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Preventing Intravenous Catheter-Associated Infections: AnUpdate
By Marlene Wellman Schmid, RN, PhD, CIC
Nosocomialor hospital-acquired infections cost several billion dollars and cause moredeaths annually per year than road accidents.1,2 The FatalityAnalysis Reporting System (FARS01 reported 37,043 fatal crashes in1999 in the US compared to the estimated 88,000 deaths in the two millionpatients who developed hospital-acquired infections, as reported by the Centersfor Disease Control and Prevention (CDC).1,3 The Institute ofMedicine (IOM) estimates the range to be 44,000 to 98,000.4 Thisequates to a 4.4 case fatality rate (88,000/2 million) for those patients whodevelop hospital-acquired infections.3
When compared to the crash fatality data, hospitalized patients are 2.4 timesmore likely to die from a hospital-acquired infection than they are from a roadaccident. In the 21st century, expenses incurred for nosocomial infectionscontinue to skyrocket, costing the healthcare industry approximately $4.6billion annually.3,6 Adding to these healthcare costs are similarinfections occurring in nursing homes, outpatient clinics, dialysis centers,infusion therapy centers, and other sites of healthcare delivery.
Of the estimated two million nosocomial infections, approximately 850,000 areclassified as catheter-associated infections (CAIs), with 50,000 categorized byCDC surveillance criteria as catheter-associated bacteremias (CABs)5-7The majority of these infections are associated with central intravenouscatheters. The case fatality rate for CABs is more than 20% (10,000deaths/50,000 cases) and the attributable mortality 35%.7Attributable mortality essentially means that of those patients who undergointravenous therapy and develop complications and subsequently die, 35% of thecause of his/her death can be attributed to the presence of the intravenouscatheter. This percentage is derived from hospitalized patient data comparingthose who have intravenous catheters that complicate and die compared to similarpatients who do not have intravenous catheters but complicate and die.8
Central Line Infections and Intensive Care Units
The CDC's National Nosocomial Infections Surveillance (NNIS) program for the285 participating US hospitals reported a significant decline in bloodstreaminfections from 1990 to 1999.3,6 The greatest decline was reported inmedical (nonsurgical) intensive care units (ICUs) followed by coronary ICUs,pediatric ICUs, and surgical ICUs.3,6 During this same time period,patient acuity has increased sharply. Patients admitted to hospitals today aresicker and experience shorter lengths of stay. Those admitted to intensive careunits (ICUs) are five to ten times more likely to acquire nosocomial infectionsthan other hospital patients.9-11 While ICU patients are at increasedrisk, their frequency of infections at the different anatomic sites and theirrisk of developing the infection vary by the type of ICU where they areadmitted.
Sources of Organisms in Catheter-Associated Infections
Epidemics are defined as rates of disease or events significantlyhigher than the usual frequency while endemic rates reflect the usualfrequency of disease or events.12 Maki's criteria of >15 colonyforming units (CFUs) continues as the gold standard for discriminating betweencatheter-related infections versus catheter colonization.13,14Infection means the invasion of the body (or a site if localized into one area)by pathogenic microorganisms that reproduce and multiple (>15 CFUs onculture), causing disease and tissue damage.13-15 The primary sourcesfor most pathogens causing endemic catheter-associated bloodstream infectionsare the catheter insertion site or the catheter hub.16 Contaminationmay result from the patients' own flora or from healthcare workers' hands duringinsertion or manipulation, or both.
