Central venous catheter (CVC) management: evidence round-up

Sarah Chapman looks at evidence from Cochrane Reviews on central venous catheter (CVC) management in this blog for nurses.

When it comes to preventing complications associated with central venous catheters, there is a good deal of variation between and within countries, in guidelines and clinical practice. With the updating of a Cochrane review on normal saline (0.9% sodium chloride) versus heparin intermittent flushing for the prevention of occlusion in long‐term central venous catheters in infants and children, this seems like a good time to have a round-up of Cochrane evidence on this and other aspects of managing CVCs.

Heparin vs normal saline for flushing CVCs

In children with CVCs

Published in April 2020, the latest version of the Cochrane Review on intermittent flushing with normal saline versus heparin to prevent occlusion in long-term CVCs in infants and children highlights that there is still an evidence gap. One new study was added but there are only four included in all with 255 people. There is continued uncertainty about how they compare in terms of occlusion and CVC-related blood stream infection (very low and low-certainty evidence). There is moderate-certainty evidence that there is probably little or no difference between them for the duration of catheter placement.

In adults with CVCs

A Cochrane Review comparing heparin with normal saline locking for prevention of occlusion in central venous catheters in adults (11 studies with a total of 2392 people, published July 2018) found that it remains uncertain how intermittent locking with heparin or normal saline compare (very low-certainty evidence) and that heparin may have little or no effect on catheter patency (low-certainty evidence).

The review authors also say that while they found no evidence of a difference between them in terms of sepsis, mortality, or haemorrhage, the combined trials are not powered to detect rare adverse events such as heparin‐induced thrombocytopaenia.

The previous version of this review was used as a Cochrane Quality and Productivity Case Study for NICE, to help the NHS identify practices that could be reduced or stopped completely, releasing resources without negatively affecting quality of care. Cochrane evidence at the time (as now, with five studies added) showed no good evidence that flushing CVCs with heparin is better than flushing with normal saline. Heparin is more expensive and NICE estimated that switching to saline would result in an estimated 91% saving (at 2015 prices £3.30 per single day use vs £0.30).

Infection prevention measures

Infection prevention is of huge importance when it comes to vascular access devices. Micro-organisms can get into the bloodstream through the point where the skin has been penetrated and along the outer surface of the catheter, or internally through the catheter and its connectors. Minor infections at the entry site or in device connectors can lead to more serious bloodstream infections. The possible consequences include the whole gamut of infection-related miseries for the patient, including pain, anxiety, delayed treatments and a longer stay in hospital as well as greater demands on resources.

Antimicrobial-impregnated CVCs

 This is one approach to preventing catheter-related bloodstream infection (BSI). A Cochrane Review (September 2015) looking at whether antimicrobial-impregnated CVCs can help prevent bloodstream infection in newborns found only one small study, not enough evidence to guide practice. Nor is there any trial data to tell us whether early removal of CVCs in neonates with BSI is beneficial, according to another Cochrane Review, which had hoped to compare early removal with expectant management of CVCs in neonates with BSI.

A Cochrane Review (March 2016) on catheter impregnation, coating or bonding for reducing CVC-related infections in adults found reliable (high-certainty) evidence from 57 studies with 16,784 catheters that antimicrobial CVCs are effective in reducing catheter colonisation and catheter-related BSI in adults, but they do not appear to reduce clinically diagnosed sepsis or deaths from all causes.

In adults who need a central venous catheter (CVC), using an antimicrobial‐impregnated catheter, compared with non‐impregnated catheter, reduces the risk of catheter-related bloodstream infections (high-certainty evidence) and probably reduces the risk of catheter colonization (moderate-certainty evidence). Impregnated CVCs make little or no difference to the risk of death from any cause (high-certainty evidence) and probably make little or no difference to the risk of sepsis or local infection (moderate-certainty evidence). Impregnated catheters, compared with non-impregnated catheters, make little or no difference to the risk of adverse effects such as clots, bleeding, pain or redness at the insertion site (high-certainty evidence).Cochrane Review (published March 2016); 57 studies, 16,784 catheters and 11 types of impregnations (the total number of patients was unclear, as some studies did not provide this information). Studies compared impregnated catheters versus non‐impregnated catheters.

Skin antisepsis

Here in the UK, NICE guidance recommends using 2% chlorhexidine gluconate in 70% alcohol, or povidone iodine in alcohol for patients sensitive to chlorhexidine to clean the CVC site during dressing changes. It also suggests considering daily cleansing with chlorhexidine in adults with a CVC as a strategy to reduce catheter-related bloodstream infection.

A Cochrane Review (July 2016) on skin antisepsis for reducing CVC-related infections brought together data from 12 studies with 3446 CVCs (number of patients unknown), comparing different skin antisepsis regimens with each other and with none. Whilst there is nothing here to overturn the guidance, the evidence is mostly low or very low-certainty and, beyond saying that chlorhexidine solution may be more effective than povidone iodine, any questions about which regimen is best or whether skin antisepsis benefits patients are left unanswered.

