Publications by authors named "Tarja J Karpanen"

8 Publications

  • Page 1 of 1

A clinical evaluation of two central venous catheter stabilization systems.

Ann Intensive Care 2019 Apr 17;9(1):49. Epub 2019 Apr 17.

Corporate Division, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB, UK.

Background: Central venous catheters (CVCs) are commonly secured with sutures which are associated with microbial colonization and infection. We report a comparison of a suture-free system with standard sutures for securing short-term CVC in an international multicentre, prospective, randomized, non-blinded, observational feasibility study. Consented critical care patients who had a CVC inserted as part of their clinical management were randomized to receive either sutures or the suture-free system to secure their CVC. The main outcome measures were CVC migration (daily measurement of catheter movement) and unplanned catheter removals.

Results: The per cent of unplanned CVC removal in the two study groups was 2% (suture group 2 out of 86 patients) and 6% (suture-free group 5 out of 85 patients). Both securement methods were well tolerated in terms of skin irritation. The time and ease of application and removal of either securement systems were not rated significantly different. There was also no significant difference in CVC migration between the two securement systems in exploratory univariate and multivariate analyses. Overall, 42% (36 out of 86) of the CVC secured with sutures and 56% (48 out of 85) of the CVC secured with the suture-free securement system had CVC migration of ≥ 2 mm.

Conclusions: The two securement systems performed similarly in terms of CVC migration and unplanned removal of CVC; however, the feasibility study was not powered to detect statistically significant differences in these two parameters.

Trial Registration: ISRCTN, ISRCTN13939744. Registered 9 July 2015, .
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April 2019

An in vitro comparison of standard cleaning to a continuous passive disinfection cap for the decontamination of needle-free connectors.

Antimicrob Resist Infect Control 2018 5;7:50. Epub 2018 Apr 5.

University Hospitals Birmingham NHS Foundation Trust, Birmingham, B15 2TH UK.

Background: The optimal decontamination method for needle-free connectors is still unresolved. The objective of this study was to determine if a continuous passive disinfection cap is as effective as standard cleaning for the microbial decontamination of injection ports of two types of needle-free connectors.

Methods: The injection ports of needle-free connectors were inoculated with and allowed to dry. Disinfection caps containing 70% (/) isopropyl alcohol (IPA) were attached to the connectors for one, three or 7 days and were compared with needle-free connectors cleaned with 2% (/) chlorhexidine gluconate (CHG) in 70% () IPA. The number of remaining on the injection ports was evaluated. Median log reductions and 95% confidence interval (CI) were calculated and data analyzed using the Mann-Whitney test.

Results: The application of the disinfection cap resulted in a significantly higher reduction in than the 2% (/) CHG in 70% (/) IPA wipe, achieving a > 5 Log reduction in CFU at each time point.

Conclusions: The disinfection caps resulted in a significantly higher reduction in on the injection ports when compared to the use of a 2% () CHG in 70% () IPA wipe. This offers an explanation for the lower rates of central-line associated bloodstream infection (CLABSI) associated with the use of disinfection caps reported in clinical studies.
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July 2019

The risk of microbial contamination associated with six different needle-free connectors.

Br J Nurs 2018 Jan;27(2):S18-S26

Consultant Microbiologist, University Hospitals Birmingham NHS Foundation Trust, Birmingham.

Background: needle-free connectors are widely used in clinical practice. The aim of this study was to identify any differences between microbial ingress into six different connectors (three neutral-displacement, one negative-displacement and two anti-reflux connectors).

Methods: each connector underwent a 7-day clinical simulation involving repeated microbial contamination of the connector's injection ports with Staphylococcus aureus followed by decontamination and then saline flushes through each connector. The simulation was designed to be a surrogate marker for the potential risk of contamination in clinical practice.

Results: increasing numbers of S. aureus were detected in the flushes over the 7 days of sampling despite adherence to a rigorous decontamination programme. Significant differences in the number of S. aureus recovered from the saline flush of some types of connectors were also detected. Two different durations (5- and 15-second) of decontamination of the injection ports with 70% isopropyl alcohol (IPA) wipes were also investigated. There was no significant difference between the median number of S. aureus recovered in the saline flushes following a 5-second (165.5, 95% CI=93-260) or a 15-second decontamination regimen (75, 10-190).

Conclusions: The findings suggest that there may be differences in the risk of internal microbial contamination with different types of connectors and that even 15 seconds of decontamination may not fully eradicate microorganisms from the injection ports of some devices.
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January 2018

Clinical evaluation of a chlorhexidine intravascular catheter gel dressing on short-term central venous catheters.

Am J Infect Control 2016 Jan 9;44(1):54-60. Epub 2015 Oct 9.

