Pulse cooximeters have long been used
to identify and measure the levels of carbon monoxide (CO) in the blood of
patients or firefighters. But new research, presented at CHEST 2007, the
73rd annual international scientific assembly of the American College of
Chest Physicians (ACCP), indicates that the device has another use — it
can quickly, inexpensively, and noninvasively identify a person who smokes.
The study argues that if smokers know their blood CO levels, they may be
more prone to quit or more likely to never start in the first place.

“By using this device in the office, the poisoning of the hemoglobin or
blood with carbon monoxide can be detected and shown to the patient before
they actually develop a clinical disease such as emphysema or cancer,” said
study author Sridhar P. Reddy, MD, MPH, FCCP, St. Clair Pulmonary and
Critical Care, St. Clair, MI. “In our practice, when the carboxyhemoglobin
is 10%, it’s easy to tell a patient that 10% of his or her blood is
poisoned and unable to carry oxygen. By doing this, we catch the patient’s
attention right away and can begin smoking cessation counseling.”

The study originated as a high school science project. Carried out by
Dr. Reddy’s son. At each outpatient visit, Dr. Reddy measured patients’
carboxyhemoglobin, blood poisoned by CO, and methhemoglobin, blood
transformed by other substances, such as nitrogen dioxide, with a pulse
cooximeter. And, as part of his project, his son, who was a sophomore at
Detroit Country Day School, developed and distributed questionnaires
regarding the patients’ smoking status.

“When I was searching for a science project, I realized that the
question of how much carboxyhemoglobin is needed to suggest smoking seemed
unanswered,” said coauthor and son Ashray Reddy. “I thought that by trying
to answer this question, I could help people quit smoking.”

Researchers used the pulse cooximeter, a device that is clipped to the
patient’s finger and reads the percentages of poisoned blood through a
light that is shined through the nail bed. A total of 476 patients who
visited the clinic participated. Patients were identified as a smoker,
based on a combination of their questionnaire responses and if they’re CO
levels exceeded 6% of their blood. Researchers were also able to identify
secondhand smokers based on slight changes found in their levels, as well.
Results showed that 98 patients were smokers, 72 were secondhand smokers,
and 306 were nonsmokers.

“For the first time, the entire smoking cessation story can be quickly
and noninvasively played out from beginning to end-detection, revealing the
effect, and intervention, all while being respectful of available
resources,” said Dr. Reddy. “Using this device, we can deliver the whole
package, and based on our data, we believe it should be routinely used in
any program geared toward smoking cessation.”

Researchers conclude that pulse cooximetery is a quick, inexpensive,
and noninvasive way to detect patients’ smoking status, and that the
outpatient clinic is an ideal setting for its use. They also suggest its
use for screening smoking status in multiple settings and populations, such
as smoking cessation programs, high schools, hospitals, and the workplace.

“Physicians need to be able to identify a patient’s smoking status in
order to effectively counsel them about smoking cessation,” said Alvin V.
Thomas, Jr., MD, FCCP, President of the American College of Chest
Physicians. “A method or device that could help physicians do this, and
potentially reduce the number of people who smoke, is a method that is
worth further exploration.”

CHEST 2007 is the 73rd annual international scientific assembly of the
American College of Chest Physicians, held October 20-25 in Chicago, IL.
ACCP represents 17,000 members who provide patient care in the areas of
pulmonary, critical care, and sleep medicine in the United States and
throughout the world. The ACCP’s mission is to promote the prevention and
treatment of diseases of the chest through leadership, education, research,
and communication. For more information about the ACCP, please visit the
ACCP Web site at chestnet.

American College of Chest Physicians
chestnet