AJIC: American Journal of Infection Control
Volume 36, Issue 10 , Pages S175.e1-S175.e4, December 2008

Clinical use of disinfectable needle-free connectors

  • Juan C. Yébenes, MD, PhD

      Affiliations

    • Intensive Care Unit, Hospital de Mataró, Barcelona, Spain
    • Corresponding Author InformationAddress correspondence to Juan C. Yébenes, MD, PhD, Hospital de Mataró, Intensive Care Unit, 08304 Mataro, Barcelona, Spain.
    • ,
  • Mateu Serra-Prat, MD, PhD, MPH

      Affiliations

    • Research Unit, Hospital de Mataró, Barcelona, Spain

Article Outline

Background

In 1992, the United States Food and Drug Administration required health care services to adopt needle-free devices to prevent health care workers’ exposure to bloodborne pathogens resulting from needlestick injuries, and several systems of disinfectable needle-free connectors (DNC) were introduced.

Studies: Microbial colonization

Experimental studies showed that DNCs designed with a split septum (SS-DNCs) and mechanical valve systems (MLV-DNC) prevented endoluminal colonization as effectively as needles or conventional caps. A comparison of the microbiologic barrier effect of SS-DNCs, MLV-DNCs, and passive positive-pressure (PPV)-DNCs found that PPV-DNCs were least effective in providing protection under experimental conditions of poor handling practices and high microorganism concentrations.

Prevention of catheter-related bloodstream infections

Some randomized trials show a positive or neutral effect of DNC use on the prevention of catheter-related bloodstream infections (CR-BSIs); however, some investigators have reported outbreaks of CR-BSIs following the introductions of DNCs that could be related to noncompliance with DNC handling recommendations or the use of PPV-DNCs.

Conclusion

Strategies focused in the implication of the nurse staff in CRBSI surveillance increase compliance with DNC handling recommendations and minimize the risk of developing a CR-BSI. DNCs can be used safely if staff complies with recommendations for use.

 

Patients in intensive care units (ICUs) are at increased risk of suffering health care-associated infections (HAIs) related to invasive procedures and the use of intravascular catheters (IVC), urinary devices, or mechanical ventilation. Catheter-related bloodstream infection (CR-BSIs) is the most common health care-associated bacteremia in critically ill patients.1 CR-BSIs have been defined as the isolation of a significant number of colony forming units (cfu) of the same microorganism strains from both catheter and peripheral blood cultures from a patient with clinical signs of sepsis.2 CR-BSIs affect approximately 50,000 critically ill patients each year in the United States, with an attributable mortality rate of up to 35%.3

The incidence of CR-BSIs rates are especially high in acutely ill patients who are in ICUs, where the infection rate can be as high as 10 CR-BSIs/1000 catheter-days.4 The use of peripheral vein catheters is associated with lower rates of CR-BSIs than with central venous catheters.5 The incremental costs of CR-BSIs have been calculated up to $30,000 per case, primarily resulting from increased length of stay that can be as much as 20 days.6, 7, 8

IVCs can be colonized by organisms on the patient's skin when the catheter is inserted (extraluminal colonization) or on the catheter hubs (endoluminal colonization) when health care workers manipulate the catheter to draw blood samples or to infuse drugs or parenteral nutrition.9 The most important risk factor for colonization is the duration of catheter use. When catheter is colonized during the first week of use, the skin is the main source of catheter colonization. With longer periods of use, endoluminal colonization is more important and is probably related to increased hub manipulation.10, 11

It is essential to establish protocols and clinical guidelines for the insertion and handling of catheters to minimize the incidence of CR-BSIs. The cornerstone of these is the recommendations of the Centers for Disease Control and Prevention12: (1) considering the insertion of IVCs as a surgical procedure and maintaining sterile conditions and (2) following proper procedures when manipulating catheter connections. Compliance with these 2 recommendations can be poor in emergency or high-workload situations, even though personal perception of compliance may be high. In critically ill patients, frequent manipulation of the catheter can lead to contamination by microorganisms from the patient's skin or health care worker's hands, despite adherence to the guidelines. When clinical guidelines are not enough to reduce rates of CR-BSIs, complementary strategies such as technologic innovations can also be used.

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Needlestick injuries with intravenous line handling 

Use of IVCs poses risks for both patients and health care workers. Percutaneous injuries from accidental needlesticks are associated with the highest risk for occupational transmission of bloodborne pathogens including hepatitis B and C viruses and HIV. In our hospital, 20% of accidental needlestick injuries occur in the patient's room and are directly related to the handling of infusion systems or drug administration through intravenous lines.

