Wound Bed Preparation and Assessment

Wound Bed Preparation

Wound bed preparation is a systematic approach to wound care, widely used for at least 30 years. While many of the past principles of wound bed preparation still hold true, the practice continues to evolve as new evidence-based approaches are developed. This article reviews the latest concepts from “Wound Bed Preparation 2021.”1

Wound bed preparation is more than just the wound

Wound care specialists are often called in to manage difficult, chronic wounds, but that does not mean their focus is solely on the wound itself. Clinicians should appropriately treat the patient’s pain, support healthy diet and exercise, and educate patients on the dangers of smoking and uncontrolled blood sugars. Is the patient taking any medications or agents that are interfering with wound healing? Is there an identifiable cause of the wound? If so, that should be the primary focus of treatment. If you can eliminate the cause, you can potentially eliminate the wound. In other words, wound bed preparation includes thinking about the patient’s condition holistically.

Wound bed preparation starts with careful wound assessment

Chronic wounds heal slowly and unevenly. To document progress (or lack of progress), wound bed preparation starts with careful assessment. For each wound, document the longest length by the widest width. Note the shape and location of the wound. Is there exudate, undermining or tunneling? How do the wound margins and surrounding skin look? A picture is worth a thousand words, especially when documenting chronic wounds. Make an assessment with photoimaging before and after the initial intervention.

TIME for modern times

While less emphasis was placed on the acronym TIME in “Wound Bed Preparation 2021,” it is still quite useful. TIME stands for:

T – Tissue

Non-viable tissue such as necrotic tissue, slough or eschar must be identified and removed. The type of debridement required will vary. Sharp surgical debridement that results in bleeding tissue is usually reserved for healable wounds with a good blood supply (consider audible handheld Doppler over traditional ankle-brachial pressure index). On the other hand, wounds that are unlikely to heal may only require conservative surgical debridement such as autolytic with dressings, enzymatic or biologic approaches. 

I – Infection/Inflammation

Assume local infection is present if three or more NERDS criteria are present:

  • Nonhealing 
  • Exudate increase 
  • Red friable granulation 
  • Debris or dead cells 
  • Smell

Treat local infections with topical antimicrobials such as preparations containing silver, iodine, chlorhexidine, or surfactants. 

Infection that extends beyond the wound, i.e., deep infection should be assumed if there are three or more STONES criteria present:

  • Size enlargement
  • Temperature at least 3° F higher compared to opposite limb temperature
  • Os (exposed bone), 
  • New areas of break down on the wound margin
  • Exudate increase, Erythema and/or Edema 
  • Smell

Deep infection should be treated with systemic antimicrobials according to local resistance patterns and tissue cultures (if accurate cultures can be obtained). 

Inflammation, if present apart from infection, should be managed directly with anti-inflammatory agents either topical, systemic, or perhaps both.

M – Moisture

The ideal wound bed is one that is not dry, not wet, but moist. A moist environment allows the cells and molecules involved in wound healing to operate in the proper concentrations and locations. Choosing the right wound dressing can help create the appropriate amount of moisture. The following dressings are listed by their indicated wound environments, from dry wounds to heavily exudative wounds. In other words, dressings at the top donate moisture while dressings farther down balance or absorb moisture to greater degrees.

  • Hydrogel – Adds moisture to the wound
  • Transparent film – Neutral (no change in wound moisture)
  • Hydrocolloid – Slightly hydrating or absorbing
  • Acrylic – Slightly absorbing
  • Alginate – Moderately absorbing (also good for long term applications)
  • Foam – Exchanges moisture
  • Super Absorbent – Highly moisture absorbent and moisture-trapping

E – Edge (of the wound)

Dead spaces such as undermined areas and wound tunneling should be filled with appropriate dressings. Moistened ribbon gauze (or equivalent product) can be used to gently pack the dead spaces leaving the end clearly visible for easy removal (i.e., so it is not forgotten). When properly packed, the wound edges should migrate and contract during healing. Remember, though, to avoid situations in which these moistened gauze strips effectively become wet-to-dry dressings, which can destroy granulation tissue, slow the healing process, and cause significant pain during dressing changes. 

Frequent dressing changes and re-assessments

Wounds are dynamic and ever-changing. In fact, if wound bed preparation has been successful, the wound characteristics will change as it heals (for the better). But not all wound healing is linear. Clinicians should be ready to adapt to new infections, changes in exudate levels, or the need for additional debridement as the wound evolves. For these reasons, frequent dressing changes and wound assessments are critical. Indeed, the principles of wound bed preparation should be continuously applied until the wound is completely healed.

“Wound Bed Preparation 2021” provides relatively little guidance on dressing changes or adhesives. This is odd considering patients with chronic wounds may need to undergo dozens of dressing changes over the course of treatment. The guide does caution against the use of acrylic tapes that can adhere to aggressively. It speaks favorably about silicone adhesive tapes because they are gentle on skin, but these agents adhere very weakly and are relatively expensive.

Medical tape in wound bed preparation

Hy-Tape may be the ideal tape for wound bed preparation when frequent dressing changes are required (e.g., chronic wounds). Hy-Tape is occlusive, waterproof, and washable. Unlike silicone adhesive tapes, Hy-Tape can adhere to wet, oily, or dry skin. The tape conforms to natural curves of the body and irregular wound edges alike. This means Hy-Tape can create a tight seal between dressing and skin, which is important for wound moisture balancing. Perhaps most importantly, Hy-Tape does not adhere aggressively like acrylic tape. Hy-Tape releases gently and cleanly with minimal trauma to the skin. Thus, Hy-Tape can securely hold dressings in place without adding to the discomfort of dressing changes.  Indeed, Hy-Tape may be the ideal medical tape for wound bed preparation.


1. Sibbald RG, Elliott JA, Persaud-Jaimangal R, et al. Wound Bed Preparation 2021. Adv Skin Wound Care. 2021;34(4):183-195. 10.1097/01.ASW.0000733724.87630.d6