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Wound assessment, cleansing and debridement

Una Adderley
RGN DN BSc BA
Research Nurse
Centre for Evidence Based Nursing
Department of Health Studies
University of York
District Nurse Scarborough and NE Yorks NHS Trust

Effective clinical decisions regarding wound care need to be underpinned by skilled wound assessment. An initial assessment should enable the clinician to arrive at a clinical diagnosis of the cause of wounding and to decide on treatment. 
Regular reassessment is needed to identify significant changes, monitor the effectiveness of treatment and the impact of a wound on the patient's general wellbeing and to promote continuity of care. Documentation of wound assessment is also a legal requirement that you ignore at your peril.

Wound assessment
In wound assessment it is tempting to concentrate on the actual wound itself. However, the first step is to consider the whole patient, paying particular attention to problems that may impact on wound healing or wound formation, such as overall health, nutritional status, mobility, cardiovascular status, psychological status, pain, current medication, age and any allergies. This is essential to arrive at an accurate diagnosis of the cause of wounding and to identify realistic aims: unfortunately not all wounds can heal. 
Assessment of environmental and social conditions may also identify significant information. There may be implications regarding the availability of time, expertise and cost in relation to where the patient is receiving care (eg, within a clinic or at home). The patient's ability and desire to self-care should be considered within the context of safety and patient choice. The patient is likely to be dealing with an altered body image that may be permanent or long term. The wound may be associated with significant life changes for the patient, such as loss of fertility or cancer. There may also be social implications, as patients with wounds may have to deal with loss of earnings, the additional burden of cost of dressings and dependence on a healthcare professional. 
Assessment of the wound site should focus on identifying factors that may delay healing (such as infection) and include documentation of the wound conditions for future reference. This may improve patient concordance by providing evidence of healing or deterioration.
Strategies for wound assessment can be broadly divided into written description and wound measurement.

Written description of wounds
Written description is cheap, universal and potentially accurate but may be tainted by subjectivity. One clinician's "moderate exudate" can be another's "maceration". Written description of wounds should include:

  • The cause of the wound.
  • Whether healing is being sought by primary or secondary intention.
  • The position and size of the wound.
  • Its duration and the condition of the wound margin.

Issues such as haematoma, pain, evidence of infection, exudate (amount and colour), oedema or foreign bodies within the wound should be considered. For postsurgical wounds it is important to be aware of the nature of the surgery, the method of closure and the presence of drains. For wounds healing by secondary intention the amount of tissue loss and the nature of the wound bed should be noted.

Measurement of wounds
Wound measurement can be achieved through a variety of means such as ruler-based measurement, wound tracing, photography, and technological techniques such as ultrasound. At present there are no systematic reviews in relation to wound measurement. One trial has compared computerised digitisation of photos with acetate tracings and found very little difference between the two methods.(1) An evidence-based framework is useful for decision-making. (Figure 1).

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Patients may have strong preferences, which must be respected, although research evidence may support one particular type of technique. Resources have to be considered, and clinical expertise is important in judging the appropriateness of a particular technique for an individual patient. 
Various factors can hamper accurate wound measurement. It can be difficult to get access to the wound site, and the curvature of the body may affect accuracy. Wounds can alter shape according to the patient's position and the wound margin can be difficult to define. However, despite these difficulties, wound measurement is an essential part of wound assessment.

Wound cleansing
"Wound cleansing is a naturally occurring physiological response to injury.(3) When a wound occurs, exudate washes the surface of the wound and provides an optimal moist local environment. However, in order to promote wound healing, additional therapeutic wound cleansing will remove excessive debris, keep the surrounding skin clean, facilitate wound assessment, minimise wound trauma when removing dressings, promote patient comfort and, where necessary, rehydrate the surface of the wound. 
At present there are no systematic reviews of wound cleansing to inform practice. When considering methods of wound cleansing both technique and type of wound cleansing solution need to be considered.
For years, aseptic technique (ie, sterile dressing pack with sterile gloves) has been the gold standard. However, using an aseptic technique for all situations may be ritualistic, unnecessarily complex, unrealistic and often ineffective.(4) A clean technique (using clean rather than sterile gloves and equipment) may be more appropriate when the hands are not in contact with a sterile body part. A risk assessment for each individual patient is required when deciding between an aseptic or clean technique, but whichever technique is chosen, effective handwashing and a new clean apron remain essential for each dressing procedure.

Swab, irrigate or soak?
There is little evidence regarding whether wounds should be swabbed, irrigated or bathed/soaked. Swabbing may simply redistribute bacteria across the surface of the wound, cause further tissue trauma and increase patient discomfort. Wound irrigation using sprays or ampoules of solution is commonly accepted practice, although some practitioners may choose to bathe chronic wounds in buckets of warm water. Many patients find bathing of psychological benefit, but clinicians should be aware that when open wounds receive prolonged soaking, water is absorbed and this can lead to increased exudate. 
The ideal wound cleansing solution should be non-toxic, effective in the presence of organic matter, reduce microorganisms, widely available and cost-effective with a long shelf-life. In the UK, water is cheap, clean and readily available, although it is essential to ensure that the container is kept clean and dry between dressings. In a trial comparing tap water and saline for cleaning traumatic wounds, wounds cleaned with tap water had a lower rate of infection.5 Saline is easily available as a sterile solution and, being isotonic, it does not donate or draw fluid. Antiseptics have become less popular since the emergence of evidence suggesting doubtful effectiveness and possible toxicity to tissue.

