There are many frameworks available to aid a systematic approach to wound assessment (Flanagan [32]), though individually none are considered optimal (Greatrex‐White and Moxey [36]).

The ‘TIME’ (tissue, infection/inflammation, moisture balance and edge of wound) acronym was developed in 2002 by an international group of wound care experts to provide a systematic approach to wound assessment and wound bed preparation (Dowsett and Ayello [26], Leaper et al. [61], Werdin et al. [114]) (Table 18.1).

Wound bed preparation (WBP) is a concept used to guide clinicians to focus on identifying and proactively addressing local barriers to wound healing in order to adequately ‘prepare’ the wound environment for healing (Kamolz and Wild [57]).

Goals of care should be determined early in the assessment process as full healing may not be the intention in fungating wounds or wounds at end of life. The underlying cause of the wound should be assessed, with a focus on details such as location, size and depth (Baranoski and Ayello [8]). The wound should be assessed each time a dressing is applied or if it gives cause for concern. The aim of assessing the wound is to determine the extent of healing and establish which treatment will best provide the ideal environment for healing. Regular wound photography provides a useful cumulative timeline of healing observation, but patient consent should always be gained (Baranoski and Ayello [8]). Figure 18.5 is an example of a wound assessment chart.

The rate of wound healing varies depending on the general health, age and mobility of the individual; the location of the wound; the degree of tissue damage; and the treatment applied. It is necessary when assessing and treating a wound that all potential detrimental factors are addressed and minimized, where possible, in order to provide the optimum systemic, local and external conditions for healing.

Factors that may delay healing include disease, poor nutritional state, infection, body mass (Hess [47]) and medications such as chemotherapeutic drugs and steroids (Guo and DiPietro [38]) (Table 18.2). Lifestyle factors such as smoking, alcohol consumption and stress (Guo and DiPietro [38], McDaniel and Browning [67]) can also affect wound healing. Other influences relate to the local microenvironment of the wound, including temperature, pH, humidity, air gas composition, oxygen tension, blood supply, inflammation and the presence of non‐viable tissue (Hess [47], Storch and Rice [100]). Whether this influence is positive or negative may depend on the stage of wound healing that has been reached. Other important considerations are external variables such as continuing trauma or the presence of foreign bodies.

Improving the blood flow to the wound bed will increase the availability of nutrients, oxygen, active cells and growth factors within the wound environment (Collier [13]). This may be achieved, if appropriate, through consideration of revascularization approaches or advanced therapies (Atkin et al. [6]).

There has been much debate and discussion as to which technique to use when obtaining a wound swab – the Z technique or the Levine technique (Myers [75]). The Z technique involves moving the swab in a zig‐zag pattern across the wound while rotating the probe to achieve 10 points of contact without touching the edges of the wound. In the Levine technique, a swab is rotated over a 1 cm² area for 5 seconds with sufficient pressure to extract fluid (Copeland‐Halperin et al. [17]).

The literature highlights that the Levine technique is more accurate when swabbing wounds than the Z technique because it takes samples from both the surface of the wound and the wound tissue due to the application of pressure to extract fluid (Angel et al. [2]). The Z technique has 63% sensitivity and 53% specificity while the Levine technique has 91% sensitivity and 57% specificity (Bonham [9], Stotts [101]), which suggests that the Levine technique is more reliable in determining the organism in acute and chronic wounds when wound swabs are used to collect sample and cultures than the Z technique (Angel et al. [2]).

The procedure of obtaining a wound swab (see Chapter c13: Diagnostic tests) must always be explained to the patient and they must be informed that there may be some discomfort. The Levine technique involves cleansing the wound with normal saline. This will remove any debris on the wound bed. Avoid using antiseptics or antimicrobial agents prior to swabbing as this may influence the results (Reynolds [91]). Rotate the swab over a 1 cm² area of clean viable tissue with enough pressure to extract fluid from the inner part of the wound (Huang et al. [51], IWII [52]).

