Richard A. Read, BVSc(Hons), PhD, FACVSc
Professor, Small Animal Surgery, Murdoch University, Murdoch, Western Australia, Australia
Clinical experience tells us that the potential for wounds to heal well is enormous. Our knowledge of wound healing should help us to appreciate the various roles of the four processes involved in wound healing:
The relative importance of epithelialisation and wound contraction varies with each particular wound, and in particular with the type of wound closure technique that we choose for a particular case. Emergency management of wounds is not fundamentally different from general wound management--it is the timing of decision making and the decisions about ordering the steps of the treatment that are important in the management of emergency wounds.
In emergency medicine, patients will present with very different types of wounds. For example:
Acute fresh wounds due to laceration injuries in which hemorrhage may be the major issue
Acute fresh degloving injuries due to motor vehicle trauma where open joints, desiccation of deeper structures and pain are the major issues
Dog bite injuries where deep necrosis and sepsis are the major issues
Grossly infected wounds in animals that have been injured and have gone missing for days, where the main issues are often sepsis and its systemic effects
The first steps in wound management will vary with each of these situations. There are some situations where the wound itself is life-threatening (e.g., wounds that penetrate the thorax or trachea), but in most situations the wound can be temporarily managed while other life-threatening issues are addressed.
Decisions in Managing Emergency Wounds
1. What are the life-threatening issues for this patient?
2. Will this wound be managed initially by temporary measures followed by definitive treatment, or is immediate definitive treatment indicated?
3. What major impediments to wound healing are present in this wound?
4. Is there likely to be sufficient local skin available for closure?
Haemodynamic stability--is there serious haemorrhage that needs immediate attention, either by pressure bandage or immediate sedation/anaesthesia and surgery?
Is respiratory function compromised (e.g., thoracic/neck wounds)?
Neurological status of the patient (spinal or head trauma)?
SIRS/MODS/Sepsis issues present?
Initial Temporary Treatment vs Definitive Treatment?
How exposed are underlying tissues (desiccation, hypothermia, contamination issues)?
Life-threatening issues take precedence over wound needs (head trauma, respiratory compromise, cardiovascular instability, SIRS/MODS issues)?
Physical location of the wound--how easy is it to temporarily cover this wound?
Impediments to Wound Healing?
Presence of necrotic tissue or foreign material?
Desiccated deeper tissues needing rehydration?
Presence of sepsis?
Lack of blood/nerve supply to wounded region?
Sufficient Local Skin for Closure?
Can the edges of the wound be roughly approximated?
Is all the local skin viable?
Anatomical location and availability of skin for local flaps?
Once these questions have been addressed, the answers need to be communicated with the animal owner and the importance of each of these factors explained in full. Following this, a treatment plan can be established, laying out the priorities and the steps in managing the patient in the order that they will be addressed.
Problems in Wound Management
The most common reasons for failure of a wound to heal are:
Foreign body/material in the wound
Necrotic tissue present in the wound
Failure to create the right local wound environment (choice of dressing material)
Lack of available skin/tension on wound edges.
It is important for the emergency clinician to have this list in mind when making decisions about the emergency treatment of wounds. However, regardless of whether we are dealing with an emergency wound, or a problem wound, the principles of wound treatment/ management remain the same.
1. Remove any barrier to healing
2. Create an environment that supports and encourages wound healing
3. Repair any underlying deficiency (nutrition, vascular or nerve supply)
Steps in Managing Emergency Wounds--Debridement, Cleaning, Covering
Debridement is the removal from the wound of gross contaminating material and tissue which is either necrotic or of questionable viability. More specifically, the aims of debridement are:
Thorough wound exploration--may require substantial but gentle dissection to expose deep lacerations
Remove dead, damaged and contaminated tissue
Remove foreign bodies
Restore structural normality where possible
Provide drainage of dead space
In some emergency situations, wounds will be very fresh and require minimal if any debridement.
Surgical debridement involving surgical excision of unwanted material and tissue is the most commonly used method. In cases where there is abundant loose skin available, this may involve "en bloc" resection including the wound margins and an area around them to create a surgically clean wound. However in many cases, particularly involving the head and limbs, conservation of viable tissue is paramount. Deeper structures need to be conserved where possible, e.g., tendons and nerves. Surgical debridement in many wounds will be achieved in a number of stages, particularly where the viability of certain important structures is questionable.
Bandage/dressing debridement: certain types of wound dressings (e.g., wet-to-dry saline gauze dressings) which adhere to the wound surface can be used to remove necrotic tissue because the adhesion results in the necrotic tissue being removed with the bandage when it is changed. Alternatively, hydrocolloid and hydrogel dressings assist debridement by mixing with wound exudate which can then be washed from the wound.
Cleaning the wound involves decisions on the nature of the cleaning solution and how it is to be delivered to the wound. Antiseptic solutions must be carefully diluted so that the concentration used is not toxic to the remaining tissue fibroblasts that will help initiate healing. There is a strong tendency towards the use of more gentle wound cleaning solutions such as normal saline or Lactated Ringers solution to minimize any damage to remaining host cells. The volume of fluid used is far more important than the type of fluid--in some heavily contaminated wounds, the use of moderate pressure warm tap water is warranted simply due to the large volumes that can be rapidly delivered.
The use of sugar and honey as a topical treatment in the management of wounds has a long history and a resurgence in interest has recently been evident in the veterinary literature. Unpasteurised honey is best as it contains a number of chemically active constituents that can assist wound healing. Both sugar and honey act through a number of mechanisms, including acting as a source of nutrition for local cells, as a medium for cleaning wounds and through local antibacterial effects. Regular sugar is certainly a cheap wound cleaning material and is useful in the emergency treatment of certain wounds.
Covering relates to the type of bandage that will be used to protect the wound during healing. The functions of wound dressings/bandages are:
Maintain wound hydration
Maintain wound temperature
There are now many different types of wound dressing materials marketed in most countries. These various types of dressings all can contribute in many different ways to creating a wound environment that is conducive to normal wound healing. The cost of these dressings varies considerably, and it is not always true that the most expensive dressing is the best dressing for a particular wound. However, if a wound is not healing normally, even in the emergency situation and the ensuing 5 days, it is important that the reason for this poor healing is identified and changes made to the dressing/bandaging regime if indicated.
1. Mathews K & Binnington A. Comp Contin Educ 24: 41-52 and 53-60.