Burns in MWDs are typically caused by structure fires, motor vehicle mufflers, scalding liquids (i.e., boiling water, frying oil, etc.), caustic chemicals or explosions. While uncommon, these injuries can cause not only severe pain and complicated local wounds but also result in serious metabolic abnormalities and systemic infection that can lead to life-threatening compromise.

BURN CLASSIFICATION IN MWDS5-7

Burns affecting dogs are physically similar to those in humans. Carefully clip over burned areas for adequate assessment. Be sure to evaluate the paw pads for burns, evident by depigmentation of pads, pads appearing grossly hyperemic and swollen, loss of hair adjacent to pads, exudation, lameness, and reluctance to walk.

- Superficial (equivalent to first-degree) burns are red and painful, similar to a sunburn, and involve the outer layer of the epidermis.
- Partial thickness (equivalent to second-degree)
  - Superficial partial thickness burns are red or mottled, with epidermal sloughing, fluid leakage, swelling, extreme hypersensitivity (pain), and involve the epidermis and variable amounts of the dermis. Hair should not easily pull out.
  - Deep partial-thickness burns are black or yellow-white and hair follicles are destroyed. The skin surface is dry. These burns are usually less painful as nerve endings are destroyed. If any hair remains, it will pull out easily.
- Full-thickness (equivalent to third-degree) burns are black, dry, and leathery. These burns have destroyed the epidermis and dermis and expose underlying connective tissue, muscle, and bone. Any eschar that forms is painless.

INHALATION INJURY

Burn patients may have significant inhalation injury that occurs primarily in the pharynx and upper trachea. Perform an oral exam to look for evidence of thermal injuries in the mouth that could indicate thermal injuries lower in the airway. Clinical signs of inhalation and pulmonary injuries may not manifest for several hours, and the full extent may not be observed for 24 to 36 hours. Clinical signs of inhalation injury include stertor or stridor, harsh upper airway sounds, coughing, production of dark sputum, tachypnea, and respiratory distress.

Diagnostics include thoracic radiographs, pulse oximetry, and venous or arterial blood gas analysis. Treatment involves oxygen supplementation in addition to nebulization with sterile saline, chest coupage, and analgesic medications. Observe MWDs with inhalation injuries closely for respiratory distress to assess if orotracheal intubation or (uncommonly) tracheostomy or cricothyrotomy is needed.5

Carbon monoxide (CO) is the most frequent cause of immediate death following smoke inhalation in humans. CO displaces oxygen on red blood cells which can lead to significant tissue hypoxia that is most prevalent in high oxygen demand tissues such as the brain and heart. Hemoglobin bound to oxygen and CO appear the same when measured with pulse oximetry, therefore oxygen saturation measurements (SpO2) will be falsely elevated and as such arterial blood gas CO-oximetry (measuring carboxyhemoglobin) should be utilized to confirm CO toxicity. Additionally, the mucous membranes may appear normal, or may appear bright cherry red, masking tissue hypoxia. Early oxygen therapy is the mainstay treatment for CO toxicity.5

THERMAL OCULAR INJURY

If burns have affected the face and/or eyes of the MWD, reference the K9 Ocular Injuries CPG for additional information regarding examination, diagnosis and treatment of ocular injuries.

ESTIMATION OF TOTAL BODY SURFACE AREA BURNED

Determine the severity of the burn once the MWD has been resuscitated and stabilized. General characteristics of the wound that are important to examine include color, texture, presence or absence of pain, moistness, and extent of swelling, if present.

Estimate the percent of total body surface area (TBSA) burned using a modification of the “Rule of Nines” used for humans.6

Add the estimated percent of burn from each of the following body areas to determine TBSA burned (Figure 1).