Clinical PRACTICE DEVELOPMENT Wound bed preparation: TIME in practice Wound bed preparation is now a well established concept and the TIME framework has been developed as a practical tool to assist practitioners when assessing and managing patients with wounds. It is important, however, to remember to assess the whole patient; the wound bed preparation ‘care cycle’ promotes the treatment of the ‘whole’ patient and not just the ‘hole’ in the patient. This paper discusses the implementation of the wound bed preparation care cycle and the TIME framework, with a detailed focus on Tissue, Infection, Moisture and wound Edge (TIME). Caroline Dowsett, Heather Newton dependent on one another. Acute et al, 2003). Wound bed preparation wounds usually follow a well-defined as a concept allows the clinician to KEY WORDS process described as: focus systematically on all of the critical Wound bed preparation 8Coagulation components of a non-healing wound to Tissue 8Inflammation identify the cause of the problem, and Infection 8Cell proliferation and repair of implement a care programme so as to Moisture the matrix achieve a stable wound that has healthy 8Epithelialisation and remodelling of granulation tissue and a well vascularised Edge scar tissue. wound bed. In the past this model of healing has The TIME framework been applied to chronic wounds, but To assist with implementing the he concept of wound bed it is now known that chronic wound concept of wound bed preparation, the preparation has gained healing is different from acute wound TIME acronym was developed in 2002 T international recognition healing. Chronic wounds become ‘stuck’ by a group of wound care experts, as a framework that can provide in the inflammatory and proliferative as a practical guide for use when a structured approach to wound stages of healing (Ennis and Menses, managing patients with wounds (Schultz management. By definition wound 2000) which delays closure. The et al, 2003). The TIME table (Table 1) bed preparation is ‘the management epidermis fails to migrate at the wound summarises the four main components of a wound in order to accelerate margins, which interferes with normal of wound bed preparation: endogenous healing or to facilitate cellular migration over the wound bed 8Tissue management the effectiveness of other therapeutic (Schultz et al, 2003). 8Control of infection and measures’ (Falanga, 2000; Schultz et inflammation al, 2003). The concept focuses the In chronic wounds there appears 8Moisture imbalance clinician on optimising conditions at to be an over production of matrix 8Advancement of the epithelial edge the wound bed so as to encourage molecules resulting from underlying of the wound. normal endogenous healing. It is an cellular dysfunction and disregulation approach that should be considered for (Falanga, 2000). Fibrinogen and fibrin The TIME framework is a useful all wounds that are not progressing to are also common in chronic wounds practical tool based on identifying the normal wound healing. and it is thought that these and other barriers to healing and implementing a macromolecules scavenge growth plan of care to remove these barriers Wound healing is a complex series factors and other molecules involved and promote wound healing. of events that are interlinked and in promoting wound repair (Falanga, 2000). Chronic wound fluid is also It is important to understand wound Caroline Dowsett is Nurse Consultant in Tissue Viability, biochemically distinct from acute wound bed preparation and TIME within the Newham Primary Care Trust, London, and Heather Newton fluid; it slows down, and can block the context of total patient care. If a wound is Nurse Consultant in Tissue Viability, Royal Cornwall proliferation of cells, which are essential fails to heal there is often a complex Hospital Trust, Cornwall for the wound healing process (Schultz mix of local and host factors which 58 Wounds UK 58–70TIME.indd 2 20/10/05 8:35:35 pm Clinical PRACTICE DEVELOPMENT Table 1 TIME – Principles of wound bed preparation Clinical observations Proposed pathophysiology WBP clinical actions Effect of WBP actions Clinical outcome Tissue non-viable or deficient Defective matrix and cell Debridement (episodic or Restoration of wound base Viable wound base debris impair healing continuous): and functional extracellular 8Autolytic, sharp surgical, matrix proteins enzymatic, mechanical or biological 8Biological agents Infection or Inflammation High bacterial counts or Remove infected foci Low bacterial counts or Bacterial balance and prolonged inflammation Topical/systemic: controlled inflammation: reduced inflammation Inflammatory cytokines 8Antimicrobials Inflammatory cytokines Protease activity 8Anti-inflammatories Protease activity Growth factor activity 8Protease