June 2007
Avoiding Poisoning By CO Monitoring
by Will Chapleau
All of us in the fire service know something about carbon monoxide poisoning. We make plenty of calls for CO detectors going off in homes every year. We bring our monitors in to measure the CO content of the air and in some cases we remove people from hazardous atmospheres.
What you might not know is how large the problem is.
A byproduct of combustion, whether from exhaust from fuel burning machines or burning of any combustible, carbon monoxide is an odorless, colorless gas. Even a few minutes of exposure to high levels can cause toxic effects, including death. Common causes include machine malfunction as in furnaces or exhaust fans.
What carbon monoxide does when it gets into the bloodstream is it prevents oxygen from binding with the hemoglobin. This prevents the blood from delivering oxygen throughout the body. Exposed patients complain of headaches and nausea that can progress to cardiac complaints, seizures, loss of consciousness and death. Changes in the level of consciousness or responsiveness are important to note.
Potential For Exposure
Potential for exposure to possibly toxic concentrations of carbon monoxide can come about from poorly venting chimneys or gas or other fuel burning appliances. Other causes can be indoor use of camp stoves or other gas or charcoal grill-type devices designed for outdoors. Damaged, leaking motor vehicle exhaust systems or driving slowly in heavy traffic are other sources.
According to the Center for Disease Control (CDC), around 2,000 people die from intentional exposures to carbon monoxide poisoning in any given year and another 400 or more die from unintentional exposures.
Beyond that, tens of thousands of people are treated for carbon monoxide exposure in emergency rooms around the country annually.
Besides intentional and unintentional exposures that bring us to the scene, we face carbon monoxide exposure at fire scenes and the victims can be the occupants or ourselves as firefighters.
We’ve already noted the symptoms of exposure, but often identifying the symptoms is not enough to convince citizens, or even firefighters, they need treatment. Being able to identify level of carbon monoxide in the body would be helpful in identifying patients and rescuers at risk.
To do just that, monitors have been available for measuring atmospheres, and over the past few years, personal monitors have become available that can detect the level of exposure of individuals in environments.
Until recently however, if we were trying to determine the amount of carbon monoxide the patient has absorbed, we had to rely on symptoms or pulse oximitery readings moving in the opposite direction.
Another problem with pulse oximeters in use on patients exposed to carbon monoxide is that the devices cannot distinguish between oxygen and carbon monoxide and may report high oxygen levels when in reality, the carbon dioxide has crowded the oxygen out. Over the last few years, carbon monoxide monitors continue to improve in utility, expense and accuracy.
Carbon monoxide levels are measured in air samples as parts per million or ppm. Readings of 50 are considered Permissible Exposure Levels (PEL) for 8 hours by the Occupational Safety and Health Administration (OSHA). Levels of 200 ppm cause headaches and nausea after one to two hours. Levels of 800 ppm will cause headaches and nausea within 45 minutes, and collapse and death is possible after two hours.
Levels of 1,600 ppm bring on symptoms within 20 minutes and death within an hour. Continuing in that spectrum, 3,200 ppm can cause symptoms in 5 minutes and death in 30 minutes. Levels of 6,400 ppm bring symptoms within 1 to 2 minutes and can cause death in 10 to 15 minutes. At 12,800 ppm, loss of consciousness can be immediate, and death can occur within one to three minutes.
Utility And Accuracy
Before spending the money on CO monitors, concerns about utility and accuracy are reasonable. It make sense to question whether the machine provides accurate readings consistently and whether it is built to be useful in the environments in which we work.
Massimo, which markets the Rad-57 pulse CO-Oximeter, describes over 100 clinical studies in support of its monitor and is offering the results of two independent clinical studies to describe the effectiveness of the product.
The first study comes from the Mayo Clinic. In the study, the clinic attached the device (which works like pulse oximiters with a clamp-type finger attachment) to patients’ fingers and compared the readings on the Rad-57 to blood gas levels drawn from the patients’ arteries. These researchers concluded that the Rad-57 was accurate and would be useful in the field.
Putting Numbers On Toxins
The second study at Rhode Island Hospital and Brown Medical School Department of Emergency Medicine looked at the use of the device on the victim of a house fire. In this case the researchers felt that the device allowed for accurate non-invasive monitoring that factored in the appropriate treatment positive outcome for this patient.
The Rad-57 has what the maker describes as a revolutionary sensor that uses 7 or more wavelengths of light to collect and analyze data from the body. In its literature Masimo states this new technology eliminates the risk of missed diagnosis of potentially life-threatening CO exposures. The device monitors both oxygen and carbon monoxide levels and displays the pulse rate. Rad also passes the functionality test, as it is lightweight and durable.
Being able to put a number on the level of toxins in the body will help us prevent overlooking patients with toxic exposures. It should also help us in convincing patients they need immediate care and transportation to the hospital for further treatment.
When considering fire scenes, think about the amount of smoke in the air, even in the remote areas of the fireground. The amount of smoke at a fire scene has been shown to elevate carbon monoxide levels.
Wildfires create huge areas of smoke and the potential for toxic exposures. Consider the times you’ve had a citizen, or firefighter, who clearly was symptomatic but refused further attention or transport.
This devise should help us make the case in convincing people to opt for care. Further, being able to determine exposure levels should enable us to set policy as to what patients “must” be treated and transported for further treatment and evaluation.
Hospitals Lack Capability
Another reason to be excited about these new monitors is that even many hospitals lack the capability to monitor CO. While most larger hospitals do have the ability, a study published in the Journal of Emergency Medicine showed that only 44 percent of the hospitals looked at in the Pacific Northwest had the ability to test for carbon monoxide levels.
With the capabilities of Masimo’s Rad-57, it looks like we’ve reached the point of cost/performance, making them useful for our application.
And one last thing, for years emergency medical service educators have tried to get their hands on the Advanced Trauma Life Support textbook, but they were only available to physicians taking the ATLS course. In April, for the first time, the American College of Surgeons Committee on Trauma made the book available for open sale on its Web site at www.facs.org. Most prehospital trauma references come from this textbook.
Editor’s Note: Will Chapleau, who has 30 years of EMS experience, is the Advanced Trauma Life Support (ATLS) program manager for the American College of Surgeons. He is in charge of the trauma training programs for doctors all over the U.S. and in 50 countries around the world. He is the former chief of the Chicago Heights (Ill.) Fire Department. He has served as the chairperson for the Prehospital Trauma Life Support (PHTLS) program since 1996 and has been a member of its international faculty since 1984 and is a board member of the National Association of EMS Educators.