Renowned Expert Dennis Maki, MD Addresses Catheter-RelatedInfections
ICT spoke with Dennis G. Maki, MD, professor of medicine andhead of the Section of Infectious Disease at the University of Wisconsin-MadisonMedical School. As a world-renowned specialist in infectious disease, Makiswork puts him at the center at some of most dreaded plagues of our time: AIDS,biological warfare, chronic wasting disease. His research focuses oninstitutionally acquired infections, which are emerging as an urgent problem inthe United States and around the world. Makis research in hospital-acquireddisease has been seminal and saved countless patients worldwide; colleagues describe his accomplishments in teaching, communityoutreach, and clinical medicine as the gold standard in his field. Makihas served as a consultant to the Centers for Disease Control and Prevention(CDC) and to the Food and Drug Administration (FDA), has won numerous researchand teaching awards, and has 400- plus publications to his credit, many of themin the prestigious New England Journal of Medicine. He is considered tobe the leading authority on catheter-related infection control issues, and inthis two-part interview, speaks candidly about the techniques and the technologyof preventing CRIs.
ICT: Beforewe examine techniques and technology, what are the complications of peripheralintravenous catheters (PIVs), and are they the inevitable consequences ofplacing a hard plastic object in a soft, fragile vessel?
DM: There are probably 150 to 200million peripheral venous catheters that are placed every year in the UnitedStates. Probably 30 or 40 million of these are small scalp-vein needles that areused in children; the rest of these are small plastic catheters that are placedin a peripheral vein, such as the back of the hand or the wrist, or a littlehigher up in the arm. The most common complication is discomfort, but PIVsgenerally dont pose a major threat to the patient and dont generallyincrease hospitalization.
That said, when a needle breaks through the wall of the veinand 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 newsite. Infi ltration is very, very common, occurring maybe 10 percent to 20percent 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 irritatingeffects of the drugs given intravenously, as well as related to the movement ofthe catheter needle in the vein. Its hard to prevent a little bit of movement.
Then there is the more serious complication of infection. Therisk of infection in PIVs is not high, but when it occurs, infection can beserious because it can involve the bloodstream. Two types of serious infections occur in peripheral venouscatheters. The most common is when organisms invade the bloodstream in the tractaround the catheter. This kind of infection originates from microorganisms onthe surface of the patients skin; they invade the tract that the catheterpasses through and cause bacteremia, or bloodstream infection. The second kindof serious infection associated with PIVs is septic thrombophlebitis. Here, aclot in the vein with accompanying infl ammation becomes infected. This is avery serious infection, because even though you may remove the catheter, thepatient continues to have ongoing active bacteremia. Septic thrombophlebitis isbest treated by surgically removing the infected clot from the vein.
Now, bacteremia from peripheral venous catheters only occursin about one out of every 500 catheters or so. Its not very common, but itsa serious infection and the prolonged hospitalization it causes can belife-threatening.
Now, to examine the question as to why these more seriousPIV-related complications occur, its not so much that a solid object is goinginto a soft tissue space. I think the fundamental problem is that its apercutaneous device that passes through the skin and goes deeper into the body.The skin has enormous numbers of organisms on it. If the person carriesparticularly more virulent organisms, such as staphylococcus, he or she can getserious a bacteremic infection from a peripheral venous catheter. So, thefundamental challenge is to be able to put a catheter into a vein and to try tominimize the likelihood that microorganisms on the skin of the patient will gainaccess to the bloodstream.
ICT: Do you recommend anyparticular kind of glove and/or gown for the healthcare worker before placementof a peripheral intravenous catheter?
DM: When we put in central venouscatheters, which pose a much greater risk of infection, we routinely use maximalsterile barriers, which is a long-sleeve sterile surgical gown, a mask, a headcover, sterile gloves, and a large sterile drape called a sheet drape. Forcentral 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 thatpeople wear gloves and they may or may not use a small drape. Generally itsnot considered necessary to use maximal barrier precautions for peripheralvenous catheters if theres good technique.
ICT: Does it make a difference ifthe gloves are sterile or non-sterile?
DM: Generally, it probably does notmake that much of a difference. Sterile gloves are often used, but itsprobably not mandatory.
ICT: Do you think its a goodidea to use some sort of drape or barrier on the patient when starting a PIV?
DM: In general, I think its agood idea to use a fenestrated drape to shield the portions of the patientsanatomy that are not disinfected. If Im going to put a peripheral venous catheter in yourwrist, Im going to prep the skin vigorously, and scrub it with a cutaneousantiseptic in a circumferential manner; so, if Im targeting one specificspot in your wrist where the vein is at the surface, I may prep an area anywherefrom three to four inches around that area. Theres still un-prepped skin aboveand below. Now, if we put a sterile drape with a little hole in it, the onlything that is exposed is prepped skin; theres no likelihood that wellinadvertently touch the outside of the prepped area.
