Introduction

Preparing the wound bed to encourage and promote healing is a well-established concept. Wound healing is a complex process that progresses through several phases, including coagulation and hemostasis, inflammation, cell proliferation and repair, and epithelialization and remodeling of scar tissue.¹ In many instances, a non-healing wound can become stalled in one of the phases and fail to progress through the healing process. It is estimated that between 4% and 5% of the adult population will have a non-healing wound at some point.²

Importance of Wound Bed Preparation

Advanced wound therapies, such as the use of growth factors, bioengineered tissue, and negative pressure wound therapy, are designed to aid non-healing wounds and significantly improve patient outcomes. However, wound bed preparation is an essential element for obtaining maximal benefits from advanced wound care products. If the wound was not “prepared” properly first, it follows that whatever new technology is applied to the wound will not work.³

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Despite the introduction of advanced therapies, fewer than half of wounds heal after 12 weeks of treatment. Wound bed preparation can consist of debridement, proper moisture balance, reduction bioburden and inflammation, offloading for ulcers, and compression for venous leg ulcers. However, determining when a wound bed has been adequately prepared can be difficult.⁴ Many clinicians rely on clinical signs and symptoms to diagnose inflammation and excess bacterial levels in non-healing wounds. However, these determinations can be unreliable. Clinical tests, such as excessive inflammatory protease activity (EPA) and bacterial protease activity (BPA), can be used to enhance the reliability of diagnoses. The use of advanced therapies or products such as cellular and/or tissue-based materials should be initiated only when BPA is negative and EPA is low.⁴ Additionally, dressings and other additional advanced therapies are unable to provide their full benefit unless the fundamentals of wound bed preparation are in place.⁵ During wound healing, rapid re-epithelialization is the goal. Aggressive and proactive wound bed preparation can enhance the ability of these treatments to succeed in achieving wound closure.⁶ There are also data to support contraindications when advanced therapies are applied to wound beds that are not properly prepared. Negative pressure wound therapy is contraindicated over blood vessels and exposed nerves. Debridement is required before using this therapy over necrotic areas.⁷ In addition, the threshold between microbial colonization and clinically relevant infection can have a deleterious effect on healing of various wounds as well as skin grafts.⁸

TIMERS Framework

The TIMERS framework was developed to identify and address underlying pathophysiological characteristics of the wound and optimize conditions for healing. The components in the TIMERS framework are as follows:

• Tissue management: Tissue management is concerned with the identification of viable and non-viable tissue. Once identified, necrotic or compromised tissue should be removed to ensure a viable wound base. Debridement is generally necessary only once for acute wounds, although this treatment modality may be repeated several times with chronic wounds.⁴
• Inflammation and infection: Infection and inflammation are the most common reasons for a wound’s failure to progress through the phases of healing. Controlling the bioburden, or the presence and concentration of bacterial and fungal organisms, can optimize the wound bed conditions.⁴
• Moisture balance: A moist healing environment accelerates re-epithelialization and promotes conditions conducive to healing. The right amount of fluid stimulates the in vitro proliferation of fibroblasts, keratinocytes, and endothelial cells. These benefits do not occur when a wound is dry. Conversely, excessive moisture contributes to maceration of the wound. Too much exudate can also block cellular proliferation and angiogenesis.⁴
• Edge (epithelial) advancement: Chronic wounds frequently do not progress sequentially through the phases of healing. Assessing a wound’s tendency to advance can alter treatment methods.2 Any treatment selected should work to promote epithelialization and achieve a healthy periwound area.³
• Regeneration and repair: Looking at regeneration and repair provides a matrix to support cell infiltration. These factors can help determine treatment modalities that stimulate cell activity, such as those that use signal molecules or growth factors, the delivery of oxygen therapy, application of negative pressure wound therapy, or the use of stem cells.⁹
• Social factors: Assessment of pertinent social factors takes a holistic approach to assess and treat wounds and lends importance to patient engagement. Social factors can also impact the wound’s ability to heal. Clinicians can work with patients to encourage healthy social habits that support healing.¹⁰

Conclusion

Chronic, complex, and non-healing wounds continue to be tremendous health care challenges. Advanced treatment modalities provide many new ways to address factors that impair healing. However, proper wound bed preparation remains crucial in ensuring the success of any treatment plan.

References

1. HSE National Wound Management Guidelines. The Office of Nursing and Midwifery Services, Clinical Strategy and Programmes Division. 2018.
2. Guest JF, Ayoub N, McIlwraith T, et al. Health economic burden that different wound types impose on the UK’s National Health Service. Int Wound J. 2017;14(2):322-330.
3. Ousey K, Gilchrist B, Jaimes H. Understanding clinical practice challenges: a survey performed with wound care clinicians to explore wound assessment frameworks. Wounds Int. 2018;9(4):10-15.
4. Armstrong DG, Bauer K, Bohn G, et al. Principles of best diagnostic practice in tissue repair and wound healing: an expert consensus. Diagnostics. 2021;11(50): 1-7.
5. Kramer A, Stryja J, Haeni T, Mohamed L. Remove barriers to healing: focus on wound bed preparation. Wounds Int. 2018;9(1):44-47.
6. Everts PAM, Warbout M, de Veth D, Cirkel M, Spruijt NE, Buth J. User of epidermal skin grafts in chronic wounds: a case series. Int Wound J. 2017;14:1213-1218.
7. de Jesus L, Martins AB, Oliveira PB, Gomes F, Leve T, Dekermacher S. Negative pressure wound therapy in pediatric surgery: how and when to use. J Pediatr Surg. 2018;53:585-591.
8. Kim HS, Sun X, Lee, J, Kim H, Fu X, Leong KW. Advanced drug delivery systems and artificial skin grafts for skin wound healing. Adv Drug Deliv Rev. 2019;146:209-239.http://leonglab.bme.columbia.edu/publications/pdf/2019_HSK_ADDR.pdf. Accessed June 10, 2021.
9. Stevenson P, Schultz G. 2019 international consensus includes biofilm treatment as new standard of care. Wound Manag Prev. 2019;65(7).
10. Sin PJ. Change in chronic wound management, new TIMERS guideline further improves wound care. MIMS Multidisciplinary. 2019. https://specialty.mims.com/topic/change-in-chronic-wound-management--ne…. Accessed March 23, 2020.