CLINICAL FOCUS Exudate assessment and management
Patricia Davies Patricia Davies is Senior Lecturer and Pathway Leader in Tissue Viability, Birmingham City University Email: [email protected]
xudate is the fluid that seeps out of a wound. It is thought that the chronic wound is stuck in-between It is similar to the fluid that, when the skin is the inflammatory and proliferative stage of healing, the Eintact, would usually bathe the cells within the delicate balance in favour of the MMPs breaking down tissue dermis, providing nutrients to the cells. The waste products for too long. The presence of MMPs prevents new tissue produced by the cells are transported into the venous and from being created (Schultz, 2007). Some products indicate lymphatic circulation. When there is an injury involving the that they are able to reduce the level of MMPs at the wound tissues of the dermis, or below it, this fluid is able to leak bed to correct this balance; however, further research is out to the surface; fluid production is usually increased, due required to demonstrate the effectiveness of this clinically, in to the action of the inflammatory stage of wound healing relation to wound healing rates (Smeets et al, 2008). (World Union of Wound Healing Societies, 2007). Exudate is composed mainly of water, with electrolytes, Exudate – what needs nutrients and waste products, together with substances to be considered? directed to the wound by chemicals released on injury, Exudate assessment is an important element of the wound such as white blood cells, inflammatory mediators, growth assessment process. factors and enzymes, such as proteases (World Union of Wound Healing Societies, 2007; Romanelli et al, 2010). Effect of exudate on the patient Exudate can be beneficial to wound healing, especially Exudate is known to be problematic to patients when it in an acute wound, as it can be used to create a is not managed well. Strikethrough of exudate through moist environment, which has been demonstrated to the dressings or bandages is visually offensive, gives rise to enhance the rate of granulation tissue and epithelialisation odour and causes leakage of fluid onto furniture, bedding compared with a wound dried out in air (Alvarez et al, and clothing (Rich and McLachlan, 2003; Jones et al, 2008). 1983; Dyson et al, 1988; Thomas, 2010b). Patients with such symptoms admit to isolating themselves, The components of exudate, such as matrix and have been found to suffer from increased rates of metalloproteases (MMPs), can contribute to the breakdown depression and anxiety (Jones et al, 2008; Palfreyman, 2008). of dead and devitalised tissue, while other components, This needs to be borne in mind when dealing with known as growth factors and cytokines, contribute to frequency of dressing changes. Dressings and bandages building new tissue. MMPs participate in the clearing of should be changed before exudate strikes through to the dead tissue, then growth factors and cytokines enable the outer side, or leaks from beneath the dressing. The reason reforming of new tissue. for this is twofold: first, for patient comfort (physically and mentally), and second, to reduce the risk infection from bacteria gaining access through the wet material. Abstract An intact dry dressing prevents bacterial ingress; once Good wound management must involve an holistic approach to care; the dressing becomes sodden, bacteria have a route into without considering the whole person, appropriate management might not the dressing, through the material and thus to the wound be as good as it could be. In a time of austerity, it is important that money (Thomas, 2010b). If the skin surrounding the wound is spent appropriately on the correct wound-management technologies. becomes wet with exudate, this can cause excoriation of Exudate assessment and management are a vital part of wound the area (Benbow and Stevens, 2010), which can cause management. In this article, the focus will be on exploring the nature of pain and discomfort. exudate and tools available to evaluate exudate. Finally, suggestions will be made on the management of exudate. Colour of exudate Exudate is usually clear or straw-coloured fluid; however, in KEY WORDS certain circumstances, this colour may be changed and still Exudate w Management w Assessment w Colour viewed as ‘normal’. The colour of exudate can relate to the tissue type present at the wound bed. An example would be if there were necrotic or sloughy tissue at the wound
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Figure 1. Macerated skin Figure 2. Excoriated skin bed, the exudate colour could be brown or dark green, to Thickness of exudate reflect the tissue’s colour, which is breaking down. If using Exudate varies in its composition; it can be watery, or thicker a silver dressing, the exudate may be blue or grey in colour in nature (World Union of Wound Healing Societies, 2007). (World Union of Wound Healing Societies, 2007). The variation in thickness or viscosity is dependent upon The colour of exudate needs to be considered, so you the amount of wound fluid being produced by the patient, are to be able to make a judgement of what is normal and and the amount of white cells and bacteria present within appropriate for your patient at that specific point in time. the wound (Blackwell, 1997). White cells and bacteria, when This needs to be considered in conjunction with other present in large amounts within the wound, act in a similar signs of inflammation or infection. way to gravy granules, thickening up the exudate. It is important that the colour of the exudate is noted Pus is a form of thick exudate and is one of the classic at every dressing change, to ensure subsequent assessments signs of infection (Cutting et al, 2005). Thick exudate have relevant information with which to compare. can be associated with an infected wound; however, just
