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Best management of exudate and maceration

Caroline Graham
Tissue Viability Nurse Specialist
South and East Belfast (HSS) Trust
Knockbracken Health Care Park

The process of wound healing involves a complex and orderly series of cellular-level events that begin when tissue is damaged. The healthcare practitioner can directly influence the eventual outcome of the healing process by manipulating these cellular processes. It is necessary to establish a treatment regimen that aims to maintain an environment that will assist healing while minimising the factors that might jeopardise progress. The practitioner must have the appropriate knowledge, skills and specialist support to establish an environment for optimal healing.
Current wound care regimens owe much to the seminal work of Winter,(1) who discovered that covering wounds, and thus keeping them moist, resulted in an increased rate of healing by up to 40%. Most wounds produce a liquid output called exudate, which when trapped by a dressing will keep the wound moist. Exudate has been defined as:

"… serous fluid that has passed through the walls of a damaged vein … [it] varies from a thin watery fluid to a thick tenacious fluid depending on the condition of the wound."(2)

The exudate can also contain dead white cells and bacteria. Although the wound surface must be kept moist, the dressing must be capable of absorbing any excess exudate, otherwise periwound skin maceration, irritation, soreness or unpleasant odour can result, with obvious negative impact on the patient. Hence assessing and managing the colour, consistency, amount and type of wound exudate is a critical aspect of wound treatment.

Properties, benefits and disadvantages of exudate
The benefits of wound exudate were postulated as long ago as the Renaissance, when Paracelsus (1493-1541) stated that wound exudate was "nature's balsam" and advised surgeons not to interfere with it.(3) Holn et al supported this when they demonstrated that wound exudate exhibited antimicrobial properties and thus helped to keep the wound free of bacteria (a process now known as autolysis).(4) Before this discovery it was felt that constant cleaning of all wounds was beneficial, whereas now it is believed to be better to clean the surrounding skin rather than the wound bed as the resulting drainage of exudate will help keep it clean (see Figure 1).


While exudate has beneficial properties, it can also create problems. Excess exudate can cause maceration of the surrounding tissue, which can result in enlargement of the wound or invasion by bacteria.(5,6) Examination of the wound edges for epithelialisation, contraction or maceration must therefore be included in wound assessment.(7) Maceration of the epithelium has been described as softening of the periwound skin due to the presence of excessive exudate for an extended period (see Figure 2).(8) Rodgers et al highlight that maceration of the skin surrounding diabetic foot ulcers may be one of the less recognised factors contributing to ­inhibited healing.(9)


Wound assessment
The starting point for any successful treatment is a comprehensive and holistic assessment of the patient and the wound; it will be necessary to continually revisit and update this assessment throughout the treatment. The assessment should include: the type of wound (acute or chronic), location, a description of the clinical appearance of the wound bed, the stage of wound healing and the grade of tissue loss. The type of tissue within the wound bed can give an indication of likely level of exudate. For example, if the tissue is necrotic or black eschar, the wound is likely to be dry initially with increasing levels of exudate as the process of autolysis occurs (see Figure 3), especially when assisted by the use of dressings. Sloughy or yellow devitalised tissue can start with moderate to high levels of exudate, which decrease as slough is removed (see Figure 4). This information is useful when choosing dressings and deciding on the frequency of dressing change. The stage of wound healing can also be informative regarding exudate levels: for example, a higher level of exudate would be expected during the inflammatory stage than later during granulation or epithelialisation (see Figure 5).




While recording the type, amount, colour, consistency and odour of exudate tends to be subjective, it can help communication between practitioners. It is therefore useful to utilise standardised terms when describing the type of exudate.

Type of exudate
The type of wound exudate can be described as:

  • Serous - clear straw-coloured fluid, absent of ­visible signs of blood, pus or other debris.
  • Haemoserous - slightly bloodstained serous fluid.
  • Sanguinous - heavily bloodstained.
  • Purulent - contains pus, cloudy and viscous.
  • Haemopurulent - stained with pus and frank blood.

Amount of exudate
CREST (Clinical Resource Efficiency Support Team) gives the following terms that are useful in describing the amount of exudate produced by a wound:(10)

  • Dry - the wound does not produce exudate.
  • Low - the wound bed is moist (ie, there are scant or small amounts of exudate).
  • Moderate - the surrounding skin is wet, and there is exudate in the wound bed.
  • High - the surrounding skin is saturated ­(sometimes macerated), and the wound is bathed in fluid.

