Does cleaning venous leg ulcers help them to heal?

Background

Leg ulcers are open skin wounds that develop below the knee, usually because blood flow is poor in the lower leg. This can occur because of blockages, for example when small blood clots form in the veins. It can also happen when the valves (flaps) in the veins that prevent blood from flowing backwards stop working properly. Poor blood flow damages the skin and tissue, and creates venous leg ulcers.

Ulcers are unsightly and may become painful or infected. On average, ulcers take from six to nine months to heal. However, some ulcers can take years to heal, and a small number never do. Once ulcers have healed, they can reoccur.

The main treatment for venous leg ulcers is to use bandages or stockings that compress the leg (compression therapy), to increase blood flow in the veins. It is also thought to be important to clean the wound. Different types of cleaning solutions can be used, including: normal saline; water; antiseptics (solutions that stop or slow down the growth of micro-organisms such as bacteria); detergents (solutions that remove bacteria and dirt); or disinfectants (solutions such as bleach, that kill micro-organisms).

Cleaning solutions can be applied to the ulcer using a swab (similar to a cotton bud), a syringe with a needle, or a spray canister. Ulcers can also be bathed in the cleaning solution, using a basin or bucket, or during a shower. Cleaning can cause discomfort, and may be painful.

What did we want to find out?

We wanted to find out:

- whether cleaning venous leg ulcers helps them to become smaller and heal;

- whether some cleaning solutions, or methods of applying solutions, are more effective than others;

- which cleaning solution people prefer and find easiest to use;

- whether cleaning wounds has an impact on quality of life;

- how much cleaning wounds costs; and

- whether cleaning wounds is associated with adverse (unwanted) effects such as pain, infection or skin damage.

Our methods

First, we searched for randomised controlled studies (clinical studies where the treatment or care people receive is chosen at random). These studies provide the most reliable health evidence about the effects of a treatment. We then compared the results and summarised the evidence from all the studies. Finally, we rated our confidence in the evidence, based on factors such as study methods and sizes, and the consistency of findings across studies.

What we found

We found four studies that involved a total of 254 people with venous leg ulcers. There were 108 men and 144 women, all over 18 years old (information about gender was missing for two people).

The studies compared the effects of:

- a disinfectant and antiseptic agent (polyhexamethylene biguanide) applied using a syringe with a needle to flush (irrigate) the ulcer with fluid, against a salt (saline) solution;

- a gentle spray of a bleaching and antiseptic agent (aqueous oxygen peroxide, which is ozone dissolved in water), against sterile water;

- a detergent (propyl betaine combined with polyhexanide), against a saline solution – method of application not reported; and

- an antiseptic (octenidine dihydrochloride combined with phenoxyethanol) sprayed onto the wound, against a solution of several salts dissolved in water (Ringer’s solution).

No studies compared cleaning with no cleaning, or compared different cleaning methods.

We cannot tell whether cleaning wounds is beneficial or associated with any unwanted effects. This is because we have too little confidence in the evidence available regarding healing, changes in ulcer size, pain and unwanted effects. No study reported on patient preference, ease of use, cost or impact on quality of life.

What does this mean?

We do not know whether cleaning solutions are better than sterile water or saline solutions to help venous leg ulcers heal, or whether the choice of cleaning solution or method of application makes any difference to venous leg ulcer healing. Our confidence in the available evidence is very low. The results of our review are likely to change if more evidence becomes available.

How up-to-date is this review?

The evidence in this Cochrane Review is current to September 2019.

Authors' conclusions: 

There is currently a lack of RCT evidence to guide decision making about the effectiveness of wound cleansing compared with no cleansing and the optimal approaches to cleansing of venous leg ulcers. From the four studies identified, there is insufficient evidence to demonstrate whether the use of PHMB solution compared with saline solution; aqueous oxygen peroxide compared with sterile water; propyl betaine and polihexanide compared with a saline solution; or OHP compared with Ringer's solution makes any difference in the treatment of venous leg ulcers. Evidence from three of the studies is of very low certainty, due to study limitations and imprecision. One study did not present data for the primary or secondary outcomes. Further well-designed studies that address important clinical, quality of life and economic outcomes may be important, based on the clinical and patient priority of this uncertainty.

