The study is published in the December issue of the U.S. based and peer-reviewed journal Annals of Emergency Medicine. The researchers, led by Dr. Josh Rucker, a Toronto General Hospital research fellow and resident in the Anesthesiology training program at the University of Toronto, studied 14 subjects who were exposed to low levels of carbon monoxide (resulting in blood levels about equal to those in heavy smokers) on two occasions in order to simulate conditions during carbon monoxide poisoning.

After each exposure, which lasted one hour, the participants were given one of two "test treatments": the standard treatment of 100% oxygen, or the new method consisting of a mixture of mostly oxygen and some carbon dioxide. Each participant received both test treatments in random order. Researchers then monitored the amount of oxygen in the blood and the blood flow to the brain during exposure to carbon monoxide and during the test treatments.

KEY RESULTS

• During the standard treatment with 100% oxygen, the flow of blood to the brain diminished, decreasing oxygen delivery to the brain. Results showed that the blood flow decreased by up to 33% and the oxygen delivered to the brain decreased by up to 20%.
• Such a decrease in blood flow to the brain is sufficient to contribute to brain damage in a patient with severe carbon monoxide poisoning.
• However, during treatment with the combination of oxygen and carbon dioxide, two effects were observed:
• The delivery of oxygen to the brain was greater than during treatment with oxygen alone;
• The rate of elimination of carbon monoxide increased by more than 20%.

"These results are intrig
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Contact: Marlene de Chellis
416-340-4636
University of Toronto
3-Dec-2002