ICT: Isthere 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 canuse the back of the hand when there are limited sites, but thats not a firstchoice only because if theres infiltration, the subcutaneous tissue there isvery thin and is more uncomfortable with infi ltrates. The veins are also alittle more fragile in the dorsum of the hand. I think the forearm between thewrist and the elbow is the ideal place to put the catheter. Often, peripheralvenous catheters are put in the crook of the elbow if the veins are right at thesurface there.
I dont like them placed there, because you have to put thepatients arm on an arm board to keep it straight. Otherwise, the bending ofthe arm will cause infiltration of the catheter, and it will come out of thevein. I think its very uncomfortable for a patient to have his or her armimmobilized straight for prolonged periods of time.
I think the ideal place to put a peripheral venous catheter isbetween the wrist and the elbow, but not the antecubital fossa. The forearm isthe most comfortable place. You can move the wrist, you can move the elbow, itdoesnt interfere with the motion in the joints, and its most comfortablefor the patient.
ICT: Is there any skin prep,beyond isopropyl alcohol, that should be used before inserting an peripheralintravenous catheter?
DM: Yes. Evidence indicates thatthere are differences in the capacity of different chemical antiseptics toreduce the number of organisms on the skin. And the more effective you are atreducing the numbers of organisms you never eliminate them all thebetter. I think the evidence is clear that chlorhexadine is a superior cutaneousantiseptic for vascular access. In my opinion, it ought to be used for all formsof vascular access, not just central venous catheters. I think if youreputting in peripheral venous catheters, arterial catheters, peripherallyinserted central catheters, a chlorhexadine product is the choice. If you cantuse chlorhexadine, either 70 percent alcohol or povidone iodine are acceptable. However, chlorhexadine should be the first choice if itsavailable.
ICT: Regarding the CDCrecommendation that absent infection or phlebitis peripheral intervenouscatheters may remain in place for 96 hours in adults: Does that recommendationaffect how one should prep skin for PIV insertion?
DM: No, I dont think so. I thinkthe prepping is the same no matter how long the intended catheter use. I wouldsimply make the argument that, unless theres a compelling reason not to usechlorhexadine, that should be the choice. And it doesnt matter if the catheter is going to stay infor 12 hours or 96 hours. You often dont know at the time you put it in howlong youre going to be able to, or need to, use the site.
ICT: Isnt site infection rarewith peripheral intravenous catheters?
DM: Its rare, but its notzero. As I said before, it is in the range of 0.2 percent, and it may have risena little bit in recent years.
ICT: Is there a preferred kind ofcatheter, either from a patient-safety or a needlestick safety point of view?
DM: Theres evidence that suggeststhat polyetherurethane, which is one polymer used in making catheters, may causeless phlebitis or inflammation (independent of infection) than Tefloncatheters. But both of them are perfectly fine.
ICT: Regarding safety mechanisms,do you have a preference?
DM: I think its ideal withperipheral venous catheters to use catheters that, once theyre in the vein,the needlestick safety mechanism is automatically activated so the needle cannotinadvertently stick somebody.
ICT: What about the securement ofperipheral IVs? Non-sterile tape is the traditional habitbased practice. Isthere any real evidence-base to suggest a change of technique?
DM: There is growing evidence that asecurement device that has adhesive on the back, that is very firmly attachedto the skin and the catheter, is preferred to tape and gauze. This securementdevice, which previously was studied with peripherally inserted centralcatheters and central venous catheters, has now been studied in a time-sequencedtrial in a large number of hospitals with peripheral venous catheters. I thinkthe evidence suggests pretty convincingly that the securement device resulted inmuch less infiltration, much less loss of catheters because they came outinadvertently, and less phlebitis. The securement device appeared to be superior to conventionaltape.
ICT: Given the advantages youmentioned 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 itsassociated with complications.
DM: The infi ltrated IV is anexpensive IV. The nurse needs to trouble-shoot it and evaluate whats goingon: Why it is not functioning, and why it is causing discomfort to the patient?
And if its actually infi ltrated, it must be removed; youneed 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 probablysomewhere in the range of $25 an hour and the materials and factor in the costof the catheters preventing infi ltrated catheters or dysfunction ofcatheters is very beneficial in the long run and will save money.
ICT: Do you see an advantage forone securement method over the other, regarding material costs?
DM: Again, if youre able tomaintain stable access with less infi ltration and less phlebitis, which meansyoure going to use fewer catheters to achieve the same goal, youre goingto save money in material costs. Thats all part of the cost-benefi t of asecurement technology that reduces complications.
ICT: Do antimicrobial coatingsnow make sense for peripheral intravenous catheters in view of the 96-hourthreshold established by the CDC?
DM: We dont know the answer tothat, because its not been studied. There are no commercialantimicrobial-coated peripheral venous catheters to my knowledge. And before onewould recommend that they be used routinely, I think youd need researchstudies that demonstrate they do significantly reduce infectious complicationsto justify their added cost Im sure there would be a premium in the termsof their cost. In the absence of any coated PIV catheters that are availablecommercially, or any studies that have demonstrated that coated PIV cathetersare clearly more effective or cost-effective, its a hypothetical issue atthis point.
