What type of exudate indicates infection?

BY: NANCY MORGAN, RN, BSN, MBA, WOCN, WCC, CWCMS, DWC
What exactly is wound exudate? Also known as drainage, exudate is a liquid produced by the body in response to tissue damage. We want our patients’ wounds to be moist, but not overly moist. The type of drainage can tell us what’s going on in a wound.

Table of Contents Show

Types of Wound Exudate
Considerations in Managing Exudate
Types of Exudate
Quantity of Exudate
What Do You Think?

Let’s look at the types of exudates commonly seen with wounds.

Serous drainage is clear, thin, watery plasma. It’s normal during the inflammatory stage of wound healing and smaller amounts is considered normal wound drainage. However, a moderate to heavy amount may indicate a high bioburden.
Sanguinous exudate is fresh bleeding, seen in deep partial-thickness and full-thickness wounds. A small amount may be normal during the inflammatory stage, but we don’t want to see blood in the wound exudate, as this may indicate trauma to the wound bed.

Next we have the famous serosanguineous exudate, which is thin, watery, and pale red to pink in color. It seems to be everyone’s favorite type of drainage to document, but unfortunately, it’s not what we want to see in a wound. The pink tinge, which comes from red blood cells, indicates damage to the capillaries with dressing changes.
Seropurulent exudate is thin, watery, cloudy, and yellow to tan in color.

Purulent exudate is thick and opaque. It can be tan, yellow, green, or brown in color. It’s never normal in a wound bed.

So what types of drainage do you see being documented? The famous serosanguineous exudate? Are you really seeing drainage that indicates trauma to the wound bed, or is the drainage type mislabeled? Are you rethinking the need for a contact layer on the wound bed now?

DISCLAIMER: All clinical recommendations are intended to assist with determining the appropriate wound therapy for the patient. Responsibility for final decisions and actions related to care of specific patients shall remain the obligation of the institution, its staff, and the patients’ attending physicians. Nothing in this information shall be deemed to constitute the providing of medical care or the diagnosis of any medical condition. Individuals should contact their healthcare providers for medical-related information.

What is wound exudate?

Most frequently referred to as wound “drainage,” exudate is a liquid produced by the body in response to tissue damage. It bathes the wound continuously, keeping it moist, supplying nutrients, and providing the best conditions for migration of new tissue to heal the wound. Open wounds should be moist, but not overly moist. A healthy healing wound should be moist without measurable exudate.

Exudate terminology

• Serous—thin clear watery plasma (seen in partial thickness wounds/venous ulcerations). A moderate to heavy amount may indicate heavy bacteria level. This is normal in the first phases of wound healing.

• Sanguinous—bloody (fresh bleeding). This indicates new blood vessel growth or disruption of blood vessels.

• Serosanguineous—thin, watery, pale red to pink plasma with red blood cells.

• Seropurulent—thin, watery, cloudy, yellow to tan in color.

• Purulent—thick, opaque, tan, yellow, green or brown. This is never normal.

Significance of exudate color

• Clear/amber—serous exudate, often considered “normal,” but may be associated with infection by fibrinolysin-producing bacteria such as Staphyloccocus auerus; may also be due to fluid from a urinary or lymphatic fistula.

• Cloudy/milky—may indicate the presence of fibrin strands or infection.

• Pink/red—due to the presence of red blood cells; indicates capillary damage.

• Green—may be indicative of bacterial infection, e.g., Pseudomonas aeruginosa.

• Yellow/brown—may be due to the presence of wound slough or material from an enteric or urinary fistula

• Gray/blue—may be related to the use of silver-containing dressings.

From the December 01, 2009 Issue of McKnight's Long-Term Care News

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By Lindsay D. Andronaco RN, BSN, CWCN, WOC, DAPWCA, FAACWS

Wound exudate and how to properly assess and manage it has been a long standing clinical challenge in wound care. Assessing the exudate color, odor, volume, viscosity, and if it is causing maceration of the periwound skin are all important to note when creating a care plan for the patient. If there is not proper management of the exudate, then the high protease levels and low growth factor levels will negatively impact wound healing time.

Types of Wound Exudate

There are four types of wound drainage: serous, sanguineous, serosanguinous, and purulent. Serous drainage is clear, thin, and watery. The production of serous drainage is a typical response from the body during the normal inflammatory healing stage. Yet, if there is a large amount of serous drainage, it can be the result of a high bioburden count. Sanguineous drainage is only normal in occurrence during the inflammatory stage of healing where a small amount of this blood may leak from a full- or partial-thickness wound. If it is seen outside of the inflammatory phase, sanguineous drainage can be a result of trauma to the wound.

Serosanguinous drainage is the most common type of exudate that is seen in wounds. It is thin, pink, and watery in presentation. Purulent drainage is milky, typically thicker in consistency, and can be gray, green, or yellow in appearance. If the fluid becomes very thick, this can be a sign of infection.

