Chambers, S.T., Sanders, J., Patton, W.N., Ganly, P., Birch, M., Crump, J.A., & Spearing, R.L. (2005). Reduction of exit-site infections of tunnelled intravascular catheters among neutropenic patients by sustained-release chlorhexidine dressings: Results from a prospective randomized controlled trial. Journal of Hospital Infection, 61, 53–61.

The purpose of the study was to evaluate the efficacy of sustained-release chlorhexidine (CHX) dressings versus standard dressings.

All adult patients admitted under the hematology service that were to receive chemotherapy and had a tunneled cuffed central intravascular catheter inserted were eligible for inclusion. After insertion, all tunneled intravascular catheters were randomized, but they were treated in the same manner with a sterile gauze and porous adhesive dressings until the exit site was dry and free from ooze. Those randomized to standard catheter exit-site treatment (control group) received no dressing in accordance with BCHS guidelines. The CHX group (intervention group) were treated with CHX dressings consisting of a 2.5 cm hydrophilic polyurethane foam disk containing CHX gluconate in a sustained-release formulation. These were applied to the exit site as soon the oozing had stopped following intravascular catheter insertion, and changed as needed or weekly until the catheter was removed. The same treatment was continued for the life of the catheter but if an intravascular catheter was removed and replaced, the new catheter was randomized. Exit site and tunnels were routinely examined on a weekly basis.

The primary endpoint of this study was the development of exit-site and/or tunnel infection. The secondary endpoint was removal of the catheter for infection. In total, 114 tunneled intravascular catheters in 95 patients were randomized from August 1998 to December 2001.

• The total sample consisted of 95 patients.
• Mean age of the control group was 49 years (range = 16–70); mean age of the CHX group was 50 years (range = 15–68).
• Chemotherapy infusion was a key disease characteristic
• Total catheters in the control group were 43. 
• Total catheters in the CHX group were 52. 
• Malignancies: acute nyeloid leukemia (17% control, 17% CHX), non-Hodgkin lymphoma (9% control, 11% CHX), myeloma (5% control, 9% CHX), acute lymphoblastic leukemia (3% control, 6% CHX), breast (2% control, 1% CHX), chronic myeloid leukemia (2% control, 1% CHX). Other malignancies (amyloidosis, Ewing sarcoma, renal cell carcinoma, myelodysplasia and aplastic anemia) accounted for 6% of the CHX group.
   

A single-site inpatient hematology unit

• There were multiple phases of care
• Clinical applications were for late effects and survivorship
   

Prospective, randomized

 All patients received a 10F vascular catheter with a surecuff tissue ingrowth, vitacuff antimicrobial cuff inserted percutaneously by a radiologist using the Seldinger technique.

Definitions used:

• Exit site infection: redness, pain, and tenderness at the exit site less than 2 cm from the skin along the intravascular catheter of sufficient degree to warrant antimicrobial therapy as judged by the attending medical team.
• Tunnel infection: pain, tenderness, and swelling over the subcutaneous tunnel more than 2 cm from the exit site.
• Bacteraemia: presence of one or more species of organism in two sets of blood cultures within 24 hours (both sets from peripheral vein or one set from peripheral vein and one from central catheter).
• Intravascular catheter-related bacteraemia: evidence of bacteraemia in the presence of fever but no recognized focus of infection, with the same organism recovered from the catheter tip as from the blood cultures or exit site.
• Suspected intravascular catheter infection: positive blood cultures drawn in the presence of fever (single measure higher than 38.5ºC or two measures higher than 38ºC) with no other recognized focus of infection, causing the catheter to be removed prematurely.
• Intravascular catheter infection: suspected catheter infection in which the culture of the tip yielded more than 15 colonies of the same organism as was found in the blood cultures drawn from either the catheter or from the periphery.
• Neutropenia: less than 0.5 x 10⁹ neutrophils/L

This study has shown  that the use of CHX dressings was associated with less exit site infections (OR = 0.13, 95% CI [0.04, 0.37], p < 0.001). The rate of premature catheter removal for these infections was reduced approximately three fold in the CHX group (OR = 0.23, 95% CI [0.07, 0.77]). The failures of the CHX dressing group were associated either with a very early occurrence after insertion of the catheter, suggesting that the infecting organisms were implanted at the time of catheter insertion, or with delays in application of the CHX dressing. Positive blood cultures occurred in fewer patients in the control group (p < 0.01) with less isolates of gram-positive organisms in the control group (p < 0.05).

This study demonstrated that use of the sustained-release CHX dressing was associated with reduced extralumenal catheter infections; however, it was not associated with fewer blood stream infections.

• Small sample size (less than 100 participants)
• There was a risk of bias favoring the CHX group because the clinical team was not blinded to treatment. 
• Results were reported in terms of patients and various time points and could have been more  clear if reported in terms of total or cumulative patient catheter days. 
• No results of defined outcomes such as suspected catheter infection, etc., were reported. 
• It is unclear how immunosuppressed the sample was in order to draw relevant conclusions.
   

Sustained-release CHX dressings may help to reduce some central line-associated infections in patients with cancer who are at risk and in whom other aspects of catheter insertion and care are in place.  Further well-designed research in this area is warranted.