Renowned Expert Dennis Maki, MD Addresses Catheter-RelatedInfections

ICT spoke with Dennis G. Maki, MD, professor of medicine and head of the Section of Infectious Disease at the University of Wisconsin-Madison Medical School. As a world-renowned specialist in infectious disease, Maki’s work puts him at the center at some of most dreaded plagues of our time: AIDS, biological warfare, chronic wasting disease. His research focuses on institutionally acquired infections, which are emerging as an urgent problem in the United States and around the world. Maki’s research in hospital-acquired disease has been seminal and saved countless patients worldwide; colleagues describe his accomplishments in teaching, community outreach, and clinical medicine as “the gold standard” in his field. Maki has served as a consultant to the Centers for Disease Control and Prevention (CDC) and to the Food and Drug Administration (FDA), has won numerous research and teaching awards, and has 400- plus publications to his credit, many of them in the prestigious New England Journal of Medicine. He is considered to be the leading authority on catheter-related infection control issues, and in this two-part interview, speaks candidly about the techniques and the technology of preventing CRIs.

ICT: Before we examine techniques and technology, what are the complications of peripheral intravenous catheters (PIVs), and are they the inevitable consequences of placing a hard plastic object in a soft, fragile vessel?

DM: There are probably 150 to 200 million peripheral venous catheters that are placed every year in the United States. Probably 30 or 40 million of these are small scalp-vein needles that are used in children; the rest of these are small plastic catheters that are placed in a peripheral vein, such as the back of the hand or the wrist, or a little higher up in the arm. The most common complication is discomfort, but PIVs generally don’t pose a major threat to the patient and don’t generally increase hospitalization.

That said, when a needle breaks through the wall of the vein and fl uid leaks into the tissues, you get some swelling – infiltration – and can no longer give the material into that vein, so you must fi nd a new site. Infi ltration is very, very common, occurring maybe 10 percent to 20 percent of the time.

About 10 percent of the time, the vein becomes infl amed, tender, swollen, and hard – a fairly common condition called thrombophlebitis, or device-related thrombophlebitis. It is mainly related to the irritating effects of the drugs given intravenously, as well as related to the movement of the catheter needle in the vein. It’s hard to prevent a little bit of movement.

Then there is the more serious complication of infection. The risk of infection in PIVs is not high, but when it occurs, infection can be serious because it can involve the bloodstream. Two types of serious infections occur in peripheral venous catheters. The most common is when organisms invade the bloodstream in the tract around the catheter. This kind of infection originates from microorganisms on the surface of the patient’s skin; they invade the tract that the catheter passes through and cause bacteremia, or bloodstream infection. The second kind of serious infection associated with PIVs is septic thrombophlebitis. Here, a clot in the vein with accompanying infl ammation becomes infected. This is a very serious infection, because even though you may remove the catheter, the patient continues to have ongoing active bacteremia. Septic thrombophlebitis is best treated by surgically removing the infected clot from the vein.

Now, bacteremia from peripheral venous catheters only occurs in about one out of every 500 catheters or so. It’s not very common, but it’s a serious infection and the prolonged hospitalization it causes can be life-threatening.

Now, to examine the question as to why these more serious PIV-related complications occur, it’s not so much that a solid object is going into a soft tissue space. I think the fundamental problem is that it’s a percutaneous device that passes through the skin and goes deeper into the body. The skin has enormous numbers of organisms on it. If the person carries particularly more virulent organisms, such as staphylococcus, he or she can get serious a bacteremic infection from a peripheral venous catheter. So, the fundamental challenge is to be able to put a catheter into a vein and to try to minimize the likelihood that microorganisms on the skin of the patient will gain access to the bloodstream.

ICT: Do you recommend any particular kind of glove and/or gown for the healthcare worker before placement of a peripheral intravenous catheter?

