CVMA-ACMV

Smoke Inhalation Injury

April 22, 2016

Pets can get caught in house fires, and this can produce serious, life threatening injury.  Chemicals released from burning fabrics are just as toxic as the carbon dioxide and monoxide, and together they can produce serious injury. Smoke inhalation is more likely to kill the pet than burns. Release of cyanide from modern fabrics in the form of hydrogen cyanide can complicate the injury.  Physcial and chemical irritation, and thermal injury to the delicate respiratory membranes are also serious. Closed space fires are more dangerous than open smoke, and longer exposure more dangerous than short exposures. As well, the nature of materials can produce more (or less) of the secondary harmful chemicals such as cyanide.

Smoke inhalation will lead to difficulty breathing, blue or greyish gums and tongue, weakness, possible collapse, coughing, nose discharge, and sometimes death.  The low oxygen levels in a fire can lead to pet blindness and brain damage, sometimes with a delay of weeks to onset.  The mechanism of lung injury is still under investigation but is similar in all mammals. Changes in microcirculation—the small blood vessels, lead to a mismatch of ventilation and perfusion (breathing and blood distribution), which adds to the challenge of getting good oxygenation. Activation of the inflammation cascades can lead to considerable edema (tissue fluid) accumulation, and tissue swelling. 

Acute respiratory distress syndrome may result, and even system wide so-called systemic inflammatory response syndrome. These two syndromes are critical complications which indicate the body is overwhelmed, and destabilizing.

Inflamed airways may constrict, and the delicate tiny hairs called cilia that help to move particles back up out of the lungs can be seared off and damaged, leading to pooling of smoke debris, dead cells and mucus in the airways.

If a pet is caught in a house fire, it should be immediately taken to the veterinarian. Hospitalization may be needed for a few days or more.   Special oxygen delivery systems may be needed to assist the pet. Maintenance of good oxygen levels in the bloodstream allows for easier breathing while healing occurs.  Your vet will want to measure lactate levels and metabolic balance and electrolytes, monitor for organ function and infection, and oxygen or carbon dioxide levels in the bloodstream or in expired air. Sometimes a tube needs to be placed in the windpipe, so a machine can help the pet with breathing in severe cases.

Sometimes anti-inflammatory medicine is needed to reduce airway swelling. Concurrent burn injuries can require intensive care. Sometimes the surface of the eye is burned  due to the intense heat and smoke. Pain management is very  important.

Pneumonia, systemic infection or inflammation, respiratory distress, and delayed nervous system damage, even death represent the worst of the side effects. Other pets will respond quickly and suffer no long term damage. Hopefully this is a situation you or your pets will never have to face!

Having a sign on the home telling firefighters how many and what kind of pets are living there can assist them with possible recoveries. Remember do not stay inside the home while a fire is active and spreading since it may trap you inside—get out and let the firefighters assist professionally.