Considerations in Managing Exudate

Exudate is a byproduct of vasodilation during the inflammatory stage and in chronic wounds the drainage changes and contains proteolytic enzymes. Effective management of the exudate depends on the characteristics of the wound such as amount of exudate, location, and exudate composition. Chronic wounds often have bacteria, like pseudomonas or staphylococci, which inhibit new cell growth. In this case, cultures to combat the bacteria can be beneficial so that an accurate care plan can be initiated. This may include topical antimicrobials, topical antibiotics, antifungals, or oral/IV medications.

Other considerations are the cost and frequency of dressing changes. When a patient is changing gauze four times a day due to exudate, it would be more beneficial for the patient and financial bottom line to use a foam dressing. Changing the dressing less allows the wound bed to be left undisturbed, which allows for the migration of new cells. When wound beds are left undisturbed in an optimal moist environment, they are able to heal at a faster rate. Changing dressings only when needed also causes fewer traumas to the periwound which can be due to adhesives or maceration damage. Negative pressure wound therapy, compression, and foam dressings can be helpful in managing exudate.

Overall, it should be noted that the dressing selection should be based on the individual patient and wound characteristics. If the wound is not in the normail inflammatory phase of healing, the clinician must investigate what is the root cause and how to manage the drainage.

Sources Mulder GD. Quantifying wound fluids for the clinician and researcher. Ostomy Wound Manage 1994; 40(8): 66-9. Nix DP. Patient assessment and evaluation of healing. In Bryant RA, Nix DP, eds. Acute and Chronic Wounds: Current Management Concepts. St. Louis, MO: Mosby; 2007. 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. Stotts NA, Wipke-Tevis DD, Hopf HW. Cofactors in impaired wound healing. In Krasner DL, Rodeheaver GT, Sibbald RG, eds. Chronic Wound Care: A Clinical Source Book for Healthcare Professionals. Malvern, PA: HMP Communications; 2007:215-20.

Vowden K, Vowden P. The role of exudate in the healing process: understanding exudate management. In: White RJ, editor. Trends in Wound Care Volume III. London: Quay Books, 2004.

Published on January 29, 2016 by Keisha Smith, MA, CWCMS

Wound care clinicians need to know about the different types of exudate – and how much is present – for successful wound treatment and healing.

Ooze. Pus. Secretion. The drainage that seeps out of wounds can be called many things, but as wound care clinicians know, the technical term is exudate. This liquid, which is produced by the body in response to tissue damage, can tell us what we need to know about the wound. And while we want wounds to be moist, we don’t want them to be overly moist. Finding that balance can sometimes be a bit tricky – which is why it’s so important to know all about exudate.

Types of Exudate

First, let’s start with the types of exudate we most commonly see in our patients’ wounds. They are:

Serous – a clear, thin and watery plasma. It’s normal during the inflammatory stage of wound healing, and smaller amounts are considered normal. However, a moderate to heavy amount may indicate a high bioburden.
Sanguinous – a fresh bleeding, seen in deep partial- and full-thickness wounds. A small amount is normal during the inflammatory stage.
Serosanguineous – thin, watery and pale red to pink in color.
Seropurulent – thin, watery, cloudy and yellow to tan in color.
Purulent – a thick and opaque exudate that is tan, yellow, green or brown in color. It’s never normal in a wound bed, and is often associated with infection or high bacteria levels.

Quantity of Exudate

Besides knowing the different types of exudate, you also need to be aware of the amount present in your patients’ wounds. This can be key for proper assessment, and help you choose the best wound treatment. The different exudate levels include:

None present – the wound is dry.
Scant amount present – the wound is moist, even though no measurable amount of exudate appears on the dressing.
Small or minimal amount on the dressing – exudate covers less than 25% of the bandage.
Moderate amount – wound tissues are wet, and exudate involves 25% to 75% of the bandage.
Large or copious amount – wound tissue is filled with fluid, and exudate covers more than 75% of the bandage.

Always take into account the amount of exudate when selecting the dressing. We want to promote moist wound healing, but with no adverse effects from too much moisture, such as maceration of the periwound.

What Do You Think?

When it comes to documenting exudate, do you see one type being identified more than others – like the well-known serosanguineous? And what about the amount of drainage – do you use the terms listed above, or does your clinic use percentages instead? We would love to hear how your facility typically documents exudate, and if you encounter any specific challenges or successes with identifying or treating wounds based on exudate. Please leave your comments below.

Wound Care Education Institute® provides online and onsite courses in the fields of Skin, Wound, Diabetic and Ostomy Management. Health care professionals who meet the eligibility requirements may sit for the prestigious WCC®, DWC® and OMS national board certification examinations through the National Alliance of Wound Care and Ostomy® (NAWCO®). For more information see wcei.net.