Professor Tom SJ ElliottUniversity Hospitals Birmingham NHS Foundation

Trust, Birmingham, UK.

Tegaderm CHG dressing study in the UK.

Ramifications of the results from the clinical study.

Do bundles of care need to consider other risks in reducing CRI?

Catheter related infections (CRI) occurring duringthe first weeks after the insertion of a short termCVC (≤3 weeks) are mostly caused by a migrationof microorganisms along the external surface ofthe CVC into the blood stream from the CVCinsertion site.

The role of suture puncture sites and sutures securing CVC in developing CRI is unclear.

In surgery, microorganisms which become adherent to surgical sutures may result in various infective complications.

Use of a sutureless securement device demonstrated significant reduction in catheter related infections compared to suture securement of PICC (Yamamoto et al., 2002).

Investigators: T.J. Karpanen, A.L Casey, T. Whitehouse, P. Nightingale, I. Das and T.S.J. Elliott

To evaluate the antimicrobial efficacy of a transparent dressing containing an integrated CHG gel pad on the number of microorganisms at: the CVC insertion site

around the sutures securing the catheter

suture material

CVC tip

CVC intradermal section

• 3M™ Tegaderm™ CHG IV dressingAn adhesive, semi-permeable,

transparent polyurethane filmdressing incorporating atransparent gel pad containing2% (w/w) chlorhexidinegluconate.

• 3M™ Tegaderm™ IV dressingAn adhesive, semi-permeable,

transparent polyurethane filmdressing.

A cross-over study.

Critical care adult patients with a CVC/Vascath in place for ≥3 days.

Ethical committee and Trust approvals received prior to the study.

Written consent from the study participants.

Standard dressing phase (n=68 patients)

CHG dressing phase (n=136)

Standard dressing phase (n=69 patients)

January 2013

October 2014

On CVC removal, samples for microbiological investigation were taken from:

• Skin surrounding the CVC insertion site.

• The skin surrounding the sutures securing the CVC.

•Control skin site (from the contra-lateral body site to the CVC).

• The sutures.

• CVC intradermal and tip sections.

Study outline

A swab moistened in 0.9% (w/v) saline was used to sample skin sites. The tip of the swab was then placed into 2 mL of neutralising solution.*

Sutures were also placed into 2mL of neutralising solution.

*CHG neutralising solution: 1.17 (w/v) % Lecithin, 2% (v/v) Tween 80, 0.1% (v/v) Triton X-100, 0.5% (w/v) Sodium Thiosulphate in distilled water.

Swabs were vortexed for 1 min and sutures weresonicated in a 50Hz water bath for 10 min beforevortexing for 30 s.

250 µl of each sample solution was inoculated ontoblood agar plates in duplicate; the plates were incubatedat 37˚C in aerobic conditions for two days. Number of cfuand microbial ID determined.

The patients received standard CVC site care as per hospital policy, which included:

◦ 2% (w/v) CHG in 70% (v/v) isopropyl alcohol skin antisepsis prior to CVC insertion and during CVC dressing changes. ◦ Tegaderm standard or CHG IV dressing.◦ 7 day dressing change unless indicated earlier.

All patients except two had an antimicrobial CVC inserted (CHG and silver sulfadiazine impregnated ARROWg+ard Blue® catheters*).

All patients’ CVC were secured with braided silk sutures (Mersilk**). The median distance of sutures to CVC insertion site in both study

groups was 1.5 cm (range between 0.5 to 7.0 cm).

*Arrow International, reading, PA, USA.** Ethicon, Johnson and Johnson Medical Ltd, Livingston, UK.

A total of 273 patients were included in the study analysis.

No significant difference in demographic and background characteristics between the two study groups.

The two study groups had similar microbial loads on their control skin swabs.

Table 1. Demographic and background data for the two study groups on the CVC dressing clinical evaluation.Standard dressing group (n=137); Chlorhexidine (CHG) dressing group (n=136).

