The prognosis for burn victims is largely determined by the total body surface area affected.

Management of burns depends on the depth of injury and the total body surface area (TBSA) affected. Partial thickness burns and those affecting less than 15% of the total body surface area will require support in the form of antibiotic ointment and systemic analgesics.

Burns affecting > 15% or deep thickness burns require more aggressive therapy, utilising both medical and surgical management.

Patients with more than 50% TBSA involved have a guarded prognosis and euthanasia should be considered as a humane alternative.

Burn wounds may take up to several days to “expose themselves” as heat dissipates slowly from the skin.

Eschar will generally form within 7-10 days and should be removed early to aid in establishing a healthy granulation bed and to prevent further wound contamination and infection.

Silver sulfadiazine is the mainstay of topical treatment for burn wounds. Alginate dressings have also been used successfully. They aim to maintain a physiologically moist environment to promote healing and formation of granulation tissue. They can be rinsed away with saline irrigation and do not interfere with healing granulation tissue, which will make dressing changes less painful.

The wound should be managed with gradual debridement and progressive closure. Reconstructive techniques maybe considered once a healthy granulation bed has formed.

For useful information on dressings and further advise on cases visit: http://www.intelligentwoundcare.com

Medical Management

1. Fluid balance & urine output
Fluid therapy is important to maintain metabolic requirements. In many cases, crystalloid supplementation should be sufficient [1-2 mls/kg x percent total body surface area affected – administer half of this volume over first 8 hours, then remaining half over next 16 hours].

Urine output should be monitored with the aim to maintain 1-2mls/kg/hr. Over hydration should be avoided in the early stages of burn injury. Colloids also should be avoided in the first 6 hours to prevent protein loss into the wound and aggravation of oedema. The patient should be monitored for the development of serous nasal discharge, chemosis and rales which might signify pulmonary oedema.

As the wound becomes exudative, cats should be weighed at least twice daily. The volume of infused fluid should equal the fluid output in the form of urine and wound exudates. This total maybe difficult to ascertain clearly however if urine output is maintained then this should be fine.

2. Analgesia & Sedation for dressing changes

Providing sufficient analgesia will require rapid assessment and introduction and is one of the most important patient considerations. Various agents maybe used dependent on the patient’s cardiovascular status and level of discomfort.

Intravenous buprenorphine - 10-20 µg/kg q 6 hours
Sublingual buprenorphine – 10-20 µg/kg q 6 hours
Morphine - 0.1-0.2 mg/kg - every 4-5 hours IV, IM
Metacam (meloxicam) - 0.3 mg/kg single dose injection followed by oral suspension if there is evidence of adequate renal perfusion and patients are normotensive.

For cats that are really painful a ketamine constant rate infusion maybe used. This appears to be tolerated extremely well in human burn victims and would be useful in clinics that do not routinely have morphine (loading dose -0.2 mg/kg IV then 2-5 µg/kg/min).

In order to facilitate daily dressing changes, it is likely (and necessary) that most cats will require repeat sedation. Alfaxalone (IM - at 2 - 3 mg/kg off license) would be useful and maybe topped up IV if required. This avoids repeat propofol administration. Alfaxalone may also be combined with buprenorphine (20 ug/kg).

For feral cats that are cardiovascularly stable then dexmedetomidine and buprenorphine is another option (dexmedetomidine 20 µg/kg and buprenorphine 20 µg/kg) with alfaxalone administered IV if needed.

Midazolam / ketamine is another option but recovery might be prolonged and then if that stops them eating that’s a bad thing.

3. Blood pressure
If possible systolic blood pressure should also be measured. [Doppler technique reference range 120-160 mmHg]. Crystalloid boluses of 10ml/kg may be administered if BP <100 mmHg in an acute situation, or consider introduction of a colloid (bolus or constant rate infusion). Beware of spurious results with blood pressure monitoring and interpret in view of the patient’s clinical presentation and cardiovascular parameters.

4. Heart rate, rhythm, contractility and pulse quality
Hypovolaemic shock may cause a fall in preload. Septic and cardiogenic shock could cause a decrease in cardiac contractility. HR, rhythm and pulse quality should be monitored where possible, but intervention is unlikely to be warranted.

5. Albumin
As the wounds become more exudative, cats will have a high risk of developing hypoalbuminaemia. Ideally the cat’s albumin should be maintained greater than 20 g/l to maintain oncotic pressure. This is achieved through the use of enteral nutrition and intravenous colloids (Hetastarch 3-5 ml/kg administered as a constant rate infusion over 24 hours).

6. Oxygenation & ventilation
Direct injury to the upper respiratory tract can cause laryngeal obstruction. Lower respiratory tract injury from irritant gases and heated particulate matter can result in atelectasis, pulmonary oedema, decreased lung compliance and acute respiratory distress syndrome. Bronchopneumonia typically occurs later in the course of the condition.