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Box 1. What exudate colours tell us Colour now Colour previously Indication Action Straw-coloured or clear Straw-coloured or Normal exudate colour Continue as planned clear Blood-stained or rust- Straw-coloured or Patient may have injured the Ask the patient if they had injured the area; if coloured clear site to take back to haemostasis so, assess if it needs extra protection. stagem or the wound could be If the patient had not had an injury to the area, demonstrating a sign of infection consider if other signs of infection are present*. If other signs of infection are present, treat as advised by local wound-care formulary Straw-coloured or clear Blood-stained or Now normal exudate colour Continue as planned rust-coloured Brown, dark green or No exudate or If necrotic or sloughy tissue Continue as planned grey brown, dark green is present at wound bed, this or grey could be normal, as the body is breaking down the necrotic or sloughy tissue Fluorescent green Straw-coloured or Could indicate the bacteria Check if other signs of infection are present; if clear Pseudomonas aeruginosa is not, continue as planned. Due to the colour the present bacteria displays, this is one of the few bacteria we are able to see visual evidence of. However, being present does not necessarily indicate the wound is infected; it could be colonised (bacte- ria in lower numbers than infected rate), which is normal. If other signs of infection are present*, continue as advised by local wound care formulary Purulent green, milky or Straw-coloured or Could indicate presence of Check if other signs of infection present*; If cloudy clear infection other signs of infection are present, treat by taking a wound swab or fluid sample for culture and sensitivity; systemic antibiotics to be pre- scribed and antimicrobial dressing to be used, as advised by local wound care formulary *Note: in patients with diabetes, signs of infection such as inflammation response can be negligible or absent.
because the exudate is not thick does not mean that a bags are being used to collect the fluid; however, when wound is not infected. Clinically, several patients have been using dressings, it can be more difficult. For example, observed to be producing thin exudate, draining from a the amount of exudate absorbed by different dressings in pinhead-sized sinus, in cases of chronic osteomyelitis (bone different ways does not allow direct comparison between inflammation/infection). dressings (Thomas, 2010a). There are several suggested methods of assessing exudate level, but none as yet has Amount of exudate been identified as the best method. This is an area that The amount of exudate can vary depending on the requires further research to determine which is the most wound’s aetiology; for example, venous leg ulcers and clinically relevant. burns can produce large amounts of exudate when Falanga (2000) proposed a method of scoring for exudate, compared with arterial ulcers (Rolstad and Ovington, as part of a staging system for wound bed preparation 2007). Wound fluid amounts can also vary due to stage (Box 2). The scoring system gives some guidance on the of wound healing. In the inflammatory phase of wound degree of exudate in relation to the dressing changes. healing and early proliferative phase of wound healing, However, since this scoring system was devised, new exudate production is usually higher, due to the cellular products on the market, such as super absorbents, may activity taking place. In the later stage of the proliferative affect the frequency of dressing changes needed. phase, the amount of fluid produced usually drops (White The extent of control is also dependent on interpretation. and Cutting, 2006). The amount of exudate may also relate For example, if a patient with a very exudative wound is to the size of the wound, larger wounds producing more being dressed with a wound dressing designed to stay in exudate than smaller ones, in the main (World Union of place for 24 hours, exudate is controlled if the dressing Wound Healing Societies, 2007). lasted the 24 hours and there was no leakage, or issues with The amount of exudate is easy to determine when the skin surrounding the wound. Having a scoring system systems such as topical negative pressure devices or ostomy does highlight to the practitioner the need to consider