Colonization occurs when microorganisms are present and multiplying but arenot invading the tissue or causing damage.13-15 When aseptictechnique is used during catheter placement, then colonization typically resultsfrom the patient's own endogenous flora (originating from the patient).16These organisms migrate along the outside or inside lumen of the intravenouscatheter and seed the intravenous site causing colonization, or it may progressto a localized or systemic infection.16 Marik reported thatapproximately 25% of the central venous catheters become colonized and 20% to30% of these colonized catheters become infected.10,18-22
ICUs as High-Risk Areas
Complicating hospitalized patients' risks for catheter-associated infections,Pelletier reported that patients with coexisting infections are more likely tohave catheter-related infections or bacteremia than patients without coexistinginfections even when no differences were found in APACHE II scores, white bloodcounts (WBC), length of hospital stay, time from admission to fever, time fromfever to treatment, normalization of WBC, days of antibiotics, defervescence(diminishing or disappearance of a fever), gender, presence of comorbidities,colonization while in the ICU, or mortality rate.9
It also has been reported that an increased risk for catheter-associatedinfections occurs in patients who have pneumonia and urinary tract coexistinginfections.9,23 These authors reported that 37.3% of the intensivecare unit patients with pneumonia and 28.8% with urinary tract infections alsodeveloped catheter associated infections.9 Brown and Warren reportedpneumonia occurring in 25-50% of the ICU patients they studied but less than 3%developed urinary tract infections.23 These authors also reportedthat catheter-associated infections with bacteremias were connected to anincreased proportion of gram-negative organisms compared to those catheterinfections without bacteremia.9
Although the CDC only recognizes catheter-related bloodstream infections withbacteremia and labels those infections without bactermia as colonization,Pelletier indicated that perhaps the definition of catheter-associatedinfections should be expanded to include those bloodstream infections that arewithout the presence of systemic illness and not explained as a result ofanother infectious source.9
Most intravenous catheter infections result from either catheter seedingoccurring during catheter placement (extraluminal) or during manipulation ofhubs or catheter junctions during use (intraluminal).14 All patientswho receive intravenous therapy are at risk for catheter-related infections,although the degree of risk varies by type of device and access site.Catheter-related infections account for approximately 30% of allhospital-acquired infections. For critically ill patients bacteremia is theleading cause of nosocomial infections.24 Although diagnosis of theseinfections may be difficult, catheter-associated infections should be suspectedin patients who have these devices and develop fever, chills, and leukocytosiswith no other apparent site of infection.24
Contributing to the seriousness of nosocomial infections, especially in ICUs,is the increasing incidence of infections caused by antibiotic-resistantpathogens and specifically Staphylococcus aureus and Enterococcus.For example, more than half of the catheter-associated bloodstream infections inthe US are caused by the gram-positive organism staphylococci.10
Air, Skin, and Blood as a Source of Infection
Weinstein29 identified three main sources of bacteria responsiblefor IV-associated infections: the air, the skin, and the blood. Although thenumber of microbes per cubic foot of air varies, depending on the particulararea of the hospital involved, contamination can occur when infection is presentand bacteria escape in the form of bodily discharge onto clothing, bedding, anddressings.29 The type of organism isolated from an intravenous siteand/or blood can offer insight into its source. Gram-negative rods suggest wateror the human digestive tract as the contamination source while gram-positivebacteria is more common in soil and could be potentially be traced back to thehealthcare workers', the patients', and/or significant others' hands.29,40
Infections by Air
Airborne contaminates settle on injection ports. Intravenous tubing may beinadvertently contaminated when allowed to drape onto the floor or placed nextto the patient in a bed where urine and fecal incontinence could contaminateaccess ports or tubing exterior. Healthcare workers' (HCWs) hands may becomecontaminated while bathing or cleaning the patient or during manipulation ofdressings or devices. Subsequent manipulation of intravenous tubing and accessports without prior hand washing may inadvertently contaminate access sitesalong the intravenous system, on the IV drip rate regulator, or on IV sitesduring dressing changes.36
Airborne contamination occurs during activities such as bed making, when onecoughs or sneezes, or during suctioning, sending bacteria flying into the air onparticles of lint, pus, dried epithelium, and/or droplet nuclei.29,30,32Increased activity triggers a rise in the number of airborne particles andcreates an environment that interferes with aseptic technique and potentiallycontributes to contamination. Airborne microorganisms in patient areas andutility rooms may find their way to IV fluids and equipment via breaches inaseptic technique.