inhibition Growth factor activity Moisture imbalance Desiccation slows epithelial Apply moisture-balancing Restored epithelial cell Moisture balance cell migration dressings migration, desiccation avoided Excessive fluid causes Compression, negative Oedema, excessive fluid maceration of wound margin pressure or other methods controlled, maceration of removing fluid avoided Edge of wound — Non-migrating keratinocytes Re-assess cause or consider Migrating keratinocytes Advancing edge of wound non-advancing or Non-responsive wound cells corrective therapies: and responsive wound cells. undermining and abnormalities in extra- 8Debridement Restoration of appropriate cellular matrix or abnormal 8Skin grafts protease profile protease activity 8Biological agents 8Adjunctive therapies will need to be assessed and treated. treatments. Assessment and treatment The TIME table has been designed A full and detailed patient assessment of the underlying condition is essential to help the clinician make a systematic will highlight the underlying aetiology as the type of wound bed preparation interpretation of the observable of the wound and other factors that implemented may vary with wound characteristics of a wound and to may impede wound healing such as type. For example, sharp debridement decide on the most appropriate pain and poor nutrition (Dealey, 2000). is common in the management of intervention: With this in mind the wound bed patients with diabetic foot ulceration, preparation ‘care cycle’ was developed while compression therapy is the T — for tissue: non-viable or deficient in 2004 (Dowsett, 2004) to provide recommended treatment for patients I — for infection/inflammation a care programme that includes the with venous leg ulcers (European M — for moisture imbalance TIME framework. It focuses both on Wound Management Association, E — for edge, which is not advancing the patient and on the wound in an 2004). The cycle moves from patient or undermining. attempt to address all factors that assessment and diagnosis to assessing influence wound healing. and treating the wound using the T — Tissue TIME framework. The importance The specific characteristics of the Wound bed preparation care cycle of assessment in terms of evaluating tissue within a wound bed play a very The care cycle (Figure 1) starts with the effectiveness of the treatment is important role in the wound healing the patient and their environment of highlighted in the cycle. Those patients continuum. Accurate description of this care. Individual patient concerns need who have healed come out of the cycle tissue is an important feature of wound to be addressed as well as quality of life into a ‘prevention programme’ and assessment. Where tissue is non-viable issues in order to achieve a successful patients who have not progressed to or deficient, wound healing is delayed. care programme. Patients need to healing or who have palliative wounds It also provides a focus for infection, understand the underlying cause of remain in the cycle and are reassessed, prolongs the inflammatory response, their wound and the rationale for using TIME. mechanically obstructs contraction 60 Wounds UK Wounds UK 65 58–70TIME.indd 4 17/10/05 10:59:53 pm Clinical PRACTICE DEVELOPMENT Wound bed preparation - TIME in contex be realised. In the majority of clinical cases there is a need to remove the Start with devitalised tissue through a process of the patient debridement, however, it is important No to assess the blood flow to the affected area first, particularly if the wound is on the lower leg or foot. In cases where Identifying the limb requires revascularisation, it Prevention Yes Healed wound may not be appropriate to undertake Wound bed aetiology tissue debridement until the viability of preparation the limb is determined. Care cycle Debridement Debridement is the process of removing devitalised tissue and/or Treat & evaluate Perform TIME foreign material from a wound and TIME assessment it may occur naturally. However, in interventions Agree goals some cases the patient may have an underlying pathology which affects the ability of the body to naturally debride the wound. In a chronic wound, debridement is often required more Figure 1. The wound bed preparation care cycle. than once as the healing process can stop or slow down allowing further dark grey appearance and, when devitalised tissue to develop. Where dried out, is tough and leathery to debridement is an option for clinicians touch. Wound eschar is full thickness, the following methods may be used: dry, devitalised tissue that has arisen 8Surgical through prolonged local ischaemia 8Sharp (Gray et al, 2005). It is derived from 8Autolytic granulation tissue after the death of 8Enzymatic fibroblasts and endothelial cells and