Carbon Monoxide Poisoning
- Carbon monoxide (CO) is an odorless gas produced via incomplete combustion of carbonaceous fuels.
- CO poisoning occurs when carboxyhemoglobin and CO accumulation leads to impaired physiologic function.
CO poisoning is a leading cause of death by poisoning within the United States.
- >14,000 CO exposures were reported to the American Association of Poison Control Centers in 2015, with ~1/3 of such exposures occurring in children.
- There are >400 deaths per year in the United States.
- Seasonal cold weather and other natural disaster events lead to increases in incidence of exposure.
- Furnaces should receive regular maintenance by skilled technicians.
- Automobiles, gas-powered machinery, and nonelectrical space heaters should only be used with proper ventilation.
- CO detectors should be installed within living spaces.
- On inhalation, some CO binds to hemoglobin to form carboxyhemoglobin.
- Carboxyhemoglobin does not carry oxygen.
- Carboxyhemoglobin produces an allosteric leftward shift of the oxyhemoglobin dissociation curve.
- Carboxyhemoglobin elimination half-life
- ~4 hours in room air
- 1 to 2 hours in 100% oxygen
- 20 minutes in 100% oxygen at 3 atmospheres
- CO interacts with cellular proteins, leading to impaired mitochondrial function.
- CO is a source of oxidative stress and poisoning may begin a cascade of inflammatory vasculitis within the CNS and heart.
- Common sources of CO exposure include the following:
- Automobile or boat exhaust
- Smoke inhalation from house fires
- Oil, gas, or kerosene space heaters or cooking stoves
- Portable electricity generators and construction equipment
- Faulty home furnaces
- The solvent methylene chloride is metabolized to CO by the liver after ingestion, inhalation, or dermal absorption.
- CO is a component of cigarette smoke and environmental air pollution.
- CO is a naturally occurring by-product of the heme biosynthesis pathway.
Commonly Associated Conditions
Victims of house fires may suffer from thermal injury and/or cyanide poisoning.
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