ICT: Do you think luer-activated,needle-free valves are important?
DM: Im not sure that theyrenecessary with peripheral venous catheters. There has been growing concern thatsome of these valve systems may be vulnerable to contamination and couldincrease the risk of bacteremic infection. I participated in a meeting of usersat the recent ACAC meeting in Washington, D.C., where a number of hospitals haveseen problems with some of the valve systems, and they raise questions whetherthey might paradoxically put patients at increased risk.
ICT: Isthere a needlestick safety aspect to this issue?
DM: There is, but first of all, itsnot usually necessary to have to use a sharp needle to access a peripheralvenous catheter, and we have options that dont necessarily require the use ofneedles. Were using these valve systems almost uniformly, so Im not suretheyre necessary to prevent needlesticks. We also must balance the risk ofneedlesticks against the risk to patients.
We use valve systems to reduce the small risk of needlesticks,and I certainly dont want to see needlesticks, but a needlestick poses muchless risk than bacteremia. What if patients have a two-, three- or four-foldincreased risk of bacteremia because of these valves, that we can reduce a smallrisk of needlesticks? One might find, in a careful analysis, that in usingthese valves there is greater harm overall in terms of more seriousinfections in patients from preventing rare needlesticks that only rarelyresult in infections to healthcare workers. These technologies must bescrutinized very carefully, because whereas they may have a specific goal inmind for instance, to reduce needlesticks they may neverthelessparadoxically increase risk to patients. It that proves to be the case, thenluer-activated valves would have to be reexamined.
ICT: For peripheral IVs, is therefavorable evidence for the use of heparin vs. saline lock?
DM: If you have to lock a peripheralIV catheter, using a heparin solution will reduce the risk of it clotting off.Are there risks with the heparin?
Its a little added cost, but not a lot. Heparinized salineis pretty cheap. Is there a risk in terms of the exposed person formingantibodies to the heparin? Its a very, very low risk, but that risk isvanishing and we give enormous amounts of heparin to patients routinely. I thinkthat the added risks are minuscule. So all things being equal, if you have tolock off peripheral IV catheters for periods of time, I think using heparinizedsaline, with a very low concentration of heparin, is probably beneficial.
ICT: Regarding access sitedressings, is there any evidence-based preference?
DM: Dressings are intended to shieldthe access site from external trauma and contamination, and there are twooptions. 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 thathas adhesive on the back, fi ts over the entire catheter, and helps toimmobilize the entire device. The advantage of transparent dressings over gauze and why theyve come into wide scale use around the world over the last 20years is that, first of all, the site will never get saturated by moisturevia washing. Gauze gets saturated very easily, and then you have to replace itor it becomes heavily contaminated. Two, you can see the site at all times. Andthree, its easy to palpate the site and look for evidence of infl ammation ona daily basis. You cant see through the gauze, you can only palpate throughthe gauze.
Four, transparent, polyurethane adhesive fi lms immobilize theaccess device much more firmly than tape, which allows the device to piston andmove around.
On the other side of the equation, transparent dressings are alittle more expensive than gauze.
Yet, if you can leave a transparent dressing on for three orfour days, which you can with peripheral venous catheters very safely, itgreatly reduces our costs.
The last issue, which is an important one, is do transparentdressings increase the risk of infection, because many people view them as beingocclusive? Well, theyre not really occlusive, theyre semi-permeable. Theyallow 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 questionis, are they really semi-permeable or not; will they allow a build-up of moistureunder the dressing, which, if that occurs, increases skin colonization andperhaps the risk of infection? There have been many studies of transparentdressings; my group has done a number of them, and there have been a number ofstudies conducted all over the world.
The bottom line is that high-quality transparent dressingspose no increased risk of infection over sterile gauze. If a hospital or an IVtherapy team chooses to use a transparent dressing, its safe. It poses nogreater risk than gauze and tape. Users have an option using sterile gauze andtape or a transparent dressing; either one is acceptable.
ICT: On Aug. 2, 2004, theOccupational Safety and Health Administration (OSHA) issued a new fact sheetrequiring an annual review of catheter securement throughout the hospital withregard to both tape and suture. Is this appropriate based on the evidence?
DM: Thats simply part of the moveto enhance the safety of healthcare workers and reduce sharps injuries. Largecatheters such as central venous catheters and also arterial catheters arepretty much routinely sutured in place because its very essential that theynot migrate out. Availability of the needle-free, sutureless devices is anotheroption in that regard. I personally think thats the direction we have to bemoving on a wide scale.
I think the evidence would indicate that the securementdevices will reduce the risk of needlestick injuries. I dont think that OSHAis saying that hospitals have to use securement devices instead of tape andsuture; theyre suggesting that hospitals examine securement devices as anoption. And I think thats beneficial. I think they should examine it as an option.
ICT: Thank you very much, Dr. Maki,for your insights inregard to the care and maintenance of peripheral IV catheters. We look forwardto discussing with you the care and maintenance of central venous catheters inpart two of this interview, to appear in the February 2005 issue of ICT.