enough to make it worthwhile?,” asks Donald Krause, MD, a hospitalist at St. Joseph’s Hospital in Bangor, Maine. “I think the answer is probably yes, but I haven’t seen clear-cut evidence yet.”
Other hospitals strike a compromise and use coated catheters in situations where the risk of infection is high. In all other situations, they use noncoated catheters. Dr. Abraham, for example, recommends coated catheters only when the device will be used for more than a week.
The University of Michigan Hospital, by comparison, uses an antiseptic-coated catheter in every adult who receives a central line. The hospital has also switched to antibiotic-coated catheters for all pediatric patients because some young children develop allergic reactions to the antiseptic.
Dr. Borschel says that because the hospital made the change about a year ago, it has not yet completed a formal cost analysis of its impact. She notes, however, that an informal and conservative estimate suggests the new catheters may be saving the hospital up to $100,000 per year.
“Even saving a few infections outweighs the extra cost of the coated catheter tray enough that it’s definitely cost-effective,” Dr. Borschel says.
For most patients, she adds, the antiseptic-coated catheter may sufficiently reduce risk of infection while sidestepping any chance of antibiotic resistance or an allergic reaction to the antibiotic. “I would recommend antiseptic-coated catheters for the majority of people,” Dr. Borschel says.
Along with coated catheters, researchers are devising new techniques to fight bloodstream infections from central venous catheters.
In situations where a catheter has to be in place for a long time and can be difficult to remove, some hospitals use a technique known as antibiotic lock prophylaxis. In these cases, staff attempt to sterilize the catheter by filling the lumen with an antibiotic or antiseptic.
Although studies suggest this technique may reduce the risk of infection in certain patients, leaving an antibiotic in the catheter may allow bacteria to develop resistance.
Increasing drug resistance to antibiotics is also a concern when it comes to several other techniques, such as systemic antibiotic prophylaxis and blasting the skin around a catheter insertion site with an antibiotic ointment.
Dr. Borschel says that her hospital does not routinely use a lock technique—and that she would not offer a patient systemic antibiotic prophylaxis—because of concerns about drug resistance, and a lack of data supporting the strategy. “I wouldn’t use prophylaxis unless I thought somebody was already infected,” she explains.
Another approach calls for placing a sponge coated with chlorhexidine around the insertion site of the catheter and changing it every seven days. The flat donut-shaped object, which preliminary research suggests might reduce infection risk, allows the antiseptic to seep into the skin, bathing the site for days at a time.
And catheters made with silver might protect patients by inhibiting the growth of bacteria. Emerging research also suggests that heparin-coated catheters may prevent infection, by perhaps reducing the risk of a bug-friendly blood clot.
Finally, researchers are exploring technology that may produce electrically charged catheters that prevent bugs from colonizing the device. They are also developing techniques that block both the genes that enable bacteria to congregate on catheters and the proteins that help bacteria stick together.
It will take some time before these techniques are proved to work, cautions Dr. Borschel. “These are future directions that we may take, but we don’t have any recommendations to use them at this time,” she says.
Alison McCook is a freelance writer specializing in health care. She is based in Brooklyn, N.Y..
To prevent catheter-related infections, try getting back to basics
It may seem like obvious advice, but the most effective step you can take to protect your patients from bloodstream infections is to get back to the basics of handwashing and using sterile barriers.
A “maximal” barrier involves wearing a mask, hat, gown and gloves whenever inserting or touching a central venous catheter. You should also drape the patient with a full sterile sheet, not just a towel or two.
Studies have shown that using these extra precautions reduces infection risk better than the so-called “standard” precautions of sterile gloves and small drapes.
Although many physicians learned about the importance of this basic step in medical school, it bears repeating, says Leonard A. Mermel, DO, medical director of the department of infection control at Rhode Island Hospital.
Doctors often focus on new coatings or devices to keep bugs out of blood, Dr. Mermel says, but they lose sight of the fact that these cost money and may increase the risk of resistance if they contain antibiotics. In contrast, he says, “The bugs aren’t going to become resistant to maximal barrier precautions.”
In terms of a skin antiseptic, replacing your stocks of povidone-iodine (Betadine) with a 2 percent aqueous solution of chlorhexidine gluconate appears to reduce the rate of central catheter-related bloodstream infections even further.
And even when you wear gloves, make sure to wash your hands before and after touching the insertion site for the central catheter, and before and after you handle the catheter for any reason.
Many hospitals have now switched from requiring staff to wash their hands with soap and water to installing dispensers that contain waterless, alcohol-based cleansers.
“You can just rub your hands and keep walking,” says George Abraham, MD, assistant program director of the internal medicine residency program at St. Vincent’s Hospital in Worcester, Mass. “And it works just as efficaciously.”
Indeed, several studies have shown that health care workers wash their hands only around 40 percent of the time that they should, so anything that increases the ease with which staff can clean their hands is a good thing, according to Michael Edmond, MD, hospital epidemiologist for the Virginia Commonwealth University Medical Center in Richmond.
For more information, see the CDC’s hand hygiene recommendations online.