It is worth noting that the dressing used and frequency of change may disguise the actual levels of exudate (see Figure 6).


Knowledge of the patient's medical history is important - some authors have indicated that patients with diabetes have an impaired inflammatory response, which results in fewer leucocytes and phagocytes, thus increasing the risk of infection and leading in turn to high exudate levels.(11,12) Cancerous fungating wounds tend to have high levels of exudate as a result of high bacterial burden and tissue liquefaction (see Figure 7). High exudate levels are also associated with venous leg ulceration, which is mainly the result of venous hypertension.


High levels of exudate may indicate the presence of a foreign body or infection - hence a patient with a wound that is not responding to treatment requires further investigation into local and systemic factors that could cause delayed healing.(13) This should include checking for:

  • Foreign bodies (eg, suture material, wound care product, glass, hair or soil debris).
  • Abscess formation.
  • Haematoma.
  • Fistula formation.
  • Osteomyelitis of underlying bone (see Figure 8).
  • Epithelialisation of sinus tract.


An investigation of the source of drainage from the wound may be helpful in settling on a management regimen. For example, the exudate may be augmented with saliva, bile, pancreatic fluids, faeces or urine - all of which will change the pH value of the exudate and therefore can cause more damage to surrounding intact skin. Loss of excessive amounts of wound exudate, as is seen in burns and fistulae, can interfere with the patient's fluid balance and result in electrolyte disturbance - it may be helpful to analyse the exudate to determine the degree of electrolyte replacement required. Stotts and Whitney identified increased nutritional loss, which necessitates the use of nutritional supplements to support wound healing, especially when dealing with fistulae, complex open wounds or large tissue loss due to burns.(14) Doughty and Broadwell Jackson explained that fistulae are known as "high-output" if they drain 500ml or more in 24 hours.(15)

Colour and consistency of exudate
Both the colour and consistency of exudate are closely related to the type of exudate. The colour in particular may be a good indicator of the type of bacteria present (eg, Pseudomonas aeruginosa has a bright-green colour - see Figure 9).


Exudate odour relates to wound infection or contamination of wounds by body fluids such as faeces, as seen in fistulae. Odour may also be associated with autolysis of necrotic tissue under occlusive dressings.

Management of exudate
Treatment objectives provide the rationale for the management strategy adopted and any clinical intervention. Objectives must be shared and agreed with the patient, their carers and members of the multi-professional team.
It is important that management strategies:

  • Ensure patient comfort and support.
  • Protect the wound from pathogens and further trauma.
  • Manage to contain exudate and protect the ­surrounding skin.
  • Control odour if present.
  • Promote healing.
  • Protect granulation and epithelial tissue.
  • Are cost-effective.
  • Manage infection.

Knowledge of the amount and type of wound exudate is important as it has a major influence on the choice of dressing. It is important to remain aware when choosing a dressing that they can also promote exudate by stimulating the inflammatory process - for example, hydrocolloid dressings.
The ideal wound dressing would replicate the function of the intact skin perfectly. CREST used this fact when defining the ideal characteristics of wound ­dressings:(10)

  • Provide a moist wound environment.
  • Manage excess exudate.
  • Allow gaseous exchange.
  • Provide a constant wound temperature.
  • Protect the wound from organisms.
  • Protect the wound from debris and chemical ­damage.
  • Protect the wound from trauma.

Turner's criteria for the ideal dressing also listed the ability of the dressing to absorb excess exudate.(16) Dressings that prevent dehydration of the wound bed, while absorbing excess exudate, will accelerate healing. However, when exudate levels are high many modern wound dressings do not meet the needs of the patient, since the moisture- vapour transfer rate of the dressing may not be sufficient. Jones and Gill state that for hydrocolloid dressings this problem can be overcome by increasing the frequency of dressing changes or using an alternative dressing.(17) Patients with high wound exudate levels must have a dressing that will absorb exudate and prevent leakage. When strikethrough (visible signs of wound exudate on a dressing or leakage) occurs, the dressing must be changed, otherwise it will provide an ideal pathway for microorganisms and toxic substances to enter the wound.
Strikethrough typically occurs when managing sinus wounds or complex cavity wounds resulting from suture line dehiscence or planned surgical debridement, where the wound is allowed to heal by delayed primary intention or secondary intention. The high levels of exudate from devitalised tissue or fistulae can make management more challenging. Appropriate management of these usually includes encouraging free drainage of exudate either into an ostomy or a wound drainage appliance or into an absorbent dressing.
Wound management or ostomy appliances are particularly useful for complex draining wounds. They have a number of useful characteristics:

  • They allow easy access via ports without requiring frequent changes.
  • They allow clear inspection of the wound.
  • They insulate the wound against temperature loss.
  • They protect against bacterial invasion via soaked ­dressings.
  • They allow an accurate measurement of exudate.