Standard  CHG p‐value

Median age (range) 64 (18‐87) 59 (18‐89) 0.084a

Gender‐ Male‐ Female

90 (65.7%)47 (34.3%)

76 (55.9%)60 (44.1%)

0.108b

Type of CVC‐ Single lumen CVC‐ Quad lumen CVC‐ 5‐lumen CVC‐ Vascath

0 (0%)123 (89.9%)2 (1.5%)12 (8.8%)

1 (0.7%)121 (89.0%)1 (0.7%)13 (9.6%)

0.908b

Location of CVC‐ Internal jugular vein‐ Subclavian vein‐ Femoral vein

119 (86.9%)12 (8.8%)6 (4.4%)

112 (82.4%)17 (12.5%)7 (5.1%)

0.533b

Number of CVC*‐ One‐ Two‐ Three

98 (71.5%)37 (27.0%)2 (1.5%)

98 (72.1%)34 (25.0%)4 (2.9%)

1.0b

Median time (days) in place (range) 5 (3‐17) 6 (3‐24) 0.088a

Median number of dressing changes per CVC (range) 1 (0‐5) 1 (0‐5) 0.955a

a) Mann‐Whitney Testb) Fisher's Exact Test*at the same anatomical location

Table 2. Median aerobic cfu (and range) recovered from the CVC insertion site, suture site (per cm2) and per suture (n=273).

* Mann-Whitney test** Wilcoxon matched-pairs signed-ranks test: CVC site vs suture site.***Nonparametric repeated measures ANOVA: CVC site, suture site and sutures.

Standard dressing group(n=137)

Chlorhexidine dressing group (n=136) p-value*

Control 87.6 (0‐4.56x105) 71.52 (0‐3.04x108) 0.198

CVC site 10.19 (0‐5.16x108) 0 (0‐5.67x104) <0.001

suture site 22.29 (0‐1.70x107) 0.64 (0‐8.57x106) <0.001

p‐value** 0.034 0.028

sutures 56.0 (0‐1.18x108) 2 (0‐7.5x106) <0.001

p‐value*** <0.0001 0.0001

A significant reduction in the number of microorganisms recovered from the CVC insertion site, suture site and sutures in the CHG dressing group compared to the non-antimicrobial dressing group.

The sutures and suture site had significantly more microorganisms present as compared to the CVC site.

The use of CHG gel dressing significantly reduced the number of microorganisms at the suture site.

Microorganisms associated with sutures used for securing CVC were found to add to the microbial load at the insertion site (p<0.001, Spearman correlation).

There were significantly fewer microorganisms on the catheter surface in the CHG dressing group compared to the standard dressing group (Mann-Whitney test):

◦ Intradermal segment (p=0.003);◦ CVC tip segment (p=0.008).

There was no significant difference in the types of microorganisms isolated from the CHG and standard dressing group patients.◦ Gram positive cocci: 96.9% (Std) and 95.7% (CHG) (p=1.000,

Fisher’s Exact test); ◦ Gram positive rods: 25.0% (Std) and 13.0% (CHG)

(p=0.151);◦ Gram negative bacteria: 26.6% (Std) and 15.2% (CHG)

(p=0.170).

Did the use of 2% (w/v) CHG skin antisepsis (prior to CVC insertion and at dressing changes) and CHG impregnated CVC, together with CHG gel dressing, increase incidence of microbial resistance?

No. There was no significant difference in the microbial susceptibility to CHG in the two study groups or between the microorganisms isolated from the control skin site and CVC site.

There were no reports of severe contact dermatitisassociated with the CHG or standard dressings

Close assessment of skin condition at the CVC sitewas carried out in 273 patients who had given theirconsent:◦ Following dressing removal, mild erythema under the

adhesive was reported in one standard dressing grouppatient (0.7%, n=137) and in seven CHG dressing grouppatients (5.1%, n=136).

◦ Only one patient presented with mild erythema under theCHG gel component of the dressing (0.7%, n=136).

◦ All the above symptoms resolved within 24 h followingdressing removal.

CHG gel dressing significantly reduced the number of microorganisms colonising 1) the skin at the CVC insertion site; 2) intradermal segment and distal tip of indwelling CVC.

Sutures and their skin puncture sites had significantly more microorganisms present compared to CVC insertion site.

CHG gel dressing reduced their numbers significantly.

Sutures used to secure CVC, may be a major source of microorganisms which can subsequently colonise a CVC, increasing the risk of the development of catheter related infections.

Bundles of care should be reviewed to consider suture site care and antisepsis.

Due to the close proximity of the sutures to the catheter insertion site and high risk of contamination, other methods for securing CVC other than the use of sutures need to be considered in bundles of care aimed at reducing the risk of CRI.

We would like to thank:

• 3M Health Care (Neuss, Germany) for providing an educational grant to undertake this study.

• The critical care staff at the University Hospitals Birmingham NHS Foundation Trust for their continuous support with research.