CARBON MONOXIDE POISONING

Carbon monoxide is a toxic gas. It has no color, no odor, and is nonirritating. Carbon monoxide is easily absorbed through the lungs and competes with oxygen to bind to the hemoglobin on the red blood cell. This subsequently results in a lower amount of oxygen delivered to the tissues, especially the organs requiring the most oxygen such as the brain and the heart. Carbon monoxide has over 200 times more attraction force to bind to hemoglobin than does oxygen.

Carbon monoxide poisoning accounts for nearly 4000 deaths each year in the United States. The exposures may be intentional or accidental, with intentional carbon monoxide poisoning outnumbering accidental by a ratio of nearly 5 to 1.

Carbon monoxide is produced by incomplete combustion of fuels; common sources include furnaces, motor vehicle exhaust fumes, wood stoves, kerosene heaters, and gas heaters. Even cigarette smoking leads to an elevated carbon monoxide level in the bloodstream.

Carbon monoxide poisoning can be cured, but the diagnosis must be thought of first in order to treat it. The signs and symptoms can mimic other disease processes.

The most common symptom from carbon monoxide poisoning is headache. Other symptoms include nausea, weakness, dizziness, difficulty in concentration, chest pain, shortness of breath, and visual problems. Some of the most commonly described physical findings include cherry-red lips, bluish discoloration of the hands and feet (called cyanosis), hemorrhages of the back of the eye (the retina), and obvious mental status changes including confusion, lethargy, and coma.

In order to make the diagnosis of carbon monoxide poisoning, one must first think of it. As mentioned above, the findings can mimic other diseases. A specific blood test called carboxyhemoglobin is measured from a sample of blood obtained from the artery. This will give the concentration of carbon monoxide in the blood. Other laboratory tests can be ordered to assist in confirming the diagnosis, including a computed tomography (CT) scan of the head. Special neuropsychologic testing may also be recommended for diagnosing the neurologic abnormalities resulting from the carbon monoxide poisoning.

The first line of treatment is to remove the patient from the source of carbon monoxide exposure (e.g., automobile exhaust fumes, house fire). Thereafter 100% oxygen is administered immediately to compete for any binding sites on the hemoglobin molecule and to improve the delivery of oxygen to the oxygen-deprived tissues. Oxygen is given until the level of carboxyhemoglobin measured in the blood is zero. Depending on the severity of exposure and the gravity of illness, a mechanical ventilator may be used to deliver oxygen into the system.

Another form of treatment recommended for certain patients is hyperbaric oxygen therapy. Hyperbaric oxygen therapy increases the amount of oxygen dissolved in the blood. There are approximately 350 hyperbaric chambers located across the United States (see below for information about the hyperbaric chamber nearest you). Hyperbaric oxygen chambers are recommended to patients who have carbon monoxide poisoning and have a carboxyhemoglobin concentration greater than 40%, patients in a coma, patients who have any period of unconsciousness, and pregnant women with a carbon monoxide concentration greater than 15%. There are other indications for hyperbaric oxygen therapy, and you should consult your physician if you or anyone you know has carbon monoxide poisoning.

• Avoid enclosed garages with running automobiles in them, and report any potential exposure to carbon monoxide, especially if the above-mentioned symptoms are present.
• Remember, the best treatment is prevention. Avoiding enclosed garages with running automobiles in them, and have fuel-burning heating systems professionally maintained.
• Carbon monoxide detectors are available and are helpful in the home.

• Don't smoke. This only serves to increase the carbon monoxide level in your system and it leads to other medical problems.
• Don't use outdoor gas grills indoors.
• Don't work on an automobile that is running in a closed garage. It only takes 10 minutes before potentially life-threatening concentrations of carbon monoxide build up in your system.

• Whenever you suspect you or anyone has been exposed to carbon monoxide or if you are having symptoms of carbon monoxide poisoning.
• If you have any suicidal thoughts whatsoever.
• If you need advice on hyperbaric oxygen chamber therapy.

_______________________________________________________________________________________________________________________________
Copyright © 2000 Mosby, Inc.
All rights reserved.  No part of this publication may be reproduced or transmitted in any form or for any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher.
_______________________________________________________________________________________________
For Comments/Suggestion send email to: webmaster@apma-nc.com