32.6n Carbon Monoxide Inhalation

{{c1::Carbon monoxide}} is an odorless, tasteless, colorless gas produced from the incomplete burning of fossil fuels and other carbon-containing compounds.

Carbon monoxide is the {{c1::number-one}} cause of poisoning in industrialized countries.

Carbon monoxide can be encountered in industrial sites, such as {{c1::mines}} and {{c1::factories}}.

Carbon monoxide is present in the environment in various concentrations primarily because of {{c1::automotive exhaust emissions}}.

Most carbon monoxide poisonings occur from {{c1::automobile emissions}} and {{c1::home heating devices}} used in poorly ventilated areas.

Carbon monoxide is often used in {{c1::suicide attempts}}.

Carbon monoxide is a particular hazard for {{c1::firefighters and rescue personnel}}.

Carbon monoxide exposure is potentially life threatening because it easily binds to the {{c1::hemoglobin}} molecule.

Carbon monoxide has an affinity for hemoglobin {{c1::200 to 250}} times that of oxygen.

Once bound, receptor sites on the hemoglobin can no longer {{c1::transport oxygen to the peripheral tissues}}.

Hemoglobin with carbon monoxide bound is referred to as {{c1::carboxyhemoglobin}}.

The result is {{c1::hypoxia}} at the cellular level and, ultimately, {{c1::metabolic acidosis}}.

Carbon monoxide has been found to bind with other iron-containing proteins such as those found in the {{c1::electron transport chain (cytochrome)}}.

Because of this, some of the features of carbon monoxide poisoning are similar to those seen with {{c1::cyanide poisoning}}.

Carbon monoxide can also affect the iron-containing proteins in the brain ({{c1::neuroglobin}}) as well as those in the heart and skeletal muscle ({{c1::myoglobin}}).

The binding of carbon monoxide to these iron-containing proteins in the brain and heart are thought to be responsible for some of the {{c1::long-term complications}} of carbon monoxide poisoning.

When confronted by a patient suffering possible carbon monoxide poisoning, determine the {{c1::source of exposure}}, {{c1::exposure length}}, and {{c1::the exposure location}}.

Less time is required to develop a significant exposure in {{c1::a closed space}} compared with one in an area that is fairly well ventilated.

Signs and symptoms of carbon monoxide poisoning are {{c1::headache}}, {{c1::nausea and vomiting}}, {{c1::confusion}}, {{c1::agitation}}, {{c1::loss of coordination}}, {{c1::chest pain}}, {{c1::loss of consciousness}}, and {{c1::seizures}}.

On physical examination, the skin could be {{c1::cyanotic}} or it could be {{c1::bright cherry red}} (a very late finding).

There can be other signs of hypoxia, such as {{c1::peripheral cyanosis}} or {{c1::confusion}}.

Carboxyhemoglobin levels can now be measured noninvasively in the prehospital setting through {{c1::CO-oximetry}}.

A {{c1::CO-oximeter}} is similar to a pulse oximeter but uses eight wavelengths of light instead of two.

It can detect {{c1::carboxyhemoglobin}}, {{c1::methemoglobin}}, {{c1::oxyhemoglobin}}, and {{c1::deoxyhemogobin}}.

Carboxyhemoglobin levels (SpCO) are reported as {{c1::percentage of carboxyhemoglobin present}}.

Normally, carboxyhemoglobin levels are {{c1::less than 1 percent}} in nonsmokers and {{c1::3 percent}} in smokers.

SpCO levels {{c1::might not always correlate with symptoms}}.

Symptoms of mild carbon monoxide poisoning (<15-20% CO-Hb) include: {{c1::headache}}, {{c1::nausea}}, {{c1::vomiting}}, {{c1::dizziness}}, and {{c1::blurred vision}}.

Symptoms of moderate carbon monoxide poisioning (21-40% CO-Hb) include {{c1::confusion}}, {{c1::syncope}}, {{c1::chest pain}}, {{c1::dyspnea}}, {{c1::tachycardia}}, {{c1::tachypnea}}, and {{c1::weakness}}.

Symptoms of severe carbon monoxide poisoning (41-60%) include: {{c1::arrhythmias}}, {{c1::hypotension}}, {{c1::cardiac ischemia}}, {{c1::palpitations}}, {{c1::respiratory arrest}}, {{c1::pulmonary edema}}, {{c1::seizures}}, {{c1::coma}}, and {{c1::cardiac arrest}}.

A carbon monoxide poisoning of >60% CO-Hb is {{c1::fatal}}.

Upon detection of carbon monoxide poisoning, first {{c1::ensure the safety of rescue personnel}} and then {{c1::remove the patient from the site of exposure}}.

Ensure and maintain the {{c1::airway}}.

Administer supplemental oxygen at the {{c1::highest possible concentration}}.

If the patient is breathing spontaneously, apply a tight-fitting {{c1::nonrebreather mask}}.

Consider the use of {{c1::CPAP}} for moderate to severe exposures.

If respiratory depression is noted, {{c1::assist respirations}}.

If shock is present, {{c1::treat it}}.

Prompt transport is {{c1::essential}}.

{{c1::Hyperbaric oxygen (HBO) therapy}} can be used in the treatment of severe carbon monoxide poisoning, although the effectiveness of this treatment is questionable.

Many EMS systems have clinical guidelines established whereby patients suffering from carbon monoxide poisoning are transported to hospitals with {{c1::HBO therapy facilities}}.

Hyperbaric oxygen {{c1::increases the PaO2}}, thus promoting increased oxygen uptake and displacement of the carbon monoxide from the hemoglobin.