A particle 100 microns in size is equivalent to 0.004 inches or 25 microns =0.001 inches.29 Therefore, housekeeping departments play a pivotalrole in maintaining a clean patient care environment by decreasing theenvironmental bioburden.
To prevent intravenous tubing contamination, the HCW should cover and containdrainage from infected wounds, avoid excessive movement of linens, and keep allintravenous tubing off the floor.23 They should decontaminate accessports by scrubbing injection ports for at least one minute with 70% alcohol or30 seconds with an antiseptic microbial solution such as providone-iodine.25,35,43Thesolution should then be allowed to dry for maximum antimicrobial effect.25,35,43All intravenous-tubing sets should be replaced when they leak at injectionsites, connections, or vents, or when they become contaminated.25,35,43
Capping intravenous sites for intermittent infusion preserves IV access whenpatients no longer need continuous infusions but still need intermittent IVaccess.11,36 These caps should be changed after multiple punctureswith large bore needles and/or needleless access devices, because frequentpunctures into IV caps may compromise the integrity of the cap material andincrease the risk for the IV to leak or become contaminated. New caps should beused each time a new IV catheter is inserted.11,36
Although no textbooks or articles were found that cited exactly how manypunctures an IV cap can tolerate safely before the integrity is impaired andshould be changed, the safest guideline is to check with the manufacturer of theproduct for guidance and incorporate the information into the agency IV policyfor your specific equipment. Intuitively, the larger the needle or needlelessaccess device and the more frequently accessed, the more likely the integrity ofthe cap will become impaired.11 The Occupational Safety and HealthAdministration (OSHA) requires hospitals to use needleless systems; however, ifneedles must be used current recommendations state #20 to #25 gauge needles thatare one inch or less in length cause the least amount of damage and allow forthe cap material to reseal after puncture.33,37,43
Infections on the Skin
Although several studies are dated, they are and continue to form therationale used by the Intravenous Nurses Society (INS) to support the goldstandard of intravenous skin prepping prior to IV catheter insertion. Alcohol70% is frequently used to prepare the skin site prior to venipuncture, and whenapplied with friction for one minute, results in 75% reduction in the minimumorganism count on skin, ie., 10,000 organisms/cm2 (0.155 square inches)on normal skin to 2,500.39,42 These organisms, or resident flora, arenot simply ones that adhere to dirty skin but live deep within the epithelialstructures of the skin and are shed in large numbers with hand washing orscrubbing.39 Furthermore, patients will become colonized withorganisms from the hospital environment. Colonization rapidly increases withduration of hospital stay. Staphylococcus epidermidis, Staphylococcusaureus, and gram-negative bacilli such as Klebsiella, Enterobacter,Serratia and enterococci (intestinal flora) are ubiquitous on theskin of hospitalized patients.40,41
Abrams reported that anaerobic bacteria occurs 1000:1 aerobic in the bowel.39Fecal incontinence increases environmental contamination and the risk of accessdevices including IVs becoming contaminated subsequently increases. Whileantibiotic resistant organisms such as vancomycin-resistant enterococcus (VRE)and methicillin-resistant Staphylococcus aureus (MRSA) can be spread bydirect contact, effective handwashing by healthcare workers has been proven tobe successful in interrupting transmission.36,44, Saliva, whichcontains as many as 100 million organisms per milliliter, can also causecontamination when a worker or patient speaks during a procedure includingduring IV site placement or IV dressing changes.39 Establish the sterile fieldand equipment needed for the procedure and limit conversation to eliminatedroplet contamination of the site and equipment.36
Failure to properly prep the skin prior to catheter insertion increases apatient's risk for colonization and/or infection via the IV site. Most organismsare not visible to the human eye. When properly applied (friction rubbing forone full minute), the effect of alcohol 70% in reducing the bacterial count onnormal skin at an IV insertion site has been reported to be nearly equivalent toa 12-minute hand scrub.42 INS continues to support the use of alcohol70% as an effective IV skin prep.43
In addition to alcohol 70%, other products currently available includeiodine, iodine-containing disinfectants, and chlorhexidine.45 Theiodine and iodine-containing disinfectants continue to be reliable in preparingthe skin for venipuncture because they provide bactericidal, fungicidal, andsporicidal activity when applied with friction and allowed to dry to activatethe antimicrobial properties. Like alcohol, tincture of iodine (2% iodine in 70%alcohol) is inexpensive and also should be applied working from the center ofthe insertion site to the periphery.43 When left on the skin, iodineproducts provide a sustained antimicrobial effect up to 6 hours afterapplication.43 However, patients should be screened for allergies.Iodophor preparations require at least a minimum 30-second contact time and INSstandard recommends two-minute drying time in order for the agent's propertiesto become activated.43
In 1991, Maki reported that the use of chlorhexidine in skin preparation andIV dressing changes was associated with the lowest incidence of catheter-relatedinfections and catheter related bacteremia.41 The greatest challengehas been for manufacturer's to produce chlorhexidine in easy to use skin preppackages or swab sticks.