Read the full abstract...
Background: 

Leg ulcers are open skin wounds that occur below the knee but above the foot. The majority of leg ulcers are venous in origin, occurring as a result of venous insufficiency, where the flow of blood through the veins is impaired; they commonly arise due to blood clots and varicose veins. Compression therapy, using bandages or stockings, is the primary treatment for venous leg ulcers. Wound cleansing can be used to remove surface contaminants, bacteria, dead tissue and excess wound fluid from the wound bed and surrounding skin, however, there is uncertainty regarding the effectiveness of cleansing and the best method or solution to use.

Objectives: 

To assess the effects of wound cleansing, wound cleansing solutions and wound cleansing techniques for treating venous leg ulcers.

Search strategy: 

In September 2019 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

Selection criteria: 

We considered randomised controlled trials (RCTs) comparing wound cleansing with no wound cleansing, or RCTs comparing different wound cleansing solutions, or different wound cleansing techniques.

Data collection and analysis: 

We screened studies for their appropriateness for inclusion, assessed their risk of bias using the Cochrane 'Risk of bias' tool, and used GRADE methodology to determine the certainty of evidence. Two review authors undertook these tasks independently, using predetermined criteria. We contacted study authors for missing data where possible.

Main results: 

We included four studies with a total of 254 participants. All studies included comparisons between different types of cleansing solutions, and three of these reported our primary outcomes of complete wound healing or change in ulcer size over time, or both. Two studies reported the secondary outcome, pain. One study (27 participants), which compared polyhexamethylene biguanide (PHMB) solution with saline solution for cleansing venous leg ulcers, did not report any of the review's primary or secondary outcomes. We did not identify any studies that compared cleansing with no cleansing, or that explored comparisons between different cleansing techniques.

One study (61 participants) compared aqueous oxygen peroxide with sterile water. We are uncertain whether aqueous oxygen peroxide makes any difference to the number of wounds completely healed after 12 months of follow-up (risk ratio (RR) 1.88, 95% confidence interval (CI) 1.10 to 3.20). Similarly, we are uncertain whether aqueous oxygen peroxide makes any difference to change in ulcer size after eight weeks of follow-up (mean difference (MD) -1.38 cm2, 95% CI -4.35 to 1.59 cm2). Finally, we are uncertain whether aqueous oxygen peroxide makes any difference to pain reduction, assessed after eight weeks of follow-up using a 0 to 100 pain rating, (MD 3.80, 95% CI -10.83 to 18.43). The evidence for these outcomes is of very low certainty (we downgraded for study limitations and imprecision; for the pain outcome we also downgraded for indirectness).

Another study (40 participants) compared propyl betaine and polihexanide with a saline solution. The authors did not present the raw data in the study report so we were unable to conduct independent statistical analysis of the data. We are uncertain whether propyl betaine and polihexanide make any difference to the number of wounds completely healed, change in ulcer size over time, or wound pain reduction. The evidence is of very low certainty (we downgraded for study limitations and imprecision).

The final study (126 participants) compared octenidine dihydrochloride/phenoxyethanol (OHP) with Ringer's solution. We are uncertain whether OHP makes any difference to the number of wounds healed (RR 0.96, 95% CI 0.53 to 1.72) or to the change in ulcer size over time (we were unable to conduct independent statistical analysis of available data). The evidence is of very low certainty (we downgraded for study limitations and imprecision).

None of the studies reported patient preference, ease of use of the method of cleansing, cost or health-related quality of life. In one study comparing propyl betaine and polihexanide with saline solution the authors do not report any adverse events occurring. We are uncertain whether OHP makes any difference to the number of adverse events compared with Ringer's solution (RR 0.58, 95% CI 0.29 to 1.14). The evidence is of very low certainty (we downgraded for study limitations and imprecision).

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