Debridement
Until recently, knowledge about acute wounds has simply been extrapolated to chronic wounds; there is now suspicion that this may be a simplistic approach. Chronic wounds often have wound bed complications such as infection, slough or necrosis. Suspected infection will require antimicrobial therapy. Slough or necrotic tissue will require identification and treatment of the cause and debridement.
Although neither a recent Health Technology Assessment(6) nor recent systematic review(7) found any evidence in favour or against debriding wounds, it is widely accepted that devitalised tissue within the wound impedes healing. A current NICE report suggests debriding wounds where appropriate.(8) Sloughy wounds that are not debrided run the risk of having a prolonged inflammatory phase of healing, increased bacterial growth, increased metabolic load and psychological stress for the patient, inflammation and malodour. A sloughy wound bed also makes it difficult to assess the true depth and size of a wound. 
Debridement can be performed either mechanically (surgical excision, sharp debridement and biosurgery) or nonmechanically (autolytic, enzymatic or through the use of polysaccharide dressings). Surgical excision is usually performed only by trained surgical clinicians and includes the removal of some periwound tissue along with slough and necrotic tissue. Sharp debridement is the removal of slough and necrotic tissue only, using a sharp instrument. Clinicians undertaking sharp debridement should have received training in the procedure. Biosurgery using larvae therapy is becoming more widely accepted and practised.
Autolytic debridement is achieved using hydrogels, hydrocolloids or alginates that encourage naturally occurring autolysis leading to the liquefaction of dead tissue. Enzymatic debridement is achieved through the used of enzymatic agents that aggressively digest proteins, fibrin, collagen and elastin. Polysaccharide beads or paste are hydrophilic. Through absorbing exudate, small molecules enter the bead matrix while larger molecules stick to the surface of the beads.
Surgical and sharp debridement is quick, effective and cheap but may not be clinically indicated when patients are frail and surgery would be dangerously traumatic. Sharp debridement may not be appropriate when necrotic tissue is densely adherent or there is no visual evidence of a demarcation line between viable and nonviable tissue. Patients who are at risk of haemorrhage (eg, those with fungating wounds) are usually inappropriate candidates for sharp debridement. Although biosurgery is well established in the UK, larvae therapy is often used as a last resort despite the enthusiasm of experienced proponents who report infection control, odour reduction, and rapid debridement of wet slough. 
Autolytic debridement and polysaccharide beads are both safe approaches, but they can be slow and lead to maceration. Enzymatic debridement is usually quicker but expensive. The active ingredients are potential allergens, easily deactivated if handled too vigorously, and can potentially be absorbed into the body through the wound.
Each debridement method has advantages and disadvantages. The clinical decision must be tailored to the needs of the individual patient. 
High-quality wound assessment, cleansing and debridement are the foundation stones of effective wound management. By applying the principles of evidence-based care to these areas, clinicians will promote the best possible wound care.

References

  1. Etris MN, Pribble J, LaBecque J. Evaluation of two wound measurement methods in a multi-centre, controlled study (Cochrane Review). In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software.
  2. DiCenso A, Cullum N, Ciliska D. Implementing evidence-based nursing: some misconceptions. Evid Based Nurs 1998;1(2):38-40.
  3. Flannagan M. Wound Cleansing. In: Morison M, et al, editors. Nursing Management of Chronic Wounds. London: Mosby; 1997.
  4. Briggs M, Wilson S, Fuller A. The principles of aseptic technique in wound care. Prof Nurse 1996;11(12):805-10.
  5. Angeras MH, Brandberg A, Falk A, Seeman T. Comparison between sterile saline and tap water for the cleaning of acute traumatic wounds. Eur J Surg 1992;158:347-50.
  6. Bradley M, Cullum N, Sheldon T. The debridement of chronic wounds: a systematic review. Health Technol Assess 1999;3(17 Pt 1):iii-iv, 1-78.
  7. Lewis R, Whiting P, ter Riet G, O'Meara S, Glanville J. A rapid and systematic review of the clinical effectiveness and cost-effectiveness of debriding agents in treating surgical wounds healing by secondary intention. Health Technol Assess 2001;5(14):1-131.
  8. National Institute for Clinical Excellence. Guidance on the use of debriding agents and specialist wound care clinics for difficult to heal surgical wounds. London: NICE; 2001. (www.nice.org.uk/pdf/woundcareguidance.pdf)

Resources
Tissue Viability Society
E:tvs@dial.pipex.com
W:www.tvs.org.uk
Woundcarenet
W:www.woundcarenet.com
Wound Care Information Guide
W:www.medicaledu.com/default.htm