Top 6 veterinary questions about carbon monoxide poisoning

1. What causes carbon monoxide poisoning in pets?

Carbon monoxide has an affinity more than 200 to 250 times that of oxygen, Dr. Mazzaferro says. So when it is inhaled, it binds tightly to hemoglobin sites that typically attract oxygen. This resulting change of oxyhemoglobin (oxygen-rich hemoglobin) to carboxyhemoglobin (carbon-rich hemoglobin) leads to asphyxiation and possible death.

2. How are pets exposed to high levels of carbon monoxide?

Common ways pets and people are exposed to high levels of carbon monoxide include:

Automobile exhaust in a closed garage

Faulty car/home exhaust system

Non-vented heaters (furnace, gas water, kerosene)

Smoke inhalation (building fires)

Airplane cargo areas

3. How common is carbon monoxide poisoning in pets?

“Carbon monoxide poisoning in pets is not a very common emergency. When we do see it, it's primarily when there has been a house or other structure fire,” Dr. Mazzaferro says. “Clients are often not aware of it unless they themselves are having clinical signs of headache, sleepiness, or are smart enough to have a carbon monoxide detector at home.” To better educate pet owners about the dangers of carbon monoxide poisoning in pets and how they can help prevent it from occurring, download this client handout.

4. What are the signs and symptoms of carbon monoxide poisoning in pets?

Carbon monoxide is a colorless and odorless gas that will go unobserved without carbon monoxide detectors in place. So it's important to pay attention to the clinical signs of carbon monoxide poisoning, which are:

Drowsiness

Lethargy

Depression

Weakness

Incoordination

Difficulty breathing

Bright red color to skin or gums

Coma

Seizures

5. What should you do if you suspect carbon monoxide poisoning in pets?

If you suspect carbon monoxide poisoning, the first thing to do is get the animal(s) away from the source of carbon monoxide into fresh air. Standard methods to determine oxygenation, such as pulse oximetry, are not useful, Dr. Mazzaferro says, as the carboxyhemoglobin and oxyhemoglobin will register the same, falsely elevating the amount of oxygen in the blood. The only way to detect carbon monoxide is to perform an arterial or venous blood gas and use a co-oximeter, she says. This is not standard equipment in most veterinary hospitals, although laboratories at human hospitals often will run the test for you. In the meantime, oxygen supplementation (facemask, hood, nasal prongs/cannula, cage, or endotracheal intubation) will hasten the elimination of carbon monoxide. For the most severe cases, if available, hyperbaric oxygen also can be considered.

6. How can you help prevent carbon monoxide poisoning in pets?

No dwelling-including your veterinary practice-should be without working carbon monoxide detectors at all times. “Often, without the use of a carbon monoxide detector, clients and their pets can go to bed thinking that they just have a headache, and in their sleep, succumb to carbon monoxide toxicity and die,” Dr. Mazzaferro says. With detectors in place, when carbon monoxide levels are elevated, the sensor will emit a sound and alert residents of the danger.