Rachel is a Nurse Practitioner with experience working as a high school teacher, skin surgery center, and as a family NP.
What Is Exudate?
Exudate. Sounds like someone you used to have a relationship with. But in reality, it is closely linked to the body and its natural healing mechanism. In fact, you have probably observed it firsthand. Where exactly? Well, think about the little white cotton square on the back of a band-aid. The drainage collected on this bit of cotton is exudate. Now, let's back up a bit and explain how this exudate got onto your bandage.
Your skin is a magnificent barrier against infection. But accidents happen, and sometimes your skin barrier is broken, either because of a cut or scrape, or some other type of injury. After an injury, the body's repair mechanisms spring into action. Soldier cells, a specific type of white blood cells, are sent to the area to fight against any infection that may attempt to enter through the opened tissue.
Some of these soldier cells die, as do some of the skin cells that were damaged in the injury. All of these dead cells contribute to forming something called exudate. Exudate is the fluid produced by a wound as it heals, and it is a normal part of the healing process. However, sometimes infection sets in, changing the appearance of the exudate, as you will see.
Types of Exudate
Exudate is a great indicator as to how a wound is healing. Exudate's color, thickness, and odor are all clues as to whether a patient's wound is healing well or if there is a problem. The most common forms of exudate are:
- Serous - a clear drainage
- Sanguineous - a bloody drainage
- Serosanguineous - a clear, blood-tinged drainage
- Purulent - a thick yellow, brown, green or grey drainage
Let's look at each in a little more detail.
This is the most common form of exudate seen being emitted from a wound. It is a sign of normal wound healing. As the skin is knitting itself back together, there are natural wastes, such as dead cells and proteins. The wastes are gotten rid of via this clear, oozing liquid known as serous exudate. Serous exudate usually has no odor.
An easy way to remember about serous exudate is with the phrase 'serous is NOT serious.' This will remind you that this type of drainage from a wound is considered normal during the healing process.
This term stems from the Latin word for blood or sanguis. So the name, sanguineous, tells you all you need to know. This form of drainage is the result of bleeding in the wound. Ever drink sangria? Well, the name sangria stems from the same root word. This alcoholic beverage earned the name because it is made mostly of a dark red wine, and thus resembles blood.
Sanguineous exudate is not always a bad sign. It commonly appears when the injury first occurs, especially if it is a deeper wound. However, if a wound has a prolonged period of producing sanguineous exudate, this indicates that trauma is repeatedly happening to the wound. Sanguineous exudate usually has no odor.
Again, the name tells you everything: Serosanguineous is a mixture of serous and sanguineous discharge. So, if you mix clear with red, you usually come up with some shade of pink. This indicates that minor trauma has occurred to the wound bed, resulting in capillary rupture. Thus, a small amount of blood is mixed with the normal serous exudate.
The most common culprit for this type of drainage is improper wound dressing changes. Someone is changing the bandage too roughly, causing injury to the wound bed. Serosanguineous exudate usually has no odor.
This term stems from Latin as well. In this case the root word is pus, meaning foul or corrupt. This type of exudate is indicative of infection. The color can vary widely, but it is almost always opaque. The opaqueness comes from the bacteria that have taken up residence in the wound bed. The scent of purulent exudate is always offensive. Odors range from rotting fish to old cheese to vinegar, depending on the invading organism.
Redness and warmth often accompany purulent drainage. All of these signs in a wound bed are an indication of infection. Purulent drainage is never considered to be normal.
In summary, the fluid produced by a healing wound, or exudate, tells you a great deal as to how the wound is healing. Clear, scent-free drainage, known as serous exudate, is most often a good sign that the wound is knitting itself together properly. Sanguineous exudate, or a bloody, also non-odorous discharge, can be normal, especially at the beginning stages of a deep wound that is healing itself, along with serosanguineous, which is a clear, blood-tinged drainage that can be the result of aggressive bandage changes,. On the other hand, purulent exudate, or foul-smelling pus-like drainage, is a sure sign of infection brewing in the wound.
So, the next time you change a band-aid, don't immediately chuck it in the trash. Take a closer look at that little white square and see if you can identify the type of exudate coming from the wound.
Medical Disclaimer: The information on this site is for your information only and is not a substitute for professional medical advice.
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