In veterinary nursing, caring for a burnt patient is more common than you first might think. You may be required to nurse a patient with wounds that are relatively minor, secondary to thermal, chemical, electrical or even radiation injuries or a patient with life-threatening wounds or inhalation injuries, where the nurse is required to understand the pathophysiology and nursing management of these kinds of patients.

Facts About the Skin

The skin acts as a barrier against infection and protects the body. The skin prevents the loss of body fluids, is a sensory organ, can produce vitamin D from sunlight and also serves as a cosmetic effect to give a body shape. When the skin is burnt these functions are impaired or completely lost.

The severity of the injury depends of many factors, size of wound, depth of wound (Figure 1), position of wound on the body, age of patient, medical history of patient and if any other injuries/ complaints are evident.

Figure 1. Classification of the burn based on the depth.

The Mechanism of the Burn

Thermal

An external heat/cold source is capable of raising/ lowering the temperature of skin and deeper tissues to a level that causes cell death and protein coagulation. The extent of damage depends on the amount of energy transferred from the source.

 Causes: flames, hot liquids, hot objects or gases.

Radiation

This can be from prolonged or acute exposure to the sun's ultraviolet radiation or sources of other radiation. Radiation therapy, as veterinary oncology advances, is more commonly used and we may see more radiation wounds presenting as a problem of wound healing.

Chemical

Chemical burns are from substances with a higher or lower pH than the surrounding tissues:

 Alkali burns are commonly more severe than acid burns. Alkalis have a high pH. Common alkali substances are lye, drain cleaner, metal polishes, oven cleaners, cement, lime, ammonia, paint removers and dishwasher powders.

 Acid burns are caused by chemicals with a low pH. Common acids causing burns can be found in battery acid, toilet cleaner, artificial nail primers, phenols and cresols.

Never attempt to neutralise acids with alkali or vice versa, just use copious amounts of water, wash for at least 30 minutes. There are specific antidotes to some chemicals such as phenols and white phosphorus, but water is the antidote in the vast majority of agents. Dilution is the key.

Electrical Burns

Any electrical current can cause an array of injuries to the body. The burn results from the heat generated by an electrical current. The severity depends on the strength of the current and the duration of contact. The damage occurs between the entrance and exit wounds and follows the path of tissue of least resistance, so therefore the internal injuries can be hugely underestimated. An electrocardiogram (ECG) should always be performed to monitor the heart electrical activity and to look for heart damage.

Burn Pathology

Local

After the injury, capillaries of the damaged tissue become leaky. Plasma is lost, drawing water with it. This continues for between 3 and 36 hours and results in oedema of the tissues involved. The local effect is:

 Increase of capillary permeability causes plasma loss.

 Oedema of the damaged tissues. Local airway swelling may lead to respiratory failure. Chest wall oedema may make ventilation difficult and oedema of the limbs may cause ischaemia leading to limb loss (especially if the burn is circumferential).

Systemic

 Oedema of the tissue is further exacerbated by the development of hypoalbuminaemia, resulting from loss of albumin through 'leaky' vessels.

 Haemodynamic changes include tachycardia, decreased cardiac output and myocardial depression associated with release of inflammatory mediators. Signs include prolonged capillary refill time, pale mucous membranes, low blood pressure (if severe).

 Haematology changes can be present depending on the severity of the injury, due to haemolysis and increased red blood cell fragility.

 Inflammatory mediators (leukotrienes, prostaglandins, oxygen free radicals and histamine), released by damaged tissue.

Following severe burns (>20% total body surface area), an acute severe systemic inflammatory response may develop and lead to cardiovascular collapse and multiorgan failure.

Sepsis

One of the major causes of death in burns patients is sepsis. Sepsis can be secondary to wound, respiratory and catheter-related infection and from translocation of bacteria and endotoxins from the gastrointestinal tract, due to poor tissue perfusion and compromised integrity of the mucosal lining.