In 1992, the United States Food and Drug Administration required the use of needle-free devices to prevent health care workers’ exposure to bloodborne pathogens by needlestick injuries.13 Several disinfectable needle-free connectors (DNC) systems were developed and evaluated. Hubs were recognized as a source of contamination of endovascular catheters, and DNCs were designed to allow the external surface to be easily disinfected. Manufacturers recommended swabbing hubs with a dressing soaked in antiseptic (iodine, 70% alcohol, or clorhexidine) before handling, which is the same procedure followed before subcutaneous injections are administered.

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DNC design 

First-generation DNCs (Interlink, Bencton Drive, Franklin Lakes, NJ) were designed with a split septum (SS-DNC) that could be accessed with a blunt canula. Despite the resulting decrease in needlestick injuries,14 catheter-related infections sometimes increased because of unfamiliarity with the procedure and non-compliance with the manufacturers' recommendations.15 Removal of the cannulae was associated with negative pressure, which allowed retrograde flow that could facilitate bacterial growth or catheter occlusion.

New designs have substituted the blunt cannula by luer acces split septum as Q-Syte (Bencton Drive, Franklin Lakes, NJ) or Safeline Split System (B Braun Inc, Allentown, PA) or replaced the split-septum for mechanical luer access valve systems (MLV-DNC). Differences among these systems are mostly related to the mechanical luer valve design. In MLV-DNC such as the SmartSite safety disposables (Cardinal Health, Dublin, OH) or Clearlink (Baxter, Deerfield, IL), the valve is a silicon piston that becomes permeable when is compressed and returns to its previous position when the syringe or infusion equipment is removed, hermetically sealing the system without the need for a cap. If a new infusion or extraction from the hub is required it must be disinfected again. In other MLV-DNCs, such as Microclave (ICU Medical, San Clemente, CA) or SS-DNC such as Bionector (Vygon Corp, Montgomeryville, PA), the body of the connector has an endoluminal cylinder that enter through the connector piston or septum in the syringe or luer-type device providing a double protection system.

Third-generation designs include passive positive-pressure valves (PPV-DNCs) such as the CLC2000 (ICU medical, San Clemente, CA), SmartSite Plus positive bolus valve (Cardinal Health, Dublin, OH), or Posiflow (Bencton Drive, Franklin Lakes, NJ). PPV-DNCs prevent retrograde flow or blood clotting in the catheter when the luer connection is removed.

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Microbiologic barrier effect of DNCs under experimental conditions 

Disinfecting a catheter hub before handling can minimize migration of microorganisms from the patient's skin or from health care workers to the lumen of the catheter and prevent endoluminal colonization. Although the barrier effect of DNCs was not complete in studies using supranormal concentrations16 of microorganisms, the SS-DNCs17 and the MLV-DNCs18 seem to protect against endoluminal colonization as effectively as needles or conventional caps.

Two factors help explain these results. The removal of a catheter cap exposes a hub to contamination by external microorganisms. The risk of colonization can be increased by the presence of residual serum, blood, or hyperlipidic solutions that facilitate pathogen growth. If catheter access remains closed and an antiseptic is applied before manipulation, the possibility of microbial migration and endoluminal colonization is reduced.

To evalauate the barrier effect of these devices, a study was conducted using an 18-gauge peripheral venous catheter that was inserted into a bottle of aerobic blood culture (Bact/alert SA). Three different DNCs precontaminated with different concentrations of broth were used to close the catheters. Every 8 hours, 1 mL of saline was infused through a DNC, either following manufacturers’ recommendations or without disinfection. The sterility of experimental samples after infusion was expressed in number of sterile bottles divided by the total number of bottles (%). Results showed that the microbiologic barrier effect of DNCs is adversely affected by increasing concentration of bacterial external valve and improved by correct handling of connectors before infusion. The PPV-DNC was least effective in providing protection in these experimental conditions.19

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Clinical use of DNCs 

Three extensive prospective randomized trials have assessed the efficacy of these devices in clinical practice compared with conventional caps. Bouza et al20 observed a reduction in hub colonization (7.56 vs 24.66 CR-BSIs/1000 catheter-days, respectively, P = .0017) and in tip colonization (59.2 vs 83.6 CR-BSIs/1000 catheter-days, respectively, P = .003) in the DNC and control groups, respectively. But differences in CR-BSI incidence rates (3.78 vs 5.89 per 1000 catheter-days, respectively) were not statistically significant, probably because 30% of catheters analyzed were peripheral lines, which are associated with a low incidence of BSIs. Bouza et al20 observed a significant reduction in tip colonization, which can be used as a surrogate end point in clinical studies on CR-BSI prevention.