Intravenous sites can become seeded when organisms from distant infectionsites are transported to the access port or adhere to the catheters, asdiscussed above.9 When attempting to determine if the patient has acatheter-associated infection, Phillips.35 recommends HCWs besuspicious of an IV catheter-related infection if the blood drawn from the IVcannula has five times the organism growth compared to blood obtained from aperipheral vein. Removal is recommended when catheters are implicated incatheter-associated infections.43
Preventing Central IV Catheter-Associated Infections
Routine intravenous solutions such as normal saline, lactated ringers,and/or dextrose solutions are good for only 24 hours once the hermeticallysealed wrapper is removed.29,36,43 All intravenous solutioncontainers must be carefully inspected before hanging.29,36,43 Glassbottles may become cracked or damaged and plastic bags punctured, allowingbacteria and fungi to invade the solutions contaminating the container.25,29,36,43Healthcare workers should be aware that Pseudomonas cepacia, Acinetobacter,and Serratia are the most common organisms that grow in 5% dextrose inwater.14 Most bacteria will grow in normal saline (0.9% sodiumchloride solutions [USP] normal saline) except Candida species, which groweasily in amino acids and 25% dextrose solutions.14,29
Healthcare workers must inspect each container of intravenous solutioncarefully, holding it against a light and dark background examining for cracks,defects, turbidity, and particulate matter.29,36,43 Never use anyglass container lacking a vacuum when opened. Always label infusates with thedate, time, and your initials when hung.36,43
The pH of intravenous solutions and medications can irritate IV access sitesand forms the rationale for having multiple types of devices (peripheral,midline, PICC, and CVC) available to HCWs. For example, dextrose is slightlyacidic (pH 4.5 to 5.5) while sodium chloride solutions have pHs ranging from 6.8to 8.5.35 In general, dextrose solutions should be used as a base foracidic drugs and sodium chloride solutions should be used for alkalinemedication dilution. Intravenous medications that are widely dissimilar in pHvalues are unlikely to be compatible in solution.35 Multipleantibiotics have an acidic pH that is stable in dextrose, but alkalineantibiotics such as carbenicill, are unstable when mixed with dextrose.35The HCW should follow manufacturers' guidelines and check intravenous andmedication compatibility charts prior to administration.35
New technology currently being tested for catheter-related infections includeantibiotic and antiseptic-coated catheters, antiseptic hubs, disinfecting caps,and flushing solutions.38 Risk for developing catheter-associatedinfection varies by device. Marik (2000) reported that approximately 5% of allpatients with uncoated, indwelling central intravenous catheters would develop ablood stream infection yielding 10-infections/1,000 catheter days.10,18-22
Each organization should have established policies and procedures for theplacement of intravenous catheters. At a minimum, healthcare professionalsshould have a comprehensive understanding of anatomy and physiology, vascularassessment techniques, and insertion techniques appropriate to the specificdevice. The catheter should always be inspected for product integrity prior toinsertion. Precautions to consider when stylets, needles, and/or wires are usedto facilitate catheter placement include a) stylets that are part of the productshould never be reinserted due to the potential for severing and/or puncturingthe catheter and b) catheters must never be withdrawn through a needle.43
Intravenous Policy Issues
