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Whitepaper regarding

Disinfection procedure for removal of Certa peripheral nerve catheter

- A quality assurance project

Introduction

A novel suture-based peripheral nerve catheter has been introduced (Certa Catheter™). When placed, the catheter traverses the targeted tissue through a skin entrance hole and a skin exit hole. The catheter is placed using sterile technique. When the catheter is to be removed, the distal end protruding from the exit hole is cut off at skin level and the remaining part of the catheter is pulled back through the skin. If the remaining part of the catheter is not cleaned sufficiently, infection may therefore be introduced to the underlying tissue, when the catheter is removed.

Purpose In this quality assurance project we examined whether it is possible to disinfect the remaining part of the peripheral nerve catheter sufficiently before removal to prevent infection. The investigation was conducted by Nordsjællands Hospital in Hillerød, Denmark.

Method

According to standard of care at Nordsjællands Hospital 60 patients had peripheral nerve catheters (B.Braun Contiplex® Tuohy) placed in the adductor canal following total knee arthroplasty. The catheters were removed from the patients after 48 hours.

Before removal the skin was assessed for signs of infection. The skin and the part of the catheter protruding from the skin was disinfected twice with 0.5% chlorhexidine in alcohol (80 vol. %) (Simple disinfection).

The catheters were then randomized into two groups:

1) Further mechanical disinfection with swabs (chlorhexidine 0,5% and ethanol 82%)

2) No further disinfection.

The catheter was removed by pulling the proximal end of the catheter. Three pieces starting distally towards proximally were cut from each catheter with sterile scissors:

1) A distal part (2 cm including the tip)

2) A middle part (2 cm of the catheter adjacent to the distal part – if possible

without interfering with the “skin“ part)

3) A “skin” part (2 cm part at the transition zone at skin level with one cm below skin level and one cm above skin level.

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Samples from group 3) (Skin part) were then further divided in two sub-groups. One group was sent directly for culture, while the other was subjected to additional mechanical disinfection by scrubbing the sample with swabs twice immediately after removal.

All samples were sent for cultures in separate containers.

Sampling flowchart:

60 adductor canal catheters

Disinfection of the skin:

59 catheters

Further mechanical disinfection:

30 pieces

No mechanical disinfection:

29 catheters

Tip and middle segments: Tip: 57 pieces (1 lost during transport for analysis, 1

catheter to short)

Middle: 54 pieces (5 catheters were too short)

Sent for cultures

Skin level segments: 59 pieces

No disinfection of the skin:

1 catheter

Skin, Middle and Tip segments: 1 piece of each

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Results Twenty-nine catheters underwent simple disinfection only and 30 had further mechanical disinfection. One catheter was erroneously removed without any disinfection procedure. The results from the cultures are presented in the tables below expressed as colony forming units [CFU] counted. There was no clinically significant culture on any of the removed catheter parts in the two groups.

Tables:

Catheter treatment: Disinfected Not Disinfected

Catheter segment: No growth Growth1) Lost/Not done No growth Growth2)

Tip 51 6 2 1 0

Middle 42 12 5 0 1

Skin 1 0

Skin, incl. mech. disinfection 22 8 0

Skin, excl. mech. disinfection 26 2 1

1) Colony count: 2) Colony count: 0-5 CFU: 28 0-5 CFU: 0 5-15 CFU: 0 5-15 CFU: 0 > 15 CFU: 0 > 15 CFU: 1

Interpretation:

0-5 CFU: Contamination from the removal process

5-15 CFU: Contamination from the removal process

>15 CFU: Suspect for colonization of the catheter

Conclusion

It is possible to disinfect the part of the catheter which lies at the skin level by simple disinfection procedures. Based on this, the risk of infection due to pulling the disinfected distal end of the catheter back through the tissue is evaluated to be very low.

Weaknesses

Since peripheral nerve catheter infection is very uncommon a conclusive study would have to include a large number of patients (several thousands).

Definitions

CFU: Colony forming unit