A study in medical, surgical, and trauma patients in a university hospital ICU found a significant reduction in CR-BSI rates with the use of DNCs in central venous catheters with a mean duration of catheter use of 10 days. In the control group where catheters hubs were closed with caps, the infection rate was 5 CR-BSIs/1000 catheter-days, whereas, in the study group in whom catheter hubs were closed with DNCs, the rate was 0.7 CR-BSIs/1000 catheter-days.21 In a third study, no differences were observed, despite a subanalysis that surprisingly showed a trend toward higher risk of infection in patients with arterial lines and a trend toward the prevention of CR-BSIs in the central venous catheter group when DNCs were used.22 Recently, a prospective study observed a protective effect of DNC when compared to caps in terms of hub colonization in radial arterial lines inserted in critically ill patients.23

Despite randomized trials showing a positive or neutral effect of DNC use on the prevention of CR-BSIs, some investigators have reported outbreaks of CR-BSIs after introducing SS-DNC,15 MLV-DNC,24 and especially PPV-DNC.25, 26, 27 When the effectiveness of SS-DNCs, MLV-DNCs, and PPV-DNCs was compared in children with central venous catheters, an increased risk of CR-BSIs was observed in the group in whom the PPV-DNC system was used.28 These results could be explained by noncompliance with DNC handling recommendations and the differences in the valve design and could suggest an increased risk of infection in PPV-DNC. Swabbing the external surface of the connector valve with an antiseptic-impregnated gauze is an easy procedure, but busy workloads or lack of knowledge could decrease compliance with guidelines for correct handling of DNCs.

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Introducing DNCs into clinical practice 

The introduction of any new device into clinical practice should be preceded by a review of the institutional protocol and distribution of the updated version. Health care workers should be educated about infection-control practices and alerted to the importance of careful manipulation of the catheter during insertion, bolus infusion, or other manipulation. The use of evidence-based practice “bundles” has been reported as an effective strategy to reduce CR-BSI rates in critically ill patients.29 Establishing a catheter-related infection team can increase awareness of the need for a culture of safety and quality and introduce basic recommendations through the use of bundles, surveillance methods, and reporting of CR-BSI rates to clinicians and administrators.

A 5-recommendation bundle was used in our ICU to increase compliance with handling recommendations that included (1) involving nurses in epidemiologic surveillance; (2) selecting the safest site for catheter insertion; (3) understanding that insertion is a surgical procedure; (4) maintaining endoluminal sterility during infusion; and (5) avoiding unnecessary insertions, manipulations, or removals. Every 3 months, CR-BSI rates were reported to nurses responsible for surveillance and discussion of the results with the nursing staff. From January to September 2007, a total of 510 catheters were inserted in 229 critically ill patients and used for more than 24 hours. Of those, 273 catheters were central venous catheters, and 237 were arterial lines. The mean duration of catheter use was 6.3 ± 6.0 days with an estimated 3227 days of risk. Rates of CR-BSIs and primary bacteremia during the 9-month study were 0 and 0.62/1000 catheter days, respectively.30

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Conclusion 

The barrier effect of a DNC is related to the external contamination load and to proper disinfection before handling. Device design also influences barrier effectiveness, although clinical implications of this finding are unclear. The latest generation of PP-LV-DNCs must be specially monitored. Active involvement of health care workers in an infection control program can increase compliance with recommendations and guidelines. Educational programs, bundled recommendations, epidemiologic surveillance developed by nurses, and periodical reporting of CR-BSI rates to staff can also improve compliance with guidelines. DNCs can be used safely if staff complies with the recommendations for use.

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References 

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 Disclosures: Dr. Yébenes received an honorarium for participating in the symposium and writing this article. Dr. Yébenes has received grants to develop an educational program in his hospital from Cardinal Health. Dr. Serra-Prat reports no conflicts of interest.

PII: S0196-6553(08)00798-0

doi:10.1016/j.ajic.2008.10.013

AJIC: American Journal of Infection Control
Volume 36, Issue 10 , Pages S175.e1-S175.e4, December 2008

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