DM: When we put in central venous catheters, which pose a much greater risk of infection, we routinely use maximal sterile barriers, which is a long-sleeve sterile surgical gown, a mask, a head cover, sterile gloves, and a large sterile drape called a sheet drape. For central venous catheters, the infection risk might be 2 percent to 4 percent, not 0.2 percent, as with peripheral venous catheters.

With peripheral venous catheters, we only recommend that people wear gloves and they may or may not use a small drape. Generally it’s not considered necessary to use maximal barrier precautions for peripheral venous catheters if there’s good technique.

ICT: Does it make a difference if the gloves are sterile or non-sterile?

DM: Generally, it probably does not make that much of a difference. Sterile gloves are often used, but it’s probably not mandatory.

ICT: Do you think it’s a good idea to use some sort of drape or barrier on the patient when starting a PIV?

DM: In general, I think it’s a good idea to use a fenestrated drape to shield the portions of the patient’s anatomy that are not disinfected. If I’m going to put a peripheral venous catheter in your wrist, I’m going to prep the skin vigorously, and scrub it with a cutaneous antiseptic in a circumferential manner; so, if I’m targeting one specific spot in your wrist where the vein is at the surface, I may prep an area anywhere from three to four inches around that area. There’s still un-prepped skin above and below. Now, if we put a sterile drape with a little hole in it, the only thing that is exposed is prepped skin; there’s no likelihood that we’ll inadvertently touch the outside of the prepped area.

ICT: Is there a preferred PIV insertion site? The CDC recommends the upper extremity in adults, but specifically, do you recommend the hand, forearm, or arm? And is there a difference?

DM: I recommend the forearm. You can use the back of the hand when there are limited sites, but that’s not a first choice only because if there’s infiltration, the subcutaneous tissue there is very thin and is more uncomfortable with infi ltrates. The veins are also a little more fragile in the dorsum of the hand. I think the forearm between the wrist and the elbow is the ideal place to put the catheter. Often, peripheral venous catheters are put in the crook of the elbow if the veins are right at the surface there.

I don’t like them placed there, because you have to put the patient’s arm on an arm board to keep it straight. Otherwise, the bending of the arm will cause infiltration of the catheter, and it will come out of the vein. I think it’s very uncomfortable for a patient to have his or her arm immobilized straight for prolonged periods of time.

I think the ideal place to put a peripheral venous catheter is between the wrist and the elbow, but not the antecubital fossa. The forearm is the most comfortable place. You can move the wrist, you can move the elbow, it doesn’t interfere with the motion in the joints, and it’s most comfortable for the patient.

ICT: Is there any skin prep, beyond isopropyl alcohol, that should be used before inserting an peripheral intravenous catheter?

DM: Yes. Evidence indicates that there are differences in the capacity of different chemical antiseptics to reduce the number of organisms on the skin. And the more effective you are at reducing the numbers of organisms – you never eliminate them all – the better. I think the evidence is clear that chlorhexadine is a superior cutaneous antiseptic for vascular access. In my opinion, it ought to be used for all forms of vascular access, not just central venous catheters. I think if you’re putting in peripheral venous catheters, arterial catheters, peripherally inserted central catheters, a chlorhexadine product is the choice. If you can’t use chlorhexadine, either 70 percent alcohol or povidone iodine are acceptable. However, chlorhexadine should be the first choice if it’s available.

ICT: Regarding the CDC recommendation that – absent infection or phlebitis – peripheral intervenous catheters may remain in place for 96 hours in adults: Does that recommendation affect how one should prep skin for PIV insertion?

DM: No, I don’t think so. I think the prepping is the same no matter how long the intended catheter use. I would simply make the argument that, unless there’s a compelling reason not to use chlorhexadine, that should be the choice. And it doesn’t matter if the catheter is going to stay in for 12 hours or 96 hours. You often don’t know at the time you put it in how long you’re going to be able to, or need to, use the site.

ICT: Isn’t site infection rare with peripheral intravenous catheters?

DM: It’s rare, but it’s not zero. As I said before, it is in the range of 0.2 percent, and it may have risen a little bit in recent years.

