From The Washington Post:

It's a potentially lethal gas, but small amounts of carbon monoxide (CO) may help prevent brain damage after a stroke, Johns Hopkins researchers report.

CO, a colorless, odorless gas that can cause organ damage and death, is found in combustion fumes, such as those made by heating systems, vehicles and gas ranges. In enclosed or semi-enclosed places with poor ventilation, CO can build up and pose a serious threat.

The Hopkins team found that low amounts of inhaled carbon monoxide reduced brain damage by as much as 62.2 percent in mice with strokes induced by briefly blocking an artery to one side of the brain. The researchers believe that CO can protect nerve cells from damage.

After strokes were induced in the mice, they were exposed to either 125 parts per million (ppm), 250 ppm of CO, or air. Each group of mice was tested for post-stroke brain damage and function, mainly by observing their running patterns and reactions to certain stimuli.

Brain damage in the side of the brain where blood supply was cut off was 49.9 percent in mice exposed only to air, 33.9 percent in mice exposed to 125 ppm of CO, and 18.8 percent in mice exposed to 250 ppm of CO. Compared to those exposed only to air, the mice exposed to CO had significantly better neurological function test scores.

The protective effect was evident in mice treated at both one and three hours after stroke. This is an important point, because "many stroke victims will not receive immediate treatment," Dor said.

The researchers said CO's protective effect may be due to:

Its ability to dilate blood vessels, which increases blood flow.Its anti-inflammatory properties, which prevent cell death by inflammation.Its capacity to reduce water in the brain. Excessive water in the brain increases intracranial pressure, which kills brain cells.

The study was published in the Dec. 15 online issue of Neurotoxicity Research.

From MarketWatch:

This year, more than 20,000 people will visit the emergency room due to the No. 1 killer poison in the United States. Carbon monoxide is an odorless and colorless gas which will kill approximately 500 people over the course of the year.

Aurora Health Care and the American College of Hyperbaric Medicine are urging households to guard against CO poisoning this holiday season. The winter months see a drastic increase of CO poisoning cases. The key to not being a victim is being aware of common hazards and installing a CO detector.

"With the onset of cold weather people are turning on furnaces for the first time of the season," explains Dr. Jeffrey Niezgoda, Medical Director of the Centers of Comprehensive Wound Care and Hyperbaric Oxygen Therapy at Aurora St. Luke's Medical Center and President of the American College of Hyperbaric Medicine. "We want to remind people to have their furnaces and chimneys serviced and to replace the batteries in smoke and carbon monoxide detectors. If you do not have a carbon monoxide detector, install one on every level of your home. It may save your life."

Early symptoms of CO poisoning include headache, dizziness, flu-like symptoms, fatigue, impaired judgment or confusion.

"With minor exposures many people will quickly recover after being removed from the poisonous environment," says Niezgoda. "However, some people will show delayed symptoms, so if you have been exposed to carbon monoxide, you should go to the emergency room."

"In cases of severe carbon monoxide poisoning, hyperbaric oxygen therapy can be beneficial," says Niezgoda. "Treating a patient with hyperbaric oxygen allows for rapid removal of carbon monoxide and can prevent cellular damage, especially in the brain and heart."

Prevention, and the use of a CO detector, are big keys in preventing CO poisoning, according to the American College of Hyperbaric Medicine. Be sure your furnace and other appliances, such as gas ovens, ranges and cook tops are inspected for ventilation. Do not cook with a propane grill inside your garage. Have gas fireplaces inspected each fall to ensure the pilot light burns safely. Your home heating system, chimney and flue must be cleared of nests, leaves and residue, and should be inspected and cleaned by a qualified technician, annually. Do not operate gasoline-powered engines in confined areas such as garages or basements. Do not leave your car, mower or other vehicle running in an attached garage, even with the door open. Do not block or seal shut exhaust flues or ducts for appliances such as water heaters, ranges and clothes dryers.