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Box 2: Falanga’s wound exudate scoring system Wound Extent of control Exudate amount Dressing requirement exudate score 1 Fully None/minimal No absorptive dressings required. If clinically feasible, dressings could stay on for up to a week 2 Partially Moderate amount Dressing changes required every 2-3 days 3 Uncontrolled Very exudative Absorptive dressing changes required at least daily wound Source: Falanga (2000). some of the aspects in relation to exudate volume. the practitioner’s own experience of exuding wounds. The Bates-Jensen wound assessment tool considers Box 3 advises the practitioner what is meant by the terms exudate from the perspective of colour and exudate to enhance objectivity when assessing exudate levels in amount, using the terms none, scant, small, moderate and conjunction with the dressing. Within the article, Fletcher large. Guidance is given regarding what is meant by these (2010) also identifies other descriptors relating to colour terms, taking into account the wound, the surrounding and viscosity of exudate found on some wound assessment skin and the dressing (Bates-Jensen, 1997). charts, but these are not included within the national A first attempt at creating a national wound assessment wound assessment form at present. form uses the term ‘wound moisture level’, rather than From the assessment tools listed in Boxes 2 and 3, it can exudate (Fletcher, 2010). The choices given on the form be seen that there is a lack of consensus on the best way to are: dry, moist, wet, saturated and leaking. These terms have determine exudate amount. However, the tools do provide been chosen to reflect the work undertaken by the World the practitioner with a means of providing a more objective Union of Wound Healing Societies (WUWHS) (2007) in assessment. What matters in practice is that all members of the document on wound exudate (Box 3). It is important the team caring for the patient with a wound assess it in the that the practitioner refers to the meaning of these terms, same way, using the same definitions. It is important that as identified by the WUWHS, rather than leaving it to the everyone uses the same terms. If this does not happen, the individual practitioner to determine their own definition assessment documentation might vary, but the condition of the terms. This could potentially be problematic, as the of the wound may remain the same. It might be useful to terms are quite subjective and would be dependent upon discuss this aspect within the team you are working with.
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Box 3. World Union of Wound Healing Societies wound moisture levels Status Indicators Dry Wound bed is dry; there is no visible moisture and the primary dressing is unmarked; dressing may be adherent to the wound Moist Small amounts of fluid are visible when the dressing is removed; the primary dressing is extensively marked; dressing change frequency is appropriate for dressing type. Wet Small amounts of fluid are visible when the dressing is removed; the primary dressing is extensively marked, but strikethrough is not occurring; dressing change frequency is appropriate dressing type. Saturated Primary dressing is wet and strikethrough is occurring; dressing change is required more frequently than usual for dressing type. Leaking Dressings are saturated and exudate is escaping from primary and secondary dressings onto clothes or beyond; dressing change is required much more frequently than usual for dressing type. Table from World Union of Wound Healing Societies (2007:6)
Management of exudate some information around this aspect in the literature Moist wound healing is accepted by the wound-care for a product, but the research studies to indicate the community as being preferable to drying out wounds, in methodology of laboratory testing (in vitro testing) are not most instances (Dowsett, 2008). One such exception would always freely available (Dumville et al, 2009). be patients with dry gangrenous toes, where auto-separation A rudimentary way of testing this yourself in practice is would be enhanced by maintaining a dry environment. In using samples from the companies and wetting the product, order to enhance the body’s ability to repair itself, the wound then squeezing after a while, to see how well it retains the bed needs to be bathed with exudate, but not excessively. fluid, also noting changes to the size and shape of the dressing Getting the moisture balance correct is an important part as it absorbs. Some dressings are evaluated by clinicians with of wound management. This aspect can be challenging, as a particular client group (in vivo testing) and discussed in wound exudate levels change during the healing process. articles that identify benefits of the product, such as retention This is why the ongoing assessment of wound exudate of fluid. Unfortunately, while this is useful and interesting, the is so important. If undertaken effectively, the assessment evaluations are usually only on a few patients, so the evidence process will identify the level of exudate production; this is not able to be analysed to determine if the benefits offer information can then be used to guide the type of dressing clinical significance. A means of collecting data to answer required to produce the desired moist environment. these questions is needed, to aid in clinical decision-making. Dressings to deal with exudate come in a variety of At the moment, choice is very much based upon personal forms and absorbency levels. Dressing manufacturers usually experience, together with trial and error. give guidance on the level of absorbency of their products. The dressing performance should be evaluated at each Standardisation of tests has been attempted to determine the dressing change, to determine if the product and the time degree of absorbency. This has been achieved to some extent span left in situ are still appropriate. The condition of the in similar products, but not between different categories of wound and the surrounding tissue of the wound need to be products (Thomas, 2010b). considered, in conjunction with the patient’s needs. BJCN Dressings vary in the way they deal with exudate. Unlike
