Carbon Monoxide May Help Bypass Surgery Patients

FRIDAY May 23, 2008 -- Low doses of carbon monoxide (CO) -- the potentially lethal gas in car exhaust fumes -- may help protect the lungs of patients undergoing cardiopulmonary bypass (CPB) surgery, German researchers say.

The team gave low doses of CO to pigs that underwent beating-heart CPB.

"Our findings support that inhaled CO provides anti-inflammatory effects in the lungs and decreases the instance of cell death during CPB," study author Dr. Torsten Loop, of the anesthesiology department at the University Medical Centre Freiburg, said in a prepared statement.

"Additionally, and of greater importance, these effects occurred when CO was administered as a pre-treatment -- with the advantage of short exposure time, which limits how avidly CO can bind to hemoglobin," Loop said.

This is important, because the poisonous effects of CO occur when it's allowed to freely bind to hemoglobin within red blood cells.

The study was published in the May issue of Anesthesiology.

"Cardiac surgery is one of the most extreme situations a patient can face," Loop noted. "Although a heart-lung machine ensures that organs are supplied with blood, and therefore oxygen, the nature of heart surgery means that normal operation of the lungs is impaired -- potentially resulting in lung injury."

Only about 2 percent of cardiac surgery patients suffer life-threatening lung injuries, but death rates for these patients can exceed 60 percent. This finding suggests CO could prove useful in reducing lung inflammation and cell death during CPB.

"A fascinating aspect of this study is that pre-treatment with CO before CPB was effective in protecting the lungs. These findings may support evidence that CO can trigger the body into a state that helps to protect it against the sometimes damaging effects of CPB," Dr. John G. Laffey, of the Clinical Sciences Institute at the National University of Ireland, wrote in an accompanying editorial.

The study results lend support to the feasibility of conducting human studies to examine the potential protective effects of CO on a number of organs.

"The demonstration that CO may reduce pulmonary inflammation and injury following CPB is an important and novel finding. Relative ease of administration, probable safety when given at low doses for short periods, and likely protective effects for multiple organs make this a fascinating agent with clear therapeutic promise," Laffey noted.

More information

The MedlinePlus Medical Encyclopedia has more about heart bypass surgery.

Posted: May 2008


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