Course intro

This module is ideal for understanding exudate.

Society of Tissue Viability endorsed

This module has been through rigorous reviews to achieve endorsement from the Society of Tissue Viability, so it can be used with complete confidence. The endorsement confirms that this module provides clinicians with:

  • High-quality education that meets stated learning objectives and outcomes
  • Material that is free from product bias or promotion
  • Education that is evidence-based
  • Education that is fully accessible to members of the general wound care community

Time Required

Estimated time to complete exudate course: 60 minutes

Learning Outcomes

On completion of this exudate module, you should be able to:

  • Understand the composition and appearance of exudate
  • Identify the reasons for excessive exudate production and complications of exudate
  • Understand exudate assessment and management

In 1962, Winter identified moist wound healing as beneficial. It has been recognised that the correct level of moisture in a wound can significantly improve the healing times of a wound. A wound that has very little moisture may result in the wound bed drying out and adhering to dressings and surrounding tissues. A wound that has too much moisture will macerate surrounding tissue and cause further breakdown of the skin.

Wound exudate is often misconceived as bad. In fact, exudate is known to assist healing by:

  • Preventing the wound drying out
  • Aiding the migration of tissue-repairing cells
  • Providing essential nutrients for cell metabolism
  • Enabling the diffusion of immune and growth factors
  • Assisting separation of dead or damaged tissue (autolysis)

(WUWHS, 2019; Gardner, 2012).

Exudate is derived from fluid that has leaked out of blood vessels and closely resembles blood plasma. Fluid leaks from capillaries into body tissues at a rate that is determined by the permeability of the capillaries and the pressures (hydrostatic and osmotic) across the capillary walls (Wounds UK, 2021).

Exudate occurs in any wound as a result of vasodilatation during the early inflammatory stage of healing under the influence of inflammatory mediators such as histamine and bradykinin. It presents as serous fluid in the wound bed and is part of normal wound healing in acute wounds. However, when the wound is chronic and/or non-healing, it remains in the inflammatory phase and exudate changes from assisting healing to becoming a clinical challenge.

Exudate in these types of wounds often has higher levels of inflammatory mediators and proteolytic enzymes not seen in acute wounds. This type of exudate has justifiably been termed ‘a wounding agent in its own right’ because it has the capacity to degrade growth factors and periwound skin and can predispose to inflammation (WUWHS, 2019; Wounds UK, 2013).

Wounds healing by primary intention may leak a small amount of exudate (Gardner, 2012).

The amount of exudate produced will reduce as the wound progresses through the healing phases and usually without complication (see Module Two – Wound Healing for more information on the phases of wound healing) (Adderley, 2008). However, the suture line of wounds healing by primary intention may break down (dehisce), so healing will have to occur by secondary intention (from the bottom up).

Healing by secondary intention is also the usual mode of healing for most chronic wounds, such as leg ulcers and pressure ulcers. Wounds healing by secondary intention will usually leak exudate from the surface of the wound; the amount produced will depend on the size of the wound (Adderley, 2008).