Dressings

 There is high-certainty evidence from a Cochrane Review on dressings and securement devices for CVCs (22 studies with 7436 people, September 2015) that medication-impregnated dressings reduce the incidence of CVC-related bloodstream infection compared with all other dressing types. The review also found moderate-certainty evidence that chlorhexidine gluconate-impregnated dressings probably also reduce catheter-related bloodstream infection compared with dressings without medication.

Another Cochrane Review (March 2016) explored the evidence on antimicrobial dressings to prevent CVC-related infections in newborns, hoping to explore both effectiveness and safety. Three studies were included, with 855 infants from neonatal intensive care units; the majority of babies were in one large study. There was moderate-certainty evidence that chlorhexidine CVC dressing with alcohol skin cleansing probably carries a high risk of skin irritation and only modest reduction in catheter colonisation, without benefit in terms of clinical outcomes such as catheter-related bloodstream infection. The potential benefits and harms of silver-alginate patches remain unclear.

A Cochrane Review looking at the effects of the frequency of dressing changes for CVCs on catheter-related infections in adults patients (5 studies with 2277 people, February 2016) found that impact of the frequency of dressing changes (2 to 5 days compared with 5 to 15 days) on catheter-related bloodstream infection, catheter site infection, death from any cause, skin damage or pain remain uncertain. That’s a pretty big evidence gap on something so basic!

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Frequency of changing the administration set

The tubing, or administration set, attached to venous and arterial catheters may contribute to BSI, so does the frequency with which they are changed make a difference? This was considered in a Cochrane Review on optimal timing for intravascular administration set replacement, which included data from 5000 people in 16 trials. There was some evidence that sets that do not contain lipids, blood or blood products may be left in place for up to 96 hours without increasing the risk of infection, but the studies were mostly of low to moderate quality which means that we can’t be certain. It would be good to see this 2013 review, one of several here which has been used in guidelines, updated with new and hopefully better quality studies.

Prophylactic antibiotics

Another Cochrane Review (November 2013) looked at whether there is evidence that giving antibiotics before inserting a long-term CVC, or flushing or locking it with an antibiotic plus heparin solution, can help prevent Gram-positive catheter-related infections in adults and children being treated for cancer. Moderate-certainty evidence from 11 studies with 828 people showed that flushing the catheter with an antibiotic and heparin solution probably reduces the number of catheter-related infections. Giving antibiotics prior to catheter insertion does not seem to be helpful.

Looking ahead

There’s some really interesting work being done by the AVATAR (Alliance for Vascular Access Teaching and Research) Group, established by Professor Claire Rickard who is an author on some of the Cochrane Reviews discussed here. They state that their mission is to make vascular access complications history. They are doing some really interesting research in six broad areas. Worth taking a look.

Take-home points

Take-home points: The management of central venous catheters (CVCs) varies a great deal between and within countries, in guidelines and clinical practice. There are several Cochrane Reviews on different aspects of managing CVCs in adults and children. These reviews provide evidence to guide practice, but also highlight gaps in the evidence; sometimes around ‘everyday’ questions, such as whether the frequency of dressing changes for CVCs has an impact on important outcomes such as the incidence of catheter-related infection.  

Join in the conversation on Twitter with @CochraneUK @SarahChapman30 #eenursing or leave a comment on the blog. Please note, we cannot give medical advice and we will not publish comments that link to commercial sites or appear to endorse commercial products.

Click here for references and further reading.

Sarah Chapman has nothing to disclose.


Sarah Chapman

About Sarah Chapman

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Sarah's work as a Knowledge Broker at Cochrane UK focuses on disseminating Cochrane evidence through social media, including Evidently Cochrane blogs, blogshots and the ‘Evidence for Everyday’ series for nurses, midwives, allied health professionals and patients. A former registered general nurse, Sarah has a particular interest making evidence accessible and useful to practitioners and to others making decisions about health. Before joining Cochrane, Sarah also worked on systematic reviews for the University of Oxford and the Royal College of Nursing Institute, and obtained degrees in History from the University of Oxford and in the history of women’s health and illness in early modern England (MPhil., University of Reading).

4 Comments on this post

  1. Avatar

    Can you talk about removal of cvcs ….. one recently removed in the chair in my ICU …. catostrophic result. More frightening many ICU Staff saw no issue…..
    Another senior manager Nurse thought ok to add 20mmol mg to a pre mix 100ml bag with 40 Mmol k. Took it even further by not adding additive label but justifying his practice but saying he was helping the pt. The bedside junior icu nurse said nothing as she did not want to question a superior.
    Another issue staff using 100 ml saline bag to obtain flushes during the shift.

    Ali / Reply
  2. Avatar

    Hi Sarah,

    I’m Gillian Ray-Barruel from the Alliance for Vascular Access Teaching And Research at Griffith University, Australia. With your permission, I would like to promote your article on our blog.
    https://www.avatargroup.org.au/blog.html

    Please let me know if you agree.
    Thank you.

    Gillian Ray-Barruel / Reply
    • Sarah Chapman

      Hi,
      Thank you – you’re very welcome to link to the blog. It’s also fine to repost it as long as that is the full text and without the photos, which have been bought for use by Cochrane.
      Best wishe,
      Sarah Chapman

      Sarah Chapman / (in reply to Gillian Ray-Barruel) Reply

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