gauze or cotton wool products, the absorbent products Alvarez OM, Mertz PM, Eaglestein WH (1983) The effects of occlusive dressings tend to lock away some of the exudate with the fibres on collagen synthesis and re-epithelialisation in superficial wounds. J Surg or particles of the dressing (Thomas, 2010b). The ability Res 35(2): 142–8 Bates-Jensen B (1997) The Pressure Sore Status tool a few thousand assessments to do this varies and needs to be considered, especially if later ... Adv Wound Care 10(5): 65–73 being used on a wound that will come under compression, Benbow M, Stevens J (2010) Exudate, infection and patient quality of life. Br J either from bandages or if the patient is laying or sitting Nurs 19(20): S30, S32–6 Blackwell S (1997) Blackwells Dictonary of Nursing. Blackwell Science, Oxford on the product (Cook, 2011). Companies usually provide
Box 4. Getting the moisture balance correct Wound bed, as found at Aim Action time of dressing change Dry To increase the level moisture Donate fluid by use of hydrogel or hydrocolloid dressing Moist To maintain the moist level Continue with current dressing regime Wet To reduce the level of moisture Absorbency level needs to be increased. Revise dressing choice to a more absorbent product
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Cook L (2011) Effect of super-absorbent dressings on compression sub-bandage pressure. British Journal of Wound Care 16(3): S38–43 Cutting K, Harding K, Maloney P, Harding K (2005) Clinical identification of wound Infection. In: Moffatt CJ (ed.) Position Document Identifying Criteria For Wound Infection. MEP, London Dowsett C (2008) Exudate management: a patient-centred approach. J Wound Care 17(6): 249–252 Dumville JC, Petherick ES, O’Meara S, Raynor P, Cullum N (2009) How is research evidence used to support claims made in advertisements for wound care products? J Clin Nurs 18(10): 1422–9 Dyson M, Young S, Pendle CL, Webster DF, Lang SM (1988) Comparison of the effect of air on exposure and occlusion on dermal repair. J Invest Dermatol 91(5): 434–9 Falanga V (2000) Classifications for wound bed preparation and stimulation of chronic wounds. Wound Repair Regen 8(5): 347–52 Fletcher J (2010) Development of a new wound assessment form. Wounds UK 6(1): 92–9 Hamilton C (2008) Speculating to accumulate: reducing the cost of wound care by appropriate dressing selection. J Wound Care 17(8): 359–63 Jones JE, Robinson J, Barr W, Carlisle C (2008) Impact of exudate and odour from chronic venous leg ulceration. Nurs Stand 22(45): 53–4, 56, 58 Palfreyman S (2008) Assessing the impact of venous ulceration on quality of life. Nurs Times 104(41): 34–7 Rich A, McLachlan L (2003) How living with a leg ulcer affects people’s daily life: a nurse-led study. J Wound Care 12(2): 51–4 Rolstad BJ, Ovington LG (2007) Principles Of Wound Management. In: Bryant J, Nix DP (eds) Acute and Chronic Wounds: Current Management Concepts. 3rd edn. Mosby, St Louis Romanelli M, Vowden K, Weir D (2010) Exudate Management Made Easy. http://bit.ly/PedG5e (accessed 13 August 2012) Schultz G (2007) Molecular regulation of wound healing. In: Bryant RA, Nix DP (eds) Acute and Chronic Wounds: Current Management Concepts. 3rd edn. Mosby Elsevier, St Louis MO Smeets R, Ulrich D, Unglaub F, Wöltje M, Pallua N (2008) Effect of oxidised regenerated cellulose/collagen matrix on proteases in wound exudate of patients with chronic venous ulceration. Int Wound J 5(2): 195–203 Thomas S (2010a) Laboratory findings on the exudate-handling capabilities of cavity foam and foam-film. J Wound Care 19(5): 192, 194–9 Thomas S (2010b) Surgical Dressings and Wound Management. Medetec Publications, Cardiff White RJ, Cutting K (2006) Modern Exudate Management: A Review Of Wound Treatments. www.worldwidewounds.com/2006/september/White/ Modern-Exudate-Mgt.html (accessed 13 August 2012) World Union Of Wound Healing Societies (2007) Principles of Best Practice: Wound Exudate and the Role Of Dressings: A Consensus Document. www. woundsinternational.com/pdf/content_42.pdf (accessed 13 August 2012)
Box 5. Types of wound dressing Type of product Product properties Level of exudate Film dressing Not absorptive Minimal exudate Hydrogels and hydrocolloids Donate fluid, slightly absorptive Minimal to moderate exudate Alginates and hydrofibre Absorptive Moderate to high exudate Foams Absorptive Low to high exudate Superabsorbents Highly absorbent Moderate to very high exudate
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