Content Reviewers:Yifan Xiao, MD, Lisa Miklush, PhD, RNC, CNS, Jannah Amiel, MS, BSN, RN, Jodi Berndt, PhD, RN, CCRN-K, PCCN-K, CNE, CHSE, Gabrielle Proper, RN, BScN, MN
Emma Rogers is a 12-year-old African American female brought to the ED by paramedics.
Emma’s mother Faye called emergency services when she went to Emma’s room to wake her up and noticed she was lethargic, confused and unable to stay awake.
The paramedics found Emma in her basement bedroom which was adjacent to a hot water heater.
CO is produced from the burning of fuels that contain carbon, such as charcoal, oil, coal, wood and kerosene.
It is known as the “silent killer” because it’s odorless, tasteless, and colorless.
Some classic scenarios where CO poisoning can occur include: an individual that’s been in a fire and has inhaled smoke; someone in a poorly ventilated area with a running vehicle, fireplace, or faulty gas stove or hot water heater; or if they live in an old building with a defective heating system.
An individual may also be chronically exposed to CO, and that’s common in smokers, automobile workers, and people working in certain industries.
Now, there are some factors that may put an individual at risk for CO poisoning.
Non-modifiable risks include age, in particular young children and the elderly, as well as those with physical or mental disabilities.
These factors can make it harder for the individual to stop or escape from the situation where CO is being produced.
In addition, cigarette smoking and having an underlying lung disorder increases the risk of harm from CO poisoning.
On the other hand, modifiable risk factors include being in a building without functioning CO detectors, or being under the influence of alcohol or drugs.
Now, once CO is inhaled, it makes its way into the bloodstream.
The affinity of hemoglobin for CO is about 240 times more than its affinity for oxygen, so CO will competitively bind to hemoglobin, forming carboxyhemoglobin, or COHb, and the oxygen carrying capacity of blood decreases.
Also, the presence of CO in the blood makes it difficult for oxygen to be released into the tissue.
Ultimately, the combination of decreased oxygen carrying capacity and impaired unloading ultimately leads to tissue hypoxia and injury.
Now, the signs and symptoms associated with CO poisoning can vary and depend on the duration of CO exposure, and the amount of carboxyhemoglobin in the blood.
In acute cases, the most common symptoms include a headache, fatigue and dizziness.
Some clients may also develop abdominal pain, nausea and vomiting.
As poisoning progresses, they can have confusion, and difficulty concentrating.
If the client is found after hours of being exposed to CO, their skin and mucosal surfaces may have a characteristic pink or cherry red discoloration.
They may also have bullae, blisters, and other erythematous spots on skin.
Clients with CO poisoning often develop complications.
Fortunately, most clients who survive CO poisoning don’t develop long term complications.
However, some important ones to keep in mind include delayed neurological sequelae like cognitive deficits, personality changes, movement disorders like tremors or paralysis, and focal neurological deficits like numbness of the fingers and toes.
These deficits can last for a year or longer.
If the client’s history and symptoms suggest CO poisoning then a CO-oximeter should be used to detect the level of carboxyhemoglobin.
Regular pulse oximetry can’t differentiate between oxyhemoglobin and carboxyhemoglobin so the reading will typically be normal.
Next, arterial blood gas analysis typically shows decreased oxygen saturation and elevated carboxyhemoglobin levels, while partial pressure of oxygen remains normal.
Other diagnostic studies used include laboratory tests, such as a complete blood count, which often reveals increased leukocytes and decreased platelets.
A metabolic panel may show decreased electrolytes like sodium and potassium, elevated glucose, and elevated blood urea nitrogen and creatinine.