For frontline vets, measurement of arterial blood gases is often unavailable and results would be unlikely to alter case management. If there are concerns over a patient’s oxygenating ability, then it would be useful to place these patients in an oxygen tent. (Cat box & glad wrap!). Any further handling and diagnostic investigations should be limited until the cat appears more stable and calm. Thoracic radiographs maybe considered at this stage.

Patients with wheezes on auscultation may benefit from administration of Terbutaline (0.01 mg/kg IV or IM) or inhaled salbutamol/albuterol. Antitussives should be avoided as they will reduce airway clearance and may contribute to the development of bronchopneumonia.

Patients with from laryngeal oedema may require a temporary tracheostomy. Unfortunately these tend to be poorly tolerated in cats and require constant monitoring. The use of glucocorticoids following smoke inhalation in humans was associated with an increased incidence of bacterial pneumonia with and there was no clear clinical benefit to the patient.

Repeat (every 4-6 hours) nebulization with saline and coupage maybe helpful in many cases if the patient will tolerate the procedure.

7. Basic blood work
Basic blood work should be monitored including PCV, albumin, BUN, creatinine, and glucose.  

8. Nutrition
The importance of maintaining adequate nutrition can’t be overemphasized! This will aid in wound healing, faster recovery times, shorter hospitalisation periods and may help prevent the development of complicating factors such as hepatic lipidosis.

Enteral nutrition should be considered in all patients with:

• >10% loss of body weight
• Anorexia (failure to consume resting energy requirement for 3-5 days)
• Underlying disease such as trauma, sepsis, peritonitis, pancreatitis, hepatic lipidosis, severe burns

Resting energy requirements (kcal/day) = > 2 kg = (30 x bodyweight) + 70
                                                          = < 2kg = 70 x bodyweight0.75

Divide this total by the calorific density of the selected diet to give the total daily feed volume.

Assisted feeding is easily accomplished with the use of naso-oesophageal tubes. These maybe placed easily without the use of sedation and are generally well tolerated. If injuries allow, placement of an oesophageal feeding tube is good for longer term enteral feeding.

Mirtazapine maybe used off license as an appetite stimulant (1/4 of a 15mg tablet per cat once every 3 days).

9. Electrolytes
Control serum potassium within 3.5-4.5 mEq/L using intravenous fluid therapy supplementation with potassium chloride or potassium phosphate.

10. Antibiotics
Sepsis is one of the greatest threats to burn patients with extensive body surface area involvement. The best way to prevent local and systemic infection is to protect the wound from environmental challenge and to remove all the necrotic tissue and purulent exudates from the wound surface as aggressively as possible through serial debridement.

Systemic antibiotics are not indicated unless the patient is immunocompromised, has pneumonia, pulmonary injury or sepsis is suspected. If an infection develops it is better to culture and direct appropriate antibiotic therapy, rather than running the risk of creating a resistant bacterial population.

Most invasive burn wound infections are caused by Pseudomonas or other G-ve organisms. Antibiotics such as marbofloxacin   2mg/kg IV, SQ, PO q 24 hours would be useful.

11. Nursing care and patient mobilisation
If the cat is non-ambulatory, rotate the patient from side to side every 4-6 hours. Consider the use of physiotherapy with a passive range of motion exercises.

The cornea is extremely sensitive to heat damage. Corneal ulceration should be assessed using fluorescin stain preparations. If ulcerations are present topical lubricants should be administered every 1-2 hours.

12. Gastrointestinal motility and integrity
GI ulceration may occur due to altered sub mucosal blood flow in the immediate post burn period.  GI motility may be decreased by opiod analgesia. Patient’s defaecation should be monitored. Therapeutic options include:

• Metoclopramide 1-2 mg/kg/day IV CRI
• Ranitidine 0.5-2mg/kg IV BID or TID
• Omeprazole 0.5-1 mg/kg PO SID
• Sucralfate 250-1G TID
• Prevention of bacterial translocation amoxicillin 22mg/kg IV QID

13. Complications

Possible complications include the following:

Hepatic failure – ensure aggressive fluid therapy to maintain hepatic blood flow. Liver enzyme elevations may be apparent in 24 hours of the burn injury. In humans 90% of people who develop jaundice after a burn injury will die. Most likely to occur between days 2-6.

Multiple organ failure syndrome – often involves pulmonary, renal, hepatic, cardiac and coagulation system failure simultaneously. A high incidence of septicaemia occurs terminally in these patients. Most likely to occur between days 2-6.

Disseminated intravascular coagulation

Upper airway oedema, bronchopneumonia

Oliguria