Carbon Monoxide Test Determines Patients' Smoking Status

A new study claims that the device can quickly, inexpensively, and noninvasively identify a person who smokes. The investigators believe that if smokers know their blood CO levels, they may be more prone to quit or more likely not to start.

The pulse co-oximeter is 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 from an outpatient clinic participated in the study. Patients were identified as smokers, based on a combination of their questionnaire responses and if their CO levels exceeded 6% of their blood. Secondhand smokers were also identified 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.

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, (Port Huron, MI, USA). 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.

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, 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.

The investigators, including Dr. Reddy's son Ashray Reddy who initiated the study, concluded that pulse co-oximetery 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 suggested that it could be used for screening smoking status in multiple settings and populations, such as smoking cessation programs, high schools, hospitals, and the workplace.

The study was presented at Chest 2007, the 73rd annual international scientific assembly of the American College of Chest Physicians (ACCP), which was held in Chicago (IL, USA) on October 20-25, 2007.