Hard-to-heal wounds Made Easy
21/11/11 | Complex wounds, Wellbeing and concordance | Vowden P.
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Biomarkers to predict hard-to-heal wounds
A non-healing wound contains a number of microbial, biochemical and cellular abnormalities that will prevent or slow the healing progression. This often occurs despite a seemingly adequate wound bed. As our knowledge of the processes and biochemistry of wound healing has progressed, it has become clear that, in a number of non-healing wounds, a range of biomarkers are abnormal and that some wounds are 'locked' into a self-perpetuating inflammatory process. Diabetic patients, for example, experience a substantial deficit in wound healing with a marked pro-inflammatory reaction.
Assessment of acute wound fluid and chronic wound exudate has shown marked differences between the wound fluid from the two wound types. Exudate from non-healing chronic wounds has been reported to have destructive properties, with abnormally high levels of proteases and reduced levels of important growth factors. If left unchecked, sustained excessive protease activity in wounds start to destroy the extracellular matrix and damage newly formed tissue, preventing the wound from progressing to the proliferative stage.
The recognition that metalloproteases (MMPs) constitute one group of potential markers for delayed healing has led to work developing a point-of-care diagnostic and targeted therapeutic interventions that may assist in the management of hard-to-heal wounds. Ongoing work has identified other potential biochemical markers for delayed healing that may allow other targeted advanced wound therapies to be developed in the future. Molecular pathogen diagnostics now allow a comprehensive evaluation of the microbial bioburden, and targeted interventions based on this data have been shown to improve outcome. It remains to be seen how clinically and cost-effective such interventions will be and how early in the cycle of healing/non-healing, persistent biochemical abnormalities can be detected.
The earlier the wound healing problems are detected, the better the outcome will be for the patient[19,20].
What practical actions can assist early recognition of hard-to-heal status?
Recognition of a hard-to-heal wound requires regular reassessment with measures taken towards healing. It does, however, also demand that:
- The assessment and diagnostic process is correct
- Appropriate treatment has been applied to deal with both the requirements of the wound and the management of any underlying medical conditions that may impact on healing
- The outcome of treatment has been evaluated within a timeframe that is appropriate for a specific wound type.
Perhaps the most important element of the initial assessment in terms of predicting subsequent healing and hard-to-heal status, is to carefully map and measure the wound.
Changes in wound size during the initial phase of treatment have been shown to be a potential indicator of subsequent response to treatment and ultimately healing. These measurements will help to identify wounds that are not progressing according to predicted healing times with the standard therapy for a specific wound type.
Troxler et al1 have reviewed the potential of wound measurement to predict hard-to-heal status. Such measurements can be combined with other wound and periwound skin characteristics to give a score indicating healing potential. Digital photography can also be used to document the wound size.
Whichever technique is used, recognition of delayed healing is important and can only really be achieved by careful, detailed and repeated wound assessment and measurement.
In patients with significant comorbidities, optimising the management of the underlying medical condition can markedly improve a wound’s healing potential. In such a situation, measuring and acting on the results of biochemical parameters such as blood glucose, renal and hepatic function can be useful. Monitoring inflammatory markers and wound culture as well as wound biopsy may also assist in diagnosis and allow targeted treatment.
Using clinical criteria alone to accurately predict which wounds are unlikely to heal in a timely manner is difficult. Accurate detection of elevated protease activity or other biomarkers would aid early diagnosis and appropriate use of treatments aimed at optimising the wound environment.
However, diagnostic tests directing treatment and predicting outcomes are not yet widely available or of proven efficacy. They may however be the key to improvements in outcome for the slow or non-healing wound.
What impact does delayed healing have on the patient?
Chase et al introduced the concept of ‘forever healing’ and other work has led to the concept of permanent ‘wounding’. For the patient this requires learning to live with the pain, emotional problems and social isolation associated with delayed healing[24,25]. Wissing et al and Persoon et al both concluded that patients with chronic leg ulcers have a poorer quality of life. Similar findings have been found for people with diabetic foot and pressure ulcers.
Although it is possible to measure the direct health costs of wound care, the implications for individual patients and their family are more difficult to measure.
Treatment of a non-healing wound is demanding on both the patient and carers’ time, and frequently requires multiple clinic visits or weekly dressing appointments over many months. For younger patients this may involve time off work or loss of employment with significant financial implications for them and their families. This can also affect patients’ mobility and ability to drive a car as well as their general health and social wellbeing.
The more wound healing is delayed the more it impacts on the patient. Symptom control is important in all wounds, but particularly for those of long duration. Pain management, exudate control and odour management are some of the main issues that impact on both the patient and his/her family’s quality of life[28, 29]. Failure to control these issues will adversely affect concordance and increase the chance of non-healing.
Pragnell and Neilson emphasise the extreme psychological impact that hard-to-heal wounds have on the patient, as well as the challenge they pose to the clinical team in terms of resource expenditure. Non-healing can also have a psychological influence on clinicians who are providing care, who may be emotionally overwhelmed by their inability to alleviate suffering and achieve wound healing.
Impact of hard-to-heal wounds on resources
Reducing health costs is a recurring global issue. Wound management is a major area where there is a drive for improved cost-effectiveness. Costs are higher for hard-to-heal and long duration wounds as the frequency of therapy, staff time and product use increases[32, 33].
Reducing costs while optimising quality of life for patients with delayed wound healing requires the following:
- Early identification of hard-to-heal wounds
- Targeted use of advanced wound care products.
The latter must involve a plan to address specific issues within the wound, a defined goal and a timeline for use.