Topical antimicrobial dressings for locally infected leg ulcers: late-stage assessment

  • Health technology evaluation
  • HTE27
  • Published: 

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2 The technology

2.1

Topical antimicrobial dressings are dressings that aim to decrease the microbial burden of the wound. How they work varies, with some dressings designed to release the antimicrobial agent into the wound to kill or inhibit the growth of microorganisms. Other antimicrobial dressings have no active pharmaceutical component and aim to physically remove microorganisms from the wound. Antimicrobial dressings are one of the options available to healthcare professionals when treating locally infected leg ulcers. There are various types of wound care dressings, with different intended clinical benefits. These are shown in table 1.

Table 1 Types of dressings and their uses
Dressing types Uses

Alginate, gelling fibre and absorbent fibre

Exuding wounds, to act as an absorbent while maintaining a moist environment (alginates and gelling fibres can also be used to aid debridement of devitalised tissue)

Foams and absorbent pads

Low to high exuding wounds

Wound contact layers, for example gauze

Superficial or partial thickness wounds

Ointments, hydrogels, gels or pastes containing the antimicrobial agent, or ribbons made from one of the materials from another dressing type

Deeper wounds and wounds that need debridement of thick slough

Hydrocolloid

Aiding debridement of devitalised tissue

2.2

As well as different types of dressing, there are different antimicrobial agents used in dressings. These are the focus of this assessment. Chemically or pharmacologically active antimicrobial agents include:

  • silver

  • chitosan

  • honey

  • iodine

  • copper

  • chlorhexidine

  • enzyme alginogel

  • octenidine and

  • polyhexamethylene biguanide (PHMB).

Nonactive agents with a physical mode of action include dialkylcarbamoyl chloride (DACC).

2.3

Some agents are available in different forms (described as subagents). For example:

  • honey:

    • Manuka

    • monofloral

    • polyfloral

  • iodine:

    • cadexomer iodine

    • povidone iodine

  • silver, the subagents of which can be categorised into 3 groups based on the International Wound Infection Institute consensus update (2022):

    • silver salts and compounds:

      • ionic silver

      • silver sulphate

      • silver sulphadiazine

      • silver oxysalts

      • ionic silver complex

    • elemental silver:

      • metallic or elemental silver and

      • nanoparticulate silver and

    • ionic silver with antibiofilm agents

  • copper: cupric oxide.

2.4

There are many antimicrobial dressings available to the NHS. For this assessment NICE considered antimicrobial dressings listed on the NHS Drug Tariff Part IX.