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Materials and Concepts for Bandage Application

Bandages are frequently applied in equine veterinary medicine and are useful for a variety of purposes. Most commonly, bandages are applied to protect and manage the environment of a wound or surgical site while healing commences. At other times they are applied to help control/prevent edema, to provide compression and physical support to injured tissues, or to reduce the motion of a limb or region. A thorough discussion of the indications for and benefits of a bandage are well discussed elsewhere (see Suggested Reading at the end of this chapter) and are beyond the scope of this book. Suffice it to say that a properly applied bandage is generally beneficial to wound healing and greatly aids in the management of numerous equine disorders, but an inappropriately applied bandage may do far more harm than the issue for which that bandage was applied.

Bandage Layers

A bandage is composed of primary, secondary, and tertiary layers. Each of these layers serves a specific purpose and may be composed of a single kind or multiple types of material. In some instances a single material may serve the purpose of more than one layer. It is up to each clinician to evaluate the patient and the reasons for bandage application in order to determine which materials to use. In most cases a standard list of materials will be used, but in certain circumstances a material may be omitted, substituted, or added for a specific purpose. Additionally, the "standard bandage" will vary by where the veterinary practice is located, by practice type, client expectations, clinician preferences, and even by tradition. The bandage techniques shown in this book will represent one version of the "standard bandage" that can be broadly adopted regardless of these variables.

Primary Layer

The primary layer of a bandage is otherwise known as the contact layer or the wound dressing. The material applied in this layer directly interacts with the skin or wound below it. It may be used to deliver a medication, absorb exudate, debride tissue, or provide a sealed barrier. The most common material used as a primary layer in equine bandages is a telfa pad, which is classified as a non-adherent, non-occlusive, mildly absorptive wound dressing (Figure 1.1). Table 1.1 lists some commonly used dressings and their classifications. The effect of these dressings is more appropriate in a discussion of wound management and will not be further covered here.

Secondary Layer

The secondary layer is typically composed of a soft, conformable, compressible, and absorptive material (Figure 1.2). In wound management, this layer acts to absorb moisture (sweat) and wound exudate and creates a continuous barrier between the underlying tissue and the external environment while also holding any wound dressings in place. The secondary layer also reduces the contours of the limb, making it more cylindrical, and acts as a cushion to the limb due to its compressible nature. Both of these properties protect the underlying limb from external forces that may be applied to it. Most importantly, this layer protects and effectively distributes the forces applied to the limb by the tensioned materials of the tertiary bandage layer.

Figure 1.1 A telfa pad is a wound dressing commonly used as a primary layer of a bandage. It should be large enough to cover the wound and may either be (a) held in place with the bandager's hand while the secondary bandage layer is applied or (b) secured to the limb using inelastic woven gauze applied with no tension.

Table 1.1 Commonly used wound dressings and their classification.

Figure 1.2 Any soft, conformable, and compressible material can be used as a secondary layer of bandage. (a) Disposable materials such as loose roll cotton or CombiRoll® are convenient and commonly used when dealing with wounds that can thoroughly soil a bandage. (b) Reusable materials such as the bandage quilts shown or even soft towels can be used to reduce costs, but may be difficult to clean or become damaged before the cost is recouped.

Table 1.2 Commonly used materials for the secondary layer bandage.

Conveniently, in equine practice a disposable cotton roll is commonly used. Other disposable items such as rolled gauze or cotton cast padding may be used if absorption is of little importance or if little to no tension will be applied to the tertiary layers. Non-disposable items such as quilt wraps or even towels and cut blankets may be substituted in an emergency (Table 1.2).

Tertiary Layer

The tertiary layer of a bandage is typically composed of one or two different types of materials and has a primary purpose of providing compression (Figure 1.3). The first material applied after the secondary layer should be an inelastic, woven gauze. This inner tertiary layer provides most of the compression of the underlying bandage materials, holding the bandage together and helping to stiffen it. The second outer material is typically an extensible material that, when tension is applied to it, further compresses the underlying bandage materials and stiffens the bandage. The outer tertiary bandage material should be sturdier than the materials in the underlying layers and frequently has water-resistant properties. Both of these characteristics add an environmental protection component to the purposes of this bandage layer. Most frequently elastic, cohesive bandage materials are used as the outer tertiary bandage layer (Figure 1.4).

On occasion, a clinician may choose to omit either the inner gauze material or the outer cohesive material of the tertiary layer. This is often done as a cost-saving measure. However, in doing so the clinician must be aware of the trade-offs and decide if it is worth the risk. These trade-offs include reduced compression of the bandage material, a less stiff/sturdy bandage, reduced support to the underlying anatomy, and (in the case of omitting cohesive material) reduced environmental protection. Table 1.3 contains a partial list of the available materials used for the tertiary layer. Elastic non-cohesive bandage materials, such as an ACET bandage or a "polo" wrap, can be used with or without brown gauze as the tertiary bandage layer. Because they are reusable they can provide a measure of cost saving, especially in cases where bandages are required for many days or weeks. However, these materials do not provide the same measure of bandage stiffness/sturdiness and environmental protection as a cohesive bandage material.

Figure 1.3 The tertiary layer of a bandage may be composed of either one or multiple different materials used in various combinations to add compression and stiffness to the bandage. (a) A standard bandage is shown using...