CHICAGO A simple device for detecting carbon
monoxide in the blood may help doctors get an honest answer out
of patients who smoke, U.S. researchers said on Monday.
The device, called a pulse cooximeter, is typically used to
test for carbon monoxide levels in firefighters, but it can
also detect carbon monoxide levels in people who smoke,
offering a powerful tool for educating patients about the
effects of smoking.
"We were trying to just solve a little problem," said Dr.
Sridhar Reddy, a lung specialist in St. Clair, Michigan, who
presented the study at a scientific meeting of the American
College of Chest Physicians in Chicago, along with his
16-year-old son Ashray.
"There is no good way to screen people for smoking," said
Dr. Reddy, who encouraged Ashray to take on the study as a
school science project.
"You can ask them directly, do you smoke. But once they say
they don't smoke and they lie about it, they will never
volunteer that information," Dr. Reddy said in an interview.
Dr. Reddy was looking for a quick, convenient method to
detect whether a person smokes. Current tests involve breath,
blood or saliva samples, but the pulse cooximeter simply
involves placing a clip-like device on a finger tip.
The pulse cooximeter reads percentages of poisoned blood
through a light that is shined through the finger nail.
Dr. Reddy's son Ashray wanted to find out how much
carboxyhaemoglobin -- blood poisoned by carbon monoxide --
would indicate whether a person is a smoker.
Working with his dad, he devised a questionnaire to
determine patients' smoking habits. Meanwhile, Dr. Reddy
recruited 476 patients in his office to take the test.
Together, they determined that patients with blood carbon
monoxide levels of more than 6 percent were smokers, a finding
Ashray confirmed through his patient surveys.
Ashray and his dad think the device might be a cheap, easy
way to help doctors talk to their patients about smoking.
Dr. Reddy said most patients know what carbon monoxide is,
and they respond strongly when they find it is circulating in
Dr. Reddy now routinely uses the test as part of a patient
work-up. And instead of asking whether a patient is a smoker,
he presents the test results and asks whether the finding could
be related to smoking. His hope is this can become part of
As for Ashray, the study earned him a medal at the local