In this blog, Sarah Chapman from Cochrane UK looks at the latest evidence on dressings to treat venous leg ulcers and nurse Helen Cowan offers her perspective from clinical practice, reflecting on the importance of seeing beyond the wound.
Admittedly, it’s not going to make a good scene in a hospital drama or fly-on-the-wall, but choosing what to put on your patient’s venous leg ulcer (VLU) is a common question for practice, with a plethora of possibilities. I doubt the current coverage of the 70thbirthday of the NHS will highlight that 70 years on, we’re still asking the same questions about dressings; but we are, and so are the trialists and systematic reviewers investigating this.
A new Cochrane Review (Norman et al, 2018) on the effects of dressings or topical agents on healing VLUs includes 78 studies with over 7000 participants, the first published in 1985, when I was a student nurse, and the last in 2016, when I had long since hung up my hat (yes, a hat – long ago consigned to nursing history). It’s excellent that this review includes a network meta-analysis (NMA), as does another recent review by the same team on dressings for pressure ulcers, which you can read about in this blog, which includes a good explanation of NMA.
NMA is a technique which combines data from multiple trials and allows indirect comparisons of treatments that have not been compared directly. Treatments may then be ranked in order of effectiveness. This is the first NMA to be done on dressings and topical treatments for VLUs. 59 studies with over 5000 participants were included in the NMA, with treatments ranging from the commonplace to the experimental.
It’s very good to see that the review team ran an open consultation, inviting people to say which treatments for VLUs they would like to see considered in the review. Any dressing or topical agent applied directly to an open VLU and left in situ would be considered, while the review excluded dressing attached to external devices, such as negative pressure wound therapy. Complete wound healing was the primary outcome of interest.
What does the NMA tell us?
Sad to say, this is an example of not being able to make a silk purse out of a sow’s ear (lots of small sows’ ears, in this case). Studies were small and many were at high risk of bias, leaving the authors to conclude that there is continued uncertainty about which dressings and topical treatments are most effective for healing VLUs. Just two treatments had more than 50% probability of being the best: sucralfate and silver dressings. Comparing these two, whether one is better than the other is very uncertain.
The authors note that the ‘low certainty’ evidence of the individual comparisons and of the whole network mean that the evidence is not a sufficient basis for treatment decisions, and that it’s not clear which interventions might best be included in future trials. It’s hard not to despair at the waste of research funding this reveals, where trials that were well conducted and reported could have provided some answers, rather than leaving us running on a hamster wheel.
So where does this leave practitioners?
A practitioner’s view from Helen Cowan
In May of this year, the British Medical Journal posted an article entitled “Dressings for venous leg ulcers” in which it helpfully summarised six previous Cochrane Reviews related to dressings for venous leg ulcers (Tate et al, 2018). It concluded that there was, at that time, “no evidence to support the superiority of one dressing type over another”, and the authors keenly looked forward to the imminent Cochrane Review, as did I. It was duly released the following month (Norman et al, 2018) and shows again the continuing uncertainty in this area, as Sarah has just discussed.
So where do we go from here? The National Institute for Clinical Excellence admits that, for venous leg ulcers, confusion continues surrounding treatment, stating that, “Overall, the clinical evidence is generally uncertain and not optimal in terms of informing clinical practice” (NICE, 2016).
When the evidence is equivocal in science, can the evidence gap be bridged using other sources? I recently wrote a blog for Evidently Cochrane acknowledging that there’s a lot that we don’t know in science (Cowan, 2018). Best treatment of venous leg ulcers can now be added to the ever-growing list of ‘known unknowns’ (and the Cochrane Library is particularly good at exposing these) but it doesn’t mean that we give up. So where do we turn?
Evidence-based practice is the integration of evidence along with patient preference and clinical judgement: the contribution made by each part of the triad varies according to the clinical situation –as discussed in a recent Evidently Cochrane blog (Byatt and Chapman, 2018). When the evidence is inconclusive, opinion from the healthcare team and the patient should be sought ever more urgently. As a nurse in a care home, I would like to start a conversation around chronic wound care – in the hope that other members of the clinical team and patients themselves will themselves then come forward with reflections from practice.
When wound care works
“Yellow, green, brown, blue, pink and black: not the potting order for the coloured balls in snooker, but the colours in some of the worst wounds that I have dressed as a nurse…..”
This is how I began an article on wounds that I have seen healed as a nurse (Cowan, 2016). In reading this piece, you will see that honey has sometimes been a healer; maggots and negative pressure wound therapy (which were not included in the recent Cochrane Review) have also worked wonders for chronic wounds. During my time as a nurse, I have used alginates for absorption, silver to fight infection and foam dressings to promote the sought-after moist wound environment – all with good effect.
When wounds do heal, the effects are more than skin deep. Reduction in pain, resumption of work and leisure activities, improved mobility and better sleep can all result (Norman et al, 2018).
When wound care doesn’t work
Sometimes, however, wounds have failed to heal despite using what has been deemed to be an ideal dressing. I have come to see that this is because there is way more to wound care than the dressing used.
Whilst dressings are amazing in their design and represent inspired innovation, lifestyle, physiology and good nursing care are equally important determinants of whether a wound will heal.
I’ve tried to summarise some of the factors affecting wound healing in the following A to Z, using my own clinical experience and Guo and DiPietro (2010) as a reference, unless otherwise stated.
Bacteria (is the wound infected?)
Cancer (and other immunocompromised conditions)
Ethanol (alcohol consumption)
Frequency (how often is the dressing changed?)
Gait (is the gait unsteady, leading to falls and injury to the leg?)
Hydration (Ousey et al, 2016)
Keeping legs elevated
Longevity (increased age is a major factor for impaired wound healing)
Medications (non-steroidal anti-inflammatory drugs, chemotherapeutic drugs and glucocorticoid steroids can delay wound healing)
Retinol (vitamin A). The biological properties of vitamin A include anti-oxidant activity, increased fibroblast proliferation, modulation of cellular differentiation and proliferation, increased collagen and hyaluronate synthesis, and decreased MMP-mediated extracellular matrix degradation (Burgess, 2008).
Wrong dressing – considered in the latest Cochrane Review.
eXercise (Keylock et al, 2008).
Ychromosome (“Androgens regulate cutaneous wound healing negatively”) (Guo and DiPietro, 2010).
Next time that a wound is proving hard to heal, don’t only deliberate over the dressing to be used. See beyond the wound; look at the whole person. Isn’t that, after all, what holistic healthcare is all about?
Sarah Chapman and Helen Cowan have nothing to disclose.