Respiratory Inhalation Injury

This causes pulmonary vasoconstriction and pulmonary hypertension, which can severely affect the patient's chances of survival. When heat or chemicals are inhaled they can damage the respiratory epithelium, causing sloughing of the mucosa, decreasing mucociliary clearance and producing cellular casts that can obstruct the airway and promote bacterial growth.

First Aid Treatment at Scene of Incident

After the normal ABC, the most important first aid treatment for the burn victim is to prevent further burning by removing heat/cold source, or turning off the electrical source or removing the chemicals from the skin. This normally involves dousing the area of burn with cool running water. Cold water or ice should not be used as this can further damage the skin and cause the patient to become hypothermic. Washing the wound should continue for at least 10 minutes, 20 minutes for chemical burns. The wound then needs to be covered with a clean dressing or cling film. Avoid the patient getting cold and transfer to a veterinary practice as soon as possible.

Primary Treatment of Patient

On arrival at the practice, the patient should be first triaged. A 'capsule history' should be obtained from the owner to gain important information that could alter the early management of the patient.

When dealing with the patient, the nurse should be brisk, calm and controlled. A clear plan of action should be used, which will allow prioritisation of the patient problems and stabilisation and treatment strategies.

Primary Survey, Major Body Systems Evaluation and Detailed Examination

The mnemonic ABC should be used.

Following the primary survey the major body systems evaluation can be undertaken with a more detailed examination of the patient focusing on the major body systems, documenting the initial appearance and size of all wounds.

Fluid Therapy

The goal in burns victims is to restore and maintain perfusion to the tissues, while remembering to keep oedema to a minimum.

Analgesia

Analgesia is mandatory in all burns victims. Opioids (full or partial agonist) are advisable; non-steroidal anti-inflammatory drugs can be used when the coagulation status has been assured and only if the patient is cardiovascularly stable.

Initial Wound Care

The area of the injury should be liberally clipped as fur can hide extensive wounds and the full damage to the skin may not be evident for a few days. Gloves should be worn at all times during wound care to avoid spread of resistant organisms.

Wounds can be rinsed or soaked in sterile saline, and can then be covered. A topical broad-spectrum antibiotic may be used to prevent wound infections; silver sulfadiazine is the ointment of choice; it is soothing, has no systemic effects and can penetrate necrotic tissues. Prophylactic systemic antibiotics are usually not required.

 Superficial partial-thickness. Due to the depth of burn there is a low risk of infection, unless grossly contaminated. Dirt, broken blisters and dead epidermis can be removed with initial cleaning. Topical antibiotics are not needed. Treatment: clean, remove small blisters; apply grease gauze and soft gauze dressing.

 Deep partial-thickness. There is a higher risk of infection, due to compromised blood flow and dead tissue adhered to the dermis layer. Treatment: after initial cleaning and removal of dirt and loose dead tissue, a topical antibiotic is required to prevent infection. Grafting is often the preferred treatment for long-term function.

 Full-thickness burn. High risk for infection due to the presence of dead tissues and lack of blood flow. Surgical excision and grafting will be needed because of destruction of the entire epidermis and dermis, leaving no residual epidermal cells to repopulate. Treatment: wash the wound, remove loose tissue, use eschar-penetrating topical antibiotic. Early surgical excision and grafting are indicated.

 Eschar is non-viable tissue that has gone hard; this is of no benefit and needs to be debrided back to healthy tissue.

Inhalation Injuries

Smoke inhalation is a major cause of morbidity and mortality in the immediate post-burn period. These, often life-threatening, effects of smoke inhalation must be recognised and aggressively managed. The degree of lung damage is usually not evident for several hours.

Gastrointestinal Injuries--Ingested Chemicals

The ingestion of chemicals causes damage to tissues in the mouth/tongue, throat and the oesophagus. This causes long-term problems not just because the patient is unable to eat/swallow but there may be breathing difficulties due to swelling of the throat, and the patient may develop scarring/ strictures of the oesophagus.

Nutritional Support

Nutritional support is an important component of burn care; a high-calorie, high-fat, high-protein diet should be given.