About Purulent Drainage

Wound drainage, also called wound fluid or wound exudate, aids in assessing the status of wound management. Healthy wounds are normally moist, covered by fluid which contains specific ratios of endogenous chemicals. This fluid serves to aid in both healing the wound as well as preventing further injury. If the drainage becomes thick and purulent, it may be pus. Pus is really a collection of white blood cells and wound fluid. Its presence signifies a continuum that ranges from inflammation to florid infection, including abscess formation. (1, 216)

The character of the exudate, in amount, color and odor, can help to identify the exact nature of the infection. However, because of differences in the size of the wounds, as well as in the topical dressing applied, a meaningful estimate of drainage amount and consistency is difficult to arrive at. For example, two comparatively healthy wounds dressed in different ways may appear different. This is because some dressings absorb or react to drainage differently. Therefore, knowledge of the applied dressing and how it interacts with wound drainage is necessary. Likewise, a similar amount of drainage from two differently sized wounds may indicate different statuses. Estimates of the drainage must be made with the wound in mind. Assessment of exudative drainage can be attained by first removing the wound dressing and cleaning the wound bed of any dressing debris followed by clinical observation of the wound bed. (1, 217) Saline irrigation is the fluid of choice to remove cellular and other debris that has collected in the wound bed. Any signs of infection should be managed by a healthcare professional with expertise in wound management.

Once the underlying infection has been resolved, the improvement should be reflected in the exudate. Following treatment, purulent drainage becomes seropurulent, then serous and finally serosanguineous. The exudate should change from thick and opaque tan or yellow, to thin and watery pink. (1, 230) ¹