Where possible, do not obtain sample from slough, pus or necrotic tissue as this will not provide an accurate profile of the microflora contained within the tissue (Cross [19]). Insert the wound swab into the culture container. Re‐dress the wound after the procedure. Relevant clinical information about the patient and the wound should be provided with the sample, including the wound's aetiology, the anatomical location of the wound, current treatment, and presenting signs and symptoms (Cooper [16]).

Wound exudate usually performs a useful function by aiding autolytic debridement and providing nutrients to the healing wound bed. It is required in the process of epithelialization, to allow the movement of cells across the surface of the wound (Jones [56]). However, in the presence of excess exudate, the process of wound healing can be adversely affected. This is especially so in chronic wounds, where there is increased proteolytic activity, leading to damage in the wound bed. Matrix metalloproteases are found in exudate, and, when present in chronic exudate, their beneficial properties, such as the provision of essential nutrients for cell metabolism, are hindered. This can be a significant factor in delayed healing (Hampton [42]).

The control of oedema or elevating the affected limb (e.g. in a lower leg wound) undoubtedly helps in the reduction of wound exudate. However, if the methods for achieving these goals are unsuccessful or contraindicated then exudate must be managed through the use of wound management products. These include absorbent wound dressings (e.g. alginates, hydrofibre or foams), non‐adherent primary wound contact layers with a secondary absorbent pad, wound manager bags and negative pressure wound therapy (NPWT) (discussed later in this chapter). NPWT is highly effective in controlling excessive exudate (Probst and Huljev [88]). It is also vital to protect the skin surrounding the wound from maceration by excess exudate and excoriation from corrosive exudate. Useful products for skin protection include alcohol‐free skin barrier films and thin hydrocolloid dressings, which can be cut and used to ‘frame’ the wound edges.

Assessing and measuring the advancement of the wound edges towards wound contraction is an important indicator of wound progress (Harries et al. [45]). If wound edges fail to advance, the clinician should conduct a thorough reassessment using the TIME principles and interventions (Table 18.1).

Clinicians must select appropriate dressings based on the tissue types in the wound bed, the treatment aims and the most suitable dressing properties. Based on the wound healing continuum, Figure 18.7 is an example dressing selection guide for wounds healing by secondary intention. It provides guidance on choice of products and their desired properties in relation to the tissue types in the wound bed, treatment aims and moisture levels. Where complete healing is the main aim, the clinician should use products that will create the optimal wound bed environment, ensuring the wound progresses through the wound healing continuum and subsequently completes the four phases of wound healing.

Caution must be exercised when considering hydrating wounds on the foot and/or at the end of life. Specialist referral may be required.

With the exception of wounds where the main aim is to manage and improve symptoms, such as in malignant wounds or wounds at end of life, an ideal wound dressing must be capable of fulfilling the following functions:

Clinicians must be aware of the components of the wound care products used (Table 18.4). Dressings containing ingredients derived from animals, such as collagen and honey, may not be acceptable to patients from some faith, ethnic or ethical groups, such as Hindu, Islam, Sikhism or vegan (Eriksson et al. [30], Sood et al. [98]).

The aim of wound cleansing is to help create the optimum local conditions for wound healing (Lloyd Jones [63]). Wound cleansing takes into consideration the wound bed, wound margins and peri‐wound skin as all are central to successful healing (Kamolz and Wild [57]).

Wound cleansing can be considered ritualistic, non‐evidence‐based and often carried out unnecessarily (Lloyd Jones [63]). There is no robust evidence to suggest that routine cleansing of wounds expedites healing or reduces infection (Fernandez and Griffiths [31]). If a wound appears clean with little exudate, the clinician must consider the benefits and risks of cleansing the wound (McLain and Moore [72]).

When a wound bed is exposed to temperatures below core body temperature (36–38°C) or above 42°C, cellular activity is reduced, resulting in delayed wound healing (McGuiness et al. [69]). It can take 3 hours or longer for the wound to return to normal temperature (McKirdy [71]). Clinicians should consider warming cleansing solutions before use (HSE [50]).