Corporate Division, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK. Electronic address:

Background: A major source of microbial colonization of short-term central venous catheters (CVC) is the patients' endogenous skin microorganisms located at the CVC insertion site. The aim of this study was to determine if a transparent film dressing incorporating a 2% (weight/weight) chlorhexidine gluconate (CHG) gel decreases CVC and insertion site microbial colonization compared with a nonantimicrobial dressing in adult patients in critical care.

Methods: On CVC removal, samples for microbiological investigation were taken from both the skin surrounding the CVC insertion site and also from sutures securing the CVC. The sutures and intradermal and tip sections of the CVC were also collected for microbiological investigation. Microorganisms recovered from the samples were subsequently tested for susceptibility to CHG.

Results: There was a significant reduction in the number of microorganisms recovered from the CVC insertion site, suture site, sutures, and catheter surface in the CHG dressing group (n = 136) compared with the nonantimicrobial dressing group (n = 137). There was no significant difference in susceptibility to CHG between the microorganisms isolated from the CHG and standard dressing study patients.

Conclusion: A film dressing incorporating a CHG gel pad significantly reduced the number of microorganisms at the CVC insertion and suture sites with concomitant reduced catheter colonization.
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January 2016

A comparative study to evaluate surface microbial contamination associated with copper-containing and stainless steel pens used by nurses in the critical care unit.

Am J Infect Control 2011 Oct 12;39(8):e52-e54. Epub 2011 Jun 12.

University Hospitals Birmingham, National Health Service Foundation Trust, The Queen Elizabeth Hospital,. Electronic address:

A clinical study was undertaken to compare the surface microbial contamination associated with pens constructed of either a copper alloy or stainless steel used by nurses on intensive care units. A significantly lower level of microbial contamination was found on the copper alloy pens.
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October 2011

Antimicrobial activity of a chlorhexidine intravascular catheter site gel dressing.

J Antimicrob Chemother 2011 Aug 24;66(8):1777-84. Epub 2011 May 24.

Department of Clinical Microbiology and Infection Control, University Hospitals Birmingham NHS Foundation Trust, UK.

Objectives: The antimicrobial efficacy of a chlorhexidine gluconate (CHG) intravascular catheter gel dressing was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and an extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Chlorhexidine deposition on the skin surface and release from the gel were determined.

Methods: The antimicrobial efficacy was evaluated in in vitro studies following microbial inoculation of the dressing and application of the dressing on the inoculated surface of a silicone membrane and donor skin [with and without a catheter segment and/or 10% (v/v) serum] on diffusion cells. Antimicrobial activity was evaluated for up to 7 days. Chlorhexidine skin surface deposition and release were also determined.

Results: MRSA and E. coli were not detectable within 5 min following direct inoculation onto the CHG gel dressing. On the silicone membrane, 3 log and 6 log inocula of MRSA were eradicated within 5 min and 1 h, respectively. Time to kill was prolonged in the presence of serum and a catheter segment. Following inoculation of donor skin with 6 log cfu of MRSA, none was detected after 24 h. Chlorhexidine was released from the gel after a lag time of 30 min and increasing amounts were detected on the donor skin surface over the 48 h test period. The CHG gel dressing retained its antimicrobial activity on the artificial skin for 7 days.

Conclusions: The CHG intravascular catheter site gel dressing had detectable antimicrobial activity for up to 7 days, which should suppress bacterial growth on the skin at the catheter insertion site, thereby reducing the risk of infection.
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August 2011

Enhanced chlorhexidine skin penetration with eucalyptus oil.

BMC Infect Dis 2010 Sep 22;10:278. Epub 2010 Sep 22.

Life & Health Sciences, Aston University, Aston Triangle, Birmingham, UK.

Background: Chlorhexidine digluconate (CHG) is a widely used skin antiseptic, however it poorly penetrates the skin, limiting its efficacy against microorganisms residing beneath the surface layers of skin. The aim of the current study was to improve the delivery of chlorhexidine digluconate (CHG) when used as a skin antiseptic.

Method: Chlorhexidine was applied to the surface of donor skin and its penetration and retention under different conditions was evaluated. Skin penetration studies were performed on full-thickness donor human skin using a Franz diffusion cell system. Skin was exposed to 2% (w/v) CHG in various concentrations of eucalyptus oil (EO) and 70% (v/v) isopropyl alcohol (IPA). The concentration of CHG (μg/mg of skin) was determined to a skin depth of 1500 μm by high performance liquid chromatography (HPLC).

Results: The 2% (w/v) CHG penetration into the lower layers of skin was significantly enhanced in the presence of EO. Ten percent (v/v) EO in combination with 2% (w/v) CHG in 70% (v/v) IPA significantly increased the amount of CHG which penetrated into the skin within 2 min.

Conclusion: The delivery of CHG into the epidermis and dermis can be enhanced by combination with EO, which in turn may improve biocide contact with additional microorganisms present in the skin, thereby enhancing antisepsis.
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September 2010