Lung Damage Due to Smoke Inhalation in Dogs
In smoke inhalation, injury occurs as a result of direct heat damage to the upper airway and lining of the nose. Injury to the tissue is seen after inhalation of carbon monoxide, which decreases tissue oxygen delivery by binding to red blood cells; inhalation of other toxins that directly irritate the airway (e.g., oxidants and aldehydes); and inhalation of particulate matter that adheres to the airways and small air sacs in the lungs.
The extent of damage depends on the degree and duration of exposure to smoke and the material that was burning. Dogs may have serious lung injury with little evidence of burning on their skin. Lung reaction is initially symptomized by constriction of the lungs, airway swelling, and mucus production, followed by an inflammatory response in the trachea and bronchial area, and fluid accumulation in the lungs. Most patients show progression of lung dysfunction in the initial two to three days after exposure. Follow-up bacterial infections are a common cause of death late in the disease due to the wounded tissue being an advantageous receptor for bacteria.
Symptoms and Types
- Smoky odor
- Soot in the nasal or throat passages
- Rapid breathing and increased depth of respiration
- Breathing effort that suggests upper airway obstruction by swelling
- Postural adaptations to respiratory distress (i.e., positioning the body to make breathing easier)
- Mucous membranes may be cherry red, pale, or cyanotic (blue)
- Reddened eyes
- Hoarse cough
- Confusion, fainting
- Vomiting
- Shock
Causes
Exposure to smoke/carbon monoxide, usually the result of being trapped in a burning building.
Diagnosis
You will need to give a thorough history of your dog’s health, onset of symptoms, and possible incidents that might have preceded this condition, such as exposure to burning material. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. The blood count will show the level of red blood cells that are capable of carrying oxygen, and white cells that are capable of fighting infection. The blood profile will also show whether the arterial blood gases are at normal levels and will show the degree of oxygen shortage in the blood. The urinalysis will show how the kidney is functioning. Visual diagnostics, such as X-ray and ultrasound, may also be used to determine if there is fluid buildup in the lungs. A bronchoscopy, which uses a flexible tube with a camera attached and which can be inserted into the airway, may allow your doctor to determine the severity of airway damage.
Samples will be taken of the cells inside the mouth and in the airways and cultured to determine whether there are bacteria present. If there is tissue damage to the airways, your veterinarian may prescribe a prophylactic antibiotic to prevent infection.
Treatment
At the outset, stabilization of the respiratory function and establishment of an effective airway will be the most important. Severe upper airway swelling or obstruction may require intubation or an operation to make an opening in the trachea.
Oxygen should be administered immediately after rescue from the fire to displace carbon monoxide from hemoglobin (the oxygen carrying pigment of the blood). It will be delivered by mask, hood, oxygen cage, or nasal line. After elimination of carbon monoxide, oxygen supplementation will be continued at 40 to 60 percent as needed. Fluid administration may be required in patients with shock to support cardiovascular function but should be conservative, if possible, to minimize a buildup of fluid in the chest. Blood or plasma transfusions may be necessary to add fresh red and white blood cells to the blood stream. Nutritional support may be needed to maintain body condition and immune status.
Living and Managment
Your veterinarian will want to carefully monitor your dog’s respiratory rate and effort, mucous membrane color, heart rate and pulse quality, the sound of the lungs, packed cell volume of the blood and total solids for 24 to 72 hours. X-rays will be repeated 48 hours after the initial treatment to ensure that the condition is resolving, and your doctor will also want to monitor your dog’s system for bacterial pneumonia, which is often a side-effect of damage to the lung tissue. Most patients will have some level of deterioration during the initial 24 to 48 hours after smoke exposure and then gradually improve, unless they develop bacterial pneumonia or acute respiratory response syndrome. Severe burns or organ injury are associated with a poor prognosis.