A maximum of two attempts at cannulation by any one healthcare worker shouldbe made in order to avoid multiple unsuccessful attempts, causing unnecessarytrauma to the patient and limiting future vascular access. Catheters placed inan emergency situation where aseptic technique potentially has been compromisedshould be replaced as quickly as possible and definitely within 24 hours.36,43Current INS43standards recommend that HCWs should always followmanufacturers' guidelines for all intravenous catheters and document thecatheter placement, gauge, length and number of attempts, anatomical location,and patient's response to the procedure in the patient's medical record. PICCand CVC Central catheters should be radiopaque and placement radiologicallyconfirmed.43 Radiological confirmation should also be obtained whenthere is difficulty with catheter advancement, pain or discomfort after catheteradvancement, inability to obtain positive aspiration of blood, inability toflush the catheter easily, difficulty in removing guidewire, or guidewire notedto be bent upon removal.43
IV catheter and skin junction sites should be assessed for potentialcomplications (redness, tenderness, pus, warmth, and edema) at establishedintervals by hospital policy.3 The HCW should change gauze dressingsroutinely every 48 hours on peripheral and central catheter sites andimmediately if the integrity of the dressing is compromised.43 Ifgauze is used in combination with a transparent dressing, it is considered agauze dressing and should be changed every 48 hours.43 If transparentsemi-permeable dressings are used on peripheral IV sites and as long as theintegrity of the dressing is maintained, then the dressing is changed at thesame time as the 72-hour catheter site rotation is done.43 If acentral catheter-related infection is suspected, the HCW should change over theguidewire and culture the distal segment.43,47 Single-lumen centralcatheters should be used unless clear indication for a multi-lumen catheterexists.43,47 If catheter segments are culture positive, the cathetershould be removed.43,47 After PICC and central venous catheters areremoved, the site dressing should be changed every 24 hours and the siteassessed until epitheliazed.43 Once a central catheter has beeninserted, the HCW should never readvance if it becomes dislodged.43
According to INS standards, hospitals are expected to maintain an intravenousphlebitis rate of less than or equal to 5% with the 72-hour continuous primaryand secondary tubing administration set changes.43 Tubing continuousprimary and secondary administration sets should be changed every 48 hours ifthere is an increase in the incidence of phlebitis above recommended levelsand/or if an increase in catheter-associated infections is noted.43Primary intermittent or intermittent secondary tubing continues to be changedevery 24 hours.43 Add-on devices, such as tubing extensions, filters,stop-cocks, and needleless devices, should be changed when the administrationsets are changed.43 Some solutions, ie., total parenteral nutrition (TPN),lipids, blood and/or blood components) should dictate whether the administrationset is changed more frequently.43 Typically, administration sets usedfor TPN and lipids are changed every 24 hours while blood sets are changed everyfour hours or with each unit of blood, whichever comes first.43
Intravenous therapy continues to be the most frequent medical procedurehospitalized patients will experience. Scrupulous aseptic and sterile techniqueduring placement and maintenance of these sites will prevent catheter-associatedcomplications. Patients who are in intensive care units and who developpneumonia and urinary tract infections, are at increased risk for intravenouscatheter-associated infections. Furthermore, the increased use of antibioticscreates a patient care environment where antibiotic resistance emerges.Following INS standards for intravenous therapy will decrease the risk ofcatheter-associated infections and will improve patient outcomes.
Marlene Schmid, RN, PhD, CIC, is an associate professor at the Universityof Wisconsin School of Nursing.