The use of wound appliances such as vacuum-assisted closure (VAC) has helped greatly in managing high levels of exudate. They assist wound closure by applying localised negative pressure to the wound bed, which increases angiogenesis, improves management of exudate and helps draw the wound edges together (see Figure 10). The system consists of a VAC pump, a dressing (foam and film dressings) and a VAC canister.


The use of barrier creams and sprays can also help reduce periwound maceration. Cavilon (3M Health Care) has been widely used as it is an alcohol-free transparent barrier film that causes no stinging sensation if applied to damaged skin. This barrier film can help protect intact or damaged skin from irritation caused by adhesive stripping, digestive juices, and urine or faecal incontinence.
Alginate dressings are particularly useful and effective when managing exudate produced by sloughy tissue.
When choosing dressings it is important to be aware that they cannot be used indiscriminately. Dressings are simply a tool to help achieve a treatment objective. The practitioner must decide what that objective is. The following factors can help with decision-making:

  • Stage of healing.
  • Aetiology of the wound.
  • Type of tissue involved.
  • The patient's general health and environment.
  • Amount of exudate.
  • Size and site of the wound.
  • Odour and infection.
  • Pain and comfort.
  • Surrounding skin.
  • Allergies.
  • Research.
  • Availability (drug tariff/hospital contract).

The management regimen for a wound needs to be as individualised as the person being treated and will be influenced by local signs and symptoms. Exudate levels are an important factor in deciding on a treatment regimen, particularly dressing selection. Large amounts of exudate in particular can challenge the creativity of the practitioner to ensure that healing of the wound is not adversely affected. It is important to acknowledge that, due to other factors, healing may not be achievable and therefore long-term management of exudate may be required, which could have a significant impact on the quality of the patient's life.


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  2. Collins F, Hampton S, White R. A-Z dictionary of wound care. London: MAP; 2002.
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  4. Holn D, Pounce B, Burton R. Antimicrobial systems of the surgical wound. Am J Surg 1977;133:597-600.
  5. Nelsen A. Is exudate a clinical problem? In: Cherry G, Harding K, editors. Proceedings of the Joint Meeting of the European Wound Management and European Tissue Repair Society: management of wound exudate. London: Churchill Communications; 1997.
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  7. Cutting KF. Avoidance and management of peri-wound ­maceration of the skin. Prof Nurse 2002;18(1):33-6.
  8. Bowser PA, White RJ. Isolation, barrier properties and lipid analysis of stratum compactum, a discrete region of the stratum corneum. Br J Dermatol 1985;112:1-14.
  9. Rodgers A, Watret L. Maceration and its effect on periwound margins. Diabetic Foot 2003;6(3):S2-5.
  10. CREST. Guidelines for wound ­management in Northern Ireland. Belfast: CREST; 1998.
  11. Reiber GE, Pecoraro RE, Koepsell TD. Risk factors for ­amputation in patients with diabetes mellitus. A case controlled study. Ann Intern Med 1992;117:97-105.
  12. Kamal K, Powell RJ, Sumpio BE. The pathology of diabetes mellitus: implications for surgeons. J Am Coll Surgeons 1996;183:271-89.
  13. Carville K. Wound care manual. Perth: Silver Chain Nursing Association; 2001.
  14. Stotts N, Whitney J. Nutritional intake and status of clients in the home with open surgical wounds. J Commun Health Nurs 1990;7(2):77-86.
  15. Doughty D, Broadwell Jackson D. Gastrointestinal disorders. St Louis: Mosby; 1993.
  16. Turner TD. Which dressing and why? In: Westaby S, editor. Wound care. London: Heinemann; 1985.
  17. Jones V, Gill D. Hydrocolloid ­dressings and diabetic foot lesions. Diabetic Foot 1998;1:127-34.