ICT: Is there a preferred kind of catheter, either from a patient-safety or a needlestick safety point of view?

DM: There’s evidence that suggests that polyetherurethane, which is one polymer used in making catheters, may cause less phlebitis or inflammation (independent of infection) than Teflon catheters. But both of them are perfectly fine.

ICT: Regarding safety mechanisms, do you have a preference?

DM: I think it’s ideal with peripheral venous catheters to use catheters that, once they’re in the vein, the needlestick safety mechanism is automatically activated so the needle cannot inadvertently stick somebody.

ICT: What about the securement of peripheral IVs? Non-sterile tape is the traditional habitbased practice. Is there any real evidence-base to suggest a change of technique?

DM: There is growing evidence that a securement device that has adhesive on the back, that is very firmly attached to the skin and the catheter, is preferred to tape and gauze. This securement device, which previously was studied with peripherally inserted central catheters and central venous catheters, has now been studied in a time-sequenced trial in a large number of hospitals with peripheral venous catheters. I think the evidence suggests pretty convincingly that the securement device resulted in much less infiltration, much less loss of catheters because they came out inadvertently, and less phlebitis. The securement device appeared to be superior to conventional tape.

ICT: Given the advantages you mentioned with the securement device, does that translate into a cost benefi t? Because after all, tape seems to be a low-cost option, even though it’s associated with complications.

DM: The infi ltrated IV is an expensive IV. The nurse needs to trouble-shoot it and evaluate what’s going on: Why it is not functioning, and why it is causing discomfort to the patient?

And if it’s actually infi ltrated, it must be removed; you need continued IV therapy and continued access, and you must put in another one. Every new IV catheter is costly. When you consider nursing time is probably somewhere in the range of $25 an hour and the materials and factor in the cost of the catheters … preventing infi ltrated catheters or dysfunction of catheters is very beneficial in the long run and will save money.

ICT: Do you see an advantage for one securement method over the other, regarding material costs?

DM: Again, if you’re able to maintain stable access with less infi ltration and less phlebitis, which means you’re going to use fewer catheters to achieve the same goal, you’re going to save money in material costs. That’s all part of the cost-benefi t of a securement technology that reduces complications.

ICT: Do antimicrobial coatings now make sense for peripheral intravenous catheters in view of the 96-hour threshold established by the CDC?

DM: We don’t know the answer to that, because it’s not been studied. There are no commercial antimicrobial-coated peripheral venous catheters to my knowledge. And before one would recommend that they be used routinely, I think you’d need research studies that demonstrate they do significantly reduce infectious complications to justify their added cost – I’m sure there would be a premium in the terms of their cost. In the absence of any coated PIV catheters that are available commercially, or any studies that have demonstrated that coated PIV catheters are clearly more effective or cost-effective, it’s a hypothetical issue at this point.

ICT: Do you think luer-activated, needle-free valves are important?

DM: I’m not sure that they’re necessary with peripheral venous catheters. There has been growing concern that some of these valve systems may be vulnerable to contamination and could increase the risk of bacteremic infection. I participated in a meeting of users at the recent ACAC meeting in Washington, D.C., where a number of hospitals have seen problems with some of the valve systems, and they raise questions whether they might paradoxically put patients at increased risk.

ICT: Is there a needlestick safety aspect to this issue?

DM: There is, but first of all, it’s not usually necessary to have to use a sharp needle to access a peripheral venous catheter, and we have options that don’t necessarily require the use of needles. We’re using these valve systems almost uniformly, so I’m not sure they’re necessary to prevent needlesticks. We also must balance the risk of needlesticks against the risk to patients.

We use valve systems to reduce the small risk of needlesticks, and I certainly don’t want to see needlesticks, but a needlestick poses much less risk than bacteremia. What if patients have a two-, three- or four-fold increased risk of bacteremia because of these valves, that we can reduce a small risk of needlesticks? One might find, in a careful analysis, that in using these valves there is greater harm overall – in terms of more serious infections in patients – from preventing rare needlesticks that only rarely result in infections to healthcare workers. These technologies must be scrutinized very carefully, because whereas they may have a specific goal in mind – for instance, to reduce needlesticks – they may nevertheless paradoxically increase risk to patients. It that proves to be the case, then luer-activated valves would have to be reexamined.

ICT: For peripheral IVs, is there favorable evidence for the use of heparin vs. saline lock?

DM: If you have to lock a peripheral IV catheter, using a heparin solution will reduce the risk of it clotting off. Are there risks with the heparin?

It’s a little added cost, but not a lot. Heparinized saline is pretty cheap. Is there a risk in terms of the exposed person forming antibodies to the heparin? It’s a very, very low risk, but that risk is vanishing and we give enormous amounts of heparin to patients routinely. I think that the added risks are minuscule. So all things being equal, if you have to lock off peripheral IV catheters for periods of time, I think using heparinized saline, with a very low concentration of heparin, is probably beneficial.

ICT: Regarding access site dressings, is there any evidence-based preference?

DM: Dressings are intended to shield the access site from external trauma and contamination, and there are two options. We can use sterile gauze and tape, or we can use a sterile, transparent, polyurethane adhesive fi lm dressing. The latter is a fi lm that has adhesive on the back, fi ts over the entire catheter, and helps to immobilize the entire device. The advantage of transparent dressings over gauze – and why they’ve come into wide scale use around the world over the last 20 years – is that, first of all, the site will never get saturated by moisture via washing. Gauze gets saturated very easily, and then you have to replace it or it becomes heavily contaminated. Two, you can see the site at all times. And three, it’s easy to palpate the site and look for evidence of infl ammation on a daily basis. You can’t see through the gauze, you can only palpate through the gauze.

Four, transparent, polyurethane adhesive fi lms immobilize the access device much more firmly than tape, which allows the device to piston and move around.

On the other side of the equation, transparent dressings are a little more expensive than gauze.

Yet, if you can leave a transparent dressing on for three or four days, which you can with peripheral venous catheters very safely, it greatly reduces our costs.

The last issue, which is an important one, is do transparent dressings increase the risk of infection, because many people view them as being occlusive? Well, they’re not really occlusive, they’re semi-permeable. They allow moisture vapor from the surface of the skin to pass through the dressing. But, they prevent liquid moisture from the outside from coming in. The question is, are they really semi-permeable or not; will they allow a build-up of moisture under the dressing, which, if that occurs, increases skin colonization and perhaps the risk of infection? There have been many studies of transparent dressings; my group has done a number of them, and there have been a number of studies conducted all over the world.

The bottom line is that high-quality transparent dressings pose no increased risk of infection over sterile gauze. If a hospital or an IV therapy team chooses to use a transparent dressing, it’s safe. It poses no greater risk than gauze and tape. Users have an option using sterile gauze and tape or a transparent dressing; either one is acceptable.

ICT: On Aug. 2, 2004, the Occupational Safety and Health Administration (OSHA) issued a new fact sheet requiring an annual review of catheter securement throughout the hospital with regard to both tape and suture. Is this appropriate based on the evidence?

DM: That’s simply part of the move to enhance the safety of healthcare workers and reduce sharps injuries. Large catheters such as central venous catheters and also arterial catheters are pretty much routinely sutured in place because it’s very essential that they not migrate out. Availability of the needle-free, sutureless devices is another option in that regard. I personally think that’s the direction we have to be moving on a wide scale.

I think the evidence would indicate that the securement devices will reduce the risk of needlestick injuries. I don’t think that OSHA is saying that hospitals have to use securement devices instead of tape and suture; they’re suggesting that hospitals examine securement devices as an option. And I think that’s beneficial. I think they should examine it as an option.

ICT: Thank you very much, Dr. Maki,for your insights in regard to the care and maintenance of peripheral IV catheters. We look forward to discussing with you the care and maintenance of central venous catheters in part two of this interview